Merge branch 'develop' of https://github.com/LLNL/spack into fixes/intel_openmpi

72 files changed, 1250 insertions, 779 deletions

diff --git a/lib/spack/docs/basic_usage.rst b/lib/spack/docs/basic_usage.rst
index 0578f0c8db..f94ac3d2ba 100644
--- a/lib/spack/docs/basic_usage.rst
+++ b/lib/spack/docs/basic_usage.rst
@@ -896,7 +896,7 @@ Or, similarly with modules, you could type:
    $ spack load mpich %gcc@4.4.7
 
 These commands will add appropriate directories to your ``PATH``,
-``MANPATH``, and ``LD_LIBRARY_PATH``.  When you no longer want to use
+``MANPATH``, ``CPATH``, and ``LD_LIBRARY_PATH``.  When you no longer want to use
 a package, you can type unload or unuse similarly:
 
 .. code-block:: sh
diff --git a/lib/spack/docs/developer_guide.rst b/lib/spack/docs/developer_guide.rst
index db47de80f5..0b618aa683 100644
--- a/lib/spack/docs/developer_guide.rst
+++ b/lib/spack/docs/developer_guide.rst
@@ -73,19 +73,32 @@ with a high level view of Spack's directory structure::
   spack/                  <- installation root
      bin/
         spack             <- main spack executable
+
+     etc/
+        spack/            <- Spack config files.
+                             Can be overridden by files in ~/.spack.
+
      var/
         spack/            <- build & stage directories
+        repos/            <- contains package repositories
+           builtin/       <- pkg repository that comes with Spack
+              repo.yaml   <- descriptor for the builtin repository
+              packages/   <- directories under here contain packages
+
      opt/
         spack/            <- packages are installed here
+
      lib/
         spack/
            docs/          <- source for this documentation
            env/           <- compiler wrappers for build environment
 
+           external/      <- external libs included in Spack distro
+           llnl/          <- some general-use libraries
+
            spack/         <- spack module; contains Python code
               cmd/        <- each file in here is a spack subcommand
               compilers/  <- compiler description files
-              packages/   <- each file in here is a spack package
               test/       <- unit test modules
               util/       <- common code
 
diff --git a/lib/spack/docs/features.rst b/lib/spack/docs/features.rst
index fcb810086d..0998ba8da4 100644
--- a/lib/spack/docs/features.rst
+++ b/lib/spack/docs/features.rst
@@ -103,7 +103,7 @@ creates a simple python file:
 It doesn't take much python coding to get from there to a working
 package:
 
-.. literalinclude:: ../../../var/spack/packages/libelf/package.py
+.. literalinclude:: ../../../var/spack/repos/builtin/packages/libelf/package.py
    :lines: 25-
 
 Spack also provides wrapper functions around common commands like
diff --git a/lib/spack/docs/getting_started.rst b/lib/spack/docs/getting_started.rst
index 67ca18e71a..2c5b68ea65 100644
--- a/lib/spack/docs/getting_started.rst
+++ b/lib/spack/docs/getting_started.rst
@@ -22,7 +22,7 @@ go:
    $ spack install libelf
 
 For a richer experience, use Spack's `shell support
-<http://llnl.github.io/spack/basic_usage.html#environment-modules>`_:
+<http://software.llnl.gov/spack/basic_usage.html#environment-modules>`_:
 
 .. code-block:: sh
 
diff --git a/lib/spack/docs/packaging_guide.rst b/lib/spack/docs/packaging_guide.rst
index 59ba63fa35..b7e0b6a4f3 100644
--- a/lib/spack/docs/packaging_guide.rst
+++ b/lib/spack/docs/packaging_guide.rst
@@ -84,7 +84,7 @@ always choose to download just one tarball initially, and run
 
    If it fails entirely, you can get minimal boilerplate by using
    :ref:`spack-edit-f`, or you can manually create a directory and
-   ``package.py`` file for the package in ``var/spack/packages``.
+   ``package.py`` file for the package in ``var/spack/repos/builtin/packages``.
 
 .. note::
 
@@ -203,7 +203,7 @@ edit`` command:
 So, if you used ``spack create`` to create a package, then saved and
 closed the resulting file, you can get back to it with ``spack edit``.
 The ``cmake`` package actually lives in
-``$SPACK_ROOT/var/spack/packages/cmake/package.py``, but this provides
+``$SPACK_ROOT/var/spack/repos/builtin/packages/cmake/package.py``, but this provides
 a much simpler shortcut and saves you the trouble of typing the full
 path.
 
@@ -269,18 +269,18 @@ live in Spack's directory structure.  In general, `spack-create`_ and
 `spack-edit`_ handle creating package files for you, so you can skip
 most of the details here.
 
-``var/spack/packages``
+``var/spack/repos/builtin/packages``
 ~~~~~~~~~~~~~~~~~~~~~~~
 
 A Spack installation directory is structured like a standard UNIX
 install prefix (``bin``, ``lib``, ``include``, ``var``, ``opt``,
 etc.).  Most of the code for Spack lives in ``$SPACK_ROOT/lib/spack``.
-Packages themselves live in ``$SPACK_ROOT/var/spack/packages``.
+Packages themselves live in ``$SPACK_ROOT/var/spack/repos/builtin/packages``.
 
 If you ``cd`` to that directory, you will see directories for each
 package:
 
-.. command-output::  cd $SPACK_ROOT/var/spack/packages;  ls -CF
+.. command-output::  cd $SPACK_ROOT/var/spack/repos/builtin/packages;  ls -CF
    :shell:
    :ellipsis: 10
 
@@ -288,7 +288,7 @@ Each directory contains a file called ``package.py``, which is where
 all the python code for the package goes.  For example, the ``libelf``
 package lives in::
 
-   $SPACK_ROOT/var/spack/packages/libelf/package.py
+   $SPACK_ROOT/var/spack/repos/builtin/packages/libelf/package.py
 
 Alongside the ``package.py`` file, a package may contain extra
 directories or files (like patches) that it needs to build.
@@ -301,7 +301,7 @@ Packages are named after the directory containing ``package.py``.  So,
 ``libelf``'s ``package.py`` lives in a directory called ``libelf``.
 The ``package.py`` file defines a class called ``Libelf``, which
 extends Spack's ``Package`` class.  for example, here is
-``$SPACK_ROOT/var/spack/packages/libelf/package.py``:
+``$SPACK_ROOT/var/spack/repos/builtin/packages/libelf/package.py``:
 
 .. code-block:: python
    :linenos:
@@ -328,7 +328,7 @@ these:
    $ spack install libelf@0.8.13
 
 Spack sees the package name in the spec and looks for
-``libelf/package.py`` in ``var/spack/packages``.  Likewise, if you say
+``libelf/package.py`` in ``var/spack/repos/builtin/packages``.  Likewise, if you say
 ``spack install py-numpy``, then Spack looks for
 ``py-numpy/package.py``.
 
@@ -401,6 +401,35 @@ construct the new one for ``8.2.1``.
 When you supply a custom URL for a version, Spack uses that URL
 *verbatim* and does not perform extrapolation.
 
+Skipping the expand step
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Spack normally expands archives automatically after downloading
+them. If you want to skip this step (e.g., for self-extracting
+executables and other custom archive types), you can add
+``expand=False`` to a ``version`` directive.
+
+.. code-block:: python
+
+   version('8.2.1', '4136d7b4c04df68b686570afa26988ac',
+           url='http://example.com/foo-8.2.1-special-version.tar.gz', 'expand=False')
+
+When ``expand`` is set to ``False``, Spack sets the current working
+directory to the directory containing the downloaded archive before it
+calls your ``install`` method.  Within ``install``, the path to the
+downloaded archive is available as ``self.stage.archive_file``.
+
+Here is an example snippet for packages distribuetd as self-extracting
+archives.  The example sets permissions on the downloaded file to make
+it executable, then runs it with some arguments.
+
+.. code-block:: python
+
+   def install(self, spec, prefix):
+       set_executable(self.stage.archive_file)
+       installer = Executable(self.stage.archive_file)
+       installer('--prefix=%s' % prefix, 'arg1', 'arg2', 'etc.')
+
 Checksums
 ~~~~~~~~~~~~~~~~~
 
@@ -703,7 +732,7 @@ supply is a filename, then the patch needs to live within the spack
 source tree.  For example, the patch above lives in a directory
 structure like this::
 
-   $SPACK_ROOT/var/spack/packages/
+   $SPACK_ROOT/var/spack/repos/builtin/packages/
        mvapich2/
            package.py
            ad_lustre_rwcontig_open_source.patch
@@ -1533,7 +1562,7 @@ The last element of a package is its ``install()`` method.  This is
 where the real work of installation happens, and it's the main part of
 the package you'll need to customize for each piece of software.
 
-.. literalinclude::  ../../../var/spack/packages/libelf/package.py
+.. literalinclude::  ../../../var/spack/repos/builtin/packages/libelf/package.py
    :start-after: 0.8.12
    :linenos:
 
@@ -1711,15 +1740,15 @@ Compile-time library search paths
   * ``-L$dep_prefix/lib``
   * ``-L$dep_prefix/lib64``
 Runtime library search paths (RPATHs)
-  * ``-Wl,-rpath=$dep_prefix/lib``
-  * ``-Wl,-rpath=$dep_prefix/lib64``
+  * ``-Wl,-rpath,$dep_prefix/lib``
+  * ``-Wl,-rpath,$dep_prefix/lib64``
 Include search paths
   * ``-I$dep_prefix/include``
 
 An example of this would be the ``libdwarf`` build, which has one
 dependency: ``libelf``.  Every call to ``cc`` in the ``libdwarf``
 build will have ``-I$LIBELF_PREFIX/include``,
-``-L$LIBELF_PREFIX/lib``, and ``-Wl,-rpath=$LIBELF_PREFIX/lib``
+``-L$LIBELF_PREFIX/lib``, and ``-Wl,-rpath,$LIBELF_PREFIX/lib``
 inserted on the command line.  This is done transparently to the
 project's build system, which will just think it's using a system
 where ``libelf`` is readily available.  Because of this, you **do
@@ -2108,6 +2137,15 @@ Filtering functions
 
   Examples:
 
+  #. Filtering a Makefile to force it to use Spack's compiler wrappers:
+
+     .. code-block:: python
+
+        filter_file(r'^CC\s*=.*',  spack_cc,  'Makefile')
+        filter_file(r'^CXX\s*=.*', spack_cxx, 'Makefile')
+        filter_file(r'^F77\s*=.*', spack_f77, 'Makefile')
+        filter_file(r'^FC\s*=.*',  spack_fc,  'Makefile')
+
   #. Replacing ``#!/usr/bin/perl`` with ``#!/usr/bin/env perl`` in ``bib2xhtml``:
 
      .. code-block:: python
diff --git a/lib/spack/env/cc b/lib/spack/env/cc
index 644d2be1d6..6b6073db43 100755
--- a/lib/spack/env/cc
+++ b/lib/spack/env/cc
@@ -90,15 +90,15 @@ case "$command" in
         command="$SPACK_CC"
         language="C"
         ;;
-    c++|CC|g++|clang++|icpc|pgCC|xlc++)
+    c++|CC|g++|clang++|icpc|pgc++|xlc++)
         command="$SPACK_CXX"
         language="C++"
         ;;
-    f90|fc|f95|gfortran|ifort|pgf90|xlf90|nagfor)
+    f90|fc|f95|gfortran|ifort|pgfortran|xlf90|nagfor)
         command="$SPACK_FC"
         language="Fortran 90"
         ;;
-    f77|gfortran|ifort|pgf77|xlf|nagfor)
+    f77|gfortran|ifort|pgfortran|xlf|nagfor)
         command="$SPACK_F77"
         language="Fortran 77"
         ;;
@@ -138,7 +138,7 @@ if [ -z "$mode" ]; then
     done
 fi
 
