Fix issues related to the switchover to pytest. (#2685)

- Remove stale reference to `import nose` from `bin/spack` script.
- Add `py` to externals (missing dependency for `pytest`)

37 files changed, 7809 insertions, 2 deletions

diff --git a/lib/spack/external/__init__.py b/lib/spack/external/__init__.py
index 49886ae595..48fe4ec5ac 100644
--- a/lib/spack/external/__init__.py
+++ b/lib/spack/external/__init__.py
@@ -35,12 +35,15 @@ So far:
 
     jsonschema:  An implementation of JSON Schema for Python.
 
-    pytest:      Testing framework used by Spack.
-
     ordereddict: We include our own version to be Python 2.6 compatible.
 
+    py:          Needed by pytest.  Library with cross-python path,
+                 ini-parsing, io, code, and log facilities.
+
     pyqver2:     External script to query required python version of
                  python source code. Used for ensuring 2.6 compatibility.
 
+    pytest:      Testing framework used by Spack.
+
     yaml:        Used for config files.
 """
diff --git a/lib/spack/external/py/AUTHORS b/lib/spack/external/py/AUTHORS
new file mode 100644
index 0000000000..8c0cf9b71b
--- /dev/null
+++ b/lib/spack/external/py/AUTHORS
@@ -0,0 +1,24 @@
+Holger Krekel, holger at merlinux eu
+Benjamin Peterson, benjamin at python org
+Ronny Pfannschmidt, Ronny.Pfannschmidt at gmx de
+Guido Wesdorp, johnny at johnnydebris net 
+Samuele Pedroni, pedronis at openend se 
+Carl Friedrich Bolz, cfbolz at gmx de
+Armin Rigo, arigo at tunes org 
+Maciek Fijalkowski, fijal at genesilico pl
+Brian Dorsey, briandorsey at gmail com 
+Floris Bruynooghe, flub at devork be
+merlinux GmbH, Germany, office at merlinux eu
+
+Contributors include:: 
+
+Ross Lawley
+Ralf Schmitt
+Chris Lamb 
+Harald Armin Massa
+Martijn Faassen
+Ian Bicking 
+Jan Balster
+Grig Gheorghiu
+Bob Ippolito
+Christian Tismer
diff --git a/lib/spack/external/py/LICENSE b/lib/spack/external/py/LICENSE
new file mode 100644
index 0000000000..31ecdfb1db
--- /dev/null
+++ b/lib/spack/external/py/LICENSE
@@ -0,0 +1,19 @@
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+     
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+ 
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+
diff --git a/lib/spack/external/py/README.rst b/lib/spack/external/py/README.rst
new file mode 100644
index 0000000000..e836b7b50a
--- /dev/null
+++ b/lib/spack/external/py/README.rst
@@ -0,0 +1,21 @@
+.. image:: https://img.shields.io/pypi/pyversions/pytest.svg
+  :target: https://pypi.org/project/py
+.. image:: https://img.shields.io/travis/pytest-dev/py.svg
+   :target: https://travis-ci.org/pytest-dev/py
+
+The py lib is a Python development support library featuring
+the following tools and modules:
+
+* ``py.path``:  uniform local and svn path objects
+* ``py.apipkg``:  explicit API control and lazy-importing
+* ``py.iniconfig``:  easy parsing of .ini files
+* ``py.code``: dynamic code generation and introspection
+
+NOTE: prior to the 1.4 release this distribution used to
+contain py.test which is now its own package, see http://pytest.org
+
+For questions and more information please visit http://pylib.readthedocs.org
+
+Bugs and issues: https://github.com/pytest-dev/py
+
+Authors: Holger Krekel and others, 2004-2016
diff --git a/lib/spack/external/py/__init__.py b/lib/spack/external/py/__init__.py
new file mode 100644
index 0000000000..c2273a2e64
--- /dev/null
+++ b/lib/spack/external/py/__init__.py
@@ -0,0 +1,150 @@
+"""
+py.test and pylib: rapid testing and development utils
+
+this module uses apipkg.py for lazy-loading sub modules
+and classes.  The initpkg-dictionary  below specifies
+name->value mappings where value can be another namespace
+dictionary or an import path.
+
+(c) Holger Krekel and others, 2004-2014
+"""
+__version__ = '1.4.32'
+
+from py import _apipkg
+
+# so that py.error.* instances are picklable
+import sys
+sys.modules['py.error'] = _apipkg.AliasModule("py.error", "py._error", 'error')
+
+_apipkg.initpkg(__name__, attr={'_apipkg': _apipkg}, exportdefs={
+    # access to all standard lib modules
+    'std': '._std:std',
+    # access to all posix errno's as classes
+    'error': '._error:error',
+
+    '_pydir' : '.__metainfo:pydir',
+    'version': 'py:__version__', # backward compatibility
+
+    # pytest-2.0 has a flat namespace, we use alias modules
+    # to keep old references compatible
+    'test' : 'pytest',
+    'test.collect' : 'pytest',
+    'test.cmdline' : 'pytest',
+
+    # hook into the top-level standard library
+    'process' : {
+        '__doc__'        : '._process:__doc__',
+        'cmdexec'        : '._process.cmdexec:cmdexec',
+        'kill'           : '._process.killproc:kill',
+        'ForkedFunc'     : '._process.forkedfunc:ForkedFunc',
+    },
+
+    'apipkg' : {
+        'initpkg'   : '._apipkg:initpkg',
+        'ApiModule' : '._apipkg:ApiModule',
+    },
+
+    'iniconfig' : {
+        'IniConfig'      : '._iniconfig:IniConfig',
+        'ParseError'     : '._iniconfig:ParseError',
+    },
+
+    'path' : {
+        '__doc__'        : '._path:__doc__',
+        'svnwc'          : '._path.svnwc:SvnWCCommandPath',
+        'svnurl'         : '._path.svnurl:SvnCommandPath',
+        'local'          : '._path.local:LocalPath',
+        'SvnAuth'        : '._path.svnwc:SvnAuth',
+    },
+
+    # python inspection/code-generation API
+    'code' : {
+        '__doc__'           : '._code:__doc__',
+        'compile'           : '._code.source:compile_',
+        'Source'            : '._code.source:Source',
+        'Code'              : '._code.code:Code',
+        'Frame'             : '._code.code:Frame',
+        'ExceptionInfo'     : '._code.code:ExceptionInfo',
+        'Traceback'         : '._code.code:Traceback',
+        'getfslineno'       : '._code.source:getfslineno',
+        'getrawcode'        : '._code.code:getrawcode',
+        'patch_builtins'    : '._code.code:patch_builtins',
+        'unpatch_builtins'  : '._code.code:unpatch_builtins',
+        '_AssertionError'   : '._code.assertion:AssertionError',
+        '_reinterpret_old'  : '._code.assertion:reinterpret_old',
+        '_reinterpret'      : '._code.assertion:reinterpret',
+        '_reprcompare'      : '._code.assertion:_reprcompare',
+        '_format_explanation' : '._code.assertion:_format_explanation',
+    },
+
+    # backports and additions of builtins
+    'builtin' : {
+        '__doc__'        : '._builtin:__doc__',
+        'enumerate'      : '._builtin:enumerate',
+        'reversed'       : '._builtin:reversed',
+        'sorted'         : '._builtin:sorted',
+        'any'            : '._builtin:any',
+        'all'            : '._builtin:all',
+        'set'            : '._builtin:set',
+        'frozenset'      : '._builtin:frozenset',
+        'BaseException'  : '._builtin:BaseException',
+        'GeneratorExit'  : '._builtin:GeneratorExit',
+        '_sysex'         : '._builtin:_sysex',
+        'print_'         : '._builtin:print_',
+        '_reraise'       : '._builtin:_reraise',
+        '_tryimport'     : '._builtin:_tryimport',
+        'exec_'          : '._builtin:exec_',
+        '_basestring'    : '._builtin:_basestring',
+        '_totext'        : '._builtin:_totext',
+        '_isbytes'       : '._builtin:_isbytes',
+        '_istext'        : '._builtin:_istext',
+        '_getimself'     : '._builtin:_getimself',
+        '_getfuncdict'   : '._builtin:_getfuncdict',
+        '_getcode'       : '._builtin:_getcode',
+        'builtins'       : '._builtin:builtins',
+        'execfile'       : '._builtin:execfile',
+        'callable'       : '._builtin:callable',
+        'bytes'       : '._builtin:bytes',
+        'text'       : '._builtin:text',
+    },
+
+    # input-output helping
+    'io' : {
+        '__doc__'             : '._io:__doc__',
+        'dupfile'             : '._io.capture:dupfile',
+        'TextIO'              : '._io.capture:TextIO',
+        'BytesIO'             : '._io.capture:BytesIO',
+        'FDCapture'           : '._io.capture:FDCapture',
+        'StdCapture'          : '._io.capture:StdCapture',
+        'StdCaptureFD'        : '._io.capture:StdCaptureFD',
+        'TerminalWriter'      : '._io.terminalwriter:TerminalWriter',
+        'ansi_print'          : '._io.terminalwriter:ansi_print',
+        'get_terminal_width'  : '._io.terminalwriter:get_terminal_width',
+        'saferepr'            : '._io.saferepr:saferepr',
+    },
+
+    # small and mean xml/html generation
+    'xml' : {
+        '__doc__'            : '._xmlgen:__doc__',
+        'html'               : '._xmlgen:html',
+        'Tag'                : '._xmlgen:Tag',
+        'raw'                : '._xmlgen:raw',
+        'Namespace'          : '._xmlgen:Namespace',
+        'escape'             : '._xmlgen:escape',
+    },
+
+    'log' : {
+        # logging API ('producers' and 'consumers' connected via keywords)
+        '__doc__'            : '._log:__doc__',
+        '_apiwarn'           : '._log.warning:_apiwarn',
+        'Producer'           : '._log.log:Producer',
+        'setconsumer'        : '._log.log:setconsumer',
+        '_setstate'          : '._log.log:setstate',
+        '_getstate'          : '._log.log:getstate',
+        'Path'               : '._log.log:Path',
+        'STDOUT'             : '._log.log:STDOUT',
+        'STDERR'             : '._log.log:STDERR',
+        'Syslog'             : '._log.log:Syslog',
+    },
+
+})
diff --git a/lib/spack/external/py/__metainfo.py b/lib/spack/external/py/__metainfo.py
new file mode 100644
index 0000000000..12581eb7af
--- /dev/null
+++ b/lib/spack/external/py/__metainfo.py
@@ -0,0 +1,2 @@
+import py
+pydir = py.path.local(py.__file__).dirpath()
diff --git a/lib/spack/external/py/_apipkg.py b/lib/spack/external/py/_apipkg.py
new file mode 100644
index 0000000000..a73b8f6d0b
--- /dev/null
+++ b/lib/spack/external/py/_apipkg.py
@@ -0,0 +1,181 @@
+"""
+apipkg: control the exported namespace of a python package.
+
+see http://pypi.python.org/pypi/apipkg
+
+(c) holger krekel, 2009 - MIT license
+"""
+import os
+import sys
+from types import ModuleType
+
+__version__ = '1.3.dev'
+
+def _py_abspath(path):
+    """
+    special version of abspath
+    that will leave paths from jython jars alone
+    """
+    if path.startswith('__pyclasspath__'):
+
+        return path
+    else:
+        return os.path.abspath(path)
+
+def initpkg(pkgname, exportdefs, attr=dict()):
+    """ initialize given package from the export definitions. """
+    oldmod = sys.modules.get(pkgname)
+    d = {}
+    f = getattr(oldmod, '__file__', None)
+    if f:
+        f = _py_abspath(f)
+    d['__file__'] = f
+    if hasattr(oldmod, '__version__'):
+        d['__version__'] = oldmod.__version__
+    if hasattr(oldmod, '__loader__'):
+        d['__loader__'] = oldmod.__loader__
+    if hasattr(oldmod, '__path__'):
+        d['__path__'] = [_py_abspath(p) for p in oldmod.__path__]
+    if '__doc__' not in exportdefs and getattr(oldmod, '__doc__', None):
+        d['__doc__'] = oldmod.__doc__
+    d.update(attr)
+    if hasattr(oldmod, "__dict__"):
+        oldmod.__dict__.update(d)
+    mod = ApiModule(pkgname, exportdefs, implprefix=pkgname, attr=d)
+    sys.modules[pkgname] = mod
+
+def importobj(modpath, attrname):
+    module = __import__(modpath, None, None, ['__doc__'])
+    if not attrname:
+        return module
+
+    retval = module
+    names = attrname.split(".")
+    for x in names:
+        retval = getattr(retval, x)
+    return retval
+
+class ApiModule(ModuleType):
+    def __docget(self):
+        try:
+            return self.__doc
+        except AttributeError:
+            if '__doc__' in self.__map__:
+                return self.__makeattr('__doc__')
+    def __docset(self, value):
+        self.__doc = value
+    __doc__ = property(__docget, __docset)
+
+    def __init__(self, name, importspec, implprefix=None, attr=None):
+        self.__name__ = name
+        self.__all__ = [x for x in importspec if x != '__onfirstaccess__']
+        self.__map__ = {}
+        self.__implprefix__ = implprefix or name
+        if attr:
+            for name, val in attr.items():
+                # print "setting", self.__name__, name, val
+                setattr(self, name, val)
+        for name, importspec in importspec.items():
+            if isinstance(importspec, dict):
+                subname = '%s.%s' % (self.__name__, name)
+                apimod = ApiModule(subname, importspec, implprefix)
+                sys.modules[subname] = apimod
+                setattr(self, name, apimod)
+            else:
+                parts = importspec.split(':')
+                modpath = parts.pop(0)
+                attrname = parts and parts[0] or ""
+                if modpath[0] == '.':
+                    modpath = implprefix + modpath
+
+                if not attrname:
+                    subname = '%s.%s' % (self.__name__, name)
+                    apimod = AliasModule(subname, modpath)
+                    sys.modules[subname] = apimod
+                    if '.' not in name:
+                        setattr(self, name, apimod)
+                else:
+                    self.__map__[name] = (modpath, attrname)
+
+    def __repr__(self):
+        l = []
+        if hasattr(self, '__version__'):
+            l.append("version=" + repr(self.__version__))
+        if hasattr(self, '__file__'):
+            l.append('from ' + repr(self.__file__))
+        if l:
+            return '<ApiModule %r %s>' % (self.__name__, " ".join(l))
+        return '<ApiModule %r>' % (self.__name__,)
+
+    def __makeattr(self, name):
+        """lazily compute value for name or raise AttributeError if unknown."""
+        # print "makeattr", self.__name__, name
+        target = None
+        if '__onfirstaccess__' in self.__map__:
+            target = self.__map__.pop('__onfirstaccess__')
+            importobj(*target)()
+        try:
+            modpath, attrname = self.__map__[name]
+        except KeyError:
+            if target is not None and name != '__onfirstaccess__':
+                # retry, onfirstaccess might have set attrs
+                return getattr(self, name)
+            raise AttributeError(name)
+        else:
+            result = importobj(modpath, attrname)
+            setattr(self, name, result)
+            try:
+                del self.__map__[name]
+            except KeyError:
+                pass  # in a recursive-import situation a double-del can happen
+            return result
+
+    __getattr__ = __makeattr
+
+    def __dict__(self):
+        # force all the content of the module to be loaded when __dict__ is read
+        dictdescr = ModuleType.__dict__['__dict__']
+        dict = dictdescr.__get__(self)
+        if dict is not None:
+            hasattr(self, 'some')
+            for name in self.__all__:
+                try:
+                    self.__makeattr(name)
+                except AttributeError:
+                    pass
+        return dict
+    __dict__ = property(__dict__)
+
+
+def AliasModule(modname, modpath, attrname=None):
+    mod = []
+
+    def getmod():
+        if not mod:
+            x = importobj(modpath, None)
+            if attrname is not None:
+                x = getattr(x, attrname)
+            mod.append(x)
+        return mod[0]
+
+    class AliasModule(ModuleType):
+
+        def __repr__(self):
+            x = modpath
+            if attrname:
+                x += "." + attrname
+            return '<AliasModule %r for %r>' % (modname, x)
+
+        def __getattribute__(self, name):
+            try:
+                return getattr(getmod(), name)
+            except ImportError:
+                return None
+
+        def __setattr__(self, name, value):
+            setattr(getmod(), name, value)
+
+        def __delattr__(self, name):
+            delattr(getmod(), name)
+
+    return AliasModule(str(modname))
diff --git a/lib/spack/external/py/_builtin.py b/lib/spack/external/py/_builtin.py
new file mode 100644
index 0000000000..52ee9d79ca
--- /dev/null
+++ b/lib/spack/external/py/_builtin.py
@@ -0,0 +1,248 @@
+import sys
+
+try:
+    reversed = reversed
+except NameError:
+    def reversed(sequence):
+        """reversed(sequence) -> reverse iterator over values of the sequence
+
+        Return a reverse iterator
+        """
+        if hasattr(sequence, '__reversed__'):
+            return sequence.__reversed__()
+        if not hasattr(sequence, '__getitem__'):
+            raise TypeError("argument to reversed() must be a sequence")
+        return reversed_iterator(sequence)
+
+    class reversed_iterator(object):
+
+        def __init__(self, seq):
+            self.seq = seq
+            self.remaining = len(seq)
+
+        def __iter__(self):
+            return self
+
+        def next(self):
+            i = self.remaining
+            if i > 0:
+                i -= 1
+                item = self.seq[i]
+                self.remaining = i
+                return item
+            raise StopIteration
+
+        def __length_hint__(self):
+            return self.remaining
+
+try:
+    any = any
+except NameError:
+    def any(iterable):
+        for x in iterable:
+            if x:
+                return True
+        return False
+
+try:
+    all = all
+except NameError:
+    def all(iterable):
+        for x in iterable:
+            if not x:
+                return False
+        return True
+
+try:
+    sorted = sorted
+except NameError:
+    builtin_cmp = cmp # need to use cmp as keyword arg
+
+    def sorted(iterable, cmp=None, key=None, reverse=0):
+        use_cmp = None
+        if key is not None:
+            if cmp is None:
+                def use_cmp(x, y):
+                    return builtin_cmp(x[0], y[0])
+            else:
+                def use_cmp(x, y):
+                    return cmp(x[0], y[0])
+            l = [(key(element), element) for element in iterable]
+        else:
+            if cmp is not None:
+                use_cmp = cmp
+            l = list(iterable)
+        if use_cmp is not None:
+            l.sort(use_cmp)
+        else:
+            l.sort()
+        if reverse:
+            l.reverse()
+        if key is not None:
+            return [element for (_, element) in l]
+        return l
+
+try:
+    set, frozenset = set, frozenset
+except NameError:
+    from sets import set, frozenset
+
+# pass through
+enumerate = enumerate
+
+try:
+    BaseException = BaseException
+except NameError:
+    BaseException = Exception
+
+try:
+    GeneratorExit = GeneratorExit
+except NameError:
+    class GeneratorExit(Exception):
+        """ This exception is never raised, it is there to make it possible to
+        write code compatible with CPython 2.5 even in lower CPython
+        versions."""
+        pass
+    GeneratorExit.__module__ = 'exceptions'
+
+_sysex = (KeyboardInterrupt, SystemExit, MemoryError, GeneratorExit)
+
+try:
+    callable = callable
+except NameError:
+    def callable(obj):
+        return hasattr(obj, "__call__")
+
+if sys.version_info >= (3, 0):
+    exec ("print_ = print ; exec_=exec")
+    import builtins
+
+    # some backward compatibility helpers
+    _basestring = str
+    def _totext(obj, encoding=None, errors=None):
+        if isinstance(obj, bytes):
+            if errors is None:
+                obj = obj.decode(encoding)
+            else:
+                obj = obj.decode(encoding, errors)
+        elif not isinstance(obj, str):
+            obj = str(obj)
+        return obj
+
+    def _isbytes(x):
+        return isinstance(x, bytes)
+    def _istext(x):
+        return isinstance(x, str)
+
+    text = str
+    bytes = bytes
+
+
+    def _getimself(function):
+        return getattr(function, '__self__', None)
+
+    def _getfuncdict(function):
+        return getattr(function, "__dict__", None)
+
+    def _getcode(function):
+        return getattr(function, "__code__", None)
+
+    def execfile(fn, globs=None, locs=None):
+        if globs is None:
+            back = sys._getframe(1)
+            globs = back.f_globals
+            locs = back.f_locals
+            del back
+        elif locs is None:
+            locs = globs
+        fp = open(fn, "r")
+        try:
+            source = fp.read()
+        finally:
+            fp.close()
+        co = compile(source, fn, "exec", dont_inherit=True)
+        exec_(co, globs, locs)
+
+else:
+    import __builtin__ as builtins
+    _totext = unicode
+    _basestring = basestring
+    text = unicode
+    bytes = str
+    execfile = execfile
+    callable = callable
+    def _isbytes(x):
+        return isinstance(x, str)
+    def _istext(x):
+        return isinstance(x, unicode)
+
+    def _getimself(function):
+        return getattr(function, 'im_self', None)
+
+    def _getfuncdict(function):
+        return getattr(function, "__dict__", None)
+
+    def _getcode(function):
+        try:
+            return getattr(function, "__code__")
+        except AttributeError:
+            return getattr(function, "func_code", None)
+
+    def print_(*args, **kwargs):
+        """ minimal backport of py3k print statement. """
+        sep = ' '
+        if 'sep' in kwargs:
+            sep = kwargs.pop('sep')
+        end = '\n'
+        if 'end' in kwargs:
+            end = kwargs.pop('end')
+        file = 'file' in kwargs and kwargs.pop('file') or sys.stdout
+        if kwargs:
+            args = ", ".join([str(x) for x in kwargs])
+            raise TypeError("invalid keyword arguments: %s" % args)
+        at_start = True
+        for x in args:
+            if not at_start:
+                file.write(sep)
+            file.write(str(x))
+            at_start = False
+        file.write(end)
+
+    def exec_(obj, globals=None, locals=None):
+        """ minimal backport of py3k exec statement. """
+        __tracebackhide__ = True
+        if globals is None:
+            frame = sys._getframe(1)
+            globals = frame.f_globals
+            if locals is None:
+                locals = frame.f_locals
+        elif locals is None:
+            locals = globals
+        exec2(obj, globals, locals)
+
+if sys.version_info >= (3, 0):
+    def _reraise(cls, val, tb):
+        __tracebackhide__ = True
+        assert hasattr(val, '__traceback__')
+        raise cls.with_traceback(val, tb)
+else:
+    exec ("""
+def _reraise(cls, val, tb):
+    __tracebackhide__ = True
+    raise cls, val, tb
+def exec2(obj, globals, locals):
+    __tracebackhide__ = True
+    exec obj in globals, locals
+""")
+
+def _tryimport(*names):
+    """ return the first successfully imported module. """
+    assert names
+    for name in names:
+        try:
+            __import__(name)
+        except ImportError:
+            excinfo = sys.exc_info()
+        else:
+            return sys.modules[name]
+    _reraise(*excinfo)
diff --git a/lib/spack/external/py/_code/__init__.py b/lib/spack/external/py/_code/__init__.py
new file mode 100644
index 0000000000..f15acf8513
--- /dev/null
+++ b/lib/spack/external/py/_code/__init__.py
@@ -0,0 +1 @@
+""" python inspection/code generation API """
diff --git a/lib/spack/external/py/_code/_assertionnew.py b/lib/spack/external/py/_code/_assertionnew.py
new file mode 100644
index 0000000000..afb1b31ff0
--- /dev/null
+++ b/lib/spack/external/py/_code/_assertionnew.py
@@ -0,0 +1,339 @@
+"""
+Find intermediate evalutation results in assert statements through builtin AST.
+This should replace _assertionold.py eventually.
+"""
+
+import sys
+import ast
+
+import py
+from py._code.assertion import _format_explanation, BuiltinAssertionError
+
+
+if sys.platform.startswith("java") and sys.version_info < (2, 5, 2):
+    # See http://bugs.jython.org/issue1497
+    _exprs = ("BoolOp", "BinOp", "UnaryOp", "Lambda", "IfExp", "Dict",
+              "ListComp", "GeneratorExp", "Yield", "Compare", "Call",
+              "Repr", "Num", "Str", "Attribute", "Subscript", "Name",
+              "List", "Tuple")
+    _stmts = ("FunctionDef", "ClassDef", "Return", "Delete", "Assign",
+              "AugAssign", "Print", "For", "While", "If", "With", "Raise",
+              "TryExcept", "TryFinally", "Assert", "Import", "ImportFrom",
+              "Exec", "Global", "Expr", "Pass", "Break", "Continue")
+    _expr_nodes = set(getattr(ast, name) for name in _exprs)
+    _stmt_nodes = set(getattr(ast, name) for name in _stmts)
+    def _is_ast_expr(node):
+        return node.__class__ in _expr_nodes
+    def _is_ast_stmt(node):
+        return node.__class__ in _stmt_nodes
+else:
+    def _is_ast_expr(node):
+        return isinstance(node, ast.expr)
+    def _is_ast_stmt(node):
+        return isinstance(node, ast.stmt)
+
+
+class Failure(Exception):
+    """Error found while interpreting AST."""
+
+    def __init__(self, explanation=""):
+        self.cause = sys.exc_info()
+        self.explanation = explanation
+
+
+def interpret(source, frame, should_fail=False):
+    mod = ast.parse(source)
+    visitor = DebugInterpreter(frame)
+    try:
+        visitor.visit(mod)
+    except Failure:
+        failure = sys.exc_info()[1]
+        return getfailure(failure)
+    if should_fail:
+        return ("(assertion failed, but when it was re-run for "
+                "printing intermediate values, it did not fail.  Suggestions: "
+                "compute assert expression before the assert or use --no-assert)")
+
+def run(offending_line, frame=None):
+    if frame is None:
+        frame = py.code.Frame(sys._getframe(1))
+    return interpret(offending_line, frame)
+
+def getfailure(failure):
+    explanation = _format_explanation(failure.explanation)
+    value = failure.cause[1]
+    if str(value):
+        lines = explanation.splitlines()
+        if not lines:
+            lines.append("")
+        lines[0] += " << %s" % (value,)
+        explanation = "\n".join(lines)
+    text = "%s: %s" % (failure.cause[0].__name__, explanation)
+    if text.startswith("AssertionError: assert "):
+        text = text[16:]
+    return text
+
+
+operator_map = {
+    ast.BitOr : "|",
+    ast.BitXor : "^",
+    ast.BitAnd : "&",
+    ast.LShift : "<<",
+    ast.RShift : ">>",
+    ast.Add : "+",
+    ast.Sub : "-",
+    ast.Mult : "*",
+    ast.Div : "/",
+    ast.FloorDiv : "//",
+    ast.Mod : "%",
+    ast.Eq : "==",
+    ast.NotEq : "!=",
+    ast.Lt : "<",
+    ast.LtE : "<=",
+    ast.Gt : ">",
+    ast.GtE : ">=",
+    ast.Pow : "**",
+    ast.Is : "is",
+    ast.IsNot : "is not",
+    ast.In : "in",
+    ast.NotIn : "not in"
+}
+
+unary_map = {
+    ast.Not : "not %s",
+    ast.Invert : "~%s",
+    ast.USub : "-%s",
+    ast.UAdd : "+%s"
+}
+
+
+class DebugInterpreter(ast.NodeVisitor):
+    """Interpret AST nodes to gleam useful debugging information. """
+
+    def __init__(self, frame):
+        self.frame = frame
+
+    def generic_visit(self, node):
+        # Fallback when we don't have a special implementation.
+        if _is_ast_expr(node):
+            mod = ast.Expression(node)
+            co = self._compile(mod)
+            try:
+                result = self.frame.eval(co)
+            except Exception:
+                raise Failure()
+            explanation = self.frame.repr(result)
+            return explanation, result
+        elif _is_ast_stmt(node):
+            mod = ast.Module([node])
+            co = self._compile(mod, "exec")
+            try:
+                self.frame.exec_(co)
+            except Exception:
+                raise Failure()
+            return None, None
+        else:
+            raise AssertionError("can't handle %s" %(node,))
+
+    def _compile(self, source, mode="eval"):
+        return compile(source, "<assertion interpretation>", mode)
+
+    def visit_Expr(self, expr):
+        return self.visit(expr.value)
+
+    def visit_Module(self, mod):
+        for stmt in mod.body:
+            self.visit(stmt)
+
+    def visit_Name(self, name):
+        explanation, result = self.generic_visit(name)
+        # See if the name is local.
+        source = "%r in locals() is not globals()" % (name.id,)
+        co = self._compile(source)
+        try:
+            local = self.frame.eval(co)
+        except Exception:
+            # have to assume it isn't
+            local = False
+        if not local:
+            return name.id, result
+        return explanation, result
+
+    def visit_Compare(self, comp):
+        left = comp.left
+        left_explanation, left_result = self.visit(left)
+        for op, next_op in zip(comp.ops, comp.comparators):
+            next_explanation, next_result = self.visit(next_op)
+            op_symbol = operator_map[op.__class__]
+            explanation = "%s %s %s" % (left_explanation, op_symbol,
+                                        next_explanation)
+            source = "__exprinfo_left %s __exprinfo_right" % (op_symbol,)
+            co = self._compile(source)
+            try:
+                result = self.frame.eval(co, __exprinfo_left=left_result,
+                                         __exprinfo_right=next_result)
+            except Exception:
+                raise Failure(explanation)
+            try:
+                if not result:
+                    break
+            except KeyboardInterrupt:
+                raise
+            except:
+                break
+            left_explanation, left_result = next_explanation, next_result
+
+        rcomp = py.code._reprcompare
+        if rcomp:
+            res = rcomp(op_symbol, left_result, next_result)
+            if res:
+                explanation = res
+        return explanation, result
+
+    def visit_BoolOp(self, boolop):
+        is_or = isinstance(boolop.op, ast.Or)
+        explanations = []
+        for operand in boolop.values:
+            explanation, result = self.visit(operand)
+            explanations.append(explanation)
+            if result == is_or:
+                break
+        name = is_or and " or " or " and "
+        explanation = "(" + name.join(explanations) + ")"
+        return explanation, result
+
+    def visit_UnaryOp(self, unary):
+        pattern = unary_map[unary.op.__class__]
+        operand_explanation, operand_result = self.visit(unary.operand)
+        explanation = pattern % (operand_explanation,)
+        co = self._compile(pattern % ("__exprinfo_expr",))
+        try:
+            result = self.frame.eval(co, __exprinfo_expr=operand_result)
+        except Exception:
+            raise Failure(explanation)
+        return explanation, result
+
+    def visit_BinOp(self, binop):
+        left_explanation, left_result = self.visit(binop.left)
+        right_explanation, right_result = self.visit(binop.right)
+        symbol = operator_map[binop.op.__class__]
+        explanation = "(%s %s %s)" % (left_explanation, symbol,
+                                      right_explanation)
+        source = "__exprinfo_left %s __exprinfo_right" % (symbol,)
+        co = self._compile(source)
+        try:
+            result = self.frame.eval(co, __exprinfo_left=left_result,
+                                     __exprinfo_right=right_result)
+        except Exception:
+            raise Failure(explanation)
+        return explanation, result
+
+    def visit_Call(self, call):
+        func_explanation, func = self.visit(call.func)
+        arg_explanations = []
+        ns = {"__exprinfo_func" : func}
+        arguments = []
+        for arg in call.args:
+            arg_explanation, arg_result = self.visit(arg)
+            arg_name = "__exprinfo_%s" % (len(ns),)
+            ns[arg_name] = arg_result
+            arguments.append(arg_name)
+            arg_explanations.append(arg_explanation)
+        for keyword in call.keywords:
+            arg_explanation, arg_result = self.visit(keyword.value)
+            arg_name = "__exprinfo_%s" % (len(ns),)
+            ns[arg_name] = arg_result
+            keyword_source = "%s=%%s" % (keyword.arg)
+            arguments.append(keyword_source % (arg_name,))
+            arg_explanations.append(keyword_source % (arg_explanation,))
+        if call.starargs:
+            arg_explanation, arg_result = self.visit(call.starargs)
+            arg_name = "__exprinfo_star"
+            ns[arg_name] = arg_result
+            arguments.append("*%s" % (arg_name,))
+            arg_explanations.append("*%s" % (arg_explanation,))
+        if call.kwargs:
+            arg_explanation, arg_result = self.visit(call.kwargs)
+            arg_name = "__exprinfo_kwds"
+            ns[arg_name] = arg_result
+            arguments.append("**%s" % (arg_name,))
+            arg_explanations.append("**%s" % (arg_explanation,))
+        args_explained = ", ".join(arg_explanations)
+        explanation = "%s(%s)" % (func_explanation, args_explained)
+        args = ", ".join(arguments)
+        source = "__exprinfo_func(%s)" % (args,)
+        co = self._compile(source)
+        try:
+            result = self.frame.eval(co, **ns)
+        except Exception:
+            raise Failure(explanation)
+        pattern = "%s\n{%s = %s\n}"
+        rep = self.frame.repr(result)
+        explanation = pattern % (rep, rep, explanation)
+        return explanation, result
+
+    def _is_builtin_name(self, name):
+        pattern = "%r not in globals() and %r not in locals()"
+        source = pattern % (name.id, name.id)
+        co = self._compile(source)
+        try:
+            return self.frame.eval(co)
+        except Exception:
+            return False
+
+    def visit_Attribute(self, attr):
+        if not isinstance(attr.ctx, ast.Load):
+            return self.generic_visit(attr)
+        source_explanation, source_result = self.visit(attr.value)
+        explanation = "%s.%s" % (source_explanation, attr.attr)
+        source = "__exprinfo_expr.%s" % (attr.attr,)
+        co = self._compile(source)
+        try:
+            result = self.frame.eval(co, __exprinfo_expr=source_result)
+        except Exception:
+            raise Failure(explanation)
+        explanation = "%s\n{%s = %s.%s\n}" % (self.frame.repr(result),
+                                              self.frame.repr(result),
+                                              source_explanation, attr.attr)
+        # Check if the attr is from an instance.