-# Dump the version and exist if we're in testing mode.
+# Dump the version and exit if we're in testing mode.
 if [ "$SPACK_TEST_COMMAND" = "dump-mode" ]; then
     echo "$mode"
     exit
@@ -187,32 +187,44 @@ while [ -n "$1" ]; do
             ;;
         -Wl,*)
             arg="${1#-Wl,}"
-            if [ -z "$arg" ]; then shift; arg="$1"; fi
-            if [[ "$arg" = -rpath=* ]]; then
-                rpaths+=("${arg#-rpath=}")
-            elif [[ "$arg" = -rpath ]]; then
+            # TODO: Handle multiple -Wl, continuations of -Wl,-rpath
+            if [[ $arg == -rpath=* ]]; then
+                arg="${arg#-rpath=}"
+                for rpath in ${arg//,/ }; do
+                    rpaths+=("$rpath")
+                done
+            elif [[ $arg == -rpath,* ]]; then
+                arg="${arg#-rpath,}"
+                for rpath in ${arg//,/ }; do
+                    rpaths+=("$rpath")
+                done
+            elif [[ $arg == -rpath ]]; then
                 shift; arg="$1"
-                if [[ "$arg" != -Wl,* ]]; then
+                if [[ $arg != '-Wl,'* ]]; then
                     die "-Wl,-rpath was not followed by -Wl,*"
                 fi
-                rpaths+=("${arg#-Wl,}")
+                arg="${arg#-Wl,}"
+                for rpath in ${arg//,/ }; do
+                    rpaths+=("$rpath")
+                done
             else
                 other_args+=("-Wl,$arg")
             fi
             ;;
-        -Xlinker,*)
-            arg="${1#-Xlinker,}"
-            if [ -z "$arg" ]; then shift; arg="$1"; fi
-            if [[ "$arg" = -rpath=* ]]; then
+        -Xlinker)
+            shift; arg="$1";
+            if [[ $arg = -rpath=* ]]; then
                 rpaths+=("${arg#-rpath=}")
-            elif [[ "$arg" = -rpath ]]; then
+            elif [[ $arg = -rpath ]]; then
                 shift; arg="$1"
-                if [[ "$arg" != -Xlinker,* ]]; then
-                    die "-Xlinker,-rpath was not followed by -Xlinker,*"
+                if [[ $arg != -Xlinker ]]; then
+                    die "-Xlinker -rpath was not followed by -Xlinker <arg>"
                 fi
-                rpaths+=("${arg#-Xlinker,}")
+                shift; arg="$1"
+                rpaths+=("$arg")
             else
-                other_args+=("-Xlinker,$arg")
+                other_args+=("-Xlinker")
+                other_args+=("$arg")
             fi
             ;;
         *)
diff --git a/lib/spack/env/pgi/case-insensitive/pgCC b/lib/spack/env/pgi/case-insensitive/pgCC
deleted file mode 120000
index e2deb67f3b..0000000000
--- a/lib/spack/env/pgi/case-insensitive/pgCC
+++ /dev/null
@@ -1 +0,0 @@
-../../cc
\ No newline at end of file
diff --git a/lib/spack/env/pgi/pgf77 b/lib/spack/env/pgi/pgc++
index 82c2b8e90a..82c2b8e90a 120000
--- a/lib/spack/env/pgi/pgf77
+++ b/lib/spack/env/pgi/pgc++
diff --git a/lib/spack/env/pgi/pgf90 b/lib/spack/env/pgi/pgfortran
index 82c2b8e90a..82c2b8e90a 120000
--- a/lib/spack/env/pgi/pgf90
+++ b/lib/spack/env/pgi/pgfortran
diff --git a/lib/spack/llnl/util/filesystem.py b/lib/spack/llnl/util/filesystem.py
index 24cfbfde71..c4665c284c 100644
--- a/lib/spack/llnl/util/filesystem.py
+++ b/lib/spack/llnl/util/filesystem.py
@@ -25,7 +25,9 @@
 __all__ = ['set_install_permissions', 'install', 'install_tree', 'traverse_tree',
            'expand_user', 'working_dir', 'touch', 'touchp', 'mkdirp',
            'force_remove', 'join_path', 'ancestor', 'can_access', 'filter_file',
-           'FileFilter', 'change_sed_delimiter', 'is_exe', 'force_symlink']
+           'FileFilter', 'change_sed_delimiter', 'is_exe', 'force_symlink',
+           'set_executable', 'copy_mode', 'unset_executable_mode',
+           'remove_dead_links', 'remove_linked_tree']
 
 import os
 import sys
@@ -152,15 +154,28 @@ def set_install_permissions(path):
 def copy_mode(src, dest):
     src_mode = os.stat(src).st_mode
     dest_mode = os.stat(dest).st_mode
-    if src_mode | stat.S_IXUSR: dest_mode |= stat.S_IXUSR
-    if src_mode | stat.S_IXGRP: dest_mode |= stat.S_IXGRP
-    if src_mode | stat.S_IXOTH: dest_mode |= stat.S_IXOTH
+    if src_mode & stat.S_IXUSR: dest_mode |= stat.S_IXUSR
+    if src_mode & stat.S_IXGRP: dest_mode |= stat.S_IXGRP
+    if src_mode & stat.S_IXOTH: dest_mode |= stat.S_IXOTH
     os.chmod(dest, dest_mode)
 
 
+def unset_executable_mode(path):
+    mode = os.stat(path).st_mode
+    mode &= ~stat.S_IXUSR
+    mode &= ~stat.S_IXGRP
+    mode &= ~stat.S_IXOTH
+    os.chmod(path, mode)
+
+
 def install(src, dest):
     """Manually install a file to a particular location."""
     tty.debug("Installing %s to %s" % (src, dest))
+
+    # Expand dsst to its eventual full path if it is a directory.
+    if os.path.isdir(dest):
+        dest = join_path(dest, os.path.basename(src))
+
     shutil.copy(src, dest)
     set_install_permissions(dest)
     copy_mode(src, dest)
@@ -235,7 +250,7 @@ def touchp(path):
 def force_symlink(src, dest):
     try:
         os.symlink(src, dest)
-    except OSError, e:
+    except OSError as e:
         os.remove(dest)
         os.symlink(src, dest)
 
@@ -339,3 +354,41 @@ def traverse_tree(source_root, dest_root, rel_path='', **kwargs):
 
     if order == 'post':
         yield (source_path, dest_path)
+
+
+def set_executable(path):
+    st = os.stat(path)
+    os.chmod(path, st.st_mode | stat.S_IEXEC)
+
+
+def remove_dead_links(root):
+    """
+    Removes any dead link that is present in root
+
+    Args:
+        root: path where to search for dead links
+
+    """
+    for file in os.listdir(root):
+        path = join_path(root, file)
+        if os.path.islink(path):
+            real_path = os.path.realpath(path)
+            if not os.path.exists(real_path):
+                os.unlink(path)
+
+def remove_linked_tree(path):
+    """
+    Removes a directory and its contents.  If the directory is a
+    symlink, follows the link and removes the real directory before
+    removing the link.
+
+    Args:
+        path: directory to be removed
+
+    """
+    if os.path.exists(path):
+        if os.path.islink(path):
+            shutil.rmtree(os.path.realpath(path), True)
+            os.unlink(path)
+        else:
+            shutil.rmtree(path, True)
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index 1b87778080..87fc310b5a 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -177,8 +177,6 @@ def set_module_variables_for_package(pkg, m):
     """Populate the module scope of install() with some useful functions.
        This makes things easier for package writers.
     """
-    m = pkg.module
-
     # number of jobs spack will to build with.
     jobs = multiprocessing.cpu_count()
     if not pkg.parallel:
@@ -214,6 +212,13 @@ def set_module_variables_for_package(pkg, m):
     m.std_cmake_args.append('-DCMAKE_INSTALL_RPATH_USE_LINK_PATH=FALSE')
     m.std_cmake_args.append('-DCMAKE_INSTALL_RPATH=%s' % ":".join(get_rpaths(pkg)))
 
+    # Put spack compiler paths in module scope.
+    link_dir = spack.build_env_path
+    m.spack_cc  = join_path(link_dir, pkg.compiler.link_paths['cc'])
+    m.spack_cxx = join_path(link_dir, pkg.compiler.link_paths['cxx'])
+    m.spack_f77 = join_path(link_dir, pkg.compiler.link_paths['f77'])
+    m.spack_f90 = join_path(link_dir, pkg.compiler.link_paths['fc'])
+
     # Emulate some shell commands for convenience
     m.pwd          = os.getcwd
     m.cd           = os.chdir
diff --git a/lib/spack/spack/cmd/checksum.py b/lib/spack/spack/cmd/checksum.py
index b1ad89dbb8..518d2703dc 100644
--- a/lib/spack/spack/cmd/checksum.py
+++ b/lib/spack/spack/cmd/checksum.py
@@ -22,23 +22,18 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import os
-import re
 import argparse
 import hashlib
-from pprint import pprint
-from subprocess import CalledProcessError
 
 import llnl.util.tty as tty
-from llnl.util.tty.colify import colify
-
 import spack
 import spack.cmd
 import spack.util.crypto
 from spack.stage import Stage, FailedDownloadError
 from spack.version import *
 
-description ="Checksum available versions of a package."
+description = "Checksum available versions of a package."
+
 
 def setup_parser(subparser):
     subparser.add_argument(
@@ -58,25 +53,23 @@ def get_checksums(versions, urls, **kwargs):
 
     tty.msg("Downloading...")
     hashes = []
-    for i, (url, version) in enumerate(zip(urls, versions)):
-        stage = Stage(url)
+    i = 0
+    for url, version in zip(urls, versions):
         try:
-            stage.fetch()
-            if i == 0 and first_stage_function:
-                first_stage_function(stage)
-
-            hashes.append(
-                spack.util.crypto.checksum(hashlib.md5, stage.archive_file))
-        except FailedDownloadError, e:
+            with Stage(url, keep=keep_stage) as stage:
+                stage.fetch()
+                if i == 0 and first_stage_function:
+                    first_stage_function(stage)
+
+                hashes.append((version,
+                               spack.util.crypto.checksum(hashlib.md5, stage.archive_file)))
+                i += 1
+        except FailedDownloadError as e:
             tty.msg("Failed to fetch %s" % url)
-            continue
-
-        finally:
-            if not keep_stage:
-                stage.destroy()
-
-    return zip(versions, hashes)
+        except Exception as e:
+            tty.msg('Something failed on %s, skipping.\n    (%s)' % (url, e))
 
+    return hashes
 
 
 def checksum(parser, args):
@@ -95,13 +88,13 @@ def checksum(parser, args):
     else:
         versions = pkg.fetch_remote_versions()
         if not versions:
-            tty.die("Could not fetch any versions for %s." % pkg.name)
+            tty.die("Could not fetch any versions for %s" % pkg.name)
 
     sorted_versions = sorted(versions, reverse=True)
 