+        source = "%r in getattr(__exprinfo_expr, '__dict__', {})"
+        source = source % (attr.attr,)
+        co = self._compile(source)
+        try:
+            from_instance = self.frame.eval(co, __exprinfo_expr=source_result)
+        except Exception:
+            from_instance = True
+        if from_instance:
+            rep = self.frame.repr(result)
+            pattern = "%s\n{%s = %s\n}"
+            explanation = pattern % (rep, rep, explanation)
+        return explanation, result
+
+    def visit_Assert(self, assrt):
+        test_explanation, test_result = self.visit(assrt.test)
+        if test_explanation.startswith("False\n{False =") and \
+                test_explanation.endswith("\n"):
+            test_explanation = test_explanation[15:-2]
+        explanation = "assert %s" % (test_explanation,)
+        if not test_result:
+            try:
+                raise BuiltinAssertionError
+            except Exception:
+                raise Failure(explanation)
+        return explanation, test_result
+
+    def visit_Assign(self, assign):
+        value_explanation, value_result = self.visit(assign.value)
+        explanation = "... = %s" % (value_explanation,)
+        name = ast.Name("__exprinfo_expr", ast.Load(),
+                        lineno=assign.value.lineno,
+                        col_offset=assign.value.col_offset)
+        new_assign = ast.Assign(assign.targets, name, lineno=assign.lineno,
+                                col_offset=assign.col_offset)
+        mod = ast.Module([new_assign])
+        co = self._compile(mod, "exec")
+        try:
+            self.frame.exec_(co, __exprinfo_expr=value_result)
+        except Exception:
+            raise Failure(explanation)
+        return explanation, value_result
diff --git a/lib/spack/external/py/_code/_assertionold.py b/lib/spack/external/py/_code/_assertionold.py
new file mode 100644
index 0000000000..4e81fb3ef6
--- /dev/null
+++ b/lib/spack/external/py/_code/_assertionold.py
@@ -0,0 +1,555 @@
+import py
+import sys, inspect
+from compiler import parse, ast, pycodegen
+from py._code.assertion import BuiltinAssertionError, _format_explanation
+
+passthroughex = py.builtin._sysex
+
+class Failure:
+    def __init__(self, node):
+        self.exc, self.value, self.tb = sys.exc_info()
+        self.node = node
+
+class View(object):
+    """View base class.
+
+    If C is a subclass of View, then C(x) creates a proxy object around
+    the object x.  The actual class of the proxy is not C in general,
+    but a *subclass* of C determined by the rules below.  To avoid confusion
+    we call view class the class of the proxy (a subclass of C, so of View)
+    and object class the class of x.
+
+    Attributes and methods not found in the proxy are automatically read on x.
+    Other operations like setting attributes are performed on the proxy, as
+    determined by its view class.  The object x is available from the proxy
+    as its __obj__ attribute.
+
+    The view class selection is determined by the __view__ tuples and the
+    optional __viewkey__ method.  By default, the selected view class is the
+    most specific subclass of C whose __view__ mentions the class of x.
+    If no such subclass is found, the search proceeds with the parent
+    object classes.  For example, C(True) will first look for a subclass
+    of C with __view__ = (..., bool, ...) and only if it doesn't find any
+    look for one with __view__ = (..., int, ...), and then ..., object,...
+    If everything fails the class C itself is considered to be the default.
+
+    Alternatively, the view class selection can be driven by another aspect
+    of the object x, instead of the class of x, by overriding __viewkey__.
+    See last example at the end of this module.
+    """
+
+    _viewcache = {}
+    __view__ = ()
+
+    def __new__(rootclass, obj, *args, **kwds):
+        self = object.__new__(rootclass)
+        self.__obj__ = obj
+        self.__rootclass__ = rootclass
+        key = self.__viewkey__()
+        try:
+            self.__class__ = self._viewcache[key]
+        except KeyError:
+            self.__class__ = self._selectsubclass(key)
+        return self
+
+    def __getattr__(self, attr):
+        # attributes not found in the normal hierarchy rooted on View
+        # are looked up in the object's real class
+        return getattr(self.__obj__, attr)
+
+    def __viewkey__(self):
+        return self.__obj__.__class__
+
+    def __matchkey__(self, key, subclasses):
+        if inspect.isclass(key):
+            keys = inspect.getmro(key)
+        else:
+            keys = [key]
+        for key in keys:
+            result = [C for C in subclasses if key in C.__view__]
+            if result:
+                return result
+        return []
+
+    def _selectsubclass(self, key):
+        subclasses = list(enumsubclasses(self.__rootclass__))
+        for C in subclasses:
+            if not isinstance(C.__view__, tuple):
+                C.__view__ = (C.__view__,)
+        choices = self.__matchkey__(key, subclasses)
+        if not choices:
+            return self.__rootclass__
+        elif len(choices) == 1:
+            return choices[0]
+        else:
+            # combine the multiple choices
+            return type('?', tuple(choices), {})
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__rootclass__.__name__, self.__obj__)
+
+
+def enumsubclasses(cls):
+    for subcls in cls.__subclasses__():
+        for subsubclass in enumsubclasses(subcls):
+            yield subsubclass
+    yield cls
+
+
+class Interpretable(View):
+    """A parse tree node with a few extra methods."""
+    explanation = None
+
+    def is_builtin(self, frame):
+        return False
+
+    def eval(self, frame):
+        # fall-back for unknown expression nodes
+        try:
+            expr = ast.Expression(self.__obj__)
+            expr.filename = '<eval>'
+            self.__obj__.filename = '<eval>'
+            co = pycodegen.ExpressionCodeGenerator(expr).getCode()
+            result = frame.eval(co)
+        except passthroughex:
+            raise
+        except:
+            raise Failure(self)
+        self.result = result
+        self.explanation = self.explanation or frame.repr(self.result)
+
+    def run(self, frame):
+        # fall-back for unknown statement nodes
+        try:
+            expr = ast.Module(None, ast.Stmt([self.__obj__]))
+            expr.filename = '<run>'
+            co = pycodegen.ModuleCodeGenerator(expr).getCode()
+            frame.exec_(co)
+        except passthroughex:
+            raise
+        except:
+            raise Failure(self)
+
+    def nice_explanation(self):
+        return _format_explanation(self.explanation)
+
+
+class Name(Interpretable):
+    __view__ = ast.Name
+
+    def is_local(self, frame):
+        source = '%r in locals() is not globals()' % self.name
+        try:
+            return frame.is_true(frame.eval(source))
+        except passthroughex:
+            raise
+        except:
+            return False
+
+    def is_global(self, frame):
+        source = '%r in globals()' % self.name
+        try:
+            return frame.is_true(frame.eval(source))
+        except passthroughex:
+            raise
+        except:
+            return False
+
+    def is_builtin(self, frame):
+        source = '%r not in locals() and %r not in globals()' % (
+            self.name, self.name)
+        try:
+            return frame.is_true(frame.eval(source))
+        except passthroughex:
+            raise
+        except:
+            return False
+
+    def eval(self, frame):
+        super(Name, self).eval(frame)
+        if not self.is_local(frame):
+            self.explanation = self.name
+
+class Compare(Interpretable):
+    __view__ = ast.Compare
+
+    def eval(self, frame):
+        expr = Interpretable(self.expr)
+        expr.eval(frame)
+        for operation, expr2 in self.ops:
+            if hasattr(self, 'result'):
+                # shortcutting in chained expressions
+                if not frame.is_true(self.result):
+                    break
+            expr2 = Interpretable(expr2)
+            expr2.eval(frame)
+            self.explanation = "%s %s %s" % (
+                expr.explanation, operation, expr2.explanation)
+            source = "__exprinfo_left %s __exprinfo_right" % operation
+            try:
+                self.result = frame.eval(source,
+                                         __exprinfo_left=expr.result,
+                                         __exprinfo_right=expr2.result)
+            except passthroughex:
+                raise
+            except:
+                raise Failure(self)
+            expr = expr2
+
+class And(Interpretable):
+    __view__ = ast.And
+
+    def eval(self, frame):
+        explanations = []
+        for expr in self.nodes:
+            expr = Interpretable(expr)
+            expr.eval(frame)
+            explanations.append(expr.explanation)
+            self.result = expr.result
+            if not frame.is_true(expr.result):
+                break
+        self.explanation = '(' + ' and '.join(explanations) + ')'
+
+class Or(Interpretable):
+    __view__ = ast.Or
+
+    def eval(self, frame):
+        explanations = []
+        for expr in self.nodes:
+            expr = Interpretable(expr)
+            expr.eval(frame)
+            explanations.append(expr.explanation)
+            self.result = expr.result
+            if frame.is_true(expr.result):
+                break
+        self.explanation = '(' + ' or '.join(explanations) + ')'
+
+
+# == Unary operations ==
+keepalive = []
+for astclass, astpattern in {
+    ast.Not    : 'not __exprinfo_expr',
+    ast.Invert : '(~__exprinfo_expr)',
+    }.items():
+
+    class UnaryArith(Interpretable):
+        __view__ = astclass
+
+        def eval(self, frame, astpattern=astpattern):
+            expr = Interpretable(self.expr)
+            expr.eval(frame)
+            self.explanation = astpattern.replace('__exprinfo_expr',
+                                                  expr.explanation)
+            try:
+                self.result = frame.eval(astpattern,
+                                         __exprinfo_expr=expr.result)
+            except passthroughex:
+                raise
+            except:
+                raise Failure(self)
+
+    keepalive.append(UnaryArith)
+
+# == Binary operations ==
+for astclass, astpattern in {
+    ast.Add    : '(__exprinfo_left + __exprinfo_right)',
+    ast.Sub    : '(__exprinfo_left - __exprinfo_right)',
+    ast.Mul    : '(__exprinfo_left * __exprinfo_right)',
+    ast.Div    : '(__exprinfo_left / __exprinfo_right)',
+    ast.Mod    : '(__exprinfo_left % __exprinfo_right)',
+    ast.Power  : '(__exprinfo_left ** __exprinfo_right)',
+    }.items():
+
+    class BinaryArith(Interpretable):
+        __view__ = astclass
+
+        def eval(self, frame, astpattern=astpattern):
+            left = Interpretable(self.left)
+            left.eval(frame)
+            right = Interpretable(self.right)
+            right.eval(frame)
+            self.explanation = (astpattern
+                                .replace('__exprinfo_left',  left .explanation)
+                                .replace('__exprinfo_right', right.explanation))
+            try:
+                self.result = frame.eval(astpattern,
+                                         __exprinfo_left=left.result,
+                                         __exprinfo_right=right.result)
+            except passthroughex:
+                raise
+            except:
+                raise Failure(self)
+
+    keepalive.append(BinaryArith)
+
+
+class CallFunc(Interpretable):
+    __view__ = ast.CallFunc
+
+    def is_bool(self, frame):
+        source = 'isinstance(__exprinfo_value, bool)'
+        try:
+            return frame.is_true(frame.eval(source,
+                                            __exprinfo_value=self.result))
+        except passthroughex:
+            raise
+        except:
+            return False
+
+    def eval(self, frame):
+        node = Interpretable(self.node)
+        node.eval(frame)
+        explanations = []
+        vars = {'__exprinfo_fn': node.result}
+        source = '__exprinfo_fn('
+        for a in self.args:
+            if isinstance(a, ast.Keyword):
+                keyword = a.name
+                a = a.expr
+            else:
+                keyword = None
+            a = Interpretable(a)
+            a.eval(frame)
+            argname = '__exprinfo_%d' % len(vars)
+            vars[argname] = a.result
+            if keyword is None:
+                source += argname + ','
+                explanations.append(a.explanation)
+            else:
+                source += '%s=%s,' % (keyword, argname)
+                explanations.append('%s=%s' % (keyword, a.explanation))
+        if self.star_args:
+            star_args = Interpretable(self.star_args)
+            star_args.eval(frame)
+            argname = '__exprinfo_star'
+            vars[argname] = star_args.result
+            source += '*' + argname + ','
+            explanations.append('*' + star_args.explanation)
+        if self.dstar_args:
+            dstar_args = Interpretable(self.dstar_args)
+            dstar_args.eval(frame)
+            argname = '__exprinfo_kwds'
+            vars[argname] = dstar_args.result
+            source += '**' + argname + ','
+            explanations.append('**' + dstar_args.explanation)
+        self.explanation = "%s(%s)" % (
+            node.explanation, ', '.join(explanations))
+        if source.endswith(','):
+            source = source[:-1]
+        source += ')'
+        try:
+            self.result = frame.eval(source, **vars)
+        except passthroughex:
+            raise
+        except:
+            raise Failure(self)
+        if not node.is_builtin(frame) or not self.is_bool(frame):
+            r = frame.repr(self.result)
+            self.explanation = '%s\n{%s = %s\n}' % (r, r, self.explanation)
+
+class Getattr(Interpretable):
+    __view__ = ast.Getattr
+
+    def eval(self, frame):
+        expr = Interpretable(self.expr)
+        expr.eval(frame)
+        source = '__exprinfo_expr.%s' % self.attrname
+        try:
+            self.result = frame.eval(source, __exprinfo_expr=expr.result)
+        except passthroughex:
+            raise
+        except:
+            raise Failure(self)
+        self.explanation = '%s.%s' % (expr.explanation, self.attrname)
+        # if the attribute comes from the instance, its value is interesting
+        source = ('hasattr(__exprinfo_expr, "__dict__") and '
+                  '%r in __exprinfo_expr.__dict__' % self.attrname)
+        try:
+            from_instance = frame.is_true(
+                frame.eval(source, __exprinfo_expr=expr.result))
+        except passthroughex:
+            raise
+        except:
+            from_instance = True
+        if from_instance:
+            r = frame.repr(self.result)
+            self.explanation = '%s\n{%s = %s\n}' % (r, r, self.explanation)
+
+# == Re-interpretation of full statements ==
+
+class Assert(Interpretable):
+    __view__ = ast.Assert
+
+    def run(self, frame):
+        test = Interpretable(self.test)
+        test.eval(frame)
+        # simplify 'assert False where False = ...'
+        if (test.explanation.startswith('False\n{False = ') and
+            test.explanation.endswith('\n}')):
+            test.explanation = test.explanation[15:-2]
+        # print the result as  'assert <explanation>'
+        self.result = test.result
+        self.explanation = 'assert ' + test.explanation
+        if not frame.is_true(test.result):
+            try:
+                raise BuiltinAssertionError
+            except passthroughex:
+                raise
+            except:
+                raise Failure(self)
+
+class Assign(Interpretable):
+    __view__ = ast.Assign
+
+    def run(self, frame):
+        expr = Interpretable(self.expr)
+        expr.eval(frame)
+        self.result = expr.result
+        self.explanation = '... = ' + expr.explanation
+        # fall-back-run the rest of the assignment
+        ass = ast.Assign(self.nodes, ast.Name('__exprinfo_expr'))
+        mod = ast.Module(None, ast.Stmt([ass]))
+        mod.filename = '<run>'
+        co = pycodegen.ModuleCodeGenerator(mod).getCode()
+        try:
+            frame.exec_(co, __exprinfo_expr=expr.result)
+        except passthroughex:
+            raise
+        except:
+            raise Failure(self)
+
+class Discard(Interpretable):
+    __view__ = ast.Discard
+
+    def run(self, frame):
+        expr = Interpretable(self.expr)
+        expr.eval(frame)
+        self.result = expr.result
+        self.explanation = expr.explanation
+
+class Stmt(Interpretable):
+    __view__ = ast.Stmt
+
+    def run(self, frame):
+        for stmt in self.nodes:
+            stmt = Interpretable(stmt)
+            stmt.run(frame)
+
+
+def report_failure(e):
+    explanation = e.node.nice_explanation()
+    if explanation:
+        explanation = ", in: " + explanation
+    else:
+        explanation = ""
+    sys.stdout.write("%s: %s%s\n" % (e.exc.__name__, e.value, explanation))
+
+def check(s, frame=None):
+    if frame is None:
+        frame = sys._getframe(1)
+        frame = py.code.Frame(frame)
+    expr = parse(s, 'eval')
+    assert isinstance(expr, ast.Expression)
+    node = Interpretable(expr.node)
+    try:
+        node.eval(frame)
+    except passthroughex:
+        raise
+    except Failure:
+        e = sys.exc_info()[1]
+        report_failure(e)
+    else:
+        if not frame.is_true(node.result):
+            sys.stderr.write("assertion failed: %s\n" % node.nice_explanation())
+
+
+###########################################################
+# API / Entry points
+# #########################################################
+
+def interpret(source, frame, should_fail=False):
+    module = Interpretable(parse(source, 'exec').node)
+    #print "got module", module
+    if isinstance(frame, py.std.types.FrameType):
+        frame = py.code.Frame(frame)
+    try:
+        module.run(frame)
+    except Failure:
+        e = sys.exc_info()[1]
+        return getfailure(e)
+    except passthroughex:
+        raise
+    except:
+        import traceback
+        traceback.print_exc()
+    if should_fail:
+        return ("(assertion failed, but when it was re-run for "
+                "printing intermediate values, it did not fail.  Suggestions: "
+                "compute assert expression before the assert or use --nomagic)")
+    else:
+        return None
+
+def getmsg(excinfo):
+    if isinstance(excinfo, tuple):
+        excinfo = py.code.ExceptionInfo(excinfo)
+    #frame, line = gettbline(tb)
+    #frame = py.code.Frame(frame)
+    #return interpret(line, frame)
+
+    tb = excinfo.traceback[-1]
+    source = str(tb.statement).strip()
+    x = interpret(source, tb.frame, should_fail=True)
+    if not isinstance(x, str):
+        raise TypeError("interpret returned non-string %r" % (x,))
+    return x
+
+def getfailure(e):
+    explanation = e.node.nice_explanation()
+    if str(e.value):
+        lines = explanation.split('\n')
+        lines[0] += "  << %s" % (e.value,)
+        explanation = '\n'.join(lines)
+    text = "%s: %s" % (e.exc.__name__, explanation)
+    if text.startswith('AssertionError: assert '):
+        text = text[16:]
+    return text
+
+def run(s, frame=None):
+    if frame is None:
+        frame = sys._getframe(1)
+        frame = py.code.Frame(frame)
+    module = Interpretable(parse(s, 'exec').node)
+    try:
+        module.run(frame)
+    except Failure:
+        e = sys.exc_info()[1]
+        report_failure(e)
+
+
+if __name__ == '__main__':
+    # example:
+    def f():
+        return 5
+    def g():
+        return 3
+    def h(x):
+        return 'never'
+    check("f() * g() == 5")
+    check("not f()")
+    check("not (f() and g() or 0)")
+    check("f() == g()")
+    i = 4
+    check("i == f()")
+    check("len(f()) == 0")
+    check("isinstance(2+3+4, float)")
+
+    run("x = i")
+    check("x == 5")
+
+    run("assert not f(), 'oops'")
+    run("a, b, c = 1, 2")
+    run("a, b, c = f()")
+
+    check("max([f(),g()]) == 4")
+    check("'hello'[g()] == 'h'")
+    run("'guk%d' % h(f())")
diff --git a/lib/spack/external/py/_code/_py2traceback.py b/lib/spack/external/py/_code/_py2traceback.py
new file mode 100644
index 0000000000..d65e27cb73
--- /dev/null
+++ b/lib/spack/external/py/_code/_py2traceback.py
@@ -0,0 +1,79 @@
+# copied from python-2.7.3's traceback.py
+# CHANGES:
+# - some_str is replaced, trying to create unicode strings
+#
+import types
+
+def format_exception_only(etype, value):
+    """Format the exception part of a traceback.
+
+    The arguments are the exception type and value such as given by
+    sys.last_type and sys.last_value. The return value is a list of
+    strings, each ending in a newline.
+
+    Normally, the list contains a single string; however, for
+    SyntaxError exceptions, it contains several lines that (when
+    printed) display detailed information about where the syntax
+    error occurred.
+
+    The message indicating which exception occurred is always the last
+    string in the list.
+
+    """
+
+    # An instance should not have a meaningful value parameter, but
+    # sometimes does, particularly for string exceptions, such as
+    # >>> raise string1, string2  # deprecated
+    #
+    # Clear these out first because issubtype(string1, SyntaxError)
+    # would throw another exception and mask the original problem.
+    if (isinstance(etype, BaseException) or
+        isinstance(etype, types.InstanceType) or
+        etype is None or type(etype) is str):
+        return [_format_final_exc_line(etype, value)]
+
+    stype = etype.__name__
+
+    if not issubclass(etype, SyntaxError):
+        return [_format_final_exc_line(stype, value)]
+
+    # It was a syntax error; show exactly where the problem was found.
+    lines = []
+    try:
+        msg, (filename, lineno, offset, badline) = value.args
+    except Exception:
+        pass
+    else:
+        filename = filename or "<string>"
+        lines.append('  File "%s", line %d\n' % (filename, lineno))
+        if badline is not None:
+            lines.append('    %s\n' % badline.strip())
+            if offset is not None:
+                caretspace = badline.rstrip('\n')[:offset].lstrip()
+                # non-space whitespace (likes tabs) must be kept for alignment
+                caretspace = ((c.isspace() and c or ' ') for c in caretspace)
+                # only three spaces to account for offset1 == pos 0
+                lines.append('   %s^\n' % ''.join(caretspace))
+        value = msg
+
+    lines.append(_format_final_exc_line(stype, value))
+    return lines
+
+def _format_final_exc_line(etype, value):
+    """Return a list of a single line -- normal case for format_exception_only"""
+    valuestr = _some_str(value)
+    if value is None or not valuestr:
+        line = "%s\n" % etype
+    else:
+        line = "%s: %s\n" % (etype, valuestr)
+    return line
+
+def _some_str(value):
+    try:
+        return unicode(value)
+    except Exception:
+        try:
+            return str(value)
+        except Exception:
+            pass
+    return '<unprintable %s object>' % type(value).__name__
diff --git a/lib/spack/external/py/_code/assertion.py b/lib/spack/external/py/_code/assertion.py
new file mode 100644
index 0000000000..4ce80c75b1
--- /dev/null
+++ b/lib/spack/external/py/_code/assertion.py
@@ -0,0 +1,94 @@
+import sys
+import py
+
+BuiltinAssertionError = py.builtin.builtins.AssertionError
+
+_reprcompare = None # if set, will be called by assert reinterp for comparison ops
+
+def _format_explanation(explanation):
+    """This formats an explanation
+
+    Normally all embedded newlines are escaped, however there are
+    three exceptions: \n{, \n} and \n~.  The first two are intended
+    cover nested explanations, see function and attribute explanations
+    for examples (.visit_Call(), visit_Attribute()).  The last one is
+    for when one explanation needs to span multiple lines, e.g. when
+    displaying diffs.
+    """
+    raw_lines = (explanation or '').split('\n')
+    # escape newlines not followed by {, } and ~
+    lines = [raw_lines[0]]
+    for l in raw_lines[1:]:
+        if l.startswith('{') or l.startswith('}') or l.startswith('~'):
+            lines.append(l)
+        else:
+            lines[-1] += '\\n' + l
+
+    result = lines[:1]
+    stack = [0]
+    stackcnt = [0]
+    for line in lines[1:]:
+        if line.startswith('{'):
+            if stackcnt[-1]:
+                s = 'and   '
+            else:
+                s = 'where '
+            stack.append(len(result))
+            stackcnt[-1] += 1
+            stackcnt.append(0)
+            result.append(' +' + '  '*(len(stack)-1) + s + line[1:])
+        elif line.startswith('}'):
+            assert line.startswith('}')
+            stack.pop()
+            stackcnt.pop()
+            result[stack[-1]] += line[1:]
+        else:
+            assert line.startswith('~')
+            result.append('  '*len(stack) + line[1:])
+    assert len(stack) == 1
+    return '\n'.join(result)
+
+
+class AssertionError(BuiltinAssertionError):
+    def __init__(self, *args):
+        BuiltinAssertionError.__init__(self, *args)
+        if args:
+            try:
+                self.msg = str(args[0])
+            except py.builtin._sysex:
+                raise
+            except:
+                self.msg = "<[broken __repr__] %s at %0xd>" %(
+                    args[0].__class__, id(args[0]))
+        else:
+            f = py.code.Frame(sys._getframe(1))
+            try:
+                source = f.code.fullsource
+                if source is not None:
+                    try:
+                        source = source.getstatement(f.lineno, assertion=True)
+                    except IndexError:
+                        source = None
+                    else:
+                        source = str(source.deindent()).strip()
+            except py.error.ENOENT:
+                source = None
+                # this can also occur during reinterpretation, when the
+                # co_filename is set to "<run>".
+            if source:
+                self.msg = reinterpret(source, f, should_fail=True)
+            else:
+                self.msg = "<could not determine information>"
+            if not self.args:
+                self.args = (self.msg,)
+
+if sys.version_info > (3, 0):
+    AssertionError.__module__ = "builtins"
+    reinterpret_old = "old reinterpretation not available for py3"
+else:
+    from py._code._assertionold import interpret as reinterpret_old
+if sys.version_info >= (2, 6) or (sys.platform.startswith("java")):
+    from py._code._assertionnew import interpret as reinterpret
+else:
+    reinterpret = reinterpret_old
+
diff --git a/lib/spack/external/py/_code/code.py b/lib/spack/external/py/_code/code.py
new file mode 100644
index 0000000000..f14c562a29
--- /dev/null
+++ b/lib/spack/external/py/_code/code.py
@@ -0,0 +1,787 @@
+import py
+import sys
+from inspect import CO_VARARGS, CO_VARKEYWORDS
+
+builtin_repr = repr
+
+reprlib = py.builtin._tryimport('repr', 'reprlib')
+
+if sys.version_info[0] >= 3:
+    from traceback import format_exception_only
+else:
+    from py._code._py2traceback import format_exception_only
+
+class Code(object):
+    """ wrapper around Python code objects """
+    def __init__(self, rawcode):
+        if not hasattr(rawcode, "co_filename"):
+            rawcode = py.code.getrawcode(rawcode)
+        try:
+            self.filename = rawcode.co_filename
+            self.firstlineno = rawcode.co_firstlineno - 1
+            self.name = rawcode.co_name
+        except AttributeError:
+            raise TypeError("not a code object: %r" %(rawcode,))
+        self.raw = rawcode
+
+    def __eq__(self, other):
+        return self.raw == other.raw
+
+    def __ne__(self, other):
+        return not self == other
+
+    @property
+    def path(self):
+        """ return a path object pointing to source code (note that it
+        might not point to an actually existing file). """
+        p = py.path.local(self.raw.co_filename)
+        # maybe don't try this checking
+        if not p.check():
+            # XXX maybe try harder like the weird logic
+            # in the standard lib [linecache.updatecache] does?
+            p = self.raw.co_filename
+        return p
+
+    @property
+    def fullsource(self):
+        """ return a py.code.Source object for the full source file of the code
+        """
+        from py._code import source
+        full, _ = source.findsource(self.raw)
+        return full
+
+    def source(self):
+        """ return a py.code.Source object for the code object's source only
+        """
+        # return source only for that part of code
+        return py.code.Source(self.raw)
+
+    def getargs(self, var=False):
+        """ return a tuple with the argument names for the code object
+
+            if 'var' is set True also return the names of the variable and
+            keyword arguments when present
+        """
+        # handfull shortcut for getting args
+        raw = self.raw
+        argcount = raw.co_argcount
+        if var:
+            argcount += raw.co_flags & CO_VARARGS
+            argcount += raw.co_flags & CO_VARKEYWORDS
+        return raw.co_varnames[:argcount]
+
+class Frame(object):
+    """Wrapper around a Python frame holding f_locals and f_globals
+    in which expressions can be evaluated."""
+
+    def __init__(self, frame):
+        self.lineno = frame.f_lineno - 1
+        self.f_globals = frame.f_globals
+        self.f_locals = frame.f_locals
+        self.raw = frame
+        self.code = py.code.Code(frame.f_code)
+
+    @property
+    def statement(self):
+        """ statement this frame is at """
+        if self.code.fullsource is None:
+            return py.code.Source("")
+        return self.code.fullsource.getstatement(self.lineno)
+
+    def eval(self, code, **vars):
+        """ evaluate 'code' in the frame
+
+            'vars' are optional additional local variables
+
+            returns the result of the evaluation
+        """
+        f_locals = self.f_locals.copy()
+        f_locals.update(vars)
+        return eval(code, self.f_globals, f_locals)
+
+    def exec_(self, code, **vars):
+        """ exec 'code' in the frame
+
+            'vars' are optiona; additional local variables
+        """
+        f_locals = self.f_locals.copy()
+        f_locals.update(vars)
+        py.builtin.exec_(code, self.f_globals, f_locals )
+
+    def repr(self, object):
+        """ return a 'safe' (non-recursive, one-line) string repr for 'object'
+        """
+        return py.io.saferepr(object)
+
+    def is_true(self, object):
+        return object
+
+    def getargs(self, var=False):
+        """ return a list of tuples (name, value) for all arguments
+
+            if 'var' is set True also include the variable and keyword
+            arguments when present
+        """
+        retval = []
+        for arg in self.code.getargs(var):
+            try:
+                retval.append((arg, self.f_locals[arg]))
+            except KeyError:
+                pass     # this can occur when using Psyco
+        return retval
+
+class TracebackEntry(object):
+    """ a single entry in a traceback """
+
+    _repr_style = None
+    exprinfo = None
+
+    def __init__(self, rawentry):
+        self._rawentry = rawentry
+        self.lineno = rawentry.tb_lineno - 1
+
+    def set_repr_style(self, mode):
+        assert mode in ("short", "long")
+        self._repr_style = mode
+
+    @property
+    def frame(self):
+        return py.code.Frame(self._rawentry.tb_frame)
+
+    @property
+    def relline(self):
+        return self.lineno - self.frame.code.firstlineno
+
+    def __repr__(self):
+        return "<TracebackEntry %s:%d>" %(self.frame.code.path, self.lineno+1)
+
+    @property
+    def statement(self):
+        """ py.code.Source object for the current statement """
+        source = self.frame.code.fullsource
+        return source.getstatement(self.lineno)
+
+    @property
+    def path(self):
+        """ path to the source code """
+        return self.frame.code.path
+
+    def getlocals(self):
+        return self.frame.f_locals
+    locals = property(getlocals, None, None, "locals of underlaying frame")
+
+    def reinterpret(self):
+        """Reinterpret the failing statement and returns a detailed information
+           about what operations are performed."""
+        if self.exprinfo is None:
+            source = str(self.statement).strip()
+            x = py.code._reinterpret(source, self.frame, should_fail=True)
+            if not isinstance(x, str):
+                raise TypeError("interpret returned non-string %r" % (x,))
+            self.exprinfo = x
+        return self.exprinfo
+
+    def getfirstlinesource(self):
+        # on Jython this firstlineno can be -1 apparently
+        return max(self.frame.code.firstlineno, 0)
+
+    def getsource(self, astcache=None):
+        """ return failing source code. """
+        # we use the passed in astcache to not reparse asttrees
+        # within exception info printing
+        from py._code.source import getstatementrange_ast
+        source = self.frame.code.fullsource
+        if source is None:
+            return None
+        key = astnode = None
+        if astcache is not None:
+            key = self.frame.code.path
+            if key is not None:
+                astnode = astcache.get(key, None)
+        start = self.getfirstlinesource()
+        try:
+            astnode, _, end = getstatementrange_ast(self.lineno, source,
+                                                    astnode=astnode)
+        except SyntaxError:
+            end = self.lineno + 1
+        else:
+            if key is not None:
+                astcache[key] = astnode
+        return source[start:end]
+
+    source = property(getsource)
+
+    def ishidden(self):
+        """ return True if the current frame has a var __tracebackhide__
+            resolving to True
+
+            mostly for internal use
+        """
+        try:
+            return self.frame.f_locals['__tracebackhide__']
+        except KeyError:
+            try:
+                return self.frame.f_globals['__tracebackhide__']
+            except KeyError:
+                return False
+
+    def __str__(self):
+        try:
+            fn = str(self.path)
+        except py.error.Error:
+            fn = '???'
+        name = self.frame.code.name
+        try:
+            line = str(self.statement).lstrip()
+        except KeyboardInterrupt:
+            raise
+        except:
+            line = "???"
+        return "  File %r:%d in %s\n  %s\n" %(fn, self.lineno+1, name, line)
+
+    def name(self):
+        return self.frame.code.raw.co_name
+    name = property(name, None, None, "co_name of underlaying code")
+
+class Traceback(list):
+    """ Traceback objects encapsulate and offer higher level
+        access to Traceback entries.
+    """
+    Entry = TracebackEntry
+    def __init__(self, tb):
+        """ initialize from given python traceback object. """
+        if hasattr(tb, 'tb_next'):
+            def f(cur):
+                while cur is not None:
+                    yield self.Entry(cur)
+                    cur = cur.tb_next
+            list.__init__(self, f(tb))
+        else:
+            list.__init__(self, tb)
+
+    def cut(self, path=None, lineno=None, firstlineno=None, excludepath=None):
+        """ return a Traceback instance wrapping part of this Traceback
+
+            by provding any combination of path, lineno and firstlineno, the
+            first frame to start the to-be-returned traceback is determined
+
+            this allows cutting the first part of a Traceback instance e.g.
+            for formatting reasons (removing some uninteresting bits that deal
+            with handling of the exception/traceback)
+        """
+        for x in self:
+            code = x.frame.code
+            codepath = code.path
+            if ((path is None or codepath == path) and
+                (excludepath is None or not hasattr(codepath, 'relto') or
+                 not codepath.relto(excludepath)) and
+                (lineno is None or x.lineno == lineno) and
+                (firstlineno is None or x.frame.code.firstlineno == firstlineno)):
+                return Traceback(x._rawentry)
+        return self
+
+    def __getitem__(self, key):
+        val = super(Traceback, self).__getitem__(key)
+        if isinstance(key, type(slice(0))):
+            val = self.__class__(val)
+        return val
+
+    def filter(self, fn=lambda x: not x.ishidden()):
+        """ return a Traceback instance with certain items removed
+
+            fn is a function that gets a single argument, a TracebackItem
+            instance, and should return True when the item should be added
+            to the Traceback, False when not
+
+            by default this removes all the TracebackItems which are hidden
+            (see ishidden() above)
+        """
+        return Traceback(filter(fn, self))
+
+    def getcrashentry(self):
+        """ return last non-hidden traceback entry that lead
+        to the exception of a traceback.
+        """
+        for i in range(-1, -len(self)-1, -1):
+            entry = self[i]
+            if not entry.ishidden():
+                return entry
+        return self[-1]
+
+    def recursionindex(self):
+        """ return the index of the frame/TracebackItem where recursion
+            originates if appropriate, None if no recursion occurred
+        """
+        cache = {}
+        for i, entry in enumerate(self):
+            # id for the code.raw is needed to work around
+            # the strange metaprogramming in the decorator lib from pypi
+            # which generates code objects that have hash/value equality
+            #XXX needs a test
+            key = entry.frame.code.path, id(entry.frame.code.raw), entry.lineno
+            #print "checking for recursion at", key
+            l = cache.setdefault(key, [])
+            if l:
+                f = entry.frame
+                loc = f.f_locals
+                for otherloc in l:
+                    if f.is_true(f.eval(co_equal,
+                        __recursioncache_locals_1=loc,
+                        __recursioncache_locals_2=otherloc)):
+                        return i
+            l.append(entry.frame.f_locals)
+        return None
+
+co_equal = compile('__recursioncache_locals_1 == __recursioncache_locals_2',
+                   '?', 'eval')
+
+class ExceptionInfo(object):
+    """ wraps sys.exc_info() objects and offers
+        help for navigating the traceback.
+    """
+    _striptext = ''
+    def __init__(self, tup=None, exprinfo=None):
+        if tup is None:
+            tup = sys.exc_info()
+            if exprinfo is None and isinstance(tup[1], AssertionError):
+                exprinfo = getattr(tup[1], 'msg', None)
+                if exprinfo is None:
+                    exprinfo = str(tup[1])
+                if exprinfo and exprinfo.startswith('assert '):
+                    self._striptext = 'AssertionError: '
+        self._excinfo = tup
+        #: the exception class
+        self.type = tup[0]
+        #: the exception instance
+        self.value = tup[1]
+        #: the exception raw traceback
+        self.tb = tup[2]
+        #: the exception type name
+        self.typename = self.type.__name__
+        #: the exception traceback (py.code.Traceback instance)
+        self.traceback = py.code.Traceback(self.tb)
+
+    def __repr__(self):
+        return "<ExceptionInfo %s tblen=%d>" % (self.typename, len(self.traceback))
+
+    def exconly(self, tryshort=False):
+        """ return the exception as a string
+
+            when 'tryshort' resolves to True, and the exception is a
+            py.code._AssertionError, only the actual exception part of
+            the exception representation is returned (so 'AssertionError: ' is
+            removed from the beginning)
+        """
+        lines = format_exception_only(self.type, self.value)
+        text = ''.join(lines)
+        text = text.rstrip()
+        if tryshort:
+            if text.startswith(self._striptext):
+                text = text[len(self._striptext):]
+        return text
+
+    def errisinstance(self, exc):
+        """ return True if the exception is an instance of exc """
+        return isinstance(self.value, exc)
+
+    def _getreprcrash(self):
+        exconly = self.exconly(tryshort=True)
+        entry = self.traceback.getcrashentry()
+        path, lineno = entry.frame.code.raw.co_filename, entry.lineno
+        return ReprFileLocation(path, lineno+1, exconly)
+
+    def getrepr(self, showlocals=False, style="long",
+            abspath=False, tbfilter=True, funcargs=False):
+        """ return str()able representation of this exception info.
+            showlocals: show locals per traceback entry
+            style: long|short|no|native traceback style
+            tbfilter: hide entries (where __tracebackhide__ is true)
+
+            in case of style==native, tbfilter and showlocals is ignored.
+        """
+        if style == 'native':
+            return ReprExceptionInfo(ReprTracebackNative(
+                py.std.traceback.format_exception(
+                    self.type,
+                    self.value,
+                    self.traceback[0]._rawentry,
+                )), self._getreprcrash())
+
+        fmt = FormattedExcinfo(showlocals=showlocals, style=style,
+            abspath=abspath, tbfilter=tbfilter, funcargs=funcargs)
+        return fmt.repr_excinfo(self)
+
+    def __str__(self):
+        entry = self.traceback[-1]
+        loc = ReprFileLocation(entry.path, entry.lineno + 1, self.exconly())
+        return str(loc)
+
+    def __unicode__(self):
+        entry = self.traceback[-1]
+        loc = ReprFileLocation(entry.path, entry.lineno + 1, self.exconly())
+        return unicode(loc)
+
+
+class FormattedExcinfo(object):
+    """ presenting information about failing Functions and Generators. """
+    # for traceback entries
+    flow_marker = ">"
+    fail_marker = "E"
+
+    def __init__(self, showlocals=False, style="long", abspath=True, tbfilter=True, funcargs=False):
+        self.showlocals = showlocals
+        self.style = style
+        self.tbfilter = tbfilter
+        self.funcargs = funcargs
+        self.abspath = abspath
+        self.astcache = {}
+
+    def _getindent(self, source):
+        # figure out indent for given source
+        try:
+            s = str(source.getstatement(len(source)-1))
+        except KeyboardInterrupt:
+            raise
+        except:
+            try:
+                s = str(source[-1])
+            except KeyboardInterrupt:
+                raise
+            except:
+                return 0
+        return 4 + (len(s) - len(s.lstrip()))
+
+    def _getentrysource(self, entry):
+        source = entry.getsource(self.astcache)
+        if source is not None:
+            source = source.deindent()
+        return source
+
+    def _saferepr(self, obj):
+        return py.io.saferepr(obj)
+
+    def repr_args(self, entry):
+        if self.funcargs:
+            args = []
+            for argname, argvalue in entry.frame.getargs(var=True):
+                args.append((argname, self._saferepr(argvalue)))
+            return ReprFuncArgs(args)
+
+    def get_source(self, source, line_index=-1, excinfo=None, short=False):
+        """ return formatted and marked up source lines. """
+        lines = []
+        if source is None or line_index >= len(source.lines):
+            source = py.code.Source("???")
+            line_index = 0
+        if line_index < 0:
+            line_index += len(source)
+        space_prefix = "    "
+        if short:
+            lines.append(space_prefix + source.lines[line_index].strip())
+        else:
+            for line in source.lines[:line_index]:
+                lines.append(space_prefix + line)
+            lines.append(self.flow_marker + "   " + source.lines[line_index])
+            for line in source.lines[line_index+1:]:
+                lines.append(space_prefix + line)
+        if excinfo is not None:
+            indent = 4 if short else self._getindent(source)
+            lines.extend(self.get_exconly(excinfo, indent=indent, markall=True))
+        return lines
+
+    def get_exconly(self, excinfo, indent=4, markall=False):
+        lines = []
+        indent = " " * indent
+        # get the real exception information out
+        exlines = excinfo.exconly(tryshort=True).split('\n')
+        failindent = self.fail_marker + indent[1:]
+        for line in exlines:
+            lines.append(failindent + line)
+            if not markall:
+                failindent = indent
+        return lines
+
+    def repr_locals(self, locals):
+        if self.showlocals:
+            lines = []
+            keys = [loc for loc in locals if loc[0] != "@"]
+            keys.sort()
+            for name in keys:
+                value = locals[name]
+                if name == '__builtins__':
+                    lines.append("__builtins__ = <builtins>")
+                else:
+                    # This formatting could all be handled by the
+                    # _repr() function, which is only reprlib.Repr in
+                    # disguise, so is very configurable.
+                    str_repr = self._saferepr(value)
+                    #if len(str_repr) < 70 or not isinstance(value,
+                    #                            (list, tuple, dict)):
+                    lines.append("%-10s = %s" %(name, str_repr))
+                    #else:
+                    #    self._line("%-10s =\\" % (name,))
+                    #    # XXX
+                    #    py.std.pprint.pprint(value, stream=self.excinfowriter)
+            return ReprLocals(lines)
+
+    def repr_traceback_entry(self, entry, excinfo=None):
+        source = self._getentrysource(entry)
+        if source is None:
+            source = py.code.Source("???")
+            line_index = 0
+        else:
+            # entry.getfirstlinesource() can be -1, should be 0 on jython
+            line_index = entry.lineno - max(entry.getfirstlinesource(), 0)
+
+        lines = []
+        style = entry._repr_style
+        if style is None:
+            style = self.style
+        if style in ("short", "long"):
+            short = style == "short"
+            reprargs = self.repr_args(entry) if not short else None
+            s = self.get_source(source, line_index, excinfo, short=short)
+            lines.extend(s)
+            if short:
+                message = "in %s" %(entry.name)
+            else:
+                message = excinfo and excinfo.typename or ""
+            path = self._makepath(entry.path)
+            filelocrepr = ReprFileLocation(path, entry.lineno+1, message)
+            localsrepr = None
+            if not short:
+                localsrepr =  self.repr_locals(entry.locals)
+            return ReprEntry(lines, reprargs, localsrepr, filelocrepr, style)
+        if excinfo:
+            lines.extend(self.get_exconly(excinfo, indent=4))
+        return ReprEntry(lines, None, None, None, style)
+
+    def _makepath(self, path):
+        if not self.abspath:
+            try:
+                np = py.path.local().bestrelpath(path)
+            except OSError:
+                return path
+            if len(np) < len(str(path)):
+                path = np
+        return path
+
+    def repr_traceback(self, excinfo):
+        traceback = excinfo.traceback
+        if self.tbfilter:
+            traceback = traceback.filter()
+        recursionindex = None
+        if excinfo.errisinstance(RuntimeError):
+            if "maximum recursion depth exceeded" in str(excinfo.value):
+                recursionindex = traceback.recursionindex()
+        last = traceback[-1]
+        entries = []
+        extraline = None
+        for index, entry in enumerate(traceback):
+            einfo = (last == entry) and excinfo or None
+            reprentry = self.repr_traceback_entry(entry, einfo)
+            entries.append(reprentry)
+            if index == recursionindex:
+                extraline = "!!! Recursion detected (same locals & position)"
+                break
+        return ReprTraceback(entries, extraline, style=self.style)
+
+    def repr_excinfo(self, excinfo):
+        reprtraceback = self.repr_traceback(excinfo)
+        reprcrash = excinfo._getreprcrash()
+        return ReprExceptionInfo(reprtraceback, reprcrash)
+
+class TerminalRepr:
+    def __str__(self):
+        s = self.__unicode__()
+        if sys.version_info[0] < 3:
+            s = s.encode('utf-8')
+        return s
+
+    def __unicode__(self):
+        # FYI this is called from pytest-xdist's serialization of exception
+        # information.
+        io = py.io.TextIO()
+        tw = py.io.TerminalWriter(file=io)
+        self.toterminal(tw)
+        return io.getvalue().strip()
+
+    def __repr__(self):
+        return "<%s instance at %0x>" %(self.__class__, id(self))
+
+
+class ReprExceptionInfo(TerminalRepr):
+    def __init__(self, reprtraceback, reprcrash):
+        self.reprtraceback = reprtraceback
+        self.reprcrash = reprcrash
+        self.sections = []
+
+    def addsection(self, name, content, sep="-"):
+        self.sections.append((name, content, sep))
+
+    def toterminal(self, tw):
+        self.reprtraceback.toterminal(tw)
+        for name, content, sep in self.sections:
+            tw.sep(sep, name)
+            tw.line(content)
+
+class ReprTraceback(TerminalRepr):
+    entrysep = "_ "
+
+    def __init__(self, reprentries, extraline, style):
+        self.reprentries = reprentries
+        self.extraline = extraline
+        self.style = style
+
+    def toterminal(self, tw):
+        # the entries might have different styles
+        last_style = None
+        for i, entry in enumerate(self.reprentries):
+            if entry.style == "long":
+                tw.line("")
+            entry.toterminal(tw)
+            if i < len(self.reprentries) - 1:
+                next_entry = self.reprentries[i+1]
+                if entry.style == "long" or \
+                   entry.style == "short" and next_entry.style == "long":
+                    tw.sep(self.entrysep)
+
+        if self.extraline:
+            tw.line(self.extraline)
+
+class ReprTracebackNative(ReprTraceback):
+    def __init__(self, tblines):
+        self.style = "native"
+        self.reprentries = [ReprEntryNative(tblines)]
+        self.extraline = None
+
+class ReprEntryNative(TerminalRepr):
+    style = "native"
+
+    def __init__(self, tblines):
+        self.lines = tblines
+
+    def toterminal(self, tw):
+        tw.write("".join(self.lines))
+
+class ReprEntry(TerminalRepr):
+    localssep = "_ "
+
+    def __init__(self, lines, reprfuncargs, reprlocals, filelocrepr, style):
+        self.lines = lines
+        self.reprfuncargs = reprfuncargs
+        self.reprlocals = reprlocals
+        self.reprfileloc = filelocrepr
+        self.style = style
+
+    def toterminal(self, tw):
+        if self.style == "short":
+            self.reprfileloc.toterminal(tw)
+            for line in self.lines:
+                red = line.startswith("E   ")
+                tw.line(line, bold=True, red=red)
+            #tw.line("")
+            return
+        if self.reprfuncargs:
+            self.reprfuncargs.toterminal(tw)
+        for line in self.lines:
+            red = line.startswith("E   ")
+            tw.line(line, bold=True, red=red)
+        if self.reprlocals:
+            #tw.sep(self.localssep, "Locals")
+            tw.line("")
+            self.reprlocals.toterminal(tw)
+        if self.reprfileloc:
+            if self.lines:
+                tw.line("")
+            self.reprfileloc.toterminal(tw)
+
+    def __str__(self):
+        return "%s\n%s\n%s" % ("\n".join(self.lines),
+                               self.reprlocals,
+                               self.reprfileloc)
+
+class ReprFileLocation(TerminalRepr):
+    def __init__(self, path, lineno, message):
+        self.path = str(path)
+        self.lineno = lineno
+        self.message = message
+
+    def toterminal(self, tw):
+        # filename and lineno output for each entry,
+        # using an output format that most editors unterstand
+        msg = self.message
+        i = msg.find("\n")
+        if i != -1:
+            msg = msg[:i]
+        tw.line("%s:%s: %s" %(self.path, self.lineno, msg))
+
+class ReprLocals(TerminalRepr):
+    def __init__(self, lines):
+        self.lines = lines
+
+    def toterminal(self, tw):
+        for line in self.lines:
+            tw.line(line)
+
+class ReprFuncArgs(TerminalRepr):
+    def __init__(self, args):
+        self.args = args
+
+    def toterminal(self, tw):
+        if self.args:
+            linesofar = ""
+            for name, value in self.args:
+                ns = "%s = %s" %(name, value)
+                if len(ns) + len(linesofar) + 2 > tw.fullwidth:
+                    if linesofar:
+                        tw.line(linesofar)
+                    linesofar =  ns
+                else:
+                    if linesofar:
+                        linesofar += ", " + ns
+                    else:
+                        linesofar = ns
+            if linesofar:
+                tw.line(linesofar)
+            tw.line("")
+
+
+
+oldbuiltins = {}
+
+def patch_builtins(assertion=True, compile=True):
+    """ put compile and AssertionError builtins to Python's builtins. """
+    if assertion:
+        from py._code import assertion
+        l = oldbuiltins.setdefault('AssertionError', [])
+        l.append(py.builtin.builtins.AssertionError)
+        py.builtin.builtins.AssertionError = assertion.AssertionError
+    if compile:
+        l = oldbuiltins.setdefault('compile', [])
+        l.append(py.builtin.builtins.compile)
+        py.builtin.builtins.compile = py.code.compile
+
+def unpatch_builtins(assertion=True, compile=True):
+    """ remove compile and AssertionError builtins from Python builtins. """
+    if assertion:
+        py.builtin.builtins.AssertionError = oldbuiltins['AssertionError'].pop()
+    if compile:
+        py.builtin.builtins.compile = oldbuiltins['compile'].pop()
+
+def getrawcode(obj, trycall=True):
+    """ return code object for given function. """
+    try:
+        return obj.__code__
+    except AttributeError:
+        obj = getattr(obj, 'im_func', obj)
+        obj = getattr(obj, 'func_code', obj)
+        obj = getattr(obj, 'f_code', obj)
+        obj = getattr(obj, '__code__', obj)
+        if trycall and not hasattr(obj, 'co_firstlineno'):
+            if hasattr(obj, '__call__') and not py.std.inspect.isclass(obj):
+                x = getrawcode(obj.__call__, trycall=False)
+                if hasattr(x, 'co_firstlineno'):
+                    return x
+        return obj
+
diff --git a/lib/spack/external/py/_code/source.py b/lib/spack/external/py/_code/source.py
new file mode 100644
index 0000000000..c8b668b2fb
--- /dev/null
+++ b/lib/spack/external/py/_code/source.py
@@ -0,0 +1,411 @@
+from __future__ import generators
+
+from bisect import bisect_right
+import sys
+import inspect, tokenize
+import py
+from types import ModuleType
+cpy_compile = compile
+
+try:
+    import _ast
+    from _ast import PyCF_ONLY_AST as _AST_FLAG
+except ImportError:
+    _AST_FLAG = 0
+    _ast = None
+
+
+class Source(object):
+    """ a immutable object holding a source code fragment,
+        possibly deindenting it.
+    """
+    _compilecounter = 0
+    def __init__(self, *parts, **kwargs):
+        self.lines = lines = []
+        de = kwargs.get('deindent', True)
+        rstrip = kwargs.get('rstrip', True)
+        for part in parts:
+            if not part:
+                partlines = []
+            if isinstance(part, Source):
+                partlines = part.lines
+            elif isinstance(part, (tuple, list)):
+                partlines = [x.rstrip("\n") for x in part]
+            elif isinstance(part, py.builtin._basestring):
+                partlines = part.split('\n')
+                if rstrip:
+                    while partlines:
+                        if partlines[-1].strip():
+                            break
+                        partlines.pop()
+            else:
+                partlines = getsource(part, deindent=de).lines
+            if de:
+                partlines = deindent(partlines)
+            lines.extend(partlines)
+
+    def __eq__(self, other):
+        try:
+            return self.lines == other.lines
+        except AttributeError:
+            if isinstance(other, str):
+                return str(self) == other
+            return False
+
+    def __getitem__(self, key):
+        if isinstance(key, int):
+            return self.lines[key]
+        else:
+            if key.step not in (None, 1):
+                raise IndexError("cannot slice a Source with a step")
+            return self.__getslice__(key.start, key.stop)
+
+    def __len__(self):
+        return len(self.lines)
+
+    def __getslice__(self, start, end):
+        newsource = Source()
+        newsource.lines = self.lines[start:end]
+        return newsource
+
+    def strip(self):
+        """ return new source object with trailing
+            and leading blank lines removed.
+        """
+        start, end = 0, len(self)
+        while start < end and not self.lines[start].strip():
+            start += 1
+        while end > start and not self.lines[end-1].strip():
+            end -= 1
+        source = Source()
+        source.lines[:] = self.lines[start:end]
+        return source
+
+    def putaround(self, before='', after='', indent=' ' * 4):
+        """ return a copy of the source object with
+            'before' and 'after' wrapped around it.
+        """
+        before = Source(before)
+        after = Source(after)
+        newsource = Source()
+        lines = [ (indent + line) for line in self.lines]
+        newsource.lines = before.lines + lines +  after.lines
+        return newsource
+
+    def indent(self, indent=' ' * 4):
+        """ return a copy of the source object with
+            all lines indented by the given indent-string.
+        """
+        newsource = Source()
+        newsource.lines = [(indent+line) for line in self.lines]
+        return newsource
+
+    def getstatement(self, lineno, assertion=False):
+        """ return Source statement which contains the
+            given linenumber (counted from 0).
+        """
+        start, end = self.getstatementrange(lineno, assertion)
+        return self[start:end]
+
+    def getstatementrange(self, lineno, assertion=False):
+        """ return (start, end) tuple which spans the minimal
+            statement region which containing the given lineno.
+        """
+        if not (0 <= lineno < len(self)):
+            raise IndexError("lineno out of range")
+        ast, start, end = getstatementrange_ast(lineno, self)
+        return start, end
+
+    def deindent(self, offset=None):
+        """ return a new source object deindented by offset.
+            If offset is None then guess an indentation offset from
+            the first non-blank line.  Subsequent lines which have a
+            lower indentation offset will be copied verbatim as
+            they are assumed to be part of multilines.
+        """
+        # XXX maybe use the tokenizer to properly handle multiline
+        #     strings etc.pp?
+        newsource = Source()
+        newsource.lines[:] = deindent(self.lines, offset)
+        return newsource
+
+    def isparseable(self, deindent=True):
+        """ return True if source is parseable, heuristically
+            deindenting it by default.
+        """
+        try:
+            import parser
+        except ImportError:
+            syntax_checker = lambda x: compile(x, 'asd', 'exec')
+        else:
+            syntax_checker = parser.suite
+
+        if deindent:
+            source = str(self.deindent())
+        else:
+            source = str(self)
+        try:
+            #compile(source+'\n', "x", "exec")
+            syntax_checker(source+'\n')
+        except KeyboardInterrupt:
+            raise
+        except Exception:
+            return False
+        else:
+            return True
+
+    def __str__(self):
+        return "\n".join(self.lines)
+
+    def compile(self, filename=None, mode='exec',
+                flag=generators.compiler_flag,
+                dont_inherit=0, _genframe=None):
+        """ return compiled code object. if filename is None
+            invent an artificial filename which displays
+            the source/line position of the caller frame.
+        """
+        if not filename or py.path.local(filename).check(file=0):
+            if _genframe is None:
+                _genframe = sys._getframe(1) # the caller
+            fn,lineno = _genframe.f_code.co_filename, _genframe.f_lineno
+            base = "<%d-codegen " % self._compilecounter
+            self.__class__._compilecounter += 1
+            if not filename:
+                filename = base + '%s:%d>' % (fn, lineno)
+            else:
+                filename = base + '%r %s:%d>' % (filename, fn, lineno)
+        source = "\n".join(self.lines) + '\n'
+        try:
+            co = cpy_compile(source, filename, mode, flag)
+        except SyntaxError:
+            ex = sys.exc_info()[1]
+            # re-represent syntax errors from parsing python strings
+            msglines = self.lines[:ex.lineno]
+            if ex.offset:
+                msglines.append(" "*ex.offset + '^')
+            msglines.append("(code was compiled probably from here: %s)" % filename)
+            newex = SyntaxError('\n'.join(msglines))
+            newex.offset = ex.offset
+            newex.lineno = ex.lineno
+            newex.text = ex.text
+            raise newex
+        else:
+            if flag & _AST_FLAG:
+                return co
+            lines = [(x + "\n") for x in self.lines]
+            py.std.linecache.cache[filename] = (1, None, lines, filename)
+            return co
+
+#
+# public API shortcut functions
+#
+
+def compile_(source, filename=None, mode='exec', flags=
+            generators.compiler_flag, dont_inherit=0):
+    """ compile the given source to a raw code object,
+        and maintain an internal cache which allows later
+        retrieval of the source code for the code object
+        and any recursively created code objects.
+    """
+    if _ast is not None and isinstance(source, _ast.AST):
+        # XXX should Source support having AST?
+        return cpy_compile(source, filename, mode, flags, dont_inherit)
+    _genframe = sys._getframe(1) # the caller
+    s = Source(source)
+    co = s.compile(filename, mode, flags, _genframe=_genframe)
+    return co
+
+
+def getfslineno(obj):
+    """ Return source location (path, lineno) for the given object.
+    If the source cannot be determined return ("", -1)
+    """
+    try:
+        code = py.code.Code(obj)
+    except TypeError:
+        try:
+            fn = (py.std.inspect.getsourcefile(obj) or
+                  py.std.inspect.getfile(obj))
+        except TypeError:
+            return "", -1
+
+        fspath = fn and py.path.local(fn) or None
+        lineno = -1
+        if fspath:
+            try:
+                _, lineno = findsource(obj)
+            except IOError:
+                pass
+    else:
+        fspath = code.path
+        lineno = code.firstlineno
+    assert isinstance(lineno, int)
+    return fspath, lineno
+
+#
+# helper functions
+#
+
+def findsource(obj):
+    try:
+        sourcelines, lineno = py.std.inspect.findsource(obj)
+    except py.builtin._sysex:
+        raise
+    except:
+        return None, -1
+    source = Source()
+    source.lines = [line.rstrip() for line in sourcelines]
+    return source, lineno
+
+def getsource(obj, **kwargs):
+    obj = py.code.getrawcode(obj)
+    try:
+        strsrc = inspect.getsource(obj)
+    except IndentationError:
+        strsrc = "\"Buggy python version consider upgrading, cannot get source\""
+    assert isinstance(strsrc, str)
+    return Source(strsrc, **kwargs)
+
+def deindent(lines, offset=None):
+    if offset is None:
+        for line in lines:
+            line = line.expandtabs()
+            s = line.lstrip()
+            if s:
+                offset = len(line)-len(s)
+                break
+        else:
+            offset = 0
+    if offset == 0:
+        return list(lines)
+    newlines = []
+    def readline_generator(lines):
+        for line in lines:
+            yield line + '\n'
+        while True:
+            yield ''
+
+    it = readline_generator(lines)
+
+    try:
+        for _, _, (sline, _), (eline, _), _ in tokenize.generate_tokens(lambda: next(it)):
+            if sline > len(lines):
+                break # End of input reached
+            if sline > len(newlines):
+                line = lines[sline - 1].expandtabs()
+                if line.lstrip() and line[:offset].isspace():
+                    line = line[offset:] # Deindent
+                newlines.append(line)
+
+            for i in range(sline, eline):
+                # Don't deindent continuing lines of
+                # multiline tokens (i.e. multiline strings)
+                newlines.append(lines[i])
+    except (IndentationError, tokenize.TokenError):
+        pass
+    # Add any lines we didn't see. E.g. if an exception was raised.
+    newlines.extend(lines[len(newlines):])
+    return newlines
+
+
+def get_statement_startend2(lineno, node):
+    import ast
+    # flatten all statements and except handlers into one lineno-list
+    # AST's line numbers start indexing at 1
+    l = []
+    for x in ast.walk(node):
+        if isinstance(x, _ast.stmt) or isinstance(x, _ast.ExceptHandler):
+            l.append(x.lineno - 1)
+            for name in "finalbody", "orelse":
+                val = getattr(x, name, None)
+                if val:
+                    # treat the finally/orelse part as its own statement
+                    l.append(val[0].lineno - 1 - 1)
+    l.sort()
+    insert_index = bisect_right(l, lineno)
+    start = l[insert_index - 1]
+    if insert_index >= len(l):
+        end = None
+    else:
+        end = l[insert_index]
+    return start, end
+
+
+def getstatementrange_ast(lineno, source, assertion=False, astnode=None):
+    if astnode is None:
+        content = str(source)
+        if sys.version_info < (2,7):
+            content += "\n"
+        try:
+            astnode = compile(content, "source", "exec", 1024)  # 1024 for AST
+        except ValueError:
+            start, end = getstatementrange_old(lineno, source, assertion)
+            return None, start, end
+    start, end = get_statement_startend2(lineno, astnode)
+    # we need to correct the end:
+    # - ast-parsing strips comments
+    # - there might be empty lines
+    # - we might have lesser indented code blocks at the end
+    if end is None:
+        end = len(source.lines)
+
+    if end > start + 1:
+        # make sure we don't span differently indented code blocks
+        # by using the BlockFinder helper used which inspect.getsource() uses itself
+        block_finder = inspect.BlockFinder()
+        # if we start with an indented line, put blockfinder to "started" mode
+        block_finder.started = source.lines[start][0].isspace()
+        it = ((x + "\n") for x in source.lines[start:end])
+        try:
+            for tok in tokenize.generate_tokens(lambda: next(it)):
+                block_finder.tokeneater(*tok)
+        except (inspect.EndOfBlock, IndentationError):
+            end = block_finder.last + start
+        except Exception:
+            pass
+
+    # the end might still point to a comment or empty line, correct it
+    while end:
+        line = source.lines[end - 1].lstrip()
+        if line.startswith("#") or not line:
+            end -= 1
+        else:
+            break
+    return astnode, start, end
+
+
+def getstatementrange_old(lineno, source, assertion=False):
+    """ return (start, end) tuple which spans the minimal
+        statement region which containing the given lineno.
+        raise an IndexError if no such statementrange can be found.
+    """
+    # XXX this logic is only used on python2.4 and below
+    # 1. find the start of the statement
+    from codeop import compile_command
+    for start in range(lineno, -1, -1):
+        if assertion:
+            line = source.lines[start]
+            # the following lines are not fully tested, change with care
+            if 'super' in line and 'self' in line and '__init__' in line:
+                raise IndexError("likely a subclass")
+            if "assert" not in line and "raise" not in line:
+                continue
+        trylines = source.lines[start:lineno+1]
+        # quick hack to prepare parsing an indented line with
+        # compile_command() (which errors on "return" outside defs)
+        trylines.insert(0, 'def xxx():')
+        trysource = '\n '.join(trylines)
+        #              ^ space here
+        try:
+            compile_command(trysource)
+        except (SyntaxError, OverflowError, ValueError):
+            continue
+
+        # 2. find the end of the statement
+        for end in range(lineno+1, len(source)+1):
+            trysource = source[start:end]
+            if trysource.isparseable():
+                return start, end
+    raise SyntaxError("no valid source range around line %d " % (lineno,))
+
+
diff --git a/lib/spack/external/py/_error.py b/lib/spack/external/py/_error.py
new file mode 100644
index 0000000000..8ca339beba
--- /dev/null
+++ b/lib/spack/external/py/_error.py
@@ -0,0 +1,89 @@
+"""
+create errno-specific classes for IO or os calls.