-    tty.msg("Found %s versions of %s." % (len(versions), pkg.name),
+    tty.msg("Found %s versions of %s" % (len(versions), pkg.name),
             *spack.cmd.elide_list(
-            ["%-10s%s" % (v, versions[v]) for v in sorted_versions]))
+                ["%-10s%s" % (v, versions[v]) for v in sorted_versions]))
     print
     archives_to_fetch = tty.get_number(
         "How many would you like to checksum?", default=5, abort='q')
@@ -116,7 +109,7 @@ def checksum(parser, args):
         keep_stage=args.keep_stage)
 
     if not version_hashes:
-        tty.die("Could not fetch any versions for %s." % pkg.name)
+        tty.die("Could not fetch any versions for %s" % pkg.name)
 
     version_lines = ["    version('%s', '%s')" % (v, h) for v, h in version_hashes]
     tty.msg("Checksummed new versions of %s:" % pkg.name, *version_lines)
diff --git a/lib/spack/spack/cmd/compiler.py b/lib/spack/spack/cmd/compiler.py
index 75b51f6b49..3e58e82184 100644
--- a/lib/spack/spack/cmd/compiler.py
+++ b/lib/spack/spack/cmd/compiler.py
@@ -96,7 +96,7 @@ def compiler_remove(args):
     compilers = spack.compilers.compilers_for_spec(cspec, scope=args.scope)
 
     if not compilers:
-        tty.die("No compilers match spec %s." % cspec)
+        tty.die("No compilers match spec %s" % cspec)
     elif not args.all and len(compilers) > 1:
         tty.error("Multiple compilers match spec %s. Choose one:" % cspec)
         colify(reversed(sorted([c.spec for c in compilers])), indent=4)
@@ -105,7 +105,7 @@ def compiler_remove(args):
 
     for compiler in compilers:
         spack.compilers.remove_compiler_from_config(compiler.spec, scope=args.scope)
-        tty.msg("Removed compiler %s." % compiler.spec)
+        tty.msg("Removed compiler %s" % compiler.spec)
 
 
 def compiler_info(args):
@@ -114,7 +114,7 @@ def compiler_info(args):
     compilers = spack.compilers.compilers_for_spec(cspec, scope=args.scope)
 
     if not compilers:
-        tty.error("No compilers match spec %s." % cspec)
+        tty.error("No compilers match spec %s" % cspec)
     else:
         for c in compilers:
             print str(c.spec) + ":"
diff --git a/lib/spack/spack/cmd/create.py b/lib/spack/spack/cmd/create.py
index 6809209046..4564143f83 100644
--- a/lib/spack/spack/cmd/create.py
+++ b/lib/spack/spack/cmd/create.py
@@ -156,7 +156,7 @@ def guess_name_and_version(url, args):
     # Try to deduce name and version of the new package from the URL
     version = spack.url.parse_version(url)
     if not version:
-        tty.die("Couldn't guess a version string from %s." % url)
+        tty.die("Couldn't guess a version string from %s" % url)
 
     # Try to guess a name.  If it doesn't work, allow the user to override.
     if args.alternate_name:
@@ -189,7 +189,7 @@ def find_repository(spec, args):
         try:
             repo = Repo(repo_path)
             if spec.namespace and spec.namespace != repo.namespace:
-                tty.die("Can't create package with namespace %s in repo with namespace %s."
+                tty.die("Can't create package with namespace %s in repo with namespace %s"
                         % (spec.namespace, repo.namespace))
         except RepoError as e:
             tty.die(str(e))
@@ -252,7 +252,7 @@ def create(parser, args):
     name = spec.name  # factors out namespace, if any
     repo = find_repository(spec, args)
 
-    tty.msg("This looks like a URL for %s version %s." % (name, version))
+    tty.msg("This looks like a URL for %s version %s" % (name, version))
     tty.msg("Creating template for package %s" % name)
 
     # Fetch tarballs (prompting user if necessary)
@@ -266,7 +266,7 @@ def create(parser, args):
         keep_stage=args.keep_stage)
 
     if not ver_hash_tuples:
-        tty.die("Could not fetch any tarballs for %s." % name)
+        tty.die("Could not fetch any tarballs for %s" % name)
 
     # Prepend 'py-' to python package names, by convention.
     if guesser.build_system == 'python':
@@ -291,4 +291,4 @@ def create(parser, args):
 
     # If everything checks out, go ahead and edit.
     spack.editor(pkg_path)
-    tty.msg("Created package %s." % pkg_path)
+    tty.msg("Created package %s" % pkg_path)
diff --git a/lib/spack/spack/cmd/diy.py b/lib/spack/spack/cmd/diy.py
index 9df53312f8..2c3a8761ab 100644
--- a/lib/spack/spack/cmd/diy.py
+++ b/lib/spack/spack/cmd/diy.py
@@ -46,6 +46,9 @@ def setup_parser(subparser):
         '--skip-patch', action='store_true',
         help="Skip patching for the DIY build.")
     subparser.add_argument(
+        '-q', '--quiet', action='store_true', dest='quiet',
+        help="Do not display verbose build output while installing.")
+    subparser.add_argument(
         'spec', nargs=argparse.REMAINDER,
         help="specs to use for install.  Must contain package AND verison.")
 
@@ -92,4 +95,5 @@ def diy(self, args):
         package.do_install(
             keep_prefix=args.keep_prefix,
             ignore_deps=args.ignore_deps,
+            verbose=not args.quiet,
             keep_stage=True)   # don't remove source dir for DIY.
diff --git a/lib/spack/spack/cmd/md5.py b/lib/spack/spack/cmd/md5.py
index 879ef9f7b7..f99fc0f8c2 100644
--- a/lib/spack/spack/cmd/md5.py
+++ b/lib/spack/spack/cmd/md5.py
@@ -22,51 +22,51 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import os
 import argparse
 import hashlib
-
-from contextlib import contextmanager
+import os
 
 import llnl.util.tty as tty
-from llnl.util.filesystem import *
-
 import spack.util.crypto
 from spack.stage import Stage, FailedDownloadError
 
 description = "Calculate md5 checksums for files/urls."
 
-@contextmanager
-def stager(url):
-    _cwd = os.getcwd()
-    _stager = Stage(url)
-    try:
-        _stager.fetch()
-        yield _stager
-    except FailedDownloadError:
-        tty.msg("Failed to fetch %s" % url)
-    finally:
-        _stager.destroy()
-        os.chdir(_cwd) # the Stage class changes the current working dir so it has to be restored
 
 def setup_parser(subparser):
     setup_parser.parser = subparser
     subparser.add_argument('files', nargs=argparse.REMAINDER,
                            help="Files to checksum.")
 
+
+def compute_md5_checksum(url):
+    if not os.path.isfile(url):
+        with Stage(url) as stage:
+            stage.fetch()
+            value = spack.util.crypto.checksum(hashlib.md5, stage.archive_file)
+    else:
+        value = spack.util.crypto.checksum(hashlib.md5, url)
+    return value
+
+
 def md5(parser, args):
     if not args.files:
         setup_parser.parser.print_help()
         return 1
 
-    for f in args.files:
-        if not os.path.isfile(f):
-            with stager(f) as stage:
-                checksum = spack.util.crypto.checksum(hashlib.md5, stage.archive_file)
-                print "%s  %s" % (checksum, f)
-        else:
-            if not can_access(f):
-                tty.die("Cannot read file: %s" % f)
+    results = []
+    for url in args.files:
+        try:
+            checksum = compute_md5_checksum(url)
+            results.append((checksum, url))
+        except FailedDownloadError as e:
+            tty.warn("Failed to fetch %s" % url)
+            tty.warn("%s" % e)
+        except IOError as e:
+            tty.warn("Error when reading %s" % url)
+            tty.warn("%s" % e)
 
-            checksum = spack.util.crypto.checksum(hashlib.md5, f)
-            print "%s  %s" % (checksum, f)
+    # Dump the MD5s at last without interleaving them with downloads
+    tty.msg("%d MD5 checksums:" % len(results))
+    for checksum, url in results:
+        print "%s  %s" % (checksum, url)
diff --git a/lib/spack/spack/cmd/mirror.py b/lib/spack/spack/cmd/mirror.py
index 8e9438c1a3..fcd15a6a90 100644
--- a/lib/spack/spack/cmd/mirror.py
+++ b/lib/spack/spack/cmd/mirror.py
@@ -126,7 +126,7 @@ def mirror_remove(args):
 
     old_value = mirrors.pop(name)
     spack.config.update_config('mirrors', mirrors, scope=args.scope)
-    tty.msg("Removed mirror %s with url %s." % (name, old_value))
+    tty.msg("Removed mirror %s with url %s" % (name, old_value))
 
 
 def mirror_list(args):
@@ -203,7 +203,7 @@ def mirror_create(args):
 
     verb = "updated" if existed else "created"
     tty.msg(
-        "Successfully %s mirror in %s." % (verb, directory),
+        "Successfully %s mirror in %s" % (verb, directory),
         "Archive stats:",
         "  %-4d already present"  % p,
         "  %-4d added"            % m,
diff --git a/lib/spack/spack/cmd/module.py b/lib/spack/spack/cmd/module.py
index a5a9570eb5..1d6867c1d9 100644
--- a/lib/spack/spack/cmd/module.py
+++ b/lib/spack/spack/cmd/module.py
@@ -58,7 +58,7 @@ def module_find(mtype, spec_array):
        should type to use that package's module.
     """
     if mtype not in module_types:
-        tty.die("Invalid module type: '%s'.  Options are %s." % (mtype, comma_or(module_types)))
+        tty.die("Invalid module type: '%s'.  Options are %s" % (mtype, comma_or(module_types)))
 
     specs = spack.cmd.parse_specs(spec_array)
     if len(specs) > 1:
@@ -78,7 +78,7 @@ def module_find(mtype, spec_array):
     mt = module_types[mtype]
     mod = mt(specs[0])
     if not os.path.isfile(mod.file_name):
-        tty.die("No %s module is installed for %s." % (mtype, spec))
+        tty.die("No %s module is installed for %s" % (mtype, spec))
 
     print mod.use_name
 
@@ -94,7 +94,7 @@ def module_refresh():
             shutil.rmtree(cls.path, ignore_errors=False)
         mkdirp(cls.path)
         for spec in specs:
-            tty.debug("   Writing file for %s." % spec)
+            tty.debug("   Writing file for %s" % spec)
             cls(spec).write()
 
 
diff --git a/lib/spack/spack/cmd/patch.py b/lib/spack/spack/cmd/patch.py
index 44fc8696db..b04b402738 100644
--- a/lib/spack/spack/cmd/patch.py
+++ b/lib/spack/spack/cmd/patch.py
@@ -24,6 +24,7 @@
 ##############################################################################
 import argparse
 