+
+"""
+import sys, os, errno
+
+class Error(EnvironmentError):
+    def __repr__(self):
+        return "%s.%s %r: %s " %(self.__class__.__module__,
+                               self.__class__.__name__,
+                               self.__class__.__doc__,
+                               " ".join(map(str, self.args)),
+                               #repr(self.args)
+                                )
+
+    def __str__(self):
+        s = "[%s]: %s" %(self.__class__.__doc__,
+                          " ".join(map(str, self.args)),
+                          )
+        return s
+
+_winerrnomap = {
+    2: errno.ENOENT,
+    3: errno.ENOENT,
+    17: errno.EEXIST,
+    18: errno.EXDEV,
+    13: errno.EBUSY, # empty cd drive, but ENOMEDIUM seems unavailiable
+    22: errno.ENOTDIR,
+    20: errno.ENOTDIR,
+    267: errno.ENOTDIR,
+    5: errno.EACCES,  # anything better?
+}
+
+class ErrorMaker(object):
+    """ lazily provides Exception classes for each possible POSIX errno
+        (as defined per the 'errno' module).  All such instances
+        subclass EnvironmentError.
+    """
+    Error = Error
+    _errno2class = {}
+
+    def __getattr__(self, name):
+        if name[0] == "_":
+            raise AttributeError(name)
+        eno = getattr(errno, name)
+        cls = self._geterrnoclass(eno)
+        setattr(self, name, cls)
+        return cls
+
+    def _geterrnoclass(self, eno):
+        try:
+            return self._errno2class[eno]
+        except KeyError:
+            clsname = errno.errorcode.get(eno, "UnknownErrno%d" %(eno,))
+            errorcls = type(Error)(clsname, (Error,),
+                    {'__module__':'py.error',
+                     '__doc__': os.strerror(eno)})
+            self._errno2class[eno] = errorcls
+            return errorcls
+
+    def checked_call(self, func, *args, **kwargs):
+        """ call a function and raise an errno-exception if applicable. """
+        __tracebackhide__ = True
+        try:
+            return func(*args, **kwargs)
+        except self.Error:
+            raise
+        except (OSError, EnvironmentError):
+            cls, value, tb = sys.exc_info()
+            if not hasattr(value, 'errno'):
+                raise
+            __tracebackhide__ = False
+            errno = value.errno
+            try:
+                if not isinstance(value, WindowsError):
+                    raise NameError
+            except NameError:
+                # we are not on Windows, or we got a proper OSError
+                cls = self._geterrnoclass(errno)
+            else:
+                try:
+                    cls = self._geterrnoclass(_winerrnomap[errno])
+                except KeyError:
+                    raise value
+            raise cls("%s%r" % (func.__name__, args))
+            __tracebackhide__ = True
+            
+
+error = ErrorMaker()
diff --git a/lib/spack/external/py/_iniconfig.py b/lib/spack/external/py/_iniconfig.py
new file mode 100644
index 0000000000..92b50bd853
--- /dev/null
+++ b/lib/spack/external/py/_iniconfig.py
@@ -0,0 +1,162 @@
+""" brain-dead simple parser for ini-style files.
+(C) Ronny Pfannschmidt, Holger Krekel -- MIT licensed
+"""
+__version__ = "0.2.dev2"
+
+__all__ = ['IniConfig', 'ParseError']
+
+COMMENTCHARS = "#;"
+
+class ParseError(Exception):
+    def __init__(self, path, lineno, msg):
+        Exception.__init__(self, path, lineno, msg)
+        self.path = path
+        self.lineno = lineno
+        self.msg = msg
+
+    def __str__(self):
+        return "%s:%s: %s" %(self.path, self.lineno+1, self.msg)
+
+class SectionWrapper(object):
+    def __init__(self, config, name):
+        self.config = config
+        self.name = name
+
+    def lineof(self, name):
+        return self.config.lineof(self.name, name)
+
+    def get(self, key, default=None, convert=str):
+        return self.config.get(self.name, key, convert=convert, default=default)
+
+    def __getitem__(self, key):
+        return self.config.sections[self.name][key]
+
+    def __iter__(self):
+        section = self.config.sections.get(self.name, [])
+        def lineof(key):
+            return self.config.lineof(self.name, key)
+        for name in sorted(section, key=lineof):
+            yield name
+
+    def items(self):
+        for name in self:
+            yield name, self[name]
+
+
+class IniConfig(object):
+    def __init__(self, path, data=None):
+        self.path = str(path) # convenience
+        if data is None:
+            f = open(self.path)
+            try:
+                tokens = self._parse(iter(f))
+            finally:
+                f.close()
+        else:
+            tokens = self._parse(data.splitlines(True))
+
+        self._sources = {}
+        self.sections = {}
+
+        for lineno, section, name, value in tokens:
+            if section is None:
+                self._raise(lineno, 'no section header defined')
+            self._sources[section, name] = lineno
+            if name is None:
+                if section in self.sections:
+                    self._raise(lineno, 'duplicate section %r'%(section, ))
+                self.sections[section] = {}
+            else:
+                if name in self.sections[section]:
+                    self._raise(lineno, 'duplicate name %r'%(name, ))
+                self.sections[section][name] = value
+
+    def _raise(self, lineno, msg):
+        raise ParseError(self.path, lineno, msg)
+
+    def _parse(self, line_iter):
+        result = []
+        section = None
+        for lineno, line in enumerate(line_iter):
+            name, data = self._parseline(line, lineno)
+            # new value
+            if name is not None and data is not None:
+                result.append((lineno, section, name, data))
+            # new section
+            elif name is not None and data is None:
+                if not name:
+                    self._raise(lineno, 'empty section name')
+                section = name
+                result.append((lineno, section, None, None))
+            # continuation
+            elif name is None and data is not None:
+                if not result:
+                    self._raise(lineno, 'unexpected value continuation')
+                last = result.pop()
+                last_name, last_data = last[-2:]
+                if last_name is None:
+                    self._raise(lineno, 'unexpected value continuation')
+
+                if last_data:
+                    data = '%s\n%s' % (last_data, data)
+                result.append(last[:-1] + (data,))
+        return result
+
+    def _parseline(self, line, lineno):
+        # blank lines
+        if iscommentline(line):
+            line = ""
+        else:
+            line = line.rstrip()
+        if not line:
+            return None, None
+        # section
+        if line[0] == '[':
+            realline = line
+            for c in COMMENTCHARS:
+                line = line.split(c)[0].rstrip()
+            if line[-1] == "]":
+                return line[1:-1], None
+            return None, realline.strip()
+        # value
+        elif not line[0].isspace():
+            try:
+                name, value = line.split('=', 1)
+                if ":" in name:
+                    raise ValueError()
+            except ValueError:
+                try:
+                    name, value = line.split(":", 1)
+                except ValueError:
+                    self._raise(lineno, 'unexpected line: %r' % line)
+            return name.strip(), value.strip()
+        # continuation
+        else:
+            return None, line.strip()
+
+    def lineof(self, section, name=None):
+        lineno = self._sources.get((section, name))
+        if lineno is not None:
+            return lineno + 1
+
+    def get(self, section, name, default=None, convert=str):
+        try:
+            return convert(self.sections[section][name])
+        except KeyError:
+            return default
+
+    def __getitem__(self, name):
+        if name not in self.sections:
+            raise KeyError(name)
+        return SectionWrapper(self, name)
+
+    def __iter__(self):
+        for name in sorted(self.sections, key=self.lineof):
+            yield SectionWrapper(self, name)
+
+    def __contains__(self, arg):
+        return arg in self.sections
+
+def iscommentline(line):
+    c = line.lstrip()[:1]
+    return c in COMMENTCHARS
diff --git a/lib/spack/external/py/_io/__init__.py b/lib/spack/external/py/_io/__init__.py
new file mode 100644
index 0000000000..835f01f3ab
--- /dev/null
+++ b/lib/spack/external/py/_io/__init__.py
@@ -0,0 +1 @@
+""" input/output helping """
diff --git a/lib/spack/external/py/_io/capture.py b/lib/spack/external/py/_io/capture.py
new file mode 100644
index 0000000000..bc157ed978
--- /dev/null
+++ b/lib/spack/external/py/_io/capture.py
@@ -0,0 +1,371 @@
+import os
+import sys
+import py
+import tempfile
+
+try:
+    from io import StringIO
+except ImportError:
+    from StringIO import StringIO
+
+if sys.version_info < (3,0):
+    class TextIO(StringIO):
+        def write(self, data):
+            if not isinstance(data, unicode):
+                data = unicode(data, getattr(self, '_encoding', 'UTF-8'), 'replace')
+            StringIO.write(self, data)
+else:
+    TextIO = StringIO
+
+try:
+    from io import BytesIO
+except ImportError:
+    class BytesIO(StringIO):
+        def write(self, data):
+            if isinstance(data, unicode):
+                raise TypeError("not a byte value: %r" %(data,))
+            StringIO.write(self, data)
+
+patchsysdict = {0: 'stdin', 1: 'stdout', 2: 'stderr'}
+
+class FDCapture:
+    """ Capture IO to/from a given os-level filedescriptor. """
+
+    def __init__(self, targetfd, tmpfile=None, now=True, patchsys=False):
+        """ save targetfd descriptor, and open a new
+            temporary file there.  If no tmpfile is
+            specified a tempfile.Tempfile() will be opened
+            in text mode.
+        """
+        self.targetfd = targetfd
+        if tmpfile is None and targetfd != 0:
+            f = tempfile.TemporaryFile('wb+')
+            tmpfile = dupfile(f, encoding="UTF-8")
+            f.close()
+        self.tmpfile = tmpfile
+        self._savefd = os.dup(self.targetfd)
+        if patchsys:
+            self._oldsys = getattr(sys, patchsysdict[targetfd])
+        if now:
+            self.start()
+
+    def start(self):
+        try:
+            os.fstat(self._savefd)
+        except OSError:
+            raise ValueError("saved filedescriptor not valid, "
+                "did you call start() twice?")
+        if self.targetfd == 0 and not self.tmpfile:
+            fd = os.open(devnullpath, os.O_RDONLY)
+            os.dup2(fd, 0)
+            os.close(fd)
+            if hasattr(self, '_oldsys'):
+                setattr(sys, patchsysdict[self.targetfd], DontReadFromInput())
+        else:
+            os.dup2(self.tmpfile.fileno(), self.targetfd)
+            if hasattr(self, '_oldsys'):
+                setattr(sys, patchsysdict[self.targetfd], self.tmpfile)
+
+    def done(self):
+        """ unpatch and clean up, returns the self.tmpfile (file object)
+        """
+        os.dup2(self._savefd, self.targetfd)
+        os.close(self._savefd)
+        if self.targetfd != 0:
+            self.tmpfile.seek(0)
+        if hasattr(self, '_oldsys'):
+            setattr(sys, patchsysdict[self.targetfd], self._oldsys)
+        return self.tmpfile
+
+    def writeorg(self, data):
+        """ write a string to the original file descriptor
+        """
+        tempfp = tempfile.TemporaryFile()
+        try:
+            os.dup2(self._savefd, tempfp.fileno())
+            tempfp.write(data)
+        finally:
+            tempfp.close()
+
+
+def dupfile(f, mode=None, buffering=0, raising=False, encoding=None):
+    """ return a new open file object that's a duplicate of f
+
+        mode is duplicated if not given, 'buffering' controls
+        buffer size (defaulting to no buffering) and 'raising'
+        defines whether an exception is raised when an incompatible
+        file object is passed in (if raising is False, the file
+        object itself will be returned)
+    """
+    try:
+        fd = f.fileno()
+        mode = mode or f.mode
+    except AttributeError:
+        if raising:
+            raise
+        return f
+    newfd = os.dup(fd)
+    if sys.version_info >= (3,0):
+        if encoding is not None:
+            mode = mode.replace("b", "")
+            buffering = True
+        return os.fdopen(newfd, mode, buffering, encoding, closefd=True)
+    else:
+        f = os.fdopen(newfd, mode, buffering)
+        if encoding is not None:
+            return EncodedFile(f, encoding)
+        return f
+
+class EncodedFile(object):
+    def __init__(self, _stream, encoding):
+        self._stream = _stream
+        self.encoding = encoding
+
+    def write(self, obj):
+        if isinstance(obj, unicode):
+            obj = obj.encode(self.encoding)
+        elif isinstance(obj, str):
+            pass
+        else:
+            obj = str(obj)
+        self._stream.write(obj)
+
+    def writelines(self, linelist):
+        data = ''.join(linelist)
+        self.write(data)
+
+    def __getattr__(self, name):
+        return getattr(self._stream, name)
+
+class Capture(object):
+    def call(cls, func, *args, **kwargs):
+        """ return a (res, out, err) tuple where
+            out and err represent the output/error output
+            during function execution.
+            call the given function with args/kwargs
+            and capture output/error during its execution.
+        """
+        so = cls()
+        try:
+            res = func(*args, **kwargs)
+        finally:
+            out, err = so.reset()
+        return res, out, err
+    call = classmethod(call)
+
+    def reset(self):
+        """ reset sys.stdout/stderr and return captured output as strings. """
+        if hasattr(self, '_reset'):
+            raise ValueError("was already reset")
+        self._reset = True
+        outfile, errfile = self.done(save=False)
+        out, err = "", ""
+        if outfile and not outfile.closed:
+            out = outfile.read()
+            outfile.close()
+        if errfile and errfile != outfile and not errfile.closed:
+            err = errfile.read()
+            errfile.close()
+        return out, err
+
+    def suspend(self):
+        """ return current snapshot captures, memorize tempfiles. """
+        outerr = self.readouterr()
+        outfile, errfile = self.done()
+        return outerr
+
+
+class StdCaptureFD(Capture):
+    """ This class allows to capture writes to FD1 and FD2
+        and may connect a NULL file to FD0 (and prevent
+        reads from sys.stdin).  If any of the 0,1,2 file descriptors
+        is invalid it will not be captured.
+    """
+    def __init__(self, out=True, err=True, mixed=False,
+        in_=True, patchsys=True, now=True):
+        self._options = {
+            "out": out,
+            "err": err,
+            "mixed": mixed,
+            "in_": in_,
+            "patchsys": patchsys,
+            "now": now,
+        }
+        self._save()
+        if now:
+            self.startall()
+
+    def _save(self):
+        in_ = self._options['in_']
+        out = self._options['out']
+        err = self._options['err']
+        mixed = self._options['mixed']
+        patchsys = self._options['patchsys']
+        if in_:
+            try:
+                self.in_ = FDCapture(0, tmpfile=None, now=False,
+                    patchsys=patchsys)
+            except OSError:
+                pass
+        if out:
+            tmpfile = None
+            if hasattr(out, 'write'):
+                tmpfile = out
+            try:
+                self.out = FDCapture(1, tmpfile=tmpfile,
+                           now=False, patchsys=patchsys)
+                self._options['out'] = self.out.tmpfile
+            except OSError:
+                pass
+        if err:
+            if out and mixed:
+                tmpfile = self.out.tmpfile
+            elif hasattr(err, 'write'):
+                tmpfile = err
+            else:
+                tmpfile = None
+            try:
+                self.err = FDCapture(2, tmpfile=tmpfile,
+                           now=False, patchsys=patchsys)
+                self._options['err'] = self.err.tmpfile
+            except OSError:
+                pass
+
+    def startall(self):
+        if hasattr(self, 'in_'):
+            self.in_.start()
+        if hasattr(self, 'out'):
+            self.out.start()
+        if hasattr(self, 'err'):
+            self.err.start()
+
+    def resume(self):
+        """ resume capturing with original temp files. """
+        self.startall()
+
+    def done(self, save=True):
+        """ return (outfile, errfile) and stop capturing. """
+        outfile = errfile = None
+        if hasattr(self, 'out') and not self.out.tmpfile.closed:
+            outfile = self.out.done()
+        if hasattr(self, 'err') and not self.err.tmpfile.closed:
+            errfile = self.err.done()
+        if hasattr(self, 'in_'):
+            tmpfile = self.in_.done()
+        if save:
+            self._save()
+        return outfile, errfile
+
+    def readouterr(self):
+        """ return snapshot value of stdout/stderr capturings. """
+        if hasattr(self, "out"):
+            out = self._readsnapshot(self.out.tmpfile)
+        else:
+            out = ""
+        if hasattr(self, "err"):
+            err = self._readsnapshot(self.err.tmpfile)
+        else:
+            err = ""
+        return [out, err]
+
+    def _readsnapshot(self, f):
+        f.seek(0)
+        res = f.read()
+        enc = getattr(f, "encoding", None)
+        if enc:
+            res = py.builtin._totext(res, enc, "replace")
+        f.truncate(0)
+        f.seek(0)
+        return res
+
+
+class StdCapture(Capture):
+    """ This class allows to capture writes to sys.stdout|stderr "in-memory"
+        and will raise errors on tries to read from sys.stdin. It only
+        modifies sys.stdout|stderr|stdin attributes and does not
+        touch underlying File Descriptors (use StdCaptureFD for that).
+    """
+    def __init__(self, out=True, err=True, in_=True, mixed=False, now=True):
+        self._oldout = sys.stdout
+        self._olderr = sys.stderr
+        self._oldin  = sys.stdin
+        if out and not hasattr(out, 'file'):
+            out = TextIO()
+        self.out = out
+        if err:
+            if mixed:
+                err = out
+            elif not hasattr(err, 'write'):
+                err = TextIO()
+        self.err = err
+        self.in_ = in_
+        if now:
+            self.startall()
+
+    def startall(self):
+        if self.out:
+            sys.stdout = self.out
+        if self.err:
+            sys.stderr = self.err
+        if self.in_:
+            sys.stdin  = self.in_  = DontReadFromInput()
+
+    def done(self, save=True):
+        """ return (outfile, errfile) and stop capturing. """
+        outfile = errfile = None
+        if self.out and not self.out.closed:
+            sys.stdout = self._oldout
+            outfile = self.out
+            outfile.seek(0)
+        if self.err and not self.err.closed:
+            sys.stderr = self._olderr
+            errfile = self.err
+            errfile.seek(0)
+        if self.in_:
+            sys.stdin = self._oldin
+        return outfile, errfile
+
+    def resume(self):
+        """ resume capturing with original temp files. """
+        self.startall()
+
+    def readouterr(self):
+        """ return snapshot value of stdout/stderr capturings. """
+        out = err = ""
+        if self.out:
+            out = self.out.getvalue()
+            self.out.truncate(0)
+            self.out.seek(0)
+        if self.err:
+            err = self.err.getvalue()
+            self.err.truncate(0)
+            self.err.seek(0)
+        return out, err
+
+class DontReadFromInput:
+    """Temporary stub class.  Ideally when stdin is accessed, the
+    capturing should be turned off, with possibly all data captured
+    so far sent to the screen.  This should be configurable, though,
+    because in automated test runs it is better to crash than
+    hang indefinitely.
+    """
+    def read(self, *args):
+        raise IOError("reading from stdin while output is captured")
+    readline = read
+    readlines = read
+    __iter__ = read
+
+    def fileno(self):
+        raise ValueError("redirected Stdin is pseudofile, has no fileno()")
+    def isatty(self):
+        return False
+    def close(self):
+        pass
+
+try:
+    devnullpath = os.devnull
+except AttributeError:
+    if os.name == 'nt':
+        devnullpath = 'NUL'
+    else:
+        devnullpath = '/dev/null'
diff --git a/lib/spack/external/py/_io/saferepr.py b/lib/spack/external/py/_io/saferepr.py
new file mode 100644
index 0000000000..8518290efd
--- /dev/null
+++ b/lib/spack/external/py/_io/saferepr.py
@@ -0,0 +1,71 @@
+import py
+import sys
+
+builtin_repr = repr
+
+reprlib = py.builtin._tryimport('repr', 'reprlib')
+
+class SafeRepr(reprlib.Repr):
+    """ subclass of repr.Repr that limits the resulting size of repr()
+        and includes information on exceptions raised during the call.
+    """
+    def repr(self, x):
+        return self._callhelper(reprlib.Repr.repr, self, x)
+
+    def repr_unicode(self, x, level):
+        # Strictly speaking wrong on narrow builds
+        def repr(u):
+            if "'" not in u:
+                return py.builtin._totext("'%s'") % u
+            elif '"' not in u:
+                return py.builtin._totext('"%s"') % u
+            else:
+                return py.builtin._totext("'%s'") % u.replace("'", r"\'")
+        s = repr(x[:self.maxstring])
+        if len(s) > self.maxstring:
+            i = max(0, (self.maxstring-3)//2)
+            j = max(0, self.maxstring-3-i)
+            s = repr(x[:i] + x[len(x)-j:])
+            s = s[:i] + '...' + s[len(s)-j:]
+        return s
+
+    def repr_instance(self, x, level):
+        return self._callhelper(builtin_repr, x)
+
+    def _callhelper(self, call, x, *args):
+        try:
+            # Try the vanilla repr and make sure that the result is a string
+            s = call(x, *args)
+        except py.builtin._sysex:
+            raise
+        except:
+            cls, e, tb = sys.exc_info()
+            exc_name = getattr(cls, '__name__', 'unknown')
+            try:
+                exc_info = str(e)
+            except py.builtin._sysex:
+                raise
+            except:
+                exc_info = 'unknown'
+            return '<[%s("%s") raised in repr()] %s object at 0x%x>' % (
+                exc_name, exc_info, x.__class__.__name__, id(x))
+        else:
+            if len(s) > self.maxsize:
+                i = max(0, (self.maxsize-3)//2)
+                j = max(0, self.maxsize-3-i)
+                s = s[:i] + '...' + s[len(s)-j:]
+            return s
+
+def saferepr(obj, maxsize=240):
+    """ return a size-limited safe repr-string for the given object.
+    Failing __repr__ functions of user instances will be represented
+    with a short exception info and 'saferepr' generally takes
+    care to never raise exceptions itself.  This function is a wrapper
+    around the Repr/reprlib functionality of the standard 2.6 lib.
+    """
+    # review exception handling
+    srepr = SafeRepr()
+    srepr.maxstring = maxsize
+    srepr.maxsize = maxsize
+    srepr.maxother = 160
+    return srepr.repr(obj)
diff --git a/lib/spack/external/py/_io/terminalwriter.py b/lib/spack/external/py/_io/terminalwriter.py
new file mode 100644
index 0000000000..390e8ca7b9
--- /dev/null
+++ b/lib/spack/external/py/_io/terminalwriter.py
@@ -0,0 +1,357 @@
+"""
+
+Helper functions for writing to terminals and files.
+
+"""
+
+
+import sys, os
+import py
+py3k = sys.version_info[0] >= 3
+from py.builtin import text, bytes
+
+win32_and_ctypes = False
+colorama = None
+if sys.platform == "win32":
+    try:
+        import colorama
+    except ImportError:
+        try:
+            import ctypes
+            win32_and_ctypes = True
+        except ImportError:
+            pass
+
+
+def _getdimensions():
+    import termios,fcntl,struct
+    call = fcntl.ioctl(1,termios.TIOCGWINSZ,"\000"*8)
+    height,width = struct.unpack( "hhhh", call ) [:2]
+    return height, width
+
+
+def get_terminal_width():
+    height = width = 0
+    try:
+        height, width = _getdimensions()
+    except py.builtin._sysex:
+        raise
+    except:
+        # pass to fallback below
+        pass
+
+    if width == 0:
+        # FALLBACK:
+        # * some exception happened
+        # * or this is emacs terminal which reports (0,0)
+        width = int(os.environ.get('COLUMNS', 80))
+
+    # XXX the windows getdimensions may be bogus, let's sanify a bit
+    if width < 40:
+        width = 80
+    return width
+
+terminal_width = get_terminal_width()
+
+# XXX unify with _escaped func below
+def ansi_print(text, esc, file=None, newline=True, flush=False):
+    if file is None:
+        file = sys.stderr
+    text = text.rstrip()
+    if esc and not isinstance(esc, tuple):
+        esc = (esc,)
+    if esc and sys.platform != "win32" and file.isatty():
+        text = (''.join(['\x1b[%sm' % cod for cod in esc])  +
+                text +
+                '\x1b[0m')     # ANSI color code "reset"
+    if newline:
+        text += '\n'
+
+    if esc and win32_and_ctypes and file.isatty():
+        if 1 in esc:
+            bold = True
+            esc = tuple([x for x in esc if x != 1])
+        else:
+            bold = False
+        esctable = {()   : FOREGROUND_WHITE,                 # normal
+                    (31,): FOREGROUND_RED,                   # red
+                    (32,): FOREGROUND_GREEN,                 # green
+                    (33,): FOREGROUND_GREEN|FOREGROUND_RED,  # yellow
+                    (34,): FOREGROUND_BLUE,                  # blue
+                    (35,): FOREGROUND_BLUE|FOREGROUND_RED,   # purple
+                    (36,): FOREGROUND_BLUE|FOREGROUND_GREEN, # cyan
+                    (37,): FOREGROUND_WHITE,                 # white
+                    (39,): FOREGROUND_WHITE,                 # reset
+                    }
+        attr = esctable.get(esc, FOREGROUND_WHITE)
+        if bold:
+            attr |= FOREGROUND_INTENSITY
+        STD_OUTPUT_HANDLE = -11
+        STD_ERROR_HANDLE = -12
+        if file is sys.stderr:
+            handle = GetStdHandle(STD_ERROR_HANDLE)
+        else:
+            handle = GetStdHandle(STD_OUTPUT_HANDLE)
+        oldcolors = GetConsoleInfo(handle).wAttributes
+        attr |= (oldcolors & 0x0f0)
+        SetConsoleTextAttribute(handle, attr)
+        while len(text) > 32768:
+            file.write(text[:32768])
+            text = text[32768:]
+        if text:
+            file.write(text)
+        SetConsoleTextAttribute(handle, oldcolors)
+    else:
+        file.write(text)
+
+    if flush:
+        file.flush()
+
+def should_do_markup(file):
+    if os.environ.get('PY_COLORS') == '1':
+        return True
+    if os.environ.get('PY_COLORS') == '0':
+        return False
+    return hasattr(file, 'isatty') and file.isatty() \
+           and os.environ.get('TERM') != 'dumb' \
+           and not (sys.platform.startswith('java') and os._name == 'nt')
+
+class TerminalWriter(object):
+    _esctable = dict(black=30, red=31, green=32, yellow=33,
+                     blue=34, purple=35, cyan=36, white=37,
+                     Black=40, Red=41, Green=42, Yellow=43,
+                     Blue=44, Purple=45, Cyan=46, White=47,
+                     bold=1, light=2, blink=5, invert=7)
+
+    # XXX deprecate stringio argument
+    def __init__(self, file=None, stringio=False, encoding=None):
+        if file is None:
+            if stringio:
+                self.stringio = file = py.io.TextIO()
+            else:
+                file = py.std.sys.stdout
+        elif py.builtin.callable(file) and not (
+             hasattr(file, "write") and hasattr(file, "flush")):
+            file = WriteFile(file, encoding=encoding)
+        if hasattr(file, "isatty") and file.isatty() and colorama:
+            file = colorama.AnsiToWin32(file).stream
+        self.encoding = encoding or getattr(file, 'encoding', "utf-8")
+        self._file = file
+        self.hasmarkup = should_do_markup(file)
+        self._lastlen = 0
+
+    @property
+    def fullwidth(self):
+        if hasattr(self, '_terminal_width'):
+            return self._terminal_width
+        return get_terminal_width()
+
+    @fullwidth.setter
+    def fullwidth(self, value):
+        self._terminal_width = value
+
+    def _escaped(self, text, esc):
+        if esc and self.hasmarkup:
+            text = (''.join(['\x1b[%sm' % cod for cod in esc])  +
+                text +'\x1b[0m')
+        return text
+
+    def markup(self, text, **kw):
+        esc = []
+        for name in kw:
+            if name not in self._esctable:
+                raise ValueError("unknown markup: %r" %(name,))
+            if kw[name]:
+                esc.append(self._esctable[name])
+        return self._escaped(text, tuple(esc))
+
+    def sep(self, sepchar, title=None, fullwidth=None, **kw):
+        if fullwidth is None:
+            fullwidth = self.fullwidth
+        # the goal is to have the line be as long as possible
+        # under the condition that len(line) <= fullwidth
+        if sys.platform == "win32":
+            # if we print in the last column on windows we are on a
+            # new line but there is no way to verify/neutralize this
+            # (we may not know the exact line width)
+            # so let's be defensive to avoid empty lines in the output
+            fullwidth -= 1
+        if title is not None:
+            # we want 2 + 2*len(fill) + len(title) <= fullwidth
+            # i.e.    2 + 2*len(sepchar)*N + len(title) <= fullwidth
+            #         2*len(sepchar)*N <= fullwidth - len(title) - 2
+            #         N <= (fullwidth - len(title) - 2) // (2*len(sepchar))
+            N = (fullwidth - len(title) - 2) // (2*len(sepchar))
+            fill = sepchar * N
+            line = "%s %s %s" % (fill, title, fill)
+        else:
+            # we want len(sepchar)*N <= fullwidth
+            # i.e.    N <= fullwidth // len(sepchar)
+            line = sepchar * (fullwidth // len(sepchar))
+        # in some situations there is room for an extra sepchar at the right,
+        # in particular if we consider that with a sepchar like "_ " the
+        # trailing space is not important at the end of the line
+        if len(line) + len(sepchar.rstrip()) <= fullwidth:
+            line += sepchar.rstrip()
+
+        self.line(line, **kw)
+
+    def write(self, msg, **kw):
+        if msg:
+            if not isinstance(msg, (bytes, text)):
+                msg = text(msg)
+            if self.hasmarkup and kw:
+                markupmsg = self.markup(msg, **kw)
+            else:
+                markupmsg = msg
+            write_out(self._file, markupmsg)
+
+    def line(self, s='', **kw):
+        self.write(s, **kw)
+        self._checkfill(s)
+        self.write('\n')
+
+    def reline(self, line, **kw):
+        if not self.hasmarkup:
+            raise ValueError("cannot use rewrite-line without terminal")
+        self.write(line, **kw)
+        self._checkfill(line)
+        self.write('\r')
+        self._lastlen = len(line)
+
+    def _checkfill(self, line):
+        diff2last = self._lastlen - len(line)
+        if diff2last > 0:
+            self.write(" " * diff2last)
+
+class Win32ConsoleWriter(TerminalWriter):
+    def write(self, msg, **kw):
+        if msg:
+            if not isinstance(msg, (bytes, text)):
+                msg = text(msg)
+            oldcolors = None
+            if self.hasmarkup and kw:
+                handle = GetStdHandle(STD_OUTPUT_HANDLE)
+                oldcolors = GetConsoleInfo(handle).wAttributes
+                default_bg = oldcolors & 0x00F0
+                attr = default_bg
+                if kw.pop('bold', False):
+                    attr |= FOREGROUND_INTENSITY
+
+                if kw.pop('red', False):
+                    attr |= FOREGROUND_RED
+                elif kw.pop('blue', False):
+                    attr |= FOREGROUND_BLUE
+                elif kw.pop('green', False):
+                    attr |= FOREGROUND_GREEN
+                elif kw.pop('yellow', False):
+                    attr |= FOREGROUND_GREEN|FOREGROUND_RED
+                else:
+                    attr |= oldcolors & 0x0007
+
+                SetConsoleTextAttribute(handle, attr)
+            write_out(self._file, msg)
+            if oldcolors:
+                SetConsoleTextAttribute(handle, oldcolors)
+
+class WriteFile(object):
+    def __init__(self, writemethod, encoding=None):
+        self.encoding = encoding
+        self._writemethod = writemethod
+
+    def write(self, data):
+        if self.encoding:
+            data = data.encode(self.encoding, "replace")
+        self._writemethod(data)
+
+    def flush(self):
+        return
+
+
+if win32_and_ctypes:
+    TerminalWriter = Win32ConsoleWriter
+    import ctypes
+    from ctypes import wintypes
+
+    # ctypes access to the Windows console
+    STD_OUTPUT_HANDLE = -11
+    STD_ERROR_HANDLE  = -12
+    FOREGROUND_BLACK     = 0x0000 # black text
+    FOREGROUND_BLUE      = 0x0001 # text color contains blue.
+    FOREGROUND_GREEN     = 0x0002 # text color contains green.
+    FOREGROUND_RED       = 0x0004 # text color contains red.
+    FOREGROUND_WHITE     = 0x0007
+    FOREGROUND_INTENSITY = 0x0008 # text color is intensified.
+    BACKGROUND_BLACK     = 0x0000 # background color black
+    BACKGROUND_BLUE      = 0x0010 # background color contains blue.
+    BACKGROUND_GREEN     = 0x0020 # background color contains green.
+    BACKGROUND_RED       = 0x0040 # background color contains red.
+    BACKGROUND_WHITE     = 0x0070
+    BACKGROUND_INTENSITY = 0x0080 # background color is intensified.
+
+    SHORT = ctypes.c_short
+    class COORD(ctypes.Structure):
+        _fields_ = [('X', SHORT),
+                    ('Y', SHORT)]
+    class SMALL_RECT(ctypes.Structure):
+        _fields_ = [('Left', SHORT),
+                    ('Top', SHORT),
+                    ('Right', SHORT),
+                    ('Bottom', SHORT)]
+    class CONSOLE_SCREEN_BUFFER_INFO(ctypes.Structure):
+        _fields_ = [('dwSize', COORD),
+                    ('dwCursorPosition', COORD),
+                    ('wAttributes', wintypes.WORD),
+                    ('srWindow', SMALL_RECT),
+                    ('dwMaximumWindowSize', COORD)]
+
+    _GetStdHandle = ctypes.windll.kernel32.GetStdHandle
+    _GetStdHandle.argtypes = [wintypes.DWORD]
+    _GetStdHandle.restype = wintypes.HANDLE
+    def GetStdHandle(kind):
+        return _GetStdHandle(kind)
+
+    SetConsoleTextAttribute = ctypes.windll.kernel32.SetConsoleTextAttribute
+    SetConsoleTextAttribute.argtypes = [wintypes.HANDLE, wintypes.WORD]
+    SetConsoleTextAttribute.restype = wintypes.BOOL
+
+    _GetConsoleScreenBufferInfo = \
+        ctypes.windll.kernel32.GetConsoleScreenBufferInfo
+    _GetConsoleScreenBufferInfo.argtypes = [wintypes.HANDLE,
+                                ctypes.POINTER(CONSOLE_SCREEN_BUFFER_INFO)]
+    _GetConsoleScreenBufferInfo.restype = wintypes.BOOL
+    def GetConsoleInfo(handle):
+        info = CONSOLE_SCREEN_BUFFER_INFO()
+        _GetConsoleScreenBufferInfo(handle, ctypes.byref(info))
+        return info
+
+    def _getdimensions():
+        handle = GetStdHandle(STD_OUTPUT_HANDLE)
+        info = GetConsoleInfo(handle)
+        # Substract one from the width, otherwise the cursor wraps
+        # and the ending \n causes an empty line to display.
+        return info.dwSize.Y, info.dwSize.X - 1
+
+def write_out(fil, msg):
+    # XXX sometimes "msg" is of type bytes, sometimes text which
+    # complicates the situation.  Should we try to enforce unicode?
+    try:
+        # on py27 and above writing out to sys.stdout with an encoding
+        # should usually work for unicode messages (if the encoding is
+        # capable of it)
+        fil.write(msg)
+    except UnicodeEncodeError:
+        # on py26 it might not work because stdout expects bytes
+        if fil.encoding:
+            try:
+                fil.write(msg.encode(fil.encoding))
+            except UnicodeEncodeError:
+                # it might still fail if the encoding is not capable
+                pass
+            else:
+                fil.flush()
+                return
+        # fallback: escape all unicode characters
+        msg = msg.encode("unicode-escape").decode("ascii")
+        fil.write(msg)
+    fil.flush()
diff --git a/lib/spack/external/py/_log/__init__.py b/lib/spack/external/py/_log/__init__.py
new file mode 100644
index 0000000000..fad62e960d
--- /dev/null
+++ b/lib/spack/external/py/_log/__init__.py
@@ -0,0 +1,2 @@
+""" logging API ('producers' and 'consumers' connected via keywords) """
+
diff --git a/lib/spack/external/py/_log/log.py b/lib/spack/external/py/_log/log.py
new file mode 100644
index 0000000000..ce47e8c754
--- /dev/null
+++ b/lib/spack/external/py/_log/log.py
@@ -0,0 +1,186 @@
+"""
+basic logging functionality based on a producer/consumer scheme.
+
+XXX implement this API: (maybe put it into slogger.py?)
+
+        log = Logger(
+                    info=py.log.STDOUT,
+                    debug=py.log.STDOUT,
+                    command=None)
+        log.info("hello", "world")
+        log.command("hello", "world")
+
+        log = Logger(info=Logger(something=...),
+                     debug=py.log.STDOUT,
+                     command=None)
+"""
+import py, sys
+
+class Message(object):
+    def __init__(self, keywords, args):
+        self.keywords = keywords
+        self.args = args
+
+    def content(self):
+        return " ".join(map(str, self.args))
+
+    def prefix(self):
+        return "[%s] " % (":".join(self.keywords))
+
+    def __str__(self):
+        return self.prefix() + self.content()
+
+
+class Producer(object):
+    """ (deprecated) Log producer API which sends messages to be logged
+        to a 'consumer' object, which then prints them to stdout,
+        stderr, files, etc. Used extensively by PyPy-1.1.
+    """
+
+    Message = Message  # to allow later customization
+    keywords2consumer = {}
+
+    def __init__(self, keywords, keywordmapper=None, **kw):
+        if hasattr(keywords, 'split'):
+            keywords = tuple(keywords.split())
+        self._keywords = keywords
+        if keywordmapper is None:
+            keywordmapper = default_keywordmapper
+        self._keywordmapper = keywordmapper
+
+    def __repr__(self):
+        return "<py.log.Producer %s>" % ":".join(self._keywords)
+
+    def __getattr__(self, name):
+        if '_' in name:
+            raise AttributeError(name)
+        producer = self.__class__(self._keywords + (name,))
+        setattr(self, name, producer)
+        return producer
+
+    def __call__(self, *args):
+        """ write a message to the appropriate consumer(s) """
+        func = self._keywordmapper.getconsumer(self._keywords)
+        if func is not None:
+            func(self.Message(self._keywords, args))
+
+class KeywordMapper:
+    def __init__(self):
+        self.keywords2consumer = {}
+
+    def getstate(self):
+        return self.keywords2consumer.copy()
+    def setstate(self, state):
+        self.keywords2consumer.clear()
+        self.keywords2consumer.update(state)
+
+    def getconsumer(self, keywords):
+        """ return a consumer matching the given keywords.
+
+            tries to find the most suitable consumer by walking, starting from
+            the back, the list of keywords, the first consumer matching a
+            keyword is returned (falling back to py.log.default)
+        """
+        for i in range(len(keywords), 0, -1):
+            try:
+                return self.keywords2consumer[keywords[:i]]
+            except KeyError:
+                continue
+        return self.keywords2consumer.get('default', default_consumer)
+
+    def setconsumer(self, keywords, consumer):
+        """ set a consumer for a set of keywords. """
+        # normalize to tuples
+        if isinstance(keywords, str):
+            keywords = tuple(filter(None, keywords.split()))
+        elif hasattr(keywords, '_keywords'):
+            keywords = keywords._keywords
+        elif not isinstance(keywords, tuple):
+            raise TypeError("key %r is not a string or tuple" % (keywords,))
+        if consumer is not None and not py.builtin.callable(consumer):
+            if not hasattr(consumer, 'write'):
+                raise TypeError(
+                    "%r should be None, callable or file-like" % (consumer,))
+            consumer = File(consumer)
+        self.keywords2consumer[keywords] = consumer
+
+def default_consumer(msg):
+    """ the default consumer, prints the message to stdout (using 'print') """
+    sys.stderr.write(str(msg)+"\n")
+
+default_keywordmapper = KeywordMapper()
+
+def setconsumer(keywords, consumer):
+    default_keywordmapper.setconsumer(keywords, consumer)
+
+def setstate(state):
+    default_keywordmapper.setstate(state)
+def getstate():
+    return default_keywordmapper.getstate()
+
+#
+# Consumers
+#
+
+class File(object):
+    """ log consumer wrapping a file(-like) object """
+    def __init__(self, f):
+        assert hasattr(f, 'write')
+        #assert isinstance(f, file) or not hasattr(f, 'open')
+        self._file = f
+
+    def __call__(self, msg):
+        """ write a message to the log """
+        self._file.write(str(msg) + "\n")
+        if hasattr(self._file, 'flush'):
+            self._file.flush()
+
+class Path(object):
+    """ log consumer that opens and writes to a Path """
+    def __init__(self, filename, append=False,
+                 delayed_create=False, buffering=False):
+        self._append = append
+        self._filename = str(filename)
+        self._buffering = buffering
+        if not delayed_create:
+            self._openfile()
+
+    def _openfile(self):
+        mode = self._append and 'a' or 'w'
+        f = open(self._filename, mode)
+        self._file = f
+
+    def __call__(self, msg):
+        """ write a message to the log """
+        if not hasattr(self, "_file"):
+            self._openfile()
+        self._file.write(str(msg) + "\n")
+        if not self._buffering:
+            self._file.flush()
+
+def STDOUT(msg):
+    """ consumer that writes to sys.stdout """
+    sys.stdout.write(str(msg)+"\n")
+
+def STDERR(msg):
+    """ consumer that writes to sys.stderr """
+    sys.stderr.write(str(msg)+"\n")
+
+class Syslog:
+    """ consumer that writes to the syslog daemon """
+
+    def __init__(self, priority = None):
+        if priority is None:
+            priority = self.LOG_INFO
+        self.priority = priority
+
+    def __call__(self, msg):
+        """ write a message to the log """
+        py.std.syslog.syslog(self.priority, str(msg))
+
+for _prio in "EMERG ALERT CRIT ERR WARNING NOTICE INFO DEBUG".split():
+    _prio = "LOG_" + _prio
+    try:
+        setattr(Syslog, _prio, getattr(py.std.syslog, _prio))
+    except AttributeError:
+        pass
diff --git a/lib/spack/external/py/_log/warning.py b/lib/spack/external/py/_log/warning.py
new file mode 100644
index 0000000000..722e31e910
--- /dev/null
+++ b/lib/spack/external/py/_log/warning.py
@@ -0,0 +1,76 @@
+import py, sys
+
+class DeprecationWarning(DeprecationWarning):
+    def __init__(self, msg, path, lineno):
+        self.msg = msg
+        self.path = path
+        self.lineno = lineno
+    def __repr__(self):
+        return "%s:%d: %s" %(self.path, self.lineno+1, self.msg)
+    def __str__(self):
+        return self.msg
+
+def _apiwarn(startversion, msg, stacklevel=2, function=None):
+    # below is mostly COPIED from python2.4/warnings.py's def warn()
+    # Get context information
+    if isinstance(stacklevel, str):
+        frame = sys._getframe(1)
+        level = 1
+        found = frame.f_code.co_filename.find(stacklevel) != -1
+        while frame:
+            co = frame.f_code
+            if co.co_filename.find(stacklevel) == -1:
+                if found:
+                    stacklevel = level
+                    break
+            else:
+                found = True
+            level += 1
+            frame = frame.f_back
+        else:
+            stacklevel = 1
+    msg = "%s (since version %s)" %(msg, startversion)
+    warn(msg, stacklevel=stacklevel+1, function=function)
+
+def warn(msg, stacklevel=1, function=None):
+    if function is not None:
+        filename = py.std.inspect.getfile(function)
+        lineno = py.code.getrawcode(function).co_firstlineno
+    else:
+        try:
+            caller = sys._getframe(stacklevel)
+        except ValueError:
+            globals = sys.__dict__
+            lineno = 1
+        else:
+            globals = caller.f_globals
+            lineno = caller.f_lineno
+        if '__name__' in globals:
+            module = globals['__name__']
+        else:
+            module = "<string>"
+        filename = globals.get('__file__')
+    if filename:
+        fnl = filename.lower()
+        if fnl.endswith(".pyc") or fnl.endswith(".pyo"):
+            filename = filename[:-1]
+        elif fnl.endswith("$py.class"):
+            filename = filename.replace('$py.class', '.py')
+    else:
+        if module == "__main__":
+            try:
+                filename = sys.argv[0]
+            except AttributeError:
+                # embedded interpreters don't have sys.argv, see bug #839151
+                filename = '__main__'
+        if not filename:
+            filename = module
+    path = py.path.local(filename)
+    warning = DeprecationWarning(msg, path, lineno)
+    py.std.warnings.warn_explicit(warning, category=Warning,
+        filename=str(warning.path),
+        lineno=warning.lineno,
+        registry=py.std.warnings.__dict__.setdefault(
+            "__warningsregistry__", {})
+    )
+
diff --git a/lib/spack/external/py/_path/__init__.py b/lib/spack/external/py/_path/__init__.py
new file mode 100644
index 0000000000..51f3246f80
--- /dev/null
+++ b/lib/spack/external/py/_path/__init__.py
@@ -0,0 +1 @@
+""" unified file system api """
diff --git a/lib/spack/external/py/_path/cacheutil.py b/lib/spack/external/py/_path/cacheutil.py
new file mode 100644
index 0000000000..9922504750
--- /dev/null
+++ b/lib/spack/external/py/_path/cacheutil.py
@@ -0,0 +1,114 @@
+"""
+This module contains multithread-safe cache implementations.
+
+All Caches have
+
+    getorbuild(key, builder)
+    delentry(key)
+
+methods and allow configuration when instantiating the cache class.
+"""
+from time import time as gettime
+
+class BasicCache(object):
+    def __init__(self, maxentries=128):
+        self.maxentries = maxentries
+        self.prunenum = int(maxentries - maxentries/8)
+        self._dict = {}
+
+    def clear(self):
+        self._dict.clear()
+
+    def _getentry(self, key):
+        return self._dict[key]
+
+    def _putentry(self, key, entry):
+        self._prunelowestweight()
+        self._dict[key] = entry
+
+    def delentry(self, key, raising=False):
+        try:
+            del self._dict[key]
+        except KeyError:
+            if raising:
+                raise
+
+    def getorbuild(self, key, builder):
+        try:
+            entry = self._getentry(key)
+        except KeyError:
+            entry = self._build(key, builder)
+            self._putentry(key, entry)
+        return entry.value
+
+    def _prunelowestweight(self):
+        """ prune out entries with lowest weight. """
+        numentries = len(self._dict)
+        if numentries >= self.maxentries:
+            # evict according to entry's weight
+            items = [(entry.weight, key)
+                        for key, entry in self._dict.items()]
+            items.sort()
+            index = numentries - self.prunenum
+            if index > 0:
+                for weight, key in items[:index]:
+                    # in MT situations the element might be gone
+                    self.delentry(key, raising=False)
+
+class BuildcostAccessCache(BasicCache):
+    """ A BuildTime/Access-counting cache implementation.
+        the weight of a value is computed as the product of
+
+            num-accesses-of-a-value * time-to-build-the-value
+
+        The values with the least such weights are evicted
+        if the cache maxentries threshold is superceded.
+        For implementation flexibility more than one object
+        might be evicted at a time.
+    """
+    # time function to use for measuring build-times
+
+    def _build(self, key, builder):
+        start = gettime()
+        val = builder()
+        end = gettime()
+        return WeightedCountingEntry(val, end-start)
+
+
+class WeightedCountingEntry(object):
+    def __init__(self, value, oneweight):
+        self._value = value
+        self.weight = self._oneweight = oneweight
+
+    def value(self):
+        self.weight += self._oneweight
+        return self._value
+    value = property(value)
+
+class AgingCache(BasicCache):
+    """ This cache prunes out cache entries that are too old.
+    """
+    def __init__(self, maxentries=128, maxseconds=10.0):
+        super(AgingCache, self).__init__(maxentries)
+        self.maxseconds = maxseconds
+
+    def _getentry(self, key):
+        entry = self._dict[key]
+        if entry.isexpired():
+            self.delentry(key)
+            raise KeyError(key)
+        return entry
+
+    def _build(self, key, builder):
+        val = builder()
+        entry = AgingEntry(val, gettime() + self.maxseconds)
+        return entry
+
+class AgingEntry(object):
+    def __init__(self, value, expirationtime):
+        self.value = value
+        self.weight = expirationtime
+
+    def isexpired(self):
+        t = gettime()
+        return t >= self.weight
diff --git a/lib/spack/external/py/_path/common.py b/lib/spack/external/py/_path/common.py
new file mode 100644
index 0000000000..bf42ed5092
--- /dev/null
+++ b/lib/spack/external/py/_path/common.py
@@ -0,0 +1,439 @@
+"""
+"""
+import os, sys, posixpath
+import py
+
+# Moved from local.py.
+iswin32 = sys.platform == "win32" or (getattr(os, '_name', False) == 'nt')
+
+try:
+    from os import fspath
+except ImportError:
+    def fspath(path):
+        """
+        Return the string representation of the path.
+        If str or bytes is passed in, it is returned unchanged.
+        This code comes from PEP 519, modified to support earlier versions of
+        python.
+
+        This is required for python < 3.6.
+        """
+        if isinstance(path, (py.builtin.text, py.builtin.bytes)):
+            return path
+
+        # Work from the object's type to match method resolution of other magic
+        # methods.
+        path_type = type(path)
+        try:
+            return path_type.__fspath__(path)
+        except AttributeError:
+            if hasattr(path_type, '__fspath__'):
+                raise
+            try:
+                import pathlib
+            except ImportError:
+                pass
+            else:
+                if isinstance(path, pathlib.PurePath):
+                    return py.builtin.text(path)
+
+            raise TypeError("expected str, bytes or os.PathLike object, not "
+                            + path_type.__name__)
+
+class Checkers:
+    _depend_on_existence = 'exists', 'link', 'dir', 'file'
+
+    def __init__(self, path):
+        self.path = path
+
+    def dir(self):
+        raise NotImplementedError
+
+    def file(self):
+        raise NotImplementedError
+
+    def dotfile(self):
+        return self.path.basename.startswith('.')
+
+    def ext(self, arg):
+        if not arg.startswith('.'):
+            arg = '.' + arg
+        return self.path.ext == arg
+
+    def exists(self):
+        raise NotImplementedError
+
+    def basename(self, arg):
+        return self.path.basename == arg
+
+    def basestarts(self, arg):
+        return self.path.basename.startswith(arg)
+
+    def relto(self, arg):
+        return self.path.relto(arg)
+
+    def fnmatch(self, arg):
+        return self.path.fnmatch(arg)
+
+    def endswith(self, arg):
+        return str(self.path).endswith(arg)
+
+    def _evaluate(self, kw):
+        for name, value in kw.items():
+            invert = False
+            meth = None
+            try:
+                meth = getattr(self, name)
+            except AttributeError:
+                if name[:3] == 'not':
+                    invert = True
+                    try:
+                        meth = getattr(self, name[3:])
+                    except AttributeError:
+                        pass
+            if meth is None:
+                raise TypeError(
+                    "no %r checker available for %r" % (name, self.path))
+            try:
+                if py.code.getrawcode(meth).co_argcount > 1:
+                    if (not meth(value)) ^ invert:
+                        return False
+                else:
+                    if bool(value) ^ bool(meth()) ^ invert:
+                        return False
+            except (py.error.ENOENT, py.error.ENOTDIR, py.error.EBUSY):
+                # EBUSY feels not entirely correct,
+                # but its kind of necessary since ENOMEDIUM
+                # is not accessible in python
+                for name in self._depend_on_existence:
+                    if name in kw:
+                        if kw.get(name):
+                            return False
+                    name = 'not' + name
+                    if name in kw:
+                        if not kw.get(name):
+                            return False
+        return True
+
+class NeverRaised(Exception):
+    pass
+
+class PathBase(object):
+    """ shared implementation for filesystem path objects."""
+    Checkers = Checkers
+
+    def __div__(self, other):
+        return self.join(fspath(other))
+    __truediv__ = __div__ # py3k
+
+    def basename(self):
+        """ basename part of path. """
+        return self._getbyspec('basename')[0]
+    basename = property(basename, None, None, basename.__doc__)
+
+    def dirname(self):
+        """ dirname part of path. """
+        return self._getbyspec('dirname')[0]
+    dirname = property(dirname, None, None, dirname.__doc__)
+
+    def purebasename(self):
+        """ pure base name of the path."""
+        return self._getbyspec('purebasename')[0]
+    purebasename = property(purebasename, None, None, purebasename.__doc__)
+
+    def ext(self):
+        """ extension of the path (including the '.')."""
+        return self._getbyspec('ext')[0]
+    ext = property(ext, None, None, ext.__doc__)
+
+    def dirpath(self, *args, **kwargs):
+        """ return the directory path joined with any given path arguments.  """
+        return self.new(basename='').join(*args, **kwargs)
+
+    def read_binary(self):
+        """ read and return a bytestring from reading the path. """
+        with self.open('rb') as f:
+            return f.read()
+
+    def read_text(self, encoding):
+        """ read and return a Unicode string from reading the path. """
+        with self.open("r", encoding=encoding) as f:
+            return f.read()
+
+
+    def read(self, mode='r'):
+        """ read and return a bytestring from reading the path. """
+        with self.open(mode) as f:
+            return f.read()
+
+    def readlines(self, cr=1):
+        """ read and return a list of lines from the path. if cr is False, the
+newline will be removed from the end of each line. """
+        if not cr:
+            content = self.read('rU')
+            return content.split('\n')
+        else:
+            f = self.open('rU')
+            try:
+                return f.readlines()
+            finally:
+                f.close()
+
+    def load(self):
+        """ (deprecated) return object unpickled from self.read() """
+        f = self.open('rb')
+        try:
+            return py.error.checked_call(py.std.pickle.load, f)
+        finally:
+            f.close()
+
+    def move(self, target):
+        """ move this path to target. """
+        if target.relto(self):
+            raise py.error.EINVAL(target,
+                "cannot move path into a subdirectory of itself")
+        try:
+            self.rename(target)
+        except py.error.EXDEV:  # invalid cross-device link
+            self.copy(target)
+            self.remove()
+
+    def __repr__(self):
+        """ return a string representation of this path. """
+        return repr(str(self))
+
+    def check(self, **kw):
+        """ check a path for existence and properties.
+
+            Without arguments, return True if the path exists, otherwise False.
+
+            valid checkers::
+
+                file=1    # is a file
+                file=0    # is not a file (may not even exist)
+                dir=1     # is a dir
+                link=1    # is a link
+                exists=1  # exists
+
+            You can specify multiple checker definitions, for example::
+
+                path.check(file=1, link=1)  # a link pointing to a file
+        """
+        if not kw:
+            kw = {'exists' : 1}
+        return self.Checkers(self)._evaluate(kw)
+
+    def fnmatch(self, pattern):
+        """return true if the basename/fullname matches the glob-'pattern'.
+
+        valid pattern characters::
+
+            *       matches everything
+            ?       matches any single character
+            [seq]   matches any character in seq
+            [!seq]  matches any char not in seq
+
+        If the pattern contains a path-separator then the full path
+        is used for pattern matching and a '*' is prepended to the
+        pattern.
+
+        if the pattern doesn't contain a path-separator the pattern
+        is only matched against the basename.
+        """
+        return FNMatcher(pattern)(self)
+
+    def relto(self, relpath):
+        """ return a string which is the relative part of the path
+        to the given 'relpath'.
+        """
+        if not isinstance(relpath, (str, PathBase)):
+            raise TypeError("%r: not a string or path object" %(relpath,))
+        strrelpath = str(relpath)
+        if strrelpath and strrelpath[-1] != self.sep:
+            strrelpath += self.sep
+        #assert strrelpath[-1] == self.sep
+        #assert strrelpath[-2] != self.sep
+        strself = self.strpath
+        if sys.platform == "win32" or getattr(os, '_name', None) == 'nt':
+            if os.path.normcase(strself).startswith(
+               os.path.normcase(strrelpath)):
+                return strself[len(strrelpath):]
+        elif strself.startswith(strrelpath):
+            return strself[len(strrelpath):]
+        return ""
+
+    def ensure_dir(self, *args):
+        """ ensure the path joined with args is a directory. """
+        return self.ensure(*args, **{"dir": True})
+
+    def bestrelpath(self, dest):
+        """ return a string which is a relative path from self
+            (assumed to be a directory) to dest such that
+            self.join(bestrelpath) == dest and if not such
+            path can be determined return dest.
+        """
+        try:
+            if self == dest:
+                return os.curdir
+            base = self.common(dest)
+            if not base:  # can be the case on windows
+                return str(dest)
+            self2base = self.relto(base)
+            reldest = dest.relto(base)
+            if self2base:
+                n = self2base.count(self.sep) + 1
+            else:
+                n = 0
+            l = [os.pardir] * n
+            if reldest:
+                l.append(reldest)
+            target = dest.sep.join(l)
+            return target
+        except AttributeError:
+            return str(dest)
+
+    def exists(self):
+        return self.check()
+
+    def isdir(self):
+        return self.check(dir=1)
+
+    def isfile(self):
+        return self.check(file=1)
+
+    def parts(self, reverse=False):
+        """ return a root-first list of all ancestor directories
+            plus the path itself.
+        """
+        current = self
+        l = [self]
+        while 1:
+            last = current
+            current = current.dirpath()
+            if last == current:
+                break
+            l.append(current)
+        if not reverse:
+            l.reverse()
+        return l
+
+    def common(self, other):
+        """ return the common part shared with the other path
+            or None if there is no common part.
+        """
+        last = None
+        for x, y in zip(self.parts(), other.parts()):
+            if x != y:
+                return last
+            last = x
+        return last
+
+    def __add__(self, other):
+        """ return new path object with 'other' added to the basename"""
+        return self.new(basename=self.basename+str(other))
+
+    def __cmp__(self, other):
+        """ return sort value (-1, 0, +1). """
+        try:
+            return cmp(self.strpath, other.strpath)
+        except AttributeError:
+            return cmp(str(self), str(other)) # self.path, other.path)
+
+    def __lt__(self, other):
+        try:
+            return self.strpath < other.strpath
+        except AttributeError:
+            return str(self) < str(other)
+
+    def visit(self, fil=None, rec=None, ignore=NeverRaised, bf=False, sort=False):
+        """ yields all paths below the current one
+
+            fil is a filter (glob pattern or callable), if not matching the
+            path will not be yielded, defaulting to None (everything is
+            returned)
+
+            rec is a filter (glob pattern or callable) that controls whether
+            a node is descended, defaulting to None
+
+            ignore is an Exception class that is ignoredwhen calling dirlist()
+            on any of the paths (by default, all exceptions are reported)
+
+            bf if True will cause a breadthfirst search instead of the
+            default depthfirst. Default: False
+
+            sort if True will sort entries within each directory level.
+        """
+        for x in Visitor(fil, rec, ignore, bf, sort).gen(self):
+            yield x
+
+    def _sortlist(self, res, sort):
+        if sort:
+            if hasattr(sort, '__call__'):
+                res.sort(sort)
+            else:
+                res.sort()
+
+    def samefile(self, other):
+        """ return True if other refers to the same stat object as self. """
+        return self.strpath == str(other)
+
+    def __fspath__(self):
+        return str(self)
+
+class Visitor:
+    def __init__(self, fil, rec, ignore, bf, sort):
+        if isinstance(fil, py.builtin._basestring):
+            fil = FNMatcher(fil)
+        if isinstance(rec, py.builtin._basestring):
+            self.rec = FNMatcher(rec)
+        elif not hasattr(rec, '__call__') and rec:
+            self.rec = lambda path: True
+        else:
+            self.rec = rec
+        self.fil = fil
+        self.ignore = ignore
+        self.breadthfirst = bf
+        self.optsort = sort and sorted or (lambda x: x)
+
+    def gen(self, path):
+        try:
+            entries = path.listdir()
+        except self.ignore:
+            return
+        rec = self.rec
+        dirs = self.optsort([p for p in entries
+                    if p.check(dir=1) and (rec is None or rec(p))])
+        if not self.breadthfirst:
+            for subdir in dirs:
+                for p in self.gen(subdir):
+                    yield p
+        for p in self.optsort(entries):
+            if self.fil is None or self.fil(p):
+                yield p
+        if self.breadthfirst:
+            for subdir in dirs:
+                for p in self.gen(subdir):
+                    yield p
+
+class FNMatcher:
+    def __init__(self, pattern):
+        self.pattern = pattern
+
+    def __call__(self, path):
+        pattern = self.pattern
+
+        if (pattern.find(path.sep) == -1 and
+        iswin32 and
+        pattern.find(posixpath.sep) != -1):
+            # Running on Windows, the pattern has no Windows path separators,
+            # and the pattern has one or more Posix path separators. Replace
+            # the Posix path separators with the Windows path separator.
+            pattern = pattern.replace(posixpath.sep, path.sep)
+
+        if pattern.find(path.sep) == -1:
+            name = path.basename
+        else:
+            name = str(path) # path.strpath # XXX svn?
+            if not os.path.isabs(pattern):
+                pattern = '*' + path.sep + pattern
+        return py.std.fnmatch.fnmatch(name, pattern)
diff --git a/lib/spack/external/py/_path/local.py b/lib/spack/external/py/_path/local.py
new file mode 100644
index 0000000000..0d4e4c93d1
--- /dev/null
+++ b/lib/spack/external/py/_path/local.py
@@ -0,0 +1,928 @@
+"""
+local path implementation.
+"""
+from __future__ import with_statement
+
+from contextlib import contextmanager
+import sys, os, re, atexit, io
+import py
+from py._path import common
+from py._path.common import iswin32, fspath
+from stat import S_ISLNK, S_ISDIR, S_ISREG
+
+from os.path import abspath, normpath, isabs, exists, isdir, isfile, islink, dirname
+
+if sys.version_info > (3,0):
+    def map_as_list(func, iter):
+        return list(map(func, iter))
+else:
+    map_as_list = map
+
+class Stat(object):
+    def __getattr__(self, name):
+        return getattr(self._osstatresult, "st_" + name)
+
+    def __init__(self, path, osstatresult):
+        self.path = path
+        self._osstatresult = osstatresult
+
+    @property
+    def owner(self):
+        if iswin32:
+            raise NotImplementedError("XXX win32")
+        import pwd
+        entry = py.error.checked_call(pwd.getpwuid, self.uid)
+        return entry[0]
+
+    @property
+    def group(self):
+        """ return group name of file. """
+        if iswin32:
+            raise NotImplementedError("XXX win32")
+        import grp
+        entry = py.error.checked_call(grp.getgrgid, self.gid)
+        return entry[0]
+
+    def isdir(self):
+        return S_ISDIR(self._osstatresult.st_mode)
+
+    def isfile(self):
+        return S_ISREG(self._osstatresult.st_mode)
+
+    def islink(self):
+        st = self.path.lstat()
+        return S_ISLNK(self._osstatresult.st_mode)
+
+class PosixPath(common.PathBase):
+    def chown(self, user, group, rec=0):
+        """ change ownership to the given user and group.
+            user and group may be specified by a number or
+            by a name.  if rec is True change ownership
+            recursively.
+        """
+        uid = getuserid(user)
+        gid = getgroupid(group)
+        if rec:
+            for x in self.visit(rec=lambda x: x.check(link=0)):
+                if x.check(link=0):
+                    py.error.checked_call(os.chown, str(x), uid, gid)
+        py.error.checked_call(os.chown, str(self), uid, gid)
+
+    def readlink(self):
+        """ return value of a symbolic link. """
+        return py.error.checked_call(os.readlink, self.strpath)
+
+    def mklinkto(self, oldname):
+        """ posix style hard link to another name. """
+        py.error.checked_call(os.link, str(oldname), str(self))
+
+    def mksymlinkto(self, value, absolute=1):
+        """ create a symbolic link with the given value (pointing to another name). """
+        if absolute:
+            py.error.checked_call(os.symlink, str(value), self.strpath)
+        else:
+            base = self.common(value)
+            # with posix local paths '/' is always a common base
+            relsource = self.__class__(value).relto(base)
+            reldest = self.relto(base)
+            n = reldest.count(self.sep)
+            target = self.sep.join(('..', )*n + (relsource, ))
+            py.error.checked_call(os.symlink, target, self.strpath)
+
+def getuserid(user):
+    import pwd
+    if not isinstance(user, int):
+        user = pwd.getpwnam(user)[2]
+    return user
+
+def getgroupid(group):
+    import grp
+    if not isinstance(group, int):
+        group = grp.getgrnam(group)[2]
+    return group
+
+FSBase = not iswin32 and PosixPath or common.PathBase
+
+class LocalPath(FSBase):
+    """ object oriented interface to os.path and other local filesystem
+        related information.
+    """
+    class ImportMismatchError(ImportError):
+        """ raised on pyimport() if there is a mismatch of __file__'s"""
+
+    sep = os.sep
+    class Checkers(common.Checkers):
+        def _stat(self):
+            try:
+                return self._statcache
+            except AttributeError:
+                try:
+                    self._statcache = self.path.stat()
+                except py.error.ELOOP:
+                    self._statcache = self.path.lstat()
+                return self._statcache
+
+        def dir(self):
+            return S_ISDIR(self._stat().mode)
+
+        def file(self):
+            return S_ISREG(self._stat().mode)
+
+        def exists(self):
+            return self._stat()
+
+        def link(self):
+            st = self.path.lstat()
+            return S_ISLNK(st.mode)
+
+    def __init__(self, path=None, expanduser=False):
+        """ Initialize and return a local Path instance.