+import llnl.util.tty as tty
 import spack.cmd
 import spack
 
diff --git a/lib/spack/spack/cmd/repo.py b/lib/spack/spack/cmd/repo.py
index 34c755fb67..87c782000f 100644
--- a/lib/spack/spack/cmd/repo.py
+++ b/lib/spack/spack/cmd/repo.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://llnl.github.io/spack
+# For details, see https://software.llnl.gov/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -74,51 +74,7 @@ def setup_parser(subparser):
 
 def repo_create(args):
     """Create a new package repository."""
-    root = canonicalize_path(args.directory)
-    namespace = args.namespace
-
-    if not args.namespace:
-        namespace = os.path.basename(root)
-
-    if not re.match(r'\w[\.\w-]*', namespace):
-        tty.die("'%s' is not a valid namespace." % namespace)
-
-    existed = False
-    if os.path.exists(root):
-        if os.path.isfile(root):
-            tty.die('File %s already exists and is not a directory' % root)
-        elif os.path.isdir(root):
-            if not os.access(root, os.R_OK | os.W_OK):
-                tty.die('Cannot create new repo in %s: cannot access directory.' % root)
-            if os.listdir(root):
-                tty.die('Cannot create new repo in %s: directory is not empty.' % root)
-        existed = True
-
-    full_path = os.path.realpath(root)
-    parent = os.path.dirname(full_path)
-    if not os.access(parent, os.R_OK | os.W_OK):
-        tty.die("Cannot create repository in %s: can't access parent!" % root)
-
-    try:
-        config_path = os.path.join(root, repo_config_name)
-        packages_path = os.path.join(root, packages_dir_name)
-
-        mkdirp(packages_path)
-        with open(config_path, 'w') as config:
-            config.write("repo:\n")
-            config.write("  namespace: '%s'\n" % namespace)
-
-    except (IOError, OSError) as e:
-        tty.die('Failed to create new repository in %s.' % root,
-                "Caused by %s: %s" % (type(e), e))
-
-        # try to clean up.
-        if existed:
-            shutil.rmtree(config_path, ignore_errors=True)
-            shutil.rmtree(packages_path, ignore_errors=True)
-        else:
-            shutil.rmtree(root, ignore_errors=True)
-
+    full_path, namespace = create_repo(args.directory, args.namespace)
     tty.msg("Created repo with namespace '%s'." % namespace)
     tty.msg("To register it with spack, run this command:",
             'spack repo add %s' % full_path)
@@ -133,11 +89,11 @@ def repo_add(args):
 
     # check if the path exists
     if not os.path.exists(canon_path):
-        tty.die("No such file or directory: '%s'." % path)
+        tty.die("No such file or directory: %s" % path)
 
     # Make sure the path is a directory.
     if not os.path.isdir(canon_path):
-        tty.die("Not a Spack repository: '%s'." % path)
+        tty.die("Not a Spack repository: %s" % path)
 
     # Make sure it's actually a spack repository by constructing it.
     repo = Repo(canon_path)
@@ -147,7 +103,7 @@ def repo_add(args):
     if not repos: repos = []
 
     if repo.root in repos or path in repos:
-        tty.die("Repository is already registered with Spack: '%s'" % path)
+        tty.die("Repository is already registered with Spack: %s" % path)
 
     repos.insert(0, canon_path)
     spack.config.update_config('repos', repos, args.scope)
@@ -166,7 +122,7 @@ def repo_remove(args):
         if canon_path == repo_canon_path:
             repos.remove(repo_path)
             spack.config.update_config('repos', repos, args.scope)
-            tty.msg("Removed repository '%s'." % repo_path)
+            tty.msg("Removed repository %s" % repo_path)
             return
 
     # If it is a namespace, remove corresponding repo
@@ -176,13 +132,13 @@ def repo_remove(args):
             if repo.namespace == path_or_namespace:
                 repos.remove(path)
                 spack.config.update_config('repos', repos, args.scope)
-                tty.msg("Removed repository '%s' with namespace %s."
+                tty.msg("Removed repository %s with namespace '%s'."
                         % (repo.root, repo.namespace))
                 return
         except RepoError as e:
             continue
 
-    tty.die("No repository with path or namespace: '%s'"
+    tty.die("No repository with path or namespace: %s"
             % path_or_namespace)
 
 
diff --git a/lib/spack/spack/compiler.py b/lib/spack/spack/compiler.py
index 12c02e0ea2..d38c0b00b1 100644
--- a/lib/spack/spack/compiler.py
+++ b/lib/spack/spack/compiler.py
@@ -256,12 +256,12 @@ class Compiler(object):
 
 
     def __repr__(self):
-        """Return a string represntation of the compiler toolchain."""
+        """Return a string representation of the compiler toolchain."""
         return self.__str__()
 
 
     def __str__(self):
-        """Return a string represntation of the compiler toolchain."""
+        """Return a string representation of the compiler toolchain."""
         return "%s(%s)" % (
             self.name, '\n     '.join((str(s) for s in (self.cc, self.cxx, self.f77, self.fc))))
 
diff --git a/lib/spack/spack/compilers/pgi.py b/lib/spack/spack/compilers/pgi.py
index 9ac74cfbdb..c6a1078bd9 100644
--- a/lib/spack/spack/compilers/pgi.py
+++ b/lib/spack/spack/compilers/pgi.py
@@ -29,28 +29,28 @@ class Pgi(Compiler):
     cc_names = ['pgcc']
 
     # Subclasses use possible names of C++ compiler
-    cxx_names = ['pgCC']
+    cxx_names = ['pgc++', 'pgCC']
 
     # Subclasses use possible names of Fortran 77 compiler
-    f77_names = ['pgf77']
+    f77_names = ['pgfortran', 'pgf77']
 
     # Subclasses use possible names of Fortran 90 compiler
-    fc_names = ['pgf95', 'pgf90']
+    fc_names = ['pgfortran', 'pgf95', 'pgf90']
 
     # Named wrapper links within spack.build_env_path
     link_paths = { 'cc'  : 'pgi/pgcc',
-                   'cxx' : 'pgi/case-insensitive/pgCC',
-                   'f77' : 'pgi/pgf77',
-                   'fc'  : 'pgi/pgf90' }
+                   'cxx' : 'pgi/pgc++',
+                   'f77' : 'pgi/pgfortran',
+                   'fc'  : 'pgi/pgfortran' }
 
     @classmethod
     def default_version(cls, comp):
         """The '-V' option works for all the PGI compilers.
            Output looks like this::
 
-               pgf95 10.2-0 64-bit target on x86-64 Linux -tp nehalem-64
-               Copyright 1989-2000, The Portland Group, Inc.  All Rights Reserved.
-               Copyright 2000-2010, STMicroelectronics, Inc.  All Rights Reserved.
+               pgcc 15.10-0 64-bit target on x86-64 Linux -tp sandybridge
+               The Portland Group - PGI Compilers and Tools
+               Copyright (c) 2015, NVIDIA CORPORATION.  All rights reserved.
         """
         return get_compiler_version(
             comp, '-V', r'pg[^ ]* ([^ ]+) \d\d\d?-bit target')
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index 6fecde9980..576a5afa2e 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -205,7 +205,7 @@ config_scopes = OrderedDict()
 def validate_section_name(section):
     """Raise a ValueError if the section is not a valid section."""
     if section not in section_schemas:
-        raise ValueError("Invalid config section: '%s'.  Options are %s."
+        raise ValueError("Invalid config section: '%s'.  Options are %s"
                          % (section, section_schemas))
 
 
@@ -335,7 +335,7 @@ def validate_scope(scope):
         return config_scopes[scope]
 
     else:
-        raise ValueError("Invalid config scope: '%s'.  Must be one of %s."
+        raise ValueError("Invalid config scope: '%s'.  Must be one of %s"
                          % (scope, config_scopes.keys()))
 
 
@@ -350,7 +350,7 @@ def _read_config_file(filename, schema):
             "Invlaid configuration. %s exists but is not a file." % filename)
 
     elif not os.access(filename, os.R_OK):
-        raise ConfigFileError("Config file is not readable: %s." % filename)
+        raise ConfigFileError("Config file is not readable: %s" % filename)
 
     try:
         tty.debug("Reading config file %s" % filename)
diff --git a/lib/spack/spack/database.py b/lib/spack/spack/database.py
index 9cbe7de44a..089d29325e 100644
--- a/lib/spack/spack/database.py
+++ b/lib/spack/spack/database.py
@@ -330,7 +330,7 @@ class Database(object):
             found = rec.ref_count
             if not expected == found:
                 raise AssertionError(
-                    "Invalid ref_count: %s: %d (expected %d), in DB %s."
+                    "Invalid ref_count: %s: %d (expected %d), in DB %s"
                     % (key, found, expected, self._index_path))
 
 
diff --git a/lib/spack/spack/directives.py b/lib/spack/spack/directives.py
index 5745adce63..61cd303012 100644
--- a/lib/spack/spack/directives.py
+++ b/lib/spack/spack/directives.py
@@ -125,7 +125,7 @@ class directive(object):
             dicts = (dicts,)
         elif type(dicts) not in (list, tuple):
             raise TypeError(
-                "dicts arg must be list, tuple, or string. Found %s."
+                "dicts arg must be list, tuple, or string. Found %s"
                 % type(dicts))
 
         self.dicts = dicts
@@ -174,7 +174,11 @@ def version(pkg, ver, checksum=None, **kwargs):
 
 
 def _depends_on(pkg, spec, when=None):
-    if when is None:
+    # If when is False do nothing
+    if when is False:
+        return
+    # If when is None or True make sure the condition is always satisfied
+    if when is None or when is True:
         when = pkg.name
     when_spec = parse_anonymous_spec(when, pkg.name)
 
@@ -313,5 +317,5 @@ class CircularReferenceError(DirectiveError):
     def __init__(self, directive, package):
         super(CircularReferenceError, self).__init__(
             directive,
-            "Package '%s' cannot pass itself to %s." % (package, directive))
+            "Package '%s' cannot pass itself to %s" % (package, directive))
         self.package = package
diff --git a/lib/spack/spack/directory_layout.py b/lib/spack/spack/directory_layout.py
index 3e416a6a1f..242eb1afa0 100644
--- a/lib/spack/spack/directory_layout.py
+++ b/lib/spack/spack/directory_layout.py
@@ -85,6 +85,16 @@ class DirectoryLayout(object):
         raise NotImplementedError()
 
 
+    def check_installed(self, spec):
+        """Checks whether a spec is installed.
+
+        Return the spec's prefix, if it is installed, None otherwise.
+
+        Raise an exception if the install is inconsistent or corrupt.
+        """
+        raise NotImplementedError()
+
+
     def extension_map(self, spec):
         """Get a dict of currently installed extension packages for a spec.
 