+
+        Path can be relative to the current directory.
+        If path is None it defaults to the current working directory.
+        If expanduser is True, tilde-expansion is performed.
+        Note that Path instances always carry an absolute path.
+        Note also that passing in a local path object will simply return
+        the exact same path object. Use new() to get a new copy.
+        """
+        if path is None:
+            self.strpath = py.error.checked_call(os.getcwd)
+        else:
+            try:
+                path = fspath(path)
+            except TypeError:
+                raise ValueError("can only pass None, Path instances "
+                                 "or non-empty strings to LocalPath")
+            if expanduser:
+                path = os.path.expanduser(path)
+            self.strpath = abspath(path)
+
+    def __hash__(self):
+        return hash(self.strpath)
+
+    def __eq__(self, other):
+        s1 = fspath(self)
+        try:
+            s2 = fspath(other)
+        except TypeError:
+            return False
+        if iswin32:
+            s1 = s1.lower()
+            try:
+                s2 = s2.lower()
+            except AttributeError:
+                return False
+        return s1 == s2
+
+    def __ne__(self, other):
+        return not (self == other)
+
+    def __lt__(self, other):
+        return fspath(self) < fspath(other)
+
+    def __gt__(self, other):
+        return fspath(self) > fspath(other)
+
+    def samefile(self, other):
+        """ return True if 'other' references the same file as 'self'.
+        """
+        other = fspath(other)
+        if not isabs(other):
+            other = abspath(other)
+        if self == other:
+            return True
+        if iswin32:
+            return False # there is no samefile
+        return py.error.checked_call(
+                os.path.samefile, self.strpath, other)
+
+    def remove(self, rec=1, ignore_errors=False):
+        """ remove a file or directory (or a directory tree if rec=1).
+        if ignore_errors is True, errors while removing directories will
+        be ignored.
+        """
+        if self.check(dir=1, link=0):
+            if rec:
+                # force remove of readonly files on windows
+                if iswin32:
+                    self.chmod(448, rec=1) # octcal 0700
+                py.error.checked_call(py.std.shutil.rmtree, self.strpath,
+                    ignore_errors=ignore_errors)
+            else:
+                py.error.checked_call(os.rmdir, self.strpath)
+        else:
+            if iswin32:
+                self.chmod(448) # octcal 0700
+            py.error.checked_call(os.remove, self.strpath)
+
+    def computehash(self, hashtype="md5", chunksize=524288):
+        """ return hexdigest of hashvalue for this file. """
+        try:
+            try:
+                import hashlib as mod
+            except ImportError:
+                if hashtype == "sha1":
+                    hashtype = "sha"
+                mod = __import__(hashtype)
+            hash = getattr(mod, hashtype)()
+        except (AttributeError, ImportError):
+            raise ValueError("Don't know how to compute %r hash" %(hashtype,))
+        f = self.open('rb')
+        try:
+            while 1:
+                buf = f.read(chunksize)
+                if not buf:
+                    return hash.hexdigest()
+                hash.update(buf)
+        finally:
+            f.close()
+
+    def new(self, **kw):
+        """ create a modified version of this path.
+            the following keyword arguments modify various path parts::
+
+              a:/some/path/to/a/file.ext
+              xx                           drive
+              xxxxxxxxxxxxxxxxx            dirname
+                                xxxxxxxx   basename
+                                xxxx       purebasename
+                                     xxx   ext
+        """
+        obj = object.__new__(self.__class__)
+        if not kw:
+            obj.strpath = self.strpath
+            return obj
+        drive, dirname, basename, purebasename,ext = self._getbyspec(
+             "drive,dirname,basename,purebasename,ext")
+        if 'basename' in kw:
+            if 'purebasename' in kw or 'ext' in kw:
+                raise ValueError("invalid specification %r" % kw)
+        else:
+            pb = kw.setdefault('purebasename', purebasename)
+            try:
+                ext = kw['ext']
+            except KeyError:
+                pass
+            else:
+                if ext and not ext.startswith('.'):
+                    ext = '.' + ext
+            kw['basename'] = pb + ext
+
+        if ('dirname' in kw and not kw['dirname']):
+            kw['dirname'] = drive
+        else:
+            kw.setdefault('dirname', dirname)
+        kw.setdefault('sep', self.sep)
+        obj.strpath = normpath(
+            "%(dirname)s%(sep)s%(basename)s" % kw)
+        return obj
+
+    def _getbyspec(self, spec):
+        """ see new for what 'spec' can be. """
+        res = []
+        parts = self.strpath.split(self.sep)
+
+        args = filter(None, spec.split(',') )
+        append = res.append
+        for name in args:
+            if name == 'drive':
+                append(parts[0])
+            elif name == 'dirname':
+                append(self.sep.join(parts[:-1]))
+            else:
+                basename = parts[-1]
+                if name == 'basename':
+                    append(basename)
+                else:
+                    i = basename.rfind('.')
+                    if i == -1:
+                        purebasename, ext = basename, ''
+                    else:
+                        purebasename, ext = basename[:i], basename[i:]
+                    if name == 'purebasename':
+                        append(purebasename)
+                    elif name == 'ext':
+                        append(ext)
+                    else:
+                        raise ValueError("invalid part specification %r" % name)
+        return res
+
+    def dirpath(self, *args, **kwargs):
+        """ return the directory path joined with any given path arguments.  """
+        if not kwargs:
+            path = object.__new__(self.__class__)
+            path.strpath = dirname(self.strpath)
+            if args:
+                path = path.join(*args)
+            return path
+        return super(LocalPath, self).dirpath(*args, **kwargs)
+
+    def join(self, *args, **kwargs):
+        """ return a new path by appending all 'args' as path
+        components.  if abs=1 is used restart from root if any
+        of the args is an absolute path.
+        """
+        sep = self.sep
+        strargs = [fspath(arg) for arg in args]
+        strpath = self.strpath
+        if kwargs.get('abs'):
+            newargs = []
+            for arg in reversed(strargs):
+                if isabs(arg):
+                    strpath = arg
+                    strargs = newargs
+                    break
+                newargs.insert(0, arg)
+        for arg in strargs:
+            arg = arg.strip(sep)
+            if iswin32:
+                # allow unix style paths even on windows.
+                arg = arg.strip('/')
+                arg = arg.replace('/', sep)
+            strpath = strpath + sep + arg
+        obj = object.__new__(self.__class__)
+        obj.strpath = normpath(strpath)
+        return obj
+
+    def open(self, mode='r', ensure=False, encoding=None):
+        """ return an opened file with the given mode.
+
+        If ensure is True, create parent directories if needed.
+        """
+        if ensure:
+            self.dirpath().ensure(dir=1)
+        if encoding:
+            return py.error.checked_call(io.open, self.strpath, mode, encoding=encoding)
+        return py.error.checked_call(open, self.strpath, mode)
+
+    def _fastjoin(self, name):
+        child = object.__new__(self.__class__)
+        child.strpath = self.strpath + self.sep + name
+        return child
+
+    def islink(self):
+        return islink(self.strpath)
+
+    def check(self, **kw):
+        if not kw:
+            return exists(self.strpath)
+        if len(kw) == 1:
+            if "dir" in kw:
+                return not kw["dir"] ^ isdir(self.strpath)
+            if "file" in kw:
+                return not kw["file"] ^ isfile(self.strpath)
+        return super(LocalPath, self).check(**kw)
+
+    _patternchars = set("*?[" + os.path.sep)
+    def listdir(self, fil=None, sort=None):
+        """ list directory contents, possibly filter by the given fil func
+            and possibly sorted.
+        """
+        if fil is None and sort is None:
+            names = py.error.checked_call(os.listdir, self.strpath)
+            return map_as_list(self._fastjoin, names)
+        if isinstance(fil, py.builtin._basestring):
+            if not self._patternchars.intersection(fil):
+                child = self._fastjoin(fil)
+                if exists(child.strpath):
+                    return [child]
+                return []
+            fil = common.FNMatcher(fil)
+        names = py.error.checked_call(os.listdir, self.strpath)
+        res = []
+        for name in names:
+            child = self._fastjoin(name)
+            if fil is None or fil(child):
+                res.append(child)
+        self._sortlist(res, sort)
+        return res
+
+    def size(self):
+        """ return size of the underlying file object """
+        return self.stat().size
+
+    def mtime(self):
+        """ return last modification time of the path. """
+        return self.stat().mtime
+
+    def copy(self, target, mode=False, stat=False):
+        """ copy path to target.
+
+            If mode is True, will copy copy permission from path to target.
+            If stat is True, copy permission, last modification
+            time, last access time, and flags from path to target.
+        """
+        if self.check(file=1):
+            if target.check(dir=1):
+                target = target.join(self.basename)
+            assert self!=target
+            copychunked(self, target)
+            if mode:
+                copymode(self.strpath, target.strpath)
+            if stat:
+                copystat(self, target)
+        else:
+            def rec(p):
+                return p.check(link=0)
+            for x in self.visit(rec=rec):
+                relpath = x.relto(self)
+                newx = target.join(relpath)
+                newx.dirpath().ensure(dir=1)
+                if x.check(link=1):
+                    newx.mksymlinkto(x.readlink())
+                    continue
+                elif x.check(file=1):
+                    copychunked(x, newx)
+                elif x.check(dir=1):
+                    newx.ensure(dir=1)
+                if mode:
+                    copymode(x.strpath, newx.strpath)
+                if stat:
+                    copystat(x, newx)
+
+    def rename(self, target):
+        """ rename this path to target. """
+        target = fspath(target)
+        return py.error.checked_call(os.rename, self.strpath, target)
+
+    def dump(self, obj, bin=1):
+        """ pickle object into path location"""
+        f = self.open('wb')
+        try:
+            py.error.checked_call(py.std.pickle.dump, obj, f, bin)
+        finally:
+            f.close()
+
+    def mkdir(self, *args):
+        """ create & return the directory joined with args. """
+        p = self.join(*args)
+        py.error.checked_call(os.mkdir, fspath(p))
+        return p
+
+    def write_binary(self, data, ensure=False):
+        """ write binary data into path.   If ensure is True create
+        missing parent directories.
+        """
+        if ensure:
+            self.dirpath().ensure(dir=1)
+        with self.open('wb') as f:
+            f.write(data)
+
+    def write_text(self, data, encoding, ensure=False):
+        """ write text data into path using the specified encoding.
+        If ensure is True create missing parent directories.
+        """
+        if ensure:
+            self.dirpath().ensure(dir=1)
+        with self.open('w', encoding=encoding) as f:
+            f.write(data)
+
+    def write(self, data, mode='w', ensure=False):
+        """ write data into path.   If ensure is True create
+        missing parent directories.
+        """
+        if ensure:
+            self.dirpath().ensure(dir=1)
+        if 'b' in mode:
+            if not py.builtin._isbytes(data):
+                raise ValueError("can only process bytes")
+        else:
+            if not py.builtin._istext(data):
+                if not py.builtin._isbytes(data):
+                    data = str(data)
+                else:
+                    data = py.builtin._totext(data, sys.getdefaultencoding())
+        f = self.open(mode)
+        try:
+            f.write(data)
+        finally:
+            f.close()
+
+    def _ensuredirs(self):
+        parent = self.dirpath()
+        if parent == self:
+            return self
+        if parent.check(dir=0):
+            parent._ensuredirs()
+        if self.check(dir=0):
+            try:
+                self.mkdir()
+            except py.error.EEXIST:
+                # race condition: file/dir created by another thread/process.
+                # complain if it is not a dir
+                if self.check(dir=0):
+                    raise
+        return self
+
+    def ensure(self, *args, **kwargs):
+        """ ensure that an args-joined path exists (by default as
+            a file). if you specify a keyword argument 'dir=True'
+            then the path is forced to be a directory path.
+        """
+        p = self.join(*args)
+        if kwargs.get('dir', 0):
+            return p._ensuredirs()
+        else:
+            p.dirpath()._ensuredirs()
+            if not p.check(file=1):
+                p.open('w').close()
+            return p
+
+    def stat(self, raising=True):
+        """ Return an os.stat() tuple. """
+        if raising == True:
+            return Stat(self, py.error.checked_call(os.stat, self.strpath))
+        try:
+            return Stat(self, os.stat(self.strpath))
+        except KeyboardInterrupt:
+            raise
+        except Exception:
+            return None
+
+    def lstat(self):
+        """ Return an os.lstat() tuple. """
+        return Stat(self, py.error.checked_call(os.lstat, self.strpath))
+
+    def setmtime(self, mtime=None):
+        """ set modification time for the given path.  if 'mtime' is None
+        (the default) then the file's mtime is set to current time.
+
+        Note that the resolution for 'mtime' is platform dependent.
+        """
+        if mtime is None:
+            return py.error.checked_call(os.utime, self.strpath, mtime)
+        try:
+            return py.error.checked_call(os.utime, self.strpath, (-1, mtime))
+        except py.error.EINVAL:
+            return py.error.checked_call(os.utime, self.strpath, (self.atime(), mtime))
+
+    def chdir(self):
+        """ change directory to self and return old current directory """
+        try:
+            old = self.__class__()
+        except py.error.ENOENT:
+            old = None
+        py.error.checked_call(os.chdir, self.strpath)
+        return old
+
+
+    @contextmanager
+    def as_cwd(self):
+        """ return context manager which changes to current dir during the
+        managed "with" context. On __enter__ it returns the old dir.
+        """
+        old = self.chdir()
+        try:
+            yield old
+        finally:
+            old.chdir()
+
+    def realpath(self):
+        """ return a new path which contains no symbolic links."""
+        return self.__class__(os.path.realpath(self.strpath))
+
+    def atime(self):
+        """ return last access time of the path. """
+        return self.stat().atime
+
+    def __repr__(self):
+        return 'local(%r)' % self.strpath
+
+    def __str__(self):
+        """ return string representation of the Path. """
+        return self.strpath
+
+    def chmod(self, mode, rec=0):
+        """ change permissions to the given mode. If mode is an
+            integer it directly encodes the os-specific modes.
+            if rec is True perform recursively.
+        """
+        if not isinstance(mode, int):
+            raise TypeError("mode %r must be an integer" % (mode,))
+        if rec:
+            for x in self.visit(rec=rec):
+                py.error.checked_call(os.chmod, str(x), mode)
+        py.error.checked_call(os.chmod, self.strpath, mode)
+
+    def pypkgpath(self):
+        """ return the Python package path by looking for the last
+        directory upwards which still contains an __init__.py.
+        Return None if a pkgpath can not be determined.
+        """
+        pkgpath = None
+        for parent in self.parts(reverse=True):
+            if parent.isdir():
+                if not parent.join('__init__.py').exists():
+                    break
+                if not isimportable(parent.basename):
+                    break
+                pkgpath = parent
+        return pkgpath
+
+    def _ensuresyspath(self, ensuremode, path):
+        if ensuremode:
+            s = str(path)
+            if ensuremode == "append":
+                if s not in sys.path:
+                    sys.path.append(s)
+            else:
+                if s != sys.path[0]:
+                    sys.path.insert(0, s)
+
+    def pyimport(self, modname=None, ensuresyspath=True):
+        """ return path as an imported python module.
+
+        If modname is None, look for the containing package
+        and construct an according module name.
+        The module will be put/looked up in sys.modules.
+        if ensuresyspath is True then the root dir for importing
+        the file (taking __init__.py files into account) will
+        be prepended to sys.path if it isn't there already.
+        If ensuresyspath=="append" the root dir will be appended
+        if it isn't already contained in sys.path.
+        if ensuresyspath is False no modification of syspath happens.
+        """
+        if not self.check():
+            raise py.error.ENOENT(self)
+
+        pkgpath = None
+        if modname is None:
+            pkgpath = self.pypkgpath()
+            if pkgpath is not None:
+                pkgroot = pkgpath.dirpath()
+                names = self.new(ext="").relto(pkgroot).split(self.sep)
+                if names[-1] == "__init__":
+                    names.pop()
+                modname = ".".join(names)
+            else:
+                pkgroot = self.dirpath()
+                modname = self.purebasename
+
+            self._ensuresyspath(ensuresyspath, pkgroot)
+            __import__(modname)
+            mod = sys.modules[modname]
+            if self.basename == "__init__.py":
+                return mod # we don't check anything as we might
+                       # we in a namespace package ... too icky to check
+            modfile = mod.__file__
+            if modfile[-4:] in ('.pyc', '.pyo'):
+                modfile = modfile[:-1]
+            elif modfile.endswith('$py.class'):
+                modfile = modfile[:-9] + '.py'
+            if modfile.endswith(os.path.sep + "__init__.py"):
+                if self.basename != "__init__.py":
+                    modfile = modfile[:-12]
+            try:
+                issame = self.samefile(modfile)
+            except py.error.ENOENT:
+                issame = False
+            if not issame:
+                raise self.ImportMismatchError(modname, modfile, self)
+            return mod
+        else:
+            try:
+                return sys.modules[modname]
+            except KeyError:
+                # we have a custom modname, do a pseudo-import
+                mod = py.std.types.ModuleType(modname)
+                mod.__file__ = str(self)
+                sys.modules[modname] = mod
+                try:
+                    py.builtin.execfile(str(self), mod.__dict__)
+                except:
+                    del sys.modules[modname]
+                    raise
+                return mod
+
+    def sysexec(self, *argv, **popen_opts):
+        """ return stdout text from executing a system child process,
+            where the 'self' path points to executable.
+            The process is directly invoked and not through a system shell.
+        """
+        from subprocess import Popen, PIPE
+        argv = map_as_list(str, argv)
+        popen_opts['stdout'] = popen_opts['stderr'] = PIPE
+        proc = Popen([str(self)] + argv, **popen_opts)
+        stdout, stderr = proc.communicate()
+        ret = proc.wait()
+        if py.builtin._isbytes(stdout):
+            stdout = py.builtin._totext(stdout, sys.getdefaultencoding())
+        if ret != 0:
+            if py.builtin._isbytes(stderr):
+                stderr = py.builtin._totext(stderr, sys.getdefaultencoding())
+            raise py.process.cmdexec.Error(ret, ret, str(self),
+                                           stdout, stderr,)
+        return stdout
+
+    def sysfind(cls, name, checker=None, paths=None):
+        """ return a path object found by looking at the systems
+            underlying PATH specification. If the checker is not None
+            it will be invoked to filter matching paths.  If a binary
+            cannot be found, None is returned
+            Note: This is probably not working on plain win32 systems
+            but may work on cygwin.
+        """
+        if isabs(name):
+            p = py.path.local(name)
+            if p.check(file=1):
+                return p
+        else:
+            if paths is None:
+                if iswin32:
+                    paths = py.std.os.environ['Path'].split(';')
+                    if '' not in paths and '.' not in paths:
+                        paths.append('.')
+                    try:
+                        systemroot = os.environ['SYSTEMROOT']
+                    except KeyError:
+                        pass
+                    else:
+                        paths = [re.sub('%SystemRoot%', systemroot, path)
+                                 for path in paths]
+                else:
+                    paths = py.std.os.environ['PATH'].split(':')
+            tryadd = []
+            if iswin32:
+                tryadd += os.environ['PATHEXT'].split(os.pathsep)
+            tryadd.append("")
+
+            for x in paths:
+                for addext in tryadd:
+                    p = py.path.local(x).join(name, abs=True) + addext
+                    try:
+                        if p.check(file=1):
+                            if checker:
+                                if not checker(p):
+                                    continue
+                            return p
+                    except py.error.EACCES:
+                        pass
+        return None
+    sysfind = classmethod(sysfind)
+
+    def _gethomedir(cls):
+        try:
+            x = os.environ['HOME']
+        except KeyError:
+            try:
+                x = os.environ["HOMEDRIVE"] + os.environ['HOMEPATH']
+            except KeyError:
+                return None
+        return cls(x)
+    _gethomedir = classmethod(_gethomedir)
+
+    #"""
+    #special class constructors for local filesystem paths
+    #"""
+    def get_temproot(cls):
+        """ return the system's temporary directory
+            (where tempfiles are usually created in)
+        """
+        return py.path.local(py.std.tempfile.gettempdir())
+    get_temproot = classmethod(get_temproot)
+
+    def mkdtemp(cls, rootdir=None):
+        """ return a Path object pointing to a fresh new temporary directory
+            (which we created ourself).
+        """
+        import tempfile
+        if rootdir is None:
+            rootdir = cls.get_temproot()
+        return cls(py.error.checked_call(tempfile.mkdtemp, dir=str(rootdir)))
+    mkdtemp = classmethod(mkdtemp)
+
+    def make_numbered_dir(cls, prefix='session-', rootdir=None, keep=3,
+                          lock_timeout = 172800):   # two days
+        """ return unique directory with a number greater than the current
+            maximum one.  The number is assumed to start directly after prefix.
+            if keep is true directories with a number less than (maxnum-keep)
+            will be removed.
+        """
+        if rootdir is None:
+            rootdir = cls.get_temproot()
+
+        def parse_num(path):
+            """ parse the number out of a path (if it matches the prefix) """
+            bn = path.basename
+            if bn.startswith(prefix):
+                try:
+                    return int(bn[len(prefix):])
+                except ValueError:
+                    pass
+
+        # compute the maximum number currently in use with the
+        # prefix
+        lastmax = None
+        while True:
+            maxnum = -1
+            for path in rootdir.listdir():
+                num = parse_num(path)
+                if num is not None:
+                    maxnum = max(maxnum, num)
+
+            # make the new directory
+            try:
+                udir = rootdir.mkdir(prefix + str(maxnum+1))
+            except py.error.EEXIST:
+                # race condition: another thread/process created the dir
+                # in the meantime.  Try counting again
+                if lastmax == maxnum:
+                    raise
+                lastmax = maxnum
+                continue
+            break
+
+        # put a .lock file in the new directory that will be removed at
+        # process exit
+        if lock_timeout:
+            lockfile = udir.join('.lock')
+            mypid = os.getpid()
+            if hasattr(lockfile, 'mksymlinkto'):
+                lockfile.mksymlinkto(str(mypid))
+            else:
+                lockfile.write(str(mypid))
+            def try_remove_lockfile():
+                # in a fork() situation, only the last process should
+                # remove the .lock, otherwise the other processes run the
+                # risk of seeing their temporary dir disappear.  For now
+                # we remove the .lock in the parent only (i.e. we assume
+                # that the children finish before the parent).
+                if os.getpid() != mypid:
+                    return
+                try:
+                    lockfile.remove()
+                except py.error.Error:
+                    pass
+            atexit.register(try_remove_lockfile)
+
+        # prune old directories
+        if keep:
+            for path in rootdir.listdir():
+                num = parse_num(path)
+                if num is not None and num <= (maxnum - keep):
+                    lf = path.join('.lock')
+                    try:
+                        t1 = lf.lstat().mtime
+                        t2 = lockfile.lstat().mtime
+                        if not lock_timeout or abs(t2-t1) < lock_timeout:
+                            continue   # skip directories still locked
+                    except py.error.Error:
+                        pass   # assume that it means that there is no 'lf'
+                    try:
+                        path.remove(rec=1)
+                    except KeyboardInterrupt:
+                        raise
+                    except: # this might be py.error.Error, WindowsError ...
+                        pass
+
+        # make link...
+        try:
+            username = os.environ['USER']           #linux, et al
+        except KeyError:
+            try:
+                username = os.environ['USERNAME']   #windows
+            except KeyError:
+                username = 'current'
+
+        src  = str(udir)
+        dest = src[:src.rfind('-')] + '-' + username
+        try:
+            os.unlink(dest)
+        except OSError:
+            pass
+        try:
+            os.symlink(src, dest)
+        except (OSError, AttributeError, NotImplementedError):
+            pass
+
+        return udir
+    make_numbered_dir = classmethod(make_numbered_dir)
+
+def copymode(src, dest):
+    """ copy permission from src to dst. """
+    py.std.shutil.copymode(src, dest)
+
+def copystat(src, dest):
+    """ copy permission,  last modification time, last access time, and flags from src to dst."""
+    py.std.shutil.copystat(str(src), str(dest))
+
+def copychunked(src, dest):
+    chunksize = 524288 # half a meg of bytes
+    fsrc = src.open('rb')
+    try:
+        fdest = dest.open('wb')
+        try:
+            while 1:
+                buf = fsrc.read(chunksize)
+                if not buf:
+                    break
+                fdest.write(buf)
+        finally:
+            fdest.close()
+    finally:
+        fsrc.close()
+
+def isimportable(name):
+    if name and (name[0].isalpha() or name[0] == '_'):
+        name = name.replace("_", '')
+        return not name or name.isalnum()
diff --git a/lib/spack/external/py/_path/svnurl.py b/lib/spack/external/py/_path/svnurl.py
new file mode 100644
index 0000000000..78d71317ac
--- /dev/null
+++ b/lib/spack/external/py/_path/svnurl.py
@@ -0,0 +1,380 @@
+"""
+module defining a subversion path object based on the external
+command 'svn'. This modules aims to work with svn 1.3 and higher
+but might also interact well with earlier versions.
+"""
+
+import os, sys, time, re
+import py
+from py import path, process
+from py._path import common
+from py._path import svnwc as svncommon
+from py._path.cacheutil import BuildcostAccessCache, AgingCache
+
+DEBUG=False
+
+class SvnCommandPath(svncommon.SvnPathBase):
+    """ path implementation that offers access to (possibly remote) subversion
+    repositories. """
+
+    _lsrevcache = BuildcostAccessCache(maxentries=128)
+    _lsnorevcache = AgingCache(maxentries=1000, maxseconds=60.0)
+
+    def __new__(cls, path, rev=None, auth=None):
+        self = object.__new__(cls)
+        if isinstance(path, cls):
+            rev = path.rev
+            auth = path.auth
+            path = path.strpath
+        svncommon.checkbadchars(path)
+        path = path.rstrip('/')
+        self.strpath = path
+        self.rev = rev
+        self.auth = auth
+        return self
+
+    def __repr__(self):
+        if self.rev == -1:
+            return 'svnurl(%r)' % self.strpath
+        else:
+            return 'svnurl(%r, %r)' % (self.strpath, self.rev)
+
+    def _svnwithrev(self, cmd, *args):
+        """ execute an svn command, append our own url and revision """
+        if self.rev is None:
+            return self._svnwrite(cmd, *args)
+        else:
+            args = ['-r', self.rev] + list(args)
+            return self._svnwrite(cmd, *args)
+
+    def _svnwrite(self, cmd, *args):
+        """ execute an svn command, append our own url """
+        l = ['svn %s' % cmd]
+        args = ['"%s"' % self._escape(item) for item in args]
+        l.extend(args)
+        l.append('"%s"' % self._encodedurl())
+        # fixing the locale because we can't otherwise parse
+        string = " ".join(l)
+        if DEBUG:
+            print("execing %s" % string)
+        out = self._svncmdexecauth(string)
+        return out
+
+    def _svncmdexecauth(self, cmd):
+        """ execute an svn command 'as is' """
+        cmd = svncommon.fixlocale() + cmd
+        if self.auth is not None:
+            cmd += ' ' + self.auth.makecmdoptions()
+        return self._cmdexec(cmd)
+
+    def _cmdexec(self, cmd):
+        try:
+            out = process.cmdexec(cmd)
+        except py.process.cmdexec.Error:
+            e = sys.exc_info()[1]
+            if (e.err.find('File Exists') != -1 or
+                            e.err.find('File already exists') != -1):
+                raise py.error.EEXIST(self)
+            raise
+        return out
+
+    def _svnpopenauth(self, cmd):
+        """ execute an svn command, return a pipe for reading stdin """
+        cmd = svncommon.fixlocale() + cmd
+        if self.auth is not None:
+            cmd += ' ' + self.auth.makecmdoptions()
+        return self._popen(cmd)
+
+    def _popen(self, cmd):
+        return os.popen(cmd)
+
+    def _encodedurl(self):
+        return self._escape(self.strpath)
+
+    def _norev_delentry(self, path):
+        auth = self.auth and self.auth.makecmdoptions() or None
+        self._lsnorevcache.delentry((str(path), auth))
+
+    def open(self, mode='r'):
+        """ return an opened file with the given mode. """
+        if mode not in ("r", "rU",):
+            raise ValueError("mode %r not supported" % (mode,))
+        assert self.check(file=1) # svn cat returns an empty file otherwise
+        if self.rev is None:
+            return self._svnpopenauth('svn cat "%s"' % (
+                                      self._escape(self.strpath), ))
+        else:
+            return self._svnpopenauth('svn cat -r %s "%s"' % (
+                                      self.rev, self._escape(self.strpath)))
+
+    def dirpath(self, *args, **kwargs):
+        """ return the directory path of the current path joined
+            with any given path arguments.
+        """
+        l = self.strpath.split(self.sep)
+        if len(l) < 4:
+            raise py.error.EINVAL(self, "base is not valid")
+        elif len(l) == 4:
+            return self.join(*args, **kwargs)
+        else:
+            return self.new(basename='').join(*args, **kwargs)
+
+    # modifying methods (cache must be invalidated)
+    def mkdir(self, *args, **kwargs):
+        """ create & return the directory joined with args.
+        pass a 'msg' keyword argument to set the commit message.
+        """
+        commit_msg = kwargs.get('msg', "mkdir by py lib invocation")
+        createpath = self.join(*args)
+        createpath._svnwrite('mkdir', '-m', commit_msg)
+        self._norev_delentry(createpath.dirpath())
+        return createpath
+
+    def copy(self, target, msg='copied by py lib invocation'):
+        """ copy path to target with checkin message msg."""
+        if getattr(target, 'rev', None) is not None:
+            raise py.error.EINVAL(target, "revisions are immutable")
+        self._svncmdexecauth('svn copy -m "%s" "%s" "%s"' %(msg,
+                             self._escape(self), self._escape(target)))
+        self._norev_delentry(target.dirpath())
+
+    def rename(self, target, msg="renamed by py lib invocation"):
+        """ rename this path to target with checkin message msg. """
+        if getattr(self, 'rev', None) is not None:
+            raise py.error.EINVAL(self, "revisions are immutable")
+        self._svncmdexecauth('svn move -m "%s" --force "%s" "%s"' %(
+                             msg, self._escape(self), self._escape(target)))
+        self._norev_delentry(self.dirpath())
+        self._norev_delentry(self)
+
+    def remove(self, rec=1, msg='removed by py lib invocation'):
+        """ remove a file or directory (or a directory tree if rec=1) with
+checkin message msg."""
+        if self.rev is not None:
+            raise py.error.EINVAL(self, "revisions are immutable")
+        self._svncmdexecauth('svn rm -m "%s" "%s"' %(msg, self._escape(self)))
+        self._norev_delentry(self.dirpath())
+
+    def export(self, topath):
+        """ export to a local path
+
+            topath should not exist prior to calling this, returns a
+            py.path.local instance
+        """
+        topath = py.path.local(topath)
+        args = ['"%s"' % (self._escape(self),),
+                '"%s"' % (self._escape(topath),)]
+        if self.rev is not None:
+            args = ['-r', str(self.rev)] + args
+        self._svncmdexecauth('svn export %s' % (' '.join(args),))
+        return topath
+
+    def ensure(self, *args, **kwargs):
+        """ ensure that an args-joined path exists (by default as
+            a file). If you specify a keyword argument 'dir=True'
+            then the path is forced to be a directory path.
+        """
+        if getattr(self, 'rev', None) is not None:
+            raise py.error.EINVAL(self, "revisions are immutable")
+        target = self.join(*args)
+        dir = kwargs.get('dir', 0)
+        for x in target.parts(reverse=True):
+            if x.check():
+                break
+        else:
+            raise py.error.ENOENT(target, "has not any valid base!")