@@ -173,7 +183,9 @@ class YamlDirectoryLayout(DirectoryLayout):
 
         self.spec_file_name      = 'spec.yaml'
         self.extension_file_name = 'extensions.yaml'
-        self.build_log_name      = 'build.out' # TODO: use config file.
+        self.build_log_name      = 'build.out'  # build log.
+        self.build_env_name      = 'build.env'  # build environment
+        self.packages_dir        = 'repos'      # archive of package.py files
 
         # Cache of already written/read extension maps.
         self._extension_maps = {}
@@ -231,29 +243,49 @@ class YamlDirectoryLayout(DirectoryLayout):
                          self.build_log_name)
 
 
+    def build_env_path(self, spec):
+        return join_path(self.path_for_spec(spec), self.metadata_dir,
+                         self.build_env_name)
+
+
+    def build_packages_path(self, spec):
+        return join_path(self.path_for_spec(spec), self.metadata_dir,
+                         self.packages_dir)
+
+
     def create_install_directory(self, spec):
         _check_concrete(spec)
 
+        prefix = self.check_installed(spec)
+        if prefix:
+            raise InstallDirectoryAlreadyExistsError(prefix)
+
+        mkdirp(self.metadata_path(spec))
+        self.write_spec(spec, self.spec_file_path(spec))
+
+
+    def check_installed(self, spec):
+        _check_concrete(spec)
         path = self.path_for_spec(spec)
         spec_file_path = self.spec_file_path(spec)
 
-        if os.path.isdir(path):
-            if not os.path.isfile(spec_file_path):
-                raise InconsistentInstallDirectoryError(
-                    'No spec file found at path %s' % spec_file_path)
+        if not os.path.isdir(path):
+            return None
 
-            installed_spec = self.read_spec(spec_file_path)
-            if installed_spec == self.spec:
-                raise InstallDirectoryAlreadyExistsError(path)
+        if not os.path.isfile(spec_file_path):
+            raise InconsistentInstallDirectoryError(
+                'Inconsistent state: install prefix exists but contains no spec.yaml:',
+                "  " + path)
 
-            if spec.dag_hash() == installed_spec.dag_hash():
-                raise SpecHashCollisionError(installed_hash, spec_hash)
-            else:
-                raise InconsistentInstallDirectoryError(
-                    'Spec file in %s does not match hash!' % spec_file_path)
+        installed_spec = self.read_spec(spec_file_path)
+        if installed_spec == spec:
+            return path
 
-        mkdirp(self.metadata_path(spec))
-        self.write_spec(spec, spec_file_path)
+        if spec.dag_hash() == installed_spec.dag_hash():
+            raise SpecHashCollisionError(installed_hash, spec_hash)
+        else:
+            raise InconsistentInstallDirectoryError(
+                'Spec file in %s does not match hash!' % spec_file_path)
 
 
     def all_specs(self):
@@ -323,7 +355,7 @@ class YamlDirectoryLayout(DirectoryLayout):
 
                         if not dag_hash in by_hash:
                             raise InvalidExtensionSpecError(
-                                "Spec %s not found in %s." % (dag_hash, prefix))
+                                "Spec %s not found in %s" % (dag_hash, prefix))
 
                         ext_spec = by_hash[dag_hash]
                         if not prefix == ext_spec.prefix:
@@ -387,8 +419,8 @@ class YamlDirectoryLayout(DirectoryLayout):
 
 class DirectoryLayoutError(SpackError):
     """Superclass for directory layout errors."""
-    def __init__(self, message):
-        super(DirectoryLayoutError, self).__init__(message)
+    def __init__(self, message, long_msg=None):
+        super(DirectoryLayoutError, self).__init__(message, long_msg)
 
 
 class SpecHashCollisionError(DirectoryLayoutError):
@@ -410,8 +442,8 @@ class RemoveFailedError(DirectoryLayoutError):
 
 class InconsistentInstallDirectoryError(DirectoryLayoutError):
     """Raised when a package seems to be installed to the wrong place."""
-    def __init__(self, message):
-        super(InconsistentInstallDirectoryError, self).__init__(message)
+    def __init__(self, message, long_msg=None):
+        super(InconsistentInstallDirectoryError, self).__init__(message, long_msg)
 
 
 class InstallDirectoryAlreadyExistsError(DirectoryLayoutError):
@@ -438,7 +470,7 @@ class ExtensionConflictError(DirectoryLayoutError):
     """Raised when an extension is added to a package that already has it."""
     def __init__(self, spec, ext_spec, conflict):
         super(ExtensionConflictError, self).__init__(
-            "%s cannot be installed in %s because it conflicts with %s."% (
+            "%s cannot be installed in %s because it conflicts with %s"% (
                 ext_spec.short_spec, spec.short_spec, conflict.short_spec))
 
 
diff --git a/lib/spack/spack/fetch_strategy.py b/lib/spack/spack/fetch_strategy.py
index 83a2dbb59c..0d0a7db8a9 100644
--- a/lib/spack/spack/fetch_strategy.py
+++ b/lib/spack/spack/fetch_strategy.py
@@ -82,7 +82,6 @@ class FetchStrategy(object):
 
     class __metaclass__(type):
         """This metaclass registers all fetch strategies in a list."""
-
         def __init__(cls, name, bases, dict):
             type.__init__(cls, name, bases, dict)
             if cls.enabled: all_strategies.append(cls)
@@ -145,6 +144,8 @@ class URLFetchStrategy(FetchStrategy):
         self.digest = kwargs.get('md5', None)
         if not self.digest: self.digest = digest
 
+        self.expand_archive = kwargs.get('expand', True)
+
         if not self.url:
             raise ValueError("URLFetchStrategy requires a url for fetching.")
 
@@ -153,7 +154,7 @@ class URLFetchStrategy(FetchStrategy):
         self.stage.chdir()
 
         if self.archive_file:
-            tty.msg("Already downloaded %s." % self.archive_file)
+            tty.msg("Already downloaded %s" % self.archive_file)
             return
 
         tty.msg("Trying to fetch from %s" % self.url)
@@ -218,6 +219,10 @@ class URLFetchStrategy(FetchStrategy):
 
     @_needs_stage
     def expand(self):
+        if not self.expand_archive:
+            tty.msg("Skipping expand step for %s" % self.archive_file)
+            return
+
         tty.msg("Staging archive: %s" % self.archive_file)
 
         self.stage.chdir()
@@ -275,8 +280,8 @@ class URLFetchStrategy(FetchStrategy):
         checker = crypto.Checker(self.digest)
         if not checker.check(self.archive_file):
             raise ChecksumError(
-                    "%s checksum failed for %s." % (checker.hash_name, self.archive_file),
-                    "Expected %s but got %s." % (self.digest, checker.sum))
+                    "%s checksum failed for %s" % (checker.hash_name, self.archive_file),
+                    "Expected %s but got %s" % (self.digest, checker.sum))
 
     @_needs_stage
     def reset(self):
@@ -312,7 +317,7 @@ class VCSFetchStrategy(FetchStrategy):
         # Ensure that there's only one of the rev_types
         if sum(k in kwargs for k in rev_types) > 1:
             raise FetchStrategyError(
-                    "Supply only one of %s to fetch with %s." % (
+                    "Supply only one of %s to fetch with %s" % (
                         comma_or(rev_types), name))
 
         # Set attributes for each rev type.
@@ -321,7 +326,7 @@ class VCSFetchStrategy(FetchStrategy):
 
     @_needs_stage
     def check(self):
-        tty.msg("No checksum needed when fetching with %s." % self.name)
+        tty.msg("No checksum needed when fetching with %s" % self.name)
 
     @_needs_stage
     def expand(self):
@@ -395,7 +400,7 @@ class GitFetchStrategy(VCSFetchStrategy):
         self.stage.chdir()
 
         if self.stage.source_path:
-            tty.msg("Already fetched %s." % self.stage.source_path)
+            tty.msg("Already fetched %s" % self.stage.source_path)
             return
 
         args = []
@@ -505,7 +510,7 @@ class SvnFetchStrategy(VCSFetchStrategy):
         self.stage.chdir()
 
         if self.stage.source_path:
-            tty.msg("Already fetched %s." % self.stage.source_path)
+            tty.msg("Already fetched %s" % self.stage.source_path)
             return
 
         tty.msg("Trying to check out svn repository: %s" % self.url)
@@ -584,7 +589,7 @@ class HgFetchStrategy(VCSFetchStrategy):
         self.stage.chdir()
 
         if self.stage.source_path:
-            tty.msg("Already fetched %s." % self.stage.source_path)
+            tty.msg("Already fetched %s" % self.stage.source_path)
             return
 
         args = []
diff --git a/lib/spack/spack/hooks/sbang.py b/lib/spack/spack/hooks/sbang.py
new file mode 100644
index 0000000000..d78adb576e
--- /dev/null
+++ b/lib/spack/spack/hooks/sbang.py
@@ -0,0 +1,98 @@
+##############################################################################
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+import os
+
+from llnl.util.filesystem import *
+import llnl.util.tty as tty
+
+import spack
+import spack.modules
+
+# Character limit for shebang line.  Using Linux's 127 characters
+# here, as it is the shortest I could find on a modern OS.
+shebang_limit = 127
+
+def shebang_too_long(path):
+    """Detects whether a file has a shebang line that is too long."""
+    with open(path, 'r') as script:
+        bytes = script.read(2)
+        if bytes != '#!':
+            return False
+
+        line = bytes + script.readline()
+        return len(line) > shebang_limit
+
+
+def filter_shebang(path):
+    """Adds a second shebang line, using sbang, at the beginning of a file."""
+    with open(path, 'r') as original_file:
+        original = original_file.read()
+
+    # This line will be prepended to file
+    new_sbang_line = '#!/bin/bash %s/bin/sbang\n' % spack.spack_root
+
+    # Skip files that are already using sbang.
+    if original.startswith(new_sbang_line):
+        return
+
+    backup = path + ".shebang.bak"
+    os.rename(path, backup)
+
+    with open(path, 'w') as new_file:
+        new_file.write(new_sbang_line)
+        new_file.write(original)
+
+    copy_mode(backup, path)
+    unset_executable_mode(backup)
+
+    tty.warn("Patched overly long shebang in %s" % path)
+
+
+def filter_shebangs_in_directory(directory):
+    for file in os.listdir(directory):
+        path = os.path.join(directory, file)
+
+        # only handle files
+        if not os.path.isfile(path):
+            continue
+
+        # only handle links that resolve within THIS package's prefix.
+        if os.path.islink(path):
+            real_path = os.path.realpath(path)
+            if not real_path.startswith(directory + os.sep):
+                continue
+
+        # test the file for a long shebang, and filter
+        if shebang_too_long(path):
+            filter_shebang(path)
+
+
+def post_install(pkg):
+    """This hook edits scripts so that they call /bin/bash
+       $spack_prefix/bin/sbang instead of something longer than the
+       shebang limit."""
+    if not os.path.isdir(pkg.prefix.bin):
+        return
+    filter_shebangs_in_directory(pkg.prefix.bin)
diff --git a/lib/spack/spack/mirror.py b/lib/spack/spack/mirror.py
index fa29e20803..6981f69ac0 100644
--- a/lib/spack/spack/mirror.py
+++ b/lib/spack/spack/mirror.py
@@ -51,13 +51,20 @@ def mirror_archive_filename(spec, fetcher):
         raise ValueError("mirror.path requires spec with concrete version.")
 
     if isinstance(fetcher, fs.URLFetchStrategy):
-        # If we fetch this version with a URLFetchStrategy, use URL's archive type
-        ext = url.downloaded_file_extension(fetcher.url)
+        if fetcher.expand_archive:
+            # If we fetch this version with a URLFetchStrategy, use URL's archive type
+            ext = url.downloaded_file_extension(fetcher.url)
+        else:
+            # If the archive shouldn't be expanded, don't check for its extension.
+            ext = None
     else:
         # Otherwise we'll make a .tar.gz ourselves
         ext = 'tar.gz'
 
-    return "%s-%s.%s" % (spec.package.name, spec.version, ext)
+    filename = "%s-%s" % (spec.package.name, spec.version)
+    if ext:
+        filename += ".%s" % ext
+    return filename
 
 
 def mirror_archive_path(spec, fetcher):
@@ -73,7 +80,7 @@ def get_matching_versions(specs, **kwargs):
 
         # Skip any package that has no known versions.
         if not pkg.versions:
-            tty.msg("No safe (checksummed) versions for package %s." % pkg.name)
+            tty.msg("No safe (checksummed) versions for package %s" % pkg.name)
             continue
 
         num_versions = kwargs.get('num_versions', 0)
@@ -110,7 +117,6 @@ def suggest_archive_basename(resource):
     return basename
 
 
-
 def create(path, specs, **kwargs):
     """Create a directory to be used as a spack mirror, and fill it with
        package archives.
@@ -158,17 +164,29 @@ def create(path, specs, **kwargs):
                 "Cannot create directory '%s':" % mirror_root, str(e))
 
     # Things to keep track of while parsing specs.
-    present  = []
-    mirrored = []
-    error    = []
+    categories = {
+        'present': [],
+        'mirrored': [],
+        'error': []
+    }
 
     # Iterate through packages and download all the safe tarballs for each of them
-    everything_already_exists = True
     for spec in version_specs:
-        pkg = spec.package
-        tty.msg("Adding package {pkg} to mirror".format(pkg=spec.format("$_$@")))
-        try:
-            for ii, stage in enumerate(pkg.stage):
+        add_single_spec(spec, mirror_root, categories, **kwargs)
+
+    return categories['present'], categories['mirrored'], categories['error']
+
+
+def add_single_spec(spec, mirror_root, categories, **kwargs):
+    tty.msg("Adding package {pkg} to mirror".format(pkg=spec.format("$_$@")))
+    spec_exists_in_mirror = True
+    try:
+        with spec.package.stage:
+            # fetcher = stage.fetcher
+            # fetcher.fetch()
+            # ...
+            # fetcher.archive(archive_path)
+            for ii, stage in enumerate(spec.package.stage):
                 fetcher = stage.fetcher
                 if ii == 0:
                     # create a subdirectory for the current package@version
@@ -184,7 +202,7 @@ def create(path, specs, **kwargs):
                 if os.path.exists(archive_path):
                     tty.msg("{name} : already added".format(name=name))
                 else:
-                    everything_already_exists = False
+                    spec_exists_in_mirror = False
                     fetcher.fetch()
                     if not kwargs.get('no_checksum', False):
                         fetcher.check()
@@ -195,20 +213,16 @@ def create(path, specs, **kwargs):
                     fetcher.archive(archive_path)
                     tty.msg("{name} : added".format(name=name))
 
-            if everything_already_exists:
-                present.append(spec)
-            else:
-                mirrored.append(spec)
-        except Exception, e:
-            if spack.debug:
-                sys.excepthook(*sys.exc_info())
-            else:
-                tty.warn("Error while fetching %s." % spec.format('$_$@'), e.message)
-            error.append(spec)
-        finally:
-            pkg.stage.destroy()
-
-    return (present, mirrored, error)
+        if spec_exists_in_mirror:
+            categories['present'].append(spec)
+        else:
+            categories['mirrored'].append(spec)
+    except Exception as e:
+        if spack.debug:
+            sys.excepthook(*sys.exc_info())
+        else:
+            tty.warn("Error while fetching %s" % spec.format('$_$@'), e.message)
+        categories['error'].append(spec)
 
 
 class MirrorError(spack.error.SpackError):
diff --git a/lib/spack/spack/modules.py b/lib/spack/spack/modules.py
index c834763564..c27043db8c 100644
--- a/lib/spack/spack/modules.py
+++ b/lib/spack/spack/modules.py
@@ -33,6 +33,7 @@ number of directories to be appended to paths in the user's environment:
 
   * /bin directories to be appended to PATH
   * /lib* directories for LD_LIBRARY_PATH
+  * /include directories for CPATH
   * /man* and /share/man* directories for MANPATH
   * the package prefix for CMAKE_PREFIX_PATH
 
@@ -121,6 +122,7 @@ class EnvModule(object):
                     ('LIBRARY_PATH', self.spec.prefix.lib64),
                     ('LD_LIBRARY_PATH', self.spec.prefix.lib),
                     ('LD_LIBRARY_PATH', self.spec.prefix.lib64),
+                    ('CPATH', self.spec.prefix.include),
                     ('PKG_CONFIG_PATH', join_path(self.spec.prefix.lib, 'pkgconfig')),
                     ('PKG_CONFIG_PATH', join_path(self.spec.prefix.lib64, 'pkgconfig'))]:
 
diff --git a/lib/spack/spack/multimethod.py b/lib/spack/spack/multimethod.py
index df9b9b2ab1..3cd17e796a 100644
--- a/lib/spack/spack/multimethod.py
+++ b/lib/spack/spack/multimethod.py
@@ -138,7 +138,7 @@ class when(object):
        methods like install() that depend on the package's spec.
        For example:
 
-       .. code-block::
+       .. code-block:: python
 
           class SomePackage(Package):
               ...
@@ -163,26 +163,28 @@ class when(object):
        if you only have part of the install that is platform specific, you
        could do this:
 
-       class SomePackage(Package):
-           ...
-           # virtual dependence on MPI.
-           # could resolve to mpich, mpich2, OpenMPI
-           depends_on('mpi')
+       .. code-block:: python
 
-           def setup(self):
-               # do nothing in the default case
-               pass
+          class SomePackage(Package):
+              ...
+              # virtual dependence on MPI.
+              # could resolve to mpich, mpich2, OpenMPI
+              depends_on('mpi')
+
+              def setup(self):
+                  # do nothing in the default case
+                  pass
 
-           @when('^openmpi')
-           def setup(self):
-               # do something special when this is built with OpenMPI for
-               # its MPI implementations.
+              @when('^openmpi')
+              def setup(self):
+                  # do something special when this is built with OpenMPI for
+                  # its MPI implementations.
 
 
-           def install(self, prefix):
-               # Do common install stuff
-               self.setup()
-               # Do more common install stuff
+              def install(self, prefix):
+                  # Do common install stuff
+                  self.setup()
+                  # Do more common install stuff
 
        There must be one (and only one) @when clause that matches the
        package's spec.  If there is more than one, or if none match,
@@ -193,10 +195,11 @@ class when(object):
        platform-specific versions.  There's not much we can do to get
        around this because of the way decorators work.
     """
-class when(object):
     def __init__(self, spec):
         pkg = get_calling_module_name()
-        self.spec = parse_anonymous_spec(spec, pkg)
+        if spec is True:
+            spec = pkg
+        self.spec = parse_anonymous_spec(spec, pkg) if spec is not False else None
 
     def __call__(self, method):
         # Get the first definition of the method in the calling scope
@@ -207,7 +210,9 @@ class when(object):
         if not type(original_method) == SpecMultiMethod:
             original_method = SpecMultiMethod(original_method)
 
-        original_method.register(self.spec, method)
+        if self.spec is not None:
+            original_method.register(self.spec, method)
+
         return original_method
 
 
diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index 8019b29cba..ca9e9c4bd1 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -58,6 +58,7 @@ import spack.compilers
 import spack.mirror
 import spack.hooks
 import spack.directives
+import spack.repository
 import spack.build_environment
 import spack.url
 import spack.util.web
@@ -66,6 +67,7 @@ from spack.version import *
 from spack.stage import Stage, ResourceStage, StageComposite
 from spack.util.compression import allowed_archive, extension
 from spack.util.executable import ProcessError
+from spack.util.environment import dump_environment
 
 """Allowed URL schemes for spack packages."""
 _ALLOWED_URL_SCHEMES = ["http", "https", "ftp", "file", "git"]
@@ -454,7 +456,7 @@ class Package(object):
         # Construct a composite stage on top of the composite FetchStrategy
         composite_fetcher = self.fetcher
         composite_stage = StageComposite()
-        resources = self._get_resources()
+        resources = self._get_needed_resources()
         for ii, fetcher in enumerate(composite_fetcher):
             if ii == 0:
                 # Construct root stage first
@@ -465,6 +467,11 @@ class Package(object):
                 stage = self._make_resource_stage(composite_stage[0], fetcher, resource)
             # Append the item to the composite
             composite_stage.append(stage)
+
+        # Create stage on first access.  Needed because fetch, stage,
+        # patch, and install can be called independently of each
+        # other, so `with self.stage:` in do_install isn't sufficient.
+        composite_stage.create()
         return composite_stage
 
     @property
@@ -483,12 +490,14 @@ class Package(object):
 
 
     def _make_fetcher(self):
-        # Construct a composite fetcher that always contains at least one element (the root package). In case there
-        # are resources associated with the package, append their fetcher to the composite.
+        # Construct a composite fetcher that always contains at least
+        # one element (the root package). In case there are resources
+        # associated with the package, append their fetcher to the
+        # composite.
         root_fetcher = fs.for_package_version(self, self.version)
         fetcher = fs.FetchStrategyComposite()  # Composite fetcher
         fetcher.append(root_fetcher)  # Root fetcher is always present
-        resources = self._get_resources()
+        resources = self._get_needed_resources()
         for resource in resources:
             fetcher.append(resource.fetcher)
         return fetcher
@@ -685,7 +694,7 @@ class Package(object):
 
             if not ignore_checksum:
                 raise FetchError(
-                    "Will not fetch %s." % self.spec.format('$_$@'), checksum_msg)
+                    "Will not fetch %s" % self.spec.format('$_$@'), checksum_msg)
 
         self.stage.fetch(mirror_only)
 
@@ -705,6 +714,7 @@ class Package(object):
         self.stage.expand_archive()
         self.stage.chdir_to_source()
 
+
     def do_patch(self):
         """Calls do_stage(), then applied patches to the expanded tarball if they
            haven't been applied already."""
@@ -719,7 +729,7 @@ class Package(object):
 
         # If there are no patches, note it.
         if not self.patches and not has_patch_fun:
-            tty.msg("No patches needed for %s." % self.name)
+            tty.msg("No patches needed for %s" % self.name)
             return
 
         # Construct paths to special files in the archive dir used to
@@ -732,7 +742,7 @@ class Package(object):
         # If we encounter an archive that failed to patch, restage it
         # so that we can apply all the patches again.
         if os.path.isfile(bad_file):
-            tty.msg("Patching failed last time.  Restaging.")
+            tty.msg("Patching failed last time. Restaging.")
             self.stage.restage()
 
         self.stage.chdir_to_source()
@@ -742,7 +752,7 @@ class Package(object):
             tty.msg("Already patched %s" % self.name)
             return
         elif os.path.isfile(no_patches_file):
-            tty.msg("No patches needed for %s." % self.name)
+            tty.msg("No patches needed for %s" % self.name)
             return
 
         # Apply all the patches for specs that match this one
@@ -763,10 +773,10 @@ class Package(object):
         if has_patch_fun:
             try:
                 self.patch()
-                tty.msg("Ran patch() for %s." % self.name)
+                tty.msg("Ran patch() for %s" % self.name)
                 patched = True
             except:
-                tty.msg("patch() function failed for %s." % self.name)
+                tty.msg("patch() function failed for %s" % self.name)
                 touch(bad_file)
                 raise
 
@@ -797,7 +807,7 @@ class Package(object):
         mkdirp(self.prefix.man1)
 
 
-    def _get_resources(self):
+    def _get_needed_resources(self):
         resources = []
         # Select the resources that are needed for this build
         for when_spec, resource_list in self.resources.items():
@@ -824,7 +834,9 @@ class Package(object):
 
         Args:
         keep_prefix -- Keep install prefix on failure. By default, destroys it.
-        keep_stage  -- Keep stage on successful build. By default, destroys it.
+        keep_stage  -- By default, stage is destroyed only if there are no
+                       exceptions during build. Set to True to keep the stage
+                       even with exceptions.
         ignore_deps -- Do not install dependencies before installing this package.
         fake        -- Don't really build -- install fake stub files instead.
         skip_patch  -- Skip patch stage of build if True.
@@ -834,99 +846,98 @@ class Package(object):
         if not self.spec.concrete:
             raise ValueError("Can only install concrete packages.")
 