+        if x == target:
+            if not x.check(dir=dir):
+                raise dir and py.error.ENOTDIR(x) or py.error.EISDIR(x)
+            return x
+        tocreate = target.relto(x)
+        basename = tocreate.split(self.sep, 1)[0]
+        tempdir = py.path.local.mkdtemp()
+        try:
+            tempdir.ensure(tocreate, dir=dir)
+            cmd = 'svn import -m "%s" "%s" "%s"' % (
+                    "ensure %s" % self._escape(tocreate),
+                    self._escape(tempdir.join(basename)),
+                    x.join(basename)._encodedurl())
+            self._svncmdexecauth(cmd)
+            self._norev_delentry(x)
+        finally:
+            tempdir.remove()
+        return target
+
+    # end of modifying methods
+    def _propget(self, name):
+        res = self._svnwithrev('propget', name)
+        return res[:-1] # strip trailing newline
+
+    def _proplist(self):
+        res = self._svnwithrev('proplist')
+        lines = res.split('\n')
+        lines = [x.strip() for x in lines[1:]]
+        return svncommon.PropListDict(self, lines)
+
+    def info(self):
+        """ return an Info structure with svn-provided information. """
+        parent = self.dirpath()
+        nameinfo_seq = parent._listdir_nameinfo()
+        bn = self.basename
+        for name, info in nameinfo_seq:
+            if name == bn:
+                return info
+        raise py.error.ENOENT(self)
+
+
+    def _listdir_nameinfo(self):
+        """ return sequence of name-info directory entries of self """
+        def builder():
+            try:
+                res = self._svnwithrev('ls', '-v')
+            except process.cmdexec.Error:
+                e = sys.exc_info()[1]
+                if e.err.find('non-existent in that revision') != -1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.find("E200009:") != -1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.find('File not found') != -1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.find('not part of a repository')!=-1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.find('Unable to open')!=-1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.lower().find('method not allowed')!=-1:
+                    raise py.error.EACCES(self, e.err)
+                raise py.error.Error(e.err)
+            lines = res.split('\n')
+            nameinfo_seq = []
+            for lsline in lines:
+                if lsline:
+                    info = InfoSvnCommand(lsline)
+                    if info._name != '.':  # svn 1.5 produces '.' dirs,
+                        nameinfo_seq.append((info._name, info))
+            nameinfo_seq.sort()
+            return nameinfo_seq
+        auth = self.auth and self.auth.makecmdoptions() or None
+        if self.rev is not None:
+            return self._lsrevcache.getorbuild((self.strpath, self.rev, auth),
+                                               builder)
+        else:
+            return self._lsnorevcache.getorbuild((self.strpath, auth),
+                                                 builder)
+
+    def listdir(self, fil=None, sort=None):
+        """ list directory contents, possibly filter by the given fil func
+            and possibly sorted.
+        """
+        if isinstance(fil, str):
+            fil = common.FNMatcher(fil)
+        nameinfo_seq = self._listdir_nameinfo()
+        if len(nameinfo_seq) == 1:
+            name, info = nameinfo_seq[0]
+            if name == self.basename and info.kind == 'file':
+                #if not self.check(dir=1):
+                raise py.error.ENOTDIR(self)
+        paths = [self.join(name) for (name, info) in nameinfo_seq]
+        if fil:
+            paths = [x for x in paths if fil(x)]
+        self._sortlist(paths, sort)
+        return paths
+
+
+    def log(self, rev_start=None, rev_end=1, verbose=False):
+        """ return a list of LogEntry instances for this path.
+rev_start is the starting revision (defaulting to the first one).
+rev_end is the last revision (defaulting to HEAD).
+if verbose is True, then the LogEntry instances also know which files changed.
+"""
+        assert self.check() #make it simpler for the pipe
+        rev_start = rev_start is None and "HEAD" or rev_start
+        rev_end = rev_end is None and "HEAD" or rev_end
+
+        if rev_start == "HEAD" and rev_end == 1:
+            rev_opt = ""
+        else:
+            rev_opt = "-r %s:%s" % (rev_start, rev_end)
+        verbose_opt = verbose and "-v" or ""
+        xmlpipe =  self._svnpopenauth('svn log --xml %s %s "%s"' %
+                                      (rev_opt, verbose_opt, self.strpath))
+        from xml.dom import minidom
+        tree = minidom.parse(xmlpipe)
+        result = []
+        for logentry in filter(None, tree.firstChild.childNodes):
+            if logentry.nodeType == logentry.ELEMENT_NODE:
+                result.append(svncommon.LogEntry(logentry))
+        return result
+
+#01234567890123456789012345678901234567890123467
+#   2256      hpk        165 Nov 24 17:55 __init__.py
+# XXX spotted by Guido, SVN 1.3.0 has different aligning, breaks the code!!!
+#   1312 johnny           1627 May 05 14:32 test_decorators.py
+#
+class InfoSvnCommand:
+    # the '0?' part in the middle is an indication of whether the resource is
+    # locked, see 'svn help ls'
+    lspattern = re.compile(
+        r'^ *(?P<rev>\d+) +(?P<author>.+?) +(0? *(?P<size>\d+))? '
+            '*(?P<date>\w+ +\d{2} +[\d:]+) +(?P<file>.*)$')
+    def __init__(self, line):
+        # this is a typical line from 'svn ls http://...'
+        #_    1127      jum        0 Jul 13 15:28 branch/
+        match = self.lspattern.match(line)
+        data = match.groupdict()
+        self._name = data['file']
+        if self._name[-1] == '/':
+            self._name = self._name[:-1]
+            self.kind = 'dir'
+        else:
+            self.kind = 'file'
+        #self.has_props = l.pop(0) == 'P'
+        self.created_rev = int(data['rev'])
+        self.last_author = data['author']
+        self.size = data['size'] and int(data['size']) or 0
+        self.mtime = parse_time_with_missing_year(data['date'])
+        self.time = self.mtime * 1000000
+
+    def __eq__(self, other):
+        return self.__dict__ == other.__dict__
+
+
+#____________________________________________________
+#
+# helper functions
+#____________________________________________________
+def parse_time_with_missing_year(timestr):
+    """ analyze the time part from a single line of "svn ls -v"
+    the svn output doesn't show the year makes the 'timestr'
+    ambigous.
+    """
+    import calendar
+    t_now = time.gmtime()
+
+    tparts = timestr.split()
+    month = time.strptime(tparts.pop(0), '%b')[1]
+    day = time.strptime(tparts.pop(0), '%d')[2]
+    last = tparts.pop(0) # year or hour:minute
+    try:
+        if ":" in last:
+            raise ValueError()
+        year = time.strptime(last, '%Y')[0]
+        hour = minute = 0
+    except ValueError:
+        hour, minute = time.strptime(last, '%H:%M')[3:5]
+        year = t_now[0]
+
+        t_result = (year, month, day, hour, minute, 0,0,0,0)
+        if t_result > t_now:
+            year -= 1
+    t_result = (year, month, day, hour, minute, 0,0,0,0)
+    return calendar.timegm(t_result)
+
+class PathEntry:
+    def __init__(self, ppart):
+        self.strpath = ppart.firstChild.nodeValue.encode('UTF-8')
+        self.action = ppart.getAttribute('action').encode('UTF-8')
+        if self.action == 'A':
+            self.copyfrom_path = ppart.getAttribute('copyfrom-path').encode('UTF-8')
+            if self.copyfrom_path:
+                self.copyfrom_rev = int(ppart.getAttribute('copyfrom-rev'))
+
diff --git a/lib/spack/external/py/_path/svnwc.py b/lib/spack/external/py/_path/svnwc.py
new file mode 100644
index 0000000000..00d3b4bbaf
--- /dev/null
+++ b/lib/spack/external/py/_path/svnwc.py
@@ -0,0 +1,1240 @@
+"""
+svn-Command based Implementation of a Subversion WorkingCopy Path.
+
+  SvnWCCommandPath  is the main class.
+
+"""
+
+import os, sys, time, re, calendar
+import py
+import subprocess
+from py._path import common
+
+#-----------------------------------------------------------
+# Caching latest repository revision and repo-paths
+# (getting them is slow with the current implementations)
+#
+# XXX make mt-safe
+#-----------------------------------------------------------
+
+class cache:
+    proplist = {}
+    info = {}
+    entries = {}
+    prop = {}
+
+class RepoEntry:
+    def __init__(self, url, rev, timestamp):
+        self.url = url
+        self.rev = rev
+        self.timestamp = timestamp
+
+    def __str__(self):
+        return "repo: %s;%s  %s" %(self.url, self.rev, self.timestamp)
+
+class RepoCache:
+    """ The Repocache manages discovered repository paths
+    and their revisions.  If inside a timeout the cache
+    will even return the revision of the root.
+    """
+    timeout = 20 # seconds after which we forget that we know the last revision
+
+    def __init__(self):
+        self.repos = []
+
+    def clear(self):
+        self.repos = []
+
+    def put(self, url, rev, timestamp=None):
+        if rev is None:
+            return
+        if timestamp is None:
+            timestamp = time.time()
+
+        for entry in self.repos:
+            if url == entry.url:
+                entry.timestamp = timestamp
+                entry.rev = rev
+                #print "set repo", entry
+                break
+        else:
+            entry = RepoEntry(url, rev, timestamp)
+            self.repos.append(entry)
+            #print "appended repo", entry
+
+    def get(self, url):
+        now = time.time()
+        for entry in self.repos:
+            if url.startswith(entry.url):
+                if now < entry.timestamp + self.timeout:
+                    #print "returning immediate Etrny", entry
+                    return entry.url, entry.rev
+                return entry.url, -1
+        return url, -1
+
+repositories = RepoCache()
+
+
+# svn support code
+
+ALLOWED_CHARS = "_ -/\\=$.~+%" #add characters as necessary when tested
+if sys.platform == "win32":
+    ALLOWED_CHARS += ":"
+ALLOWED_CHARS_HOST = ALLOWED_CHARS + '@:'
+
+def _getsvnversion(ver=[]):
+    try:
+        return ver[0]
+    except IndexError:
+        v = py.process.cmdexec("svn -q --version")
+        v.strip()
+        v = '.'.join(v.split('.')[:2])
+        ver.append(v)
+        return v
+
+def _escape_helper(text):
+    text = str(text)
+    if py.std.sys.platform != 'win32':
+        text = str(text).replace('$', '\\$')
+    return text
+
+def _check_for_bad_chars(text, allowed_chars=ALLOWED_CHARS):
+    for c in str(text):
+        if c.isalnum():
+            continue
+        if c in allowed_chars:
+            continue
+        return True
+    return False
+
+def checkbadchars(url):
+    # (hpk) not quite sure about the exact purpose, guido w.?
+    proto, uri = url.split("://", 1)
+    if proto != "file":
+        host, uripath = uri.split('/', 1)
+        # only check for bad chars in the non-protocol parts
+        if (_check_for_bad_chars(host, ALLOWED_CHARS_HOST) \
+            or _check_for_bad_chars(uripath, ALLOWED_CHARS)):
+            raise ValueError("bad char in %r" % (url, ))
+
+
+#_______________________________________________________________
+
+class SvnPathBase(common.PathBase):
+    """ Base implementation for SvnPath implementations. """
+    sep = '/'
+
+    def _geturl(self):
+        return self.strpath
+    url = property(_geturl, None, None, "url of this svn-path.")
+
+    def __str__(self):
+        """ return a string representation (including rev-number) """
+        return self.strpath
+
+    def __hash__(self):
+        return hash(self.strpath)
+
+    def new(self, **kw):
+        """ create a modified version of this path. A 'rev' argument
+            indicates a new revision.
+            the following keyword arguments modify various path parts::
+
+              http://host.com/repo/path/file.ext
+              |-----------------------|          dirname
+                                        |------| basename
+                                        |--|     purebasename
+                                            |--| ext
+        """
+        obj = object.__new__(self.__class__)
+        obj.rev = kw.get('rev', self.rev)
+        obj.auth = kw.get('auth', self.auth)
+        dirname, basename, purebasename, ext = self._getbyspec(
+             "dirname,basename,purebasename,ext")
+        if 'basename' in kw:
+            if 'purebasename' in kw or 'ext' in kw:
+                raise ValueError("invalid specification %r" % kw)
+        else:
+            pb = kw.setdefault('purebasename', purebasename)
+            ext = kw.setdefault('ext', ext)
+            if ext and not ext.startswith('.'):
+                ext = '.' + ext
+            kw['basename'] = pb + ext
+
+        kw.setdefault('dirname', dirname)
+        kw.setdefault('sep', self.sep)
+        if kw['basename']:
+            obj.strpath = "%(dirname)s%(sep)s%(basename)s" % kw
+        else:
+            obj.strpath = "%(dirname)s" % kw
+        return obj
+
+    def _getbyspec(self, spec):
+        """ get specified parts of the path.  'arg' is a string
+            with comma separated path parts. The parts are returned
+            in exactly the order of the specification.
+
+            you may specify the following parts:
+
+            http://host.com/repo/path/file.ext
+            |-----------------------|          dirname
+                                      |------| basename
+                                      |--|     purebasename
+                                          |--| ext
+        """
+        res = []
+        parts = self.strpath.split(self.sep)
+        for name in spec.split(','):
+            name = name.strip()
+            if name == 'dirname':
+                res.append(self.sep.join(parts[:-1]))
+            elif name == 'basename':
+                res.append(parts[-1])
+            else:
+                basename = parts[-1]
+                i = basename.rfind('.')
+                if i == -1:
+                    purebasename, ext = basename, ''
+                else:
+                    purebasename, ext = basename[:i], basename[i:]
+                if name == 'purebasename':
+                    res.append(purebasename)
+                elif name == 'ext':
+                    res.append(ext)
+                else:
+                    raise NameError("Don't know part %r" % name)
+        return res
+
+    def __eq__(self, other):
+        """ return true if path and rev attributes each match """
+        return (str(self) == str(other) and
+               (self.rev == other.rev or self.rev == other.rev))
+
+    def __ne__(self, other):
+        return not self == other
+
+    def join(self, *args):
+        """ return a new Path (with the same revision) which is composed
+            of the self Path followed by 'args' path components.
+        """
+        if not args:
+            return self
+
+        args = tuple([arg.strip(self.sep) for arg in args])
+        parts = (self.strpath, ) + args
+        newpath = self.__class__(self.sep.join(parts), self.rev, self.auth)
+        return newpath
+
+    def propget(self, name):
+        """ return the content of the given property. """
+        value = self._propget(name)
+        return value
+
+    def proplist(self):
+        """ list all property names. """
+        content = self._proplist()
+        return content
+
+    def size(self):
+        """ Return the size of the file content of the Path. """
+        return self.info().size
+
+    def mtime(self):
+        """ Return the last modification time of the file. """
+        return self.info().mtime
+
+    # shared help methods
+
+    def _escape(self, cmd):
+        return _escape_helper(cmd)
+
+
+    #def _childmaxrev(self):
+    #    """ return maximum revision number of childs (or self.rev if no childs) """
+    #    rev = self.rev
+    #    for name, info in self._listdir_nameinfo():
+    #        rev = max(rev, info.created_rev)
+    #    return rev
+
+    #def _getlatestrevision(self):
+    #    """ return latest repo-revision for this path. """
+    #    url = self.strpath
+    #    path = self.__class__(url, None)
+    #
+    #    # we need a long walk to find the root-repo and revision
+    #    while 1:
+    #        try:
+    #            rev = max(rev, path._childmaxrev())
+    #            previous = path
+    #            path = path.dirpath()
+    #        except (IOError, process.cmdexec.Error):
+    #            break
+    #    if rev is None:
+    #        raise IOError, "could not determine newest repo revision for %s" % self
+    #    return rev
+
+    class Checkers(common.Checkers):
+        def dir(self):
+            try:
+                return self.path.info().kind == 'dir'
+            except py.error.Error:
+                return self._listdirworks()
+
+        def _listdirworks(self):
+            try:
+                self.path.listdir()
+            except py.error.ENOENT:
+                return False
+            else:
+                return True
+
+        def file(self):
+            try:
+                return self.path.info().kind == 'file'
+            except py.error.ENOENT:
+                return False
+
+        def exists(self):
+            try:
+                return self.path.info()
+            except py.error.ENOENT:
+                return self._listdirworks()
+
+def parse_apr_time(timestr):
+    i = timestr.rfind('.')
+    if i == -1:
+        raise ValueError("could not parse %s" % timestr)
+    timestr = timestr[:i]
+    parsedtime = time.strptime(timestr, "%Y-%m-%dT%H:%M:%S")
+    return time.mktime(parsedtime)
+
+class PropListDict(dict):
+    """ a Dictionary which fetches values (InfoSvnCommand instances) lazily"""
+    def __init__(self, path, keynames):
+        dict.__init__(self, [(x, None) for x in keynames])
+        self.path = path
+
+    def __getitem__(self, key):
+        value = dict.__getitem__(self, key)
+        if value is None:
+            value = self.path.propget(key)
+            dict.__setitem__(self, key, value)
+        return value
+
+def fixlocale():
+    if sys.platform != 'win32':
+        return 'LC_ALL=C '
+    return ''
+
+# some nasty chunk of code to solve path and url conversion and quoting issues
+ILLEGAL_CHARS = '* | \ / : < > ? \t \n \x0b \x0c \r'.split(' ')
+if os.sep in ILLEGAL_CHARS:
+    ILLEGAL_CHARS.remove(os.sep)
+ISWINDOWS = sys.platform == 'win32'
+_reg_allow_disk = re.compile(r'^([a-z]\:\\)?[^:]+$', re.I)
+def _check_path(path):
+    illegal = ILLEGAL_CHARS[:]
+    sp = path.strpath
+    if ISWINDOWS:
+        illegal.remove(':')
+        if not _reg_allow_disk.match(sp):
+            raise ValueError('path may not contain a colon (:)')
+    for char in sp:
+        if char not in string.printable or char in illegal:
+            raise ValueError('illegal character %r in path' % (char,))
+
+def path_to_fspath(path, addat=True):
+    _check_path(path)
+    sp = path.strpath
+    if addat and path.rev != -1:
+        sp = '%s@%s' % (sp, path.rev)
+    elif addat:
+        sp = '%s@HEAD' % (sp,)
+    return sp
+
+def url_from_path(path):
+    fspath = path_to_fspath(path, False)
+    quote = py.std.urllib.quote
+    if ISWINDOWS:
+        match = _reg_allow_disk.match(fspath)
+        fspath = fspath.replace('\\', '/')
+        if match.group(1):
+            fspath = '/%s%s' % (match.group(1).replace('\\', '/'),
+                                quote(fspath[len(match.group(1)):]))
+        else:
+            fspath = quote(fspath)
+    else:
+        fspath = quote(fspath)
+    if path.rev != -1:
+        fspath = '%s@%s' % (fspath, path.rev)
+    else:
+        fspath = '%s@HEAD' % (fspath,)
+    return 'file://%s' % (fspath,)
+
+class SvnAuth(object):
+    """ container for auth information for Subversion """
+    def __init__(self, username, password, cache_auth=True, interactive=True):
+        self.username = username
+        self.password = password
+        self.cache_auth = cache_auth
+        self.interactive = interactive
+
+    def makecmdoptions(self):
+        uname = self.username.replace('"', '\\"')
+        passwd = self.password.replace('"', '\\"')
+        ret = []
+        if uname:
+            ret.append('--username="%s"' % (uname,))
+        if passwd:
+            ret.append('--password="%s"' % (passwd,))
+        if not self.cache_auth:
+            ret.append('--no-auth-cache')
+        if not self.interactive:
+            ret.append('--non-interactive')
+        return ' '.join(ret)
+
+    def __str__(self):
+        return "<SvnAuth username=%s ...>" %(self.username,)
+
+rex_blame = re.compile(r'\s*(\d+)\s*(\S+) (.*)')
+
+class SvnWCCommandPath(common.PathBase):
+    """ path implementation offering access/modification to svn working copies.
+        It has methods similar to the functions in os.path and similar to the
+        commands of the svn client.
+    """
+    sep = os.sep
+
+    def __new__(cls, wcpath=None, auth=None):
+        self = object.__new__(cls)
+        if isinstance(wcpath, cls):
+            if wcpath.__class__ == cls:
+                return wcpath
+            wcpath = wcpath.localpath
+        if _check_for_bad_chars(str(wcpath),
+                                          ALLOWED_CHARS):
+            raise ValueError("bad char in wcpath %s" % (wcpath, ))
+        self.localpath = py.path.local(wcpath)
+        self.auth = auth
+        return self
+
+    strpath = property(lambda x: str(x.localpath), None, None, "string path")
+    rev = property(lambda x: x.info(usecache=0).rev, None, None, "revision")
+
+    def __eq__(self, other):
+        return self.localpath == getattr(other, 'localpath', None)
+
+    def _geturl(self):
+        if getattr(self, '_url', None) is None:
+            info = self.info()
+            self._url = info.url #SvnPath(info.url, info.rev)
+        assert isinstance(self._url, py.builtin._basestring)
+        return self._url
+
+    url = property(_geturl, None, None, "url of this WC item")
+
+    def _escape(self, cmd):
+        return _escape_helper(cmd)
+
+    def dump(self, obj):
+        """ pickle object into path location"""
+        return self.localpath.dump(obj)
+
+    def svnurl(self):
+        """ return current SvnPath for this WC-item. """
+        info = self.info()
+        return py.path.svnurl(info.url)
+
+    def __repr__(self):
+        return "svnwc(%r)" % (self.strpath) # , self._url)
+
+    def __str__(self):
+        return str(self.localpath)
+
+    def _makeauthoptions(self):
+        if self.auth is None:
+            return ''
+        return self.auth.makecmdoptions()
+
+    def _authsvn(self, cmd, args=None):
+        args = args and list(args) or []
+        args.append(self._makeauthoptions())
+        return self._svn(cmd, *args)
+
+    def _svn(self, cmd, *args):
+        l = ['svn %s' % cmd]
+        args = [self._escape(item) for item in args]
+        l.extend(args)
+        l.append('"%s"' % self._escape(self.strpath))
+        # try fixing the locale because we can't otherwise parse
+        string = fixlocale() + " ".join(l)
+        try:
+            try:
+                key = 'LC_MESSAGES'
+                hold = os.environ.get(key)
+                os.environ[key] = 'C'
+                out = py.process.cmdexec(string)
+            finally:
+                if hold:
+                    os.environ[key] = hold
+                else:
+                    del os.environ[key]
+        except py.process.cmdexec.Error:
+            e = sys.exc_info()[1]
+            strerr = e.err.lower()
+            if strerr.find('not found') != -1:
+                raise py.error.ENOENT(self)
+            elif strerr.find("E200009:") != -1:
+                raise py.error.ENOENT(self)
+            if (strerr.find('file exists') != -1 or
+                strerr.find('file already exists') != -1 or
+                strerr.find('w150002:') != -1 or
+                strerr.find("can't create directory") != -1):
+                raise py.error.EEXIST(strerr) #self)
+            raise
+        return out
+
+    def switch(self, url):
+        """ switch to given URL. """
+        self._authsvn('switch', [url])
+
+    def checkout(self, url=None, rev=None):
+        """ checkout from url to local wcpath. """
+        args = []
+        if url is None:
+            url = self.url
+        if rev is None or rev == -1:
+            if (py.std.sys.platform != 'win32' and
+                    _getsvnversion() == '1.3'):
+                url += "@HEAD"
+        else:
+            if _getsvnversion() == '1.3':
+                url += "@%d" % rev
+            else:
+                args.append('-r' + str(rev))
+        args.append(url)
+        self._authsvn('co', args)
+
+    def update(self, rev='HEAD', interactive=True):
+        """ update working copy item to given revision. (None -> HEAD). """
+        opts = ['-r', rev]
+        if not interactive:
+            opts.append("--non-interactive")
+        self._authsvn('up', opts)
+
+    def write(self, content, mode='w'):
+        """ write content into local filesystem wc. """
+        self.localpath.write(content, mode)
+
+    def dirpath(self, *args):
+        """ return the directory Path of the current Path. """
+        return self.__class__(self.localpath.dirpath(*args), auth=self.auth)
+
+    def _ensuredirs(self):
+        parent = self.dirpath()
+        if parent.check(dir=0):
+            parent._ensuredirs()
+        if self.check(dir=0):
+            self.mkdir()
+        return self
+
+    def ensure(self, *args, **kwargs):
+        """ ensure that an args-joined path exists (by default as
+            a file). if you specify a keyword argument 'directory=True'
+            then the path is forced  to be a directory path.
+        """
+        p = self.join(*args)
+        if p.check():
+            if p.check(versioned=False):
+                p.add()
+            return p
+        if kwargs.get('dir', 0):
+            return p._ensuredirs()
+        parent = p.dirpath()
+        parent._ensuredirs()
+        p.write("")
+        p.add()
+        return p
+
+    def mkdir(self, *args):
+        """ create & return the directory joined with args. """
+        if args:
+            return self.join(*args).mkdir()
+        else:
+            self._svn('mkdir')
+            return self
+
+    def add(self):
+        """ add ourself to svn """
+        self._svn('add')
+
+    def remove(self, rec=1, force=1):
+        """ remove a file or a directory tree. 'rec'ursive is
+            ignored and considered always true (because of
+            underlying svn semantics.
+        """
+        assert rec, "svn cannot remove non-recursively"
+        if not self.check(versioned=True):
+            # not added to svn (anymore?), just remove
+            py.path.local(self).remove()
+            return
+        flags = []
+        if force:
+            flags.append('--force')
+        self._svn('remove', *flags)
+
+    def copy(self, target):
+        """ copy path to target."""
+        py.process.cmdexec("svn copy %s %s" %(str(self), str(target)))
+
+    def rename(self, target):
+        """ rename this path to target. """
+        py.process.cmdexec("svn move --force %s %s" %(str(self), str(target)))
+
+    def lock(self):
+        """ set a lock (exclusive) on the resource """
+        out = self._authsvn('lock').strip()
+        if not out:
+            # warning or error, raise exception
+            raise ValueError("unknown error in svn lock command")
+
+    def unlock(self):
+        """ unset a previously set lock """
+        out = self._authsvn('unlock').strip()
+        if out.startswith('svn:'):
+            # warning or error, raise exception
+            raise Exception(out[4:])
+
+    def cleanup(self):
+        """ remove any locks from the resource """
+        # XXX should be fixed properly!!!
+        try:
+            self.unlock()
+        except:
+            pass
+
+    def status(self, updates=0, rec=0, externals=0):
+        """ return (collective) Status object for this file. """
+        # http://svnbook.red-bean.com/book.html#svn-ch-3-sect-4.3.1
+        #             2201     2192        jum   test
+        # XXX
+        if externals:
+            raise ValueError("XXX cannot perform status() "
+                             "on external items yet")
+        else:
+            #1.2 supports: externals = '--ignore-externals'
+            externals = ''
+        if rec:
+            rec= ''
+        else:
+            rec = '--non-recursive'
+
+        # XXX does not work on all subversion versions
+        #if not externals:
+        #    externals = '--ignore-externals'
+
+        if updates:
+            updates = '-u'
+        else:
+            updates = ''
+
+        try:
+            cmd = 'status -v --xml --no-ignore %s %s %s' % (
+                    updates, rec, externals)
+            out = self._authsvn(cmd)
+        except py.process.cmdexec.Error:
+            cmd = 'status -v --no-ignore %s %s %s' % (
+                    updates, rec, externals)
+            out = self._authsvn(cmd)
+            rootstatus = WCStatus(self).fromstring(out, self)
+        else:
+            rootstatus = XMLWCStatus(self).fromstring(out, self)
+        return rootstatus
+
+    def diff(self, rev=None):
+        """ return a diff of the current path against revision rev (defaulting
+            to the last one).
+        """
+        args = []
+        if rev is not None:
+            args.append("-r %d" % rev)
+        out = self._authsvn('diff', args)
+        return out
+
+    def blame(self):
+        """ return a list of tuples of three elements:
+            (revision, commiter, line)
+        """
+        out = self._svn('blame')
+        result = []
+        blamelines = out.splitlines()
+        reallines = py.path.svnurl(self.url).readlines()
+        for i, (blameline, line) in enumerate(
+                zip(blamelines, reallines)):
+            m = rex_blame.match(blameline)
+            if not m:
+                raise ValueError("output line %r of svn blame does not match "
+                                 "expected format" % (line, ))
+            rev, name, _ = m.groups()
+            result.append((int(rev), name, line))
+        return result
+
+    _rex_commit = re.compile(r'.*Committed revision (\d+)\.$', re.DOTALL)
+    def commit(self, msg='', rec=1):
+        """ commit with support for non-recursive commits """
+        # XXX i guess escaping should be done better here?!?
+        cmd = 'commit -m "%s" --force-log' % (msg.replace('"', '\\"'),)
+        if not rec:
+            cmd += ' -N'
+        out = self._authsvn(cmd)
+        try:
+            del cache.info[self]
+        except KeyError:
+            pass
+        if out:
+            m = self._rex_commit.match(out)
+            return int(m.group(1))
+
+    def propset(self, name, value, *args):
+        """ set property name to value on this path. """
+        d = py.path.local.mkdtemp()
+        try:
+            p = d.join('value')
+            p.write(value)
+            self._svn('propset', name, '--file', str(p), *args)
+        finally:
+            d.remove()
+
+    def propget(self, name):
+        """ get property name on this path. """
+        res = self._svn('propget', name)
+        return res[:-1] # strip trailing newline
+
+    def propdel(self, name):
+        """ delete property name on this path. """
+        res = self._svn('propdel', name)
+        return res[:-1] # strip trailing newline
+
+    def proplist(self, rec=0):
+        """ return a mapping of property names to property values.
+If rec is True, then return a dictionary mapping sub-paths to such mappings.
+"""
+        if rec:
+            res = self._svn('proplist -R')
+            return make_recursive_propdict(self, res)
+        else:
+            res = self._svn('proplist')
+            lines = res.split('\n')
+            lines = [x.strip() for x in lines[1:]]
+            return PropListDict(self, lines)
+
+    def revert(self, rec=0):
+        """ revert the local changes of this path. if rec is True, do so
+recursively. """
+        if rec:
+            result = self._svn('revert -R')
+        else:
+            result = self._svn('revert')
+        return result
+
+    def new(self, **kw):
+        """ create a modified version of this path. A 'rev' argument
+            indicates a new revision.
+            the following keyword arguments modify various path parts:
+
+              http://host.com/repo/path/file.ext
+              |-----------------------|          dirname
+                                        |------| basename
+                                        |--|     purebasename
+                                            |--| ext
+        """
+        if kw:
+            localpath = self.localpath.new(**kw)
+        else:
+            localpath = self.localpath
+        return self.__class__(localpath, auth=self.auth)
+
+    def join(self, *args, **kwargs):
+        """ return a new Path (with the same revision) which is composed
+            of the self Path followed by 'args' path components.
+        """
+        if not args:
+            return self
+        localpath = self.localpath.join(*args, **kwargs)
+        return self.__class__(localpath, auth=self.auth)
+
+    def info(self, usecache=1):
+        """ return an Info structure with svn-provided information. """
+        info = usecache and cache.info.get(self)
+        if not info:
+            try:
+                output = self._svn('info')
+            except py.process.cmdexec.Error:
+                e = sys.exc_info()[1]
+                if e.err.find('Path is not a working copy directory') != -1:
+                    raise py.error.ENOENT(self, e.err)
+                elif e.err.find("is not under version control") != -1:
+                    raise py.error.ENOENT(self, e.err)
+                raise
+            # XXX SVN 1.3 has output on stderr instead of stdout (while it does
+            # return 0!), so a bit nasty, but we assume no output is output
+            # to stderr...
+            if (output.strip() == '' or
+                    output.lower().find('not a versioned resource') != -1):
+                raise py.error.ENOENT(self, output)
+            info = InfoSvnWCCommand(output)
+
+            # Can't reliably compare on Windows without access to win32api
+            if py.std.sys.platform != 'win32':
+                if info.path != self.localpath:
+                    raise py.error.ENOENT(self, "not a versioned resource:" +
+                            " %s != %s" % (info.path, self.localpath))
+            cache.info[self] = info
+        return info
+
+    def listdir(self, fil=None, sort=None):
+        """ return a sequence of Paths.
+
+        listdir will return either a tuple or a list of paths
+        depending on implementation choices.
+        """
+        if isinstance(fil, str):
+            fil = common.FNMatcher(fil)
+        # XXX unify argument naming with LocalPath.listdir
+        def notsvn(path):
+            return path.basename != '.svn'
+
+        paths = []
+        for localpath in self.localpath.listdir(notsvn):
+            p = self.__class__(localpath, auth=self.auth)
+            if notsvn(p) and (not fil or fil(p)):
+                paths.append(p)
+        self._sortlist(paths, sort)
+        return paths
+
+    def open(self, mode='r'):
+        """ return an opened file with the given mode. """
+        return open(self.strpath, mode)
+
+    def _getbyspec(self, spec):
+        return self.localpath._getbyspec(spec)
+
+    class Checkers(py.path.local.Checkers):
+        def __init__(self, path):
+            self.svnwcpath = path
+            self.path = path.localpath
+        def versioned(self):
+            try:
+                s = self.svnwcpath.info()
+            except (py.error.ENOENT, py.error.EEXIST):
+                return False
+            except py.process.cmdexec.Error:
+                e = sys.exc_info()[1]
+                if e.err.find('is not a working copy')!=-1:
+                    return False
+                if e.err.lower().find('not a versioned resource') != -1:
+                    return False
+                raise
+            else:
+                return True
+
+    def log(self, rev_start=None, rev_end=1, verbose=False):
+        """ return a list of LogEntry instances for this path.