-        if os.path.exists(self.prefix):
-            tty.msg("%s is already installed in %s." % (self.name, self.prefix))
+        # Ensure package is not already installed
+        if spack.install_layout.check_installed(self.spec):
+            tty.msg("%s is already installed in %s" % (self.name, self.prefix))
             return
 
         tty.msg("Installing %s" % self.name)
 
+        # First, install dependencies recursively.
         if not ignore_deps:
             self.do_install_dependencies(
                 keep_prefix=keep_prefix, keep_stage=keep_stage, ignore_deps=ignore_deps,
-                fake=fake, skip_patch=skip_patch, verbose=verbose,
-                make_jobs=make_jobs)
-
-        start_time = time.time()
-        if not fake:
-            if not skip_patch:
-                self.do_patch()
-            else:
-                self.do_stage()
+                fake=fake, skip_patch=skip_patch, verbose=verbose, make_jobs=make_jobs)
 
-        # create the install directory.  The install layout
-        # handles this in case so that it can use whatever
-        # package naming scheme it likes.
-        spack.install_layout.create_install_directory(self.spec)
-
-        def cleanup():
-            if not keep_prefix:
-                # If anything goes wrong, remove the install prefix
-                self.remove_prefix()
-            else:
-                tty.warn("Keeping install prefix in place despite error.",
-                         "Spack will think this package is installed." +
-                         "Manually remove this directory to fix:",
-                         self.prefix, wrap=True)
+        # Set parallelism before starting build.
+        self.make_jobs = make_jobs
 
+        # Then install the package itself.
+        def build_process():
+            """Forked for each build. Has its own process and python
+               module space set up by build_environment.fork()."""
+            start_time = time.time()
+            if not fake:
+                if not skip_patch:
+                    self.do_patch()
+                else:
+                    self.do_stage()
 
-        def real_work():
-            try:
-                tty.msg("Building %s." % self.name)
+            tty.msg("Building %s" % self.name)
 
+            self.stage.keep = keep_stage
+            with self.stage:
                 # Run the pre-install hook in the child process after
                 # the directory is created.
                 spack.hooks.pre_install(self)
 
-                # Set up process's build environment before running install.
                 if fake:
                     self.do_fake_install()
                 else:
                     # Do the real install in the source directory.
-                    self.stage.chdir_to_source()
+                     self.stage.chdir_to_source()
 
-                    # This redirects I/O to a build log (and optionally to the terminal)
-                    log_path = join_path(os.getcwd(), 'spack-build.out')
-                    log_file = open(log_path, 'w')
-                    with log_output(log_file, verbose, sys.stdout.isatty(), True):
-                        self.install(self.spec, self.prefix)
+                     # Save the build environment in a file before building.
+                     env_path = join_path(os.getcwd(), 'spack-build.env')
 
-                # Ensure that something was actually installed.
-                self._sanity_check_install()
+                     try:
+                        # Redirect I/O to a build log (and optionally to the terminal)
+                        log_path = join_path(os.getcwd(), 'spack-build.out')
+                        log_file = open(log_path, 'w')
+                        with log_output(log_file, verbose, sys.stdout.isatty(), True):
+                            dump_environment(env_path)
+                            self.install(self.spec, self.prefix)
 
-                # Move build log into install directory on success
-                if not fake:
-                    log_install_path = spack.install_layout.build_log_path(self.spec)
-                    install(log_path, log_install_path)
+                     except ProcessError as e:
+                         # Annotate ProcessErrors with the location of the build log.
+                         e.build_log = log_path
+                         raise e
 
-                # On successful install, remove the stage.
-                if not keep_stage:
-                    self.stage.destroy()
+                     # Ensure that something was actually installed.
+                     self._sanity_check_install()
 
-                # Stop timer.
-                self._total_time = time.time() - start_time
-                build_time = self._total_time - self._fetch_time
+                     # Copy provenance into the install directory on success
+                     log_install_path = spack.install_layout.build_log_path(self.spec)
+                     env_install_path = spack.install_layout.build_env_path(self.spec)
+                     packages_dir = spack.install_layout.build_packages_path(self.spec)
 
-                tty.msg("Successfully installed %s." % self.name,
-                        "Fetch: %s.  Build: %s.  Total: %s."
-                        % (_hms(self._fetch_time), _hms(build_time), _hms(self._total_time)))
-                print_pkg(self.prefix)
+                     install(log_path, log_install_path)
+                     install(env_path, env_install_path)
+                     dump_packages(self.spec, packages_dir)
 
-            except ProcessError, e:
-                # Annotate with location of build log.
-                e.build_log = log_path
-                cleanup()
-                raise e
-
-            except:
-                # other exceptions just clean up and raise.
-                cleanup()
-                raise
+            # Stop timer.
+            self._total_time = time.time() - start_time
+            build_time = self._total_time - self._fetch_time
 
-        # Set parallelism before starting build.
-        self.make_jobs = make_jobs
+            tty.msg("Successfully installed %s" % self.name,
+                    "Fetch: %s.  Build: %s.  Total: %s."
+                    % (_hms(self._fetch_time), _hms(build_time), _hms(self._total_time)))
+            print_pkg(self.prefix)
 
-        # Do the build.
-        spack.build_environment.fork(self, real_work)
+        try:
+            # Create the install prefix and fork the build process.
+            spack.install_layout.create_install_directory(self.spec)
+            spack.build_environment.fork(self, build_process)
+        except:
+            # remove the install prefix if anything went wrong during install.
+            if not keep_prefix:
+                self.remove_prefix()
+            else:
+                tty.warn("Keeping install prefix in place despite error.",
+                         "Spack will think this package is installed. " +
+                         "Manually remove this directory to fix:",
+                         self.prefix, wrap=True)
+            raise
 
         # note: PARENT of the build process adds the new package to
         # the database, so that we don't need to re-read from file.
@@ -1013,7 +1024,7 @@ class Package(object):
         # Uninstalling in Spack only requires removing the prefix.
         self.remove_prefix()
         spack.installed_db.remove(self.spec)
-        tty.msg("Successfully uninstalled %s." % self.spec.short_spec)
+        tty.msg("Successfully uninstalled %s" % self.spec.short_spec)
 
         # Once everything else is done, run post install hooks
         spack.hooks.post_uninstall(self)
@@ -1060,7 +1071,7 @@ class Package(object):
         self.extendee_spec.package.activate(self, **self.extendee_args)
 
         spack.install_layout.add_extension(self.extendee_spec, self.spec)
-        tty.msg("Activated extension %s for %s."
+        tty.msg("Activated extension %s for %s"
                 % (self.spec.short_spec, self.extendee_spec.format("$_$@$+$%@")))
 
 
@@ -1112,7 +1123,7 @@ class Package(object):
         if self.activated:
             spack.install_layout.remove_extension(self.extendee_spec, self.spec)
 
-        tty.msg("Deactivated extension %s for %s."
+        tty.msg("Deactivated extension %s for %s"
                 % (self.spec.short_spec, self.extendee_spec.format("$_$@$+$%@")))
 
 
@@ -1140,8 +1151,7 @@ class Package(object):
 
     def do_clean(self):
         """Removes the package's build stage and source tarball."""
-        if os.path.exists(self.stage.path):
-            self.stage.destroy()
+        self.stage.destroy()
 
 
     def format_doc(self, **kwargs):
@@ -1180,7 +1190,7 @@ class Package(object):
         try:
             return spack.util.web.find_versions_of_archive(
                 *self.all_urls, list_url=self.list_url, list_depth=self.list_depth)
-        except spack.error.NoNetworkConnectionError, e:
+        except spack.error.NoNetworkConnectionError as e:
             tty.die("Package.fetch_versions couldn't connect to:",
                     e.url, e.message)
 
@@ -1198,8 +1208,8 @@ class Package(object):
 
     @property
     def rpath_args(self):
-        """Get the rpath args as a string, with -Wl,-rpath= for each element."""
-        return " ".join("-Wl,-rpath=%s" % p for p in self.rpath)
+        """Get the rpath args as a string, with -Wl,-rpath, for each element."""
+        return " ".join("-Wl,-rpath,%s" % p for p in self.rpath)
 
 
 def validate_package_url(url_string):
@@ -1212,6 +1222,52 @@ def validate_package_url(url_string):
         tty.die("Invalid file type in URL: '%s'" % url_string)
 
 
+def dump_packages(spec, path):
+    """Dump all package information for a spec and its dependencies.
+
+       This creates a package repository within path for every
+       namespace in the spec DAG, and fills the repos wtih package
+       files and patch files for every node in the DAG.
+    """
+    mkdirp(path)
+
+    # Copy in package.py files from any dependencies.
+    # Note that we copy them in as they are in the *install* directory
+    # NOT as they are in the repository, because we want a snapshot of
+    # how *this* particular build was done.
+    for node in spec.traverse():
+        if node is not spec:
+            # Locate the dependency package in the install tree and find
+            # its provenance information.
+            source = spack.install_layout.build_packages_path(node)
+            source_repo_root = join_path(source, node.namespace)
+
+            # There's no provenance installed for the source package.  Skip it.
+            # User can always get something current from the builtin repo.
+            if not os.path.isdir(source_repo_root):
+                continue
+
+            # Create a source repo and get the pkg directory out of it.
+            try:
+                source_repo = spack.repository.Repo(source_repo_root)
+                source_pkg_dir = source_repo.dirname_for_package_name(node.name)
+            except RepoError as e:
+                tty.warn("Warning: Couldn't copy in provenance for %s" % node.name)
+
+        # Create a destination repository
+        dest_repo_root = join_path(path, node.namespace)
+        if not os.path.exists(dest_repo_root):
+            spack.repository.create_repo(dest_repo_root)
+        repo = spack.repository.Repo(dest_repo_root)
+
+        # Get the location of the package in the dest repo.
+        dest_pkg_dir = repo.dirname_for_package_name(node.name)
+        if node is not spec:
+            install_tree(source_pkg_dir, dest_pkg_dir)
+        else:
+            spack.repo.dump_provenance(node, dest_pkg_dir)
+
+
 def print_pkg(message):
     """Outputs a message with a package icon."""
     from llnl.util.tty.color import cwrite
@@ -1262,7 +1318,7 @@ class PackageVersionError(PackageError):
     """Raised when a version URL cannot automatically be determined."""
     def __init__(self, version):
         super(PackageVersionError, self).__init__(
-            "Cannot determine a URL automatically for version %s." % version,
+            "Cannot determine a URL automatically for version %s" % version,
             "Please provide a url for this version in the package.py file.")
 