+rev_start is the starting revision (defaulting to the first one).
+rev_end is the last revision (defaulting to HEAD).
+if verbose is True, then the LogEntry instances also know which files changed.
+"""
+        assert self.check()   # make it simpler for the pipe
+        rev_start = rev_start is None and "HEAD" or rev_start
+        rev_end = rev_end is None and "HEAD" or rev_end
+        if rev_start == "HEAD" and rev_end == 1:
+                rev_opt = ""
+        else:
+            rev_opt = "-r %s:%s" % (rev_start, rev_end)
+        verbose_opt = verbose and "-v" or ""
+        locale_env = fixlocale()
+        # some blather on stderr
+        auth_opt = self._makeauthoptions()
+        #stdin, stdout, stderr  = os.popen3(locale_env +
+        #                                   'svn log --xml %s %s %s "%s"' % (
+        #                                    rev_opt, verbose_opt, auth_opt,
+        #                                    self.strpath))
+        cmd = locale_env + 'svn log --xml %s %s %s "%s"' % (
+            rev_opt, verbose_opt, auth_opt, self.strpath)
+
+        popen = subprocess.Popen(cmd,
+                    stdout=subprocess.PIPE,
+                    stderr=subprocess.PIPE,
+                    shell=True,
+        )
+        stdout, stderr = popen.communicate()
+        stdout = py.builtin._totext(stdout, sys.getdefaultencoding())
+        minidom,ExpatError = importxml()
+        try:
+            tree = minidom.parseString(stdout)
+        except ExpatError:
+            raise ValueError('no such revision')
+        result = []
+        for logentry in filter(None, tree.firstChild.childNodes):
+            if logentry.nodeType == logentry.ELEMENT_NODE:
+                result.append(LogEntry(logentry))
+        return result
+
+    def size(self):
+        """ Return the size of the file content of the Path. """
+        return self.info().size
+
+    def mtime(self):
+        """ Return the last modification time of the file. """
+        return self.info().mtime
+
+    def __hash__(self):
+        return hash((self.strpath, self.__class__, self.auth))
+
+
+class WCStatus:
+    attrnames = ('modified','added', 'conflict', 'unchanged', 'external',
+                'deleted', 'prop_modified', 'unknown', 'update_available',
+                'incomplete', 'kindmismatch', 'ignored', 'locked', 'replaced'
+                )
+
+    def __init__(self, wcpath, rev=None, modrev=None, author=None):
+        self.wcpath = wcpath
+        self.rev = rev
+        self.modrev = modrev
+        self.author = author
+
+        for name in self.attrnames:
+            setattr(self, name, [])
+
+    def allpath(self, sort=True, **kw):
+        d = {}
+        for name in self.attrnames:
+            if name not in kw or kw[name]:
+                for path in getattr(self, name):
+                    d[path] = 1
+        l = d.keys()
+        if sort:
+            l.sort()
+        return l
+
+    # XXX a bit scary to assume there's always 2 spaces between username and
+    # path, however with win32 allowing spaces in user names there doesn't
+    # seem to be a more solid approach :(
+    _rex_status = re.compile(r'\s+(\d+|-)\s+(\S+)\s+(.+?)\s{2,}(.*)')
+
+    def fromstring(data, rootwcpath, rev=None, modrev=None, author=None):
+        """ return a new WCStatus object from data 's'
+        """
+        rootstatus = WCStatus(rootwcpath, rev, modrev, author)
+        update_rev = None
+        for line in data.split('\n'):
+            if not line.strip():
+                continue
+            #print "processing %r" % line
+            flags, rest = line[:8], line[8:]
+            # first column
+            c0,c1,c2,c3,c4,c5,x6,c7 = flags
+            #if '*' in line:
+            #    print "flags", repr(flags), "rest", repr(rest)
+
+            if c0 in '?XI':
+                fn = line.split(None, 1)[1]
+                if c0 == '?':
+                    wcpath = rootwcpath.join(fn, abs=1)
+                    rootstatus.unknown.append(wcpath)
+                elif c0 == 'X':
+                    wcpath = rootwcpath.__class__(
+                        rootwcpath.localpath.join(fn, abs=1),
+                        auth=rootwcpath.auth)
+                    rootstatus.external.append(wcpath)
+                elif c0 == 'I':
+                    wcpath = rootwcpath.join(fn, abs=1)
+                    rootstatus.ignored.append(wcpath)
+
+                continue
+
+            #elif c0 in '~!' or c4 == 'S':
+            #    raise NotImplementedError("received flag %r" % c0)
+
+            m = WCStatus._rex_status.match(rest)
+            if not m:
+                if c7 == '*':
+                    fn = rest.strip()
+                    wcpath = rootwcpath.join(fn, abs=1)
+                    rootstatus.update_available.append(wcpath)
+                    continue
+                if line.lower().find('against revision:')!=-1:
+                    update_rev = int(rest.split(':')[1].strip())
+                    continue
+                if line.lower().find('status on external') > -1:
+                    # XXX not sure what to do here... perhaps we want to
+                    # store some state instead of just continuing, as right
+                    # now it makes the top-level external get added twice
+                    # (once as external, once as 'normal' unchanged item)
+                    # because of the way SVN presents external items
+                    continue
+                # keep trying
+                raise ValueError("could not parse line %r" % line)
+            else:
+                rev, modrev, author, fn = m.groups()
+            wcpath = rootwcpath.join(fn, abs=1)
+            #assert wcpath.check()
+            if c0 == 'M':
+                assert wcpath.check(file=1), "didn't expect a directory with changed content here"
+                rootstatus.modified.append(wcpath)
+            elif c0 == 'A' or c3 == '+' :
+                rootstatus.added.append(wcpath)
+            elif c0 == 'D':
+                rootstatus.deleted.append(wcpath)
+            elif c0 == 'C':
+                rootstatus.conflict.append(wcpath)
+            elif c0 == '~':
+                rootstatus.kindmismatch.append(wcpath)
+            elif c0 == '!':
+                rootstatus.incomplete.append(wcpath)
+            elif c0 == 'R':
+                rootstatus.replaced.append(wcpath)
+            elif not c0.strip():
+                rootstatus.unchanged.append(wcpath)
+            else:
+                raise NotImplementedError("received flag %r" % c0)
+
+            if c1 == 'M':
+                rootstatus.prop_modified.append(wcpath)
+            # XXX do we cover all client versions here?
+            if c2 == 'L' or c5 == 'K':
+                rootstatus.locked.append(wcpath)
+            if c7 == '*':
+                rootstatus.update_available.append(wcpath)
+
+            if wcpath == rootwcpath:
+                rootstatus.rev = rev
+                rootstatus.modrev = modrev
+                rootstatus.author = author
+                if update_rev:
+                    rootstatus.update_rev = update_rev
+                continue
+        return rootstatus
+    fromstring = staticmethod(fromstring)
+
+class XMLWCStatus(WCStatus):
+    def fromstring(data, rootwcpath, rev=None, modrev=None, author=None):
+        """ parse 'data' (XML string as outputted by svn st) into a status obj
+        """
+        # XXX for externals, the path is shown twice: once
+        # with external information, and once with full info as if
+        # the item was a normal non-external... the current way of
+        # dealing with this issue is by ignoring it - this does make
+        # externals appear as external items as well as 'normal',
+        # unchanged ones in the status object so this is far from ideal
+        rootstatus = WCStatus(rootwcpath, rev, modrev, author)
+        update_rev = None
+        minidom, ExpatError = importxml()
+        try:
+            doc = minidom.parseString(data)
+        except ExpatError:
+            e = sys.exc_info()[1]
+            raise ValueError(str(e))
+        urevels = doc.getElementsByTagName('against')
+        if urevels:
+            rootstatus.update_rev = urevels[-1].getAttribute('revision')
+        for entryel in doc.getElementsByTagName('entry'):
+            path = entryel.getAttribute('path')
+            statusel = entryel.getElementsByTagName('wc-status')[0]
+            itemstatus = statusel.getAttribute('item')
+
+            if itemstatus == 'unversioned':
+                wcpath = rootwcpath.join(path, abs=1)
+                rootstatus.unknown.append(wcpath)
+                continue
+            elif itemstatus == 'external':
+                wcpath = rootwcpath.__class__(
+                    rootwcpath.localpath.join(path, abs=1),
+                    auth=rootwcpath.auth)
+                rootstatus.external.append(wcpath)
+                continue
+            elif itemstatus == 'ignored':
+                wcpath = rootwcpath.join(path, abs=1)
+                rootstatus.ignored.append(wcpath)
+                continue
+            elif itemstatus == 'incomplete':
+                wcpath = rootwcpath.join(path, abs=1)
+                rootstatus.incomplete.append(wcpath)
+                continue
+
+            rev = statusel.getAttribute('revision')
+            if itemstatus == 'added' or itemstatus == 'none':
+                rev = '0'
+                modrev = '?'
+                author = '?'
+                date = ''
+            elif itemstatus == "replaced":
+                pass
+            else:
+                #print entryel.toxml()
+                commitel = entryel.getElementsByTagName('commit')[0]
+                if commitel:
+                    modrev = commitel.getAttribute('revision')
+                    author = ''
+                    author_els = commitel.getElementsByTagName('author')
+                    if author_els:
+                        for c in author_els[0].childNodes:
+                            author += c.nodeValue
+                    date = ''
+                    for c in commitel.getElementsByTagName('date')[0]\
+                            .childNodes:
+                        date += c.nodeValue
+
+            wcpath = rootwcpath.join(path, abs=1)
+
+            assert itemstatus != 'modified' or wcpath.check(file=1), (
+                'did\'t expect a directory with changed content here')
+
+            itemattrname = {
+                'normal': 'unchanged',
+                'unversioned': 'unknown',
+                'conflicted': 'conflict',
+                'none': 'added',
+            }.get(itemstatus, itemstatus)
+
+            attr = getattr(rootstatus, itemattrname)
+            attr.append(wcpath)
+
+            propsstatus = statusel.getAttribute('props')
+            if propsstatus not in ('none', 'normal'):
+                rootstatus.prop_modified.append(wcpath)
+
+            if wcpath == rootwcpath:
+                rootstatus.rev = rev
+                rootstatus.modrev = modrev
+                rootstatus.author = author
+                rootstatus.date = date
+
+            # handle repos-status element (remote info)
+            rstatusels = entryel.getElementsByTagName('repos-status')
+            if rstatusels:
+                rstatusel = rstatusels[0]
+                ritemstatus = rstatusel.getAttribute('item')
+                if ritemstatus in ('added', 'modified'):
+                    rootstatus.update_available.append(wcpath)
+
+            lockels = entryel.getElementsByTagName('lock')
+            if len(lockels):
+                rootstatus.locked.append(wcpath)
+
+        return rootstatus
+    fromstring = staticmethod(fromstring)
+
+class InfoSvnWCCommand:
+    def __init__(self, output):
+        # Path: test
+        # URL: http://codespeak.net/svn/std.path/trunk/dist/std.path/test
+        # Repository UUID: fd0d7bf2-dfb6-0310-8d31-b7ecfe96aada
+        # Revision: 2151
+        # Node Kind: directory
+        # Schedule: normal
+        # Last Changed Author: hpk
+        # Last Changed Rev: 2100
+        # Last Changed Date: 2003-10-27 20:43:14 +0100 (Mon, 27 Oct 2003)
+        # Properties Last Updated: 2003-11-03 14:47:48 +0100 (Mon, 03 Nov 2003)
+
+        d = {}
+        for line in output.split('\n'):
+            if not line.strip():
+                continue
+            key, value = line.split(':', 1)
+            key = key.lower().replace(' ', '')
+            value = value.strip()
+            d[key] = value
+        try:
+            self.url = d['url']
+        except KeyError:
+            raise  ValueError("Not a versioned resource")
+            #raise ValueError, "Not a versioned resource %r" % path
+        self.kind = d['nodekind'] == 'directory' and 'dir' or d['nodekind']
+        try:
+            self.rev = int(d['revision'])
+        except KeyError:
+            self.rev = None
+
+        self.path = py.path.local(d['path'])
+        self.size = self.path.size()
+        if 'lastchangedrev' in d:
+            self.created_rev = int(d['lastchangedrev'])
+        if 'lastchangedauthor' in d:
+            self.last_author = d['lastchangedauthor']
+        if 'lastchangeddate' in d:
+            self.mtime = parse_wcinfotime(d['lastchangeddate'])
+            self.time = self.mtime * 1000000
+
+    def __eq__(self, other):
+        return self.__dict__ == other.__dict__
+
+def parse_wcinfotime(timestr):
+    """ Returns seconds since epoch, UTC. """
+    # example: 2003-10-27 20:43:14 +0100 (Mon, 27 Oct 2003)
+    m = re.match(r'(\d+-\d+-\d+ \d+:\d+:\d+) ([+-]\d+) .*', timestr)
+    if not m:
+        raise ValueError("timestring %r does not match" % timestr)
+    timestr, timezone = m.groups()
+    # do not handle timezone specially, return value should be UTC
+    parsedtime = time.strptime(timestr, "%Y-%m-%d %H:%M:%S")
+    return calendar.timegm(parsedtime)
+
+def make_recursive_propdict(wcroot,
+                            output,
+                            rex = re.compile("Properties on '(.*)':")):
+    """ Return a dictionary of path->PropListDict mappings. """
+    lines = [x for x in output.split('\n') if x]
+    pdict = {}
+    while lines:
+        line = lines.pop(0)
+        m = rex.match(line)
+        if not m:
+            raise ValueError("could not parse propget-line: %r" % line)
+        path = m.groups()[0]
+        wcpath = wcroot.join(path, abs=1)
+        propnames = []
+        while lines and lines[0].startswith('  '):
+            propname = lines.pop(0).strip()
+            propnames.append(propname)
+        assert propnames, "must have found properties!"
+        pdict[wcpath] = PropListDict(wcpath, propnames)
+    return pdict
+
+
+def importxml(cache=[]):
+    if cache:
+        return cache
+    from xml.dom import minidom
+    from xml.parsers.expat import ExpatError
+    cache.extend([minidom, ExpatError])
+    return cache
+
+class LogEntry:
+    def __init__(self, logentry):
+        self.rev = int(logentry.getAttribute('revision'))
+        for lpart in filter(None, logentry.childNodes):
+            if lpart.nodeType == lpart.ELEMENT_NODE:
+                if lpart.nodeName == 'author':
+                    self.author = lpart.firstChild.nodeValue
+                elif lpart.nodeName == 'msg':
+                    if lpart.firstChild:
+                        self.msg = lpart.firstChild.nodeValue
+                    else:
+                        self.msg = ''
+                elif lpart.nodeName == 'date':
+                    #2003-07-29T20:05:11.598637Z
+                    timestr = lpart.firstChild.nodeValue
+                    self.date = parse_apr_time(timestr)
+                elif lpart.nodeName == 'paths':
+                    self.strpaths = []
+                    for ppart in filter(None, lpart.childNodes):
+                        if ppart.nodeType == ppart.ELEMENT_NODE:
+                            self.strpaths.append(PathEntry(ppart))
+    def __repr__(self):
+        return '<Logentry rev=%d author=%s date=%s>' % (
+            self.rev, self.author, self.date)
+
+
diff --git a/lib/spack/external/py/_process/__init__.py b/lib/spack/external/py/_process/__init__.py
new file mode 100644
index 0000000000..86c714ad1a
--- /dev/null
+++ b/lib/spack/external/py/_process/__init__.py
@@ -0,0 +1 @@
+""" high-level sub-process handling """
diff --git a/lib/spack/external/py/_process/cmdexec.py b/lib/spack/external/py/_process/cmdexec.py
new file mode 100644
index 0000000000..f83a249402
--- /dev/null
+++ b/lib/spack/external/py/_process/cmdexec.py
@@ -0,0 +1,49 @@
+import sys
+import subprocess
+import py
+from subprocess import Popen, PIPE
+
+def cmdexec(cmd):
+    """ return unicode output of executing 'cmd' in a separate process.
+
+    raise cmdexec.Error exeception if the command failed.
+    the exception will provide an 'err' attribute containing
+    the error-output from the command.
+    if the subprocess module does not provide a proper encoding/unicode strings
+    sys.getdefaultencoding() will be used, if that does not exist, 'UTF-8'.
+    """
+    process = subprocess.Popen(cmd, shell=True,
+            universal_newlines=True,
+            stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    out, err = process.communicate()
+    if sys.version_info[0] < 3: # on py3 we get unicode strings, on py2 not
+        try:
+            default_encoding = sys.getdefaultencoding() # jython may not have it
+        except AttributeError:
+            default_encoding = sys.stdout.encoding or 'UTF-8'
+        out = unicode(out, process.stdout.encoding or default_encoding)
+        err = unicode(err, process.stderr.encoding or default_encoding)
+    status = process.poll()
+    if status:
+        raise ExecutionFailed(status, status, cmd, out, err)
+    return out
+
+class ExecutionFailed(py.error.Error):
+    def __init__(self, status, systemstatus, cmd, out, err):
+        Exception.__init__(self)
+        self.status = status
+        self.systemstatus = systemstatus
+        self.cmd = cmd
+        self.err = err
+        self.out = out
+
+    def __str__(self):
+        return "ExecutionFailed: %d  %s\n%s" %(self.status, self.cmd, self.err)
+
+# export the exception under the name 'py.process.cmdexec.Error'
+cmdexec.Error = ExecutionFailed
+try:
+    ExecutionFailed.__module__ = 'py.process.cmdexec'
+    ExecutionFailed.__name__ = 'Error'
+except (AttributeError, TypeError):
+    pass
diff --git a/lib/spack/external/py/_process/forkedfunc.py b/lib/spack/external/py/_process/forkedfunc.py
new file mode 100644
index 0000000000..1c28530688
--- /dev/null
+++ b/lib/spack/external/py/_process/forkedfunc.py
@@ -0,0 +1,120 @@
+
+"""
+    ForkedFunc provides a way to run a function in a forked process
+    and get at its return value, stdout and stderr output as well
+    as signals and exitstatusus.
+"""
+
+import py
+import os
+import sys
+import marshal
+
+
+def get_unbuffered_io(fd, filename):
+    f = open(str(filename), "w")
+    if fd != f.fileno():
+        os.dup2(f.fileno(), fd)
+    class AutoFlush:
+        def write(self, data):
+            f.write(data)
+            f.flush()
+        def __getattr__(self, name):
+            return getattr(f, name)
+    return AutoFlush()
+
+
+class ForkedFunc:
+    EXITSTATUS_EXCEPTION = 3
+
+
+    def __init__(self, fun, args=None, kwargs=None, nice_level=0,
+                 child_on_start=None, child_on_exit=None):
+        if args is None:
+            args = []
+        if kwargs is None:
+            kwargs = {}
+        self.fun = fun
+        self.args = args
+        self.kwargs = kwargs
+        self.tempdir = tempdir = py.path.local.mkdtemp()
+        self.RETVAL = tempdir.ensure('retval')
+        self.STDOUT = tempdir.ensure('stdout')
+        self.STDERR = tempdir.ensure('stderr')
+
+        pid = os.fork()
+        if pid:  # in parent process
+            self.pid = pid
+        else:  # in child process
+            self.pid = None
+            self._child(nice_level, child_on_start, child_on_exit)
+
+    def _child(self, nice_level, child_on_start, child_on_exit):
+        # right now we need to call a function, but first we need to
+        # map all IO that might happen
+        sys.stdout = stdout = get_unbuffered_io(1, self.STDOUT)
+        sys.stderr = stderr = get_unbuffered_io(2, self.STDERR)
+        retvalf = self.RETVAL.open("wb")
+        EXITSTATUS = 0
+        try:
+            if nice_level:
+                os.nice(nice_level)
+            try:
+                if child_on_start is not None:
+                    child_on_start()
+                retval = self.fun(*self.args, **self.kwargs)
+                retvalf.write(marshal.dumps(retval))
+                if child_on_exit is not None:
+                    child_on_exit()
+            except:
+                excinfo = py.code.ExceptionInfo()
+                stderr.write(str(excinfo._getreprcrash()))
+                EXITSTATUS = self.EXITSTATUS_EXCEPTION
+        finally:
+            stdout.close()
+            stderr.close()
+            retvalf.close()
+        os.close(1)
+        os.close(2)
+        os._exit(EXITSTATUS)
+
+    def waitfinish(self, waiter=os.waitpid):
+        pid, systemstatus = waiter(self.pid, 0)
+        if systemstatus:
+            if os.WIFSIGNALED(systemstatus):
+                exitstatus = os.WTERMSIG(systemstatus) + 128
+            else:
+                exitstatus = os.WEXITSTATUS(systemstatus)
+        else:
+            exitstatus = 0
+        signal = systemstatus & 0x7f
+        if not exitstatus and not signal:
+            retval = self.RETVAL.open('rb')
+            try:
+                retval_data = retval.read()
+            finally:
+                retval.close()
+            retval = marshal.loads(retval_data)
+        else:
+            retval = None
+        stdout = self.STDOUT.read()
+        stderr = self.STDERR.read()
+        self._removetemp()
+        return Result(exitstatus, signal, retval, stdout, stderr)
+
+    def _removetemp(self):
+        if self.tempdir.check():
+            self.tempdir.remove()
+
+    def __del__(self):
+        if self.pid is not None:  # only clean up in main process
+            self._removetemp()
+
+
+class Result(object):
+    def __init__(self, exitstatus, signal, retval, stdout, stderr):
+        self.exitstatus = exitstatus
+        self.signal = signal
+        self.retval = retval
+        self.out = stdout
+        self.err = stderr
diff --git a/lib/spack/external/py/_process/killproc.py b/lib/spack/external/py/_process/killproc.py
new file mode 100644
index 0000000000..18e8310b5f
--- /dev/null
+++ b/lib/spack/external/py/_process/killproc.py
@@ -0,0 +1,23 @@
+import py
+import os, sys
+
+if sys.platform == "win32" or getattr(os, '_name', '') == 'nt':
+    try:
+        import ctypes
+    except ImportError:
+        def dokill(pid):
+            py.process.cmdexec("taskkill /F /PID %d" %(pid,))
+    else:
+        def dokill(pid):
+            PROCESS_TERMINATE = 1
+            handle = ctypes.windll.kernel32.OpenProcess(
+                        PROCESS_TERMINATE, False, pid)
+            ctypes.windll.kernel32.TerminateProcess(handle, -1)
+            ctypes.windll.kernel32.CloseHandle(handle)
+else:
+    def dokill(pid):
+        os.kill(pid, 15)
+
+def kill(pid):
+    """ kill process by id. """
+    dokill(pid)
diff --git a/lib/spack/external/py/_std.py b/lib/spack/external/py/_std.py
new file mode 100644
index 0000000000..97a9853323
--- /dev/null
+++ b/lib/spack/external/py/_std.py
@@ -0,0 +1,18 @@
+import sys
+
+class Std(object):
+    """ makes top-level python modules available as an attribute,
+        importing them on first access.
+    """
+
+    def __init__(self):
+        self.__dict__ = sys.modules
+
+    def __getattr__(self, name):
+        try:
+            m = __import__(name)
+        except ImportError:
+            raise AttributeError("py.std: could not import %s" % name)
+        return m
+
+std = Std()
diff --git a/lib/spack/external/py/_xmlgen.py b/lib/spack/external/py/_xmlgen.py
new file mode 100644
index 0000000000..1c83545884
--- /dev/null
+++ b/lib/spack/external/py/_xmlgen.py
@@ -0,0 +1,255 @@
+"""
+module for generating and serializing xml and html structures
+by using simple python objects.
+
+(c) holger krekel, holger at merlinux eu. 2009
+"""
+import sys, re
+
+if sys.version_info >= (3,0):
+    def u(s):
+        return s
+    def unicode(x, errors=None):
+        if hasattr(x, '__unicode__'):
+            return x.__unicode__()
+        return str(x)
+else:
+    def u(s):
+        return unicode(s)
+    unicode = unicode
+
+
+class NamespaceMetaclass(type):
+    def __getattr__(self, name):
+        if name[:1] == '_':
+            raise AttributeError(name)
+        if self == Namespace:
+            raise ValueError("Namespace class is abstract")
+        tagspec = self.__tagspec__
+        if tagspec is not None and name not in tagspec:
+            raise AttributeError(name)
+        classattr = {}
+        if self.__stickyname__:
+            classattr['xmlname'] = name
+        cls = type(name, (self.__tagclass__,), classattr)
+        setattr(self, name, cls)
+        return cls
+
+class Tag(list):
+    class Attr(object):
+        def __init__(self, **kwargs):
+            self.__dict__.update(kwargs)
+
+    def __init__(self, *args, **kwargs):
+        super(Tag, self).__init__(args)
+        self.attr = self.Attr(**kwargs)
+
+    def __unicode__(self):
+        return self.unicode(indent=0)
+    __str__ = __unicode__
+
+    def unicode(self, indent=2):
+        l = []
+        SimpleUnicodeVisitor(l.append, indent).visit(self)
+        return u("").join(l)
+
+    def __repr__(self):
+        name = self.__class__.__name__
+        return "<%r tag object %d>" % (name, id(self))
+
+Namespace = NamespaceMetaclass('Namespace', (object, ), {
+    '__tagspec__': None,
+    '__tagclass__': Tag,
+    '__stickyname__': False,
+})
+
+class HtmlTag(Tag):
+    def unicode(self, indent=2):
+        l = []
+        HtmlVisitor(l.append, indent, shortempty=False).visit(self)
+        return u("").join(l)
+
+# exported plain html namespace
+class html(Namespace):
+    __tagclass__ = HtmlTag
+    __stickyname__ = True
+    __tagspec__ = dict([(x,1) for x in (
+        'a,abbr,acronym,address,applet,area,article,aside,audio,b,'
+        'base,basefont,bdi,bdo,big,blink,blockquote,body,br,button,'
+        'canvas,caption,center,cite,code,col,colgroup,command,comment,'
+        'datalist,dd,del,details,dfn,dir,div,dl,dt,em,embed,'
+        'fieldset,figcaption,figure,footer,font,form,frame,frameset,h1,'
+        'h2,h3,h4,h5,h6,head,header,hgroup,hr,html,i,iframe,img,input,'
+        'ins,isindex,kbd,keygen,label,legend,li,link,listing,map,mark,'
+        'marquee,menu,meta,meter,multicol,nav,nobr,noembed,noframes,'
+        'noscript,object,ol,optgroup,option,output,p,param,pre,progress,'
+        'q,rp,rt,ruby,s,samp,script,section,select,small,source,span,'
+        'strike,strong,style,sub,summary,sup,table,tbody,td,textarea,'
+        'tfoot,th,thead,time,title,tr,track,tt,u,ul,xmp,var,video,wbr'
+    ).split(',') if x])
+
+    class Style(object):
+        def __init__(self, **kw):
+            for x, y in kw.items():
+                x = x.replace('_', '-')
+                setattr(self, x, y)
+
+
+class raw(object):
+    """just a box that can contain a unicode string that will be
+    included directly in the output"""
+    def __init__(self, uniobj):
+        self.uniobj = uniobj
+
+class SimpleUnicodeVisitor(object):
+    """ recursive visitor to write unicode. """
+    def __init__(self, write, indent=0, curindent=0, shortempty=True):
+        self.write = write
+        self.cache = {}
+        self.visited = {} # for detection of recursion
+        self.indent = indent
+        self.curindent = curindent
+        self.parents = []
+        self.shortempty = shortempty  # short empty tags or not
+
+    def visit(self, node):
+        """ dispatcher on node's class/bases name. """
+        cls = node.__class__
+        try:
+            visitmethod = self.cache[cls]
+        except KeyError:
+            for subclass in cls.__mro__:
+                visitmethod = getattr(self, subclass.__name__, None)
+                if visitmethod is not None:
+                    break
+            else:
+                visitmethod = self.__object
+            self.cache[cls] = visitmethod
+        visitmethod(node)
+
+    # the default fallback handler is marked private
+    # to avoid clashes with the tag name object
+    def __object(self, obj):
+        #self.write(obj)
+        self.write(escape(unicode(obj)))
+
+    def raw(self, obj):
+        self.write(obj.uniobj)
+
+    def list(self, obj):
+        assert id(obj) not in self.visited
+        self.visited[id(obj)] = 1
+        for elem in obj:
+            self.visit(elem)
+
+    def Tag(self, tag):
+        assert id(tag) not in self.visited
+        try:
+            tag.parent = self.parents[-1]
+        except IndexError:
+            tag.parent = None
+        self.visited[id(tag)] = 1
+        tagname = getattr(tag, 'xmlname', tag.__class__.__name__)
+        if self.curindent and not self._isinline(tagname):
+            self.write("\n" + u(' ') * self.curindent)
+        if tag:
+            self.curindent += self.indent
+            self.write(u('<%s%s>') % (tagname, self.attributes(tag)))
+            self.parents.append(tag)
+            for x in tag:
+                self.visit(x)
+            self.parents.pop()
+            self.write(u('</%s>') % tagname)
+            self.curindent -= self.indent
+        else:
+            nameattr = tagname+self.attributes(tag)
+            if self._issingleton(tagname):
+                self.write(u('<%s/>') % (nameattr,))
+            else:
+                self.write(u('<%s></%s>') % (nameattr, tagname))
+
+    def attributes(self, tag):
+        # serialize attributes
+        attrlist = dir(tag.attr)
+        attrlist.sort()
+        l = []
+        for name in attrlist:
+            res = self.repr_attribute(tag.attr, name)
+            if res is not None:
+                l.append(res)
+        l.extend(self.getstyle(tag))
+        return u("").join(l)
+
+    def repr_attribute(self, attrs, name):
+        if name[:2] != '__':
+            value = getattr(attrs, name)
+            if name.endswith('_'):
+                name = name[:-1]
+            if isinstance(value, raw):
+                insert = value.uniobj
+            else:
+                insert = escape(unicode(value))
+            return ' %s="%s"' % (name, insert)
+
+    def getstyle(self, tag):
+        """ return attribute list suitable for styling. """
+        try:
+            styledict = tag.style.__dict__
+        except AttributeError:
+            return []
+        else:
+            stylelist = [x+': ' + y for x,y in styledict.items()]
+            return [u(' style="%s"') % u('; ').join(stylelist)]
+
+    def _issingleton(self, tagname):
+        """can (and will) be overridden in subclasses"""
+        return self.shortempty
+
+    def _isinline(self, tagname):
+        """can (and will) be overridden in subclasses"""
+        return False
+
+class HtmlVisitor(SimpleUnicodeVisitor):
+
+    single = dict([(x, 1) for x in
+                ('br,img,area,param,col,hr,meta,link,base,'
+                    'input,frame').split(',')])
+    inline = dict([(x, 1) for x in
+                ('a abbr acronym b basefont bdo big br cite code dfn em font '
+                 'i img input kbd label q s samp select small span strike '
+                 'strong sub sup textarea tt u var'.split(' '))])
+
+    def repr_attribute(self, attrs, name):
+        if name == 'class_':
+            value = getattr(attrs, name)
+            if value is None:
+                return
+        return super(HtmlVisitor, self).repr_attribute(attrs, name)
+
+    def _issingleton(self, tagname):
+        return tagname in self.single
+
+    def _isinline(self, tagname):
+        return tagname in self.inline
+
+
+class _escape:
+    def __init__(self):
+        self.escape = {
+            u('"') : u('&quot;'), u('<') : u('&lt;'), u('>') : u('&gt;'),
+            u('&') : u('&amp;'), u("'") : u('&apos;'),
+            }
+        self.charef_rex = re.compile(u("|").join(self.escape.keys()))
+
+    def _replacer(self, match):
+        return self.escape[match.group(0)]
+
+    def __call__(self, ustring):
+        """ xml-escape the given unicode string. """
+        try:
+            ustring = unicode(ustring)
+        except UnicodeDecodeError:
+            ustring = unicode(ustring, 'utf-8', errors='replace')
+        return self.charef_rex.sub(self._replacer, ustring)
+
+escape = _escape()
diff --git a/lib/spack/external/py/test.py b/lib/spack/external/py/test.py
new file mode 100644
index 0000000000..aa5beb1789
--- /dev/null
+++ b/lib/spack/external/py/test.py
@@ -0,0 +1,10 @@
+import sys
+if __name__ == '__main__':
+    import pytest
+    sys.exit(pytest.main())
+else:
+    import sys, pytest
+    sys.modules['py.test'] = pytest
+
+# for more API entry points see the 'tests' definition
+# in __init__.py