 
diff --git a/lib/spack/spack/repository.py b/lib/spack/spack/repository.py
index f58cd52125..3c3ba08bcc 100644
--- a/lib/spack/spack/repository.py
+++ b/lib/spack/spack/repository.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://llnl.github.io/spack
+# For details, see https://software.llnl.gov/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -33,7 +33,7 @@ from bisect import bisect_left
 from external import yaml
 
 import llnl.util.tty as tty
-from llnl.util.filesystem import join_path
+from llnl.util.filesystem import *
 
 import spack.error
 import spack.config
@@ -156,7 +156,7 @@ class RepoPath(object):
 
         if repo.namespace in self.by_namespace:
             raise DuplicateRepoError(
-                "Package repos '%s' and '%s' both provide namespace %s."
+                "Package repos '%s' and '%s' both provide namespace %s"
                 % (repo.root, self.by_namespace[repo.namespace].root, repo.namespace))
 
         # Add repo to the pkg indexes
@@ -316,6 +316,16 @@ class RepoPath(object):
         return self.repo_for_pkg(spec).get(spec)
 
 
+    @_autospec
+    def dump_provenance(self, spec, path):
+        """Dump provenance information for a spec to a particular path.
+
+           This dumps the package file and any associated patch files.
+           Raises UnknownPackageError if not found.
+        """
+        return self.repo_for_pkg(spec).dump_provenance(spec, path)
+
+
     def dirname_for_package_name(self, pkg_name):
         return self.repo_for_pkg(pkg_name).dirname_for_package_name(pkg_name)
 
@@ -535,7 +545,7 @@ class Repo(object):
             raise UnknownPackageError(spec.name)
 
         if spec.namespace and spec.namespace != self.namespace:
-            raise UnknownPackageError("Repository %s does not contain package %s."
+            raise UnknownPackageError("Repository %s does not contain package %s"
                                       % (self.namespace, spec.fullname))
 
         key = hash(spec)
@@ -552,6 +562,35 @@ class Repo(object):
         return self._instances[key]
 
 
+    @_autospec
+    def dump_provenance(self, spec, path):
+        """Dump provenance information for a spec to a particular path.
+
+           This dumps the package file and any associated patch files.
+           Raises UnknownPackageError if not found.
+        """
+        # Some preliminary checks.
+        if spec.virtual:
+            raise UnknownPackageError(spec.name)
+
+        if spec.namespace and spec.namespace != self.namespace:
+            raise UnknownPackageError("Repository %s does not contain package %s."
+                                      % (self.namespace, spec.fullname))
+
+        # Install any patch files needed by packages.
+        mkdirp(path)
+        for spec, patches in spec.package.patches.items():
+            for patch in patches:
+                if patch.path:
+                    if os.path.exists(patch.path):
+                        install(patch.path, path)
+                    else:
+                        tty.warn("Patch file did not exist: %s" % patch.path)
+
+        # Install the package.py file itself.
+        install(self.filename_for_package_name(spec), path)
+
+
     def purge(self):
         """Clear entire package instance cache."""
         self._instances.clear()
@@ -705,6 +744,58 @@ class Repo(object):
         return self.exists(pkg_name)
 
 
+def create_repo(root, namespace=None):
+    """Create a new repository in root with the specified namespace.
+
+       If the namespace is not provided, use basename of root.
+       Return the canonicalized path and the namespace of the created repository.
+    """
+    root = canonicalize_path(root)
+    if not namespace:
+        namespace = os.path.basename(root)
+
+    if not re.match(r'\w[\.\w-]*', namespace):
+        raise InvalidNamespaceError("'%s' is not a valid namespace." % namespace)
+
+    existed = False
+    if os.path.exists(root):
+        if os.path.isfile(root):
+            raise BadRepoError('File %s already exists and is not a directory' % root)
+        elif os.path.isdir(root):
+            if not os.access(root, os.R_OK | os.W_OK):
+                raise BadRepoError('Cannot create new repo in %s: cannot access directory.' % root)
+            if os.listdir(root):
+                raise BadRepoError('Cannot create new repo in %s: directory is not empty.' % root)
+        existed = True
+
+    full_path = os.path.realpath(root)
+    parent = os.path.dirname(full_path)
+    if not os.access(parent, os.R_OK | os.W_OK):
+        raise BadRepoError("Cannot create repository in %s: can't access parent!" % root)
+
+    try:
+        config_path = os.path.join(root, repo_config_name)
+        packages_path = os.path.join(root, packages_dir_name)
+
+        mkdirp(packages_path)
+        with open(config_path, 'w') as config:
+            config.write("repo:\n")
+            config.write("  namespace: '%s'\n" % namespace)
+
+    except (IOError, OSError) as e:
+        raise BadRepoError('Failed to create new repository in %s.' % root,
+                           "Caused by %s: %s" % (type(e), e))
+
+        # try to clean up.
+        if existed:
+            shutil.rmtree(config_path, ignore_errors=True)
+            shutil.rmtree(packages_path, ignore_errors=True)
+        else:
+            shutil.rmtree(root, ignore_errors=True)
+
+    return full_path, namespace
+
+
 class RepoError(spack.error.SpackError):
     """Superclass for repository-related errors."""
 
@@ -713,6 +804,10 @@ class NoRepoConfiguredError(RepoError):
     """Raised when there are no repositories configured."""
 
 
+class InvalidNamespaceError(RepoError):
+    """Raised when an invalid namespace is encountered."""
+
+
 class BadRepoError(RepoError):
     """Raised when repo layout is invalid."""
 
@@ -730,7 +825,7 @@ class UnknownPackageError(PackageLoadError):
     def __init__(self, name, repo=None):
         msg = None
         if repo:
-            msg = "Package %s not found in repository %s." % (name, repo)
+            msg = "Package %s not found in repository %s" % (name, repo)
         else:
             msg = "Package %s not found." % name
         super(UnknownPackageError, self).__init__(msg)
diff --git a/lib/spack/spack/resource.py b/lib/spack/spack/resource.py
index 2bf92947fd..ddfaaf4cb0 100644
--- a/lib/spack/spack/resource.py
+++ b/lib/spack/spack/resource.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://llnl.github.io/spack
+# For details, see https://software.llnl.gov/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
diff --git a/lib/spack/spack/stage.py b/lib/spack/spack/stage.py
index f217450d42..f88f82fc2d 100644
--- a/lib/spack/spack/stage.py
+++ b/lib/spack/spack/stage.py
@@ -42,36 +42,54 @@ STAGE_PREFIX = 'spack-stage-'
 
 
 class Stage(object):
-    """A Stage object manages a directory where some source code is
-       downloaded and built before being installed.  It handles
-       fetching the source code, either as an archive to be expanded
-       or by checking it out of a repository.  A stage's lifecycle
-       looks like this:
-
-       Stage()
-         Constructor creates the stage directory.
-       fetch()
-         Fetch a source archive into the stage.
-       expand_archive()
-         Expand the source archive.
-       <install>
-         Build and install the archive.  This is handled by the Package class.
-       destroy()
-         Remove the stage once the package has been installed.
-
-       If spack.use_tmp_stage is True, spack will attempt to create stages
-       in a tmp directory.  Otherwise, stages are created directly in
-       spack.stage_path.
-
-       There are two kinds of stages: named and unnamed.  Named stages can
-       persist between runs of spack, e.g. if you fetched a tarball but
-       didn't finish building it, you won't have to fetch it again.
-
-       Unnamed stages are created using standard mkdtemp mechanisms or
-       similar, and are intended to persist for only one run of spack.
+    """Manages a temporary stage directory for building.
+
+    A Stage object is a context manager that handles a directory where
+    some source code is downloaded and built before being installed.
+    It handles fetching the source code, either as an archive to be
+    expanded or by checking it out of a repository.  A stage's
+    lifecycle looks like this:
+
+    ```
+    with Stage() as stage:      # Context manager creates and destroys the stage directory
+        stage.fetch()           # Fetch a source archive into the stage.
+        stage.expand_archive()  # Expand the source archive.
+        <install>               # Build and install the archive. (handled by user of Stage)
+    ```
+
+    When used as a context manager, the stage is automatically
+    destroyed if no exception is raised by the context. If an
+    excpetion is raised, the stage is left in the filesystem and NOT
+    destroyed, for potential reuse later.
+
+    You can also use the stage's create/destroy functions manually,
+    like this:
+
+    ```
+    stage = Stage()
+    try:
+        stage.create()          # Explicitly create the stage directory.
+        stage.fetch()           # Fetch a source archive into the stage.
+        stage.expand_archive()  # Expand the source archive.
+        <install>               # Build and install the archive. (handled by user of Stage)
+    finally:
+        stage.destroy()         # Explicitly destroy the stage directory.
+    ```
+
+    If spack.use_tmp_stage is True, spack will attempt to create
+    stages in a tmp directory.  Otherwise, stages are created directly
+    in spack.stage_path.
+
+    There are two kinds of stages: named and unnamed.  Named stages
+    can persist between runs of spack, e.g. if you fetched a tarball
+    but didn't finish building it, you won't have to fetch it again.
+
+    Unnamed stages are created using standard mkdtemp mechanisms or
+    similar, and are intended to persist for only one run of spack.
     """
 
-    def __init__(self, url_or_fetch_strategy, **kwargs):
+    def __init__(self, url_or_fetch_strategy,
+                 name=None, mirror_path=None, keep=False):
         """Create a stage object.
            Parameters:
              url_or_fetch_strategy
@@ -83,6 +101,17 @@ class Stage(object):
                  and will persist between runs (or if you construct another
                  stage object later).  If name is not provided, then this
                  stage will be given a unique name automatically.
+
+             mirror_path
+                 If provided, Stage will search Spack's mirrors for
+                 this archive at the mirror_path, before using the
+                 default fetch strategy.
+
+             keep
+                 By default, when used as a context manager, the Stage
+                 is deleted on exit when no exceptions are raised.
+                 Pass True to keep the stage intact even if no
+                 exceptions are raised.
         """
         # TODO: fetch/stage coupling needs to be reworked -- the logic
         # TODO: here is convoluted and not modular enough.
@@ -96,21 +125,51 @@ class Stage(object):
         self.default_fetcher = self.fetcher  # self.fetcher can change with mirrors.
         self.skip_checksum_for_mirror = True  # used for mirrored archives of repositories.
 
-        self.name = kwargs.get('name')
-        self.mirror_path = kwargs.get('mirror_path')
+        # TODO : this uses a protected member of tempfile, but seemed the only way to get a temporary name
+        # TODO : besides, the temporary link name won't be the same as the temporary stage area in tmp_root
+        self.name = name
+        if name is None:
+            self.name = STAGE_PREFIX + next(tempfile._get_candidate_names())
+        self.mirror_path = mirror_path
         self.tmp_root = find_tmp_root()
 
-        self.path = None
-        self._setup()
+        # Try to construct here a temporary name for the stage directory
+        # If this is a named stage, then construct a named path.
+        self.path = join_path(spack.stage_path, self.name)
+
+        # Flag to decide whether to delete the stage folder on exit or not
+        self.keep = keep
+
+
+    def __enter__(self):
+        """
+        Entering a stage context will create the stage directory
+
+        Returns:
+            self
+        """
+        self.create()
+        return self
+
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        """
+        Exiting from a stage context will delete the stage directory unless:
+        - it was explicitly requested not to do so
+        - an exception has been raised
+
+        Args:
+            exc_type: exception type
+            exc_val: exception value
+            exc_tb: exception traceback
+
+        Returns:
+            Boolean
+        """
+        # Delete when there are no exceptions, unless asked to keep.
+        if exc_type is None and not self.keep:
+            self.destroy()
 
-    def _cleanup_dead_links(self):
-        """Remove any dead links in the stage directory."""
-        for file in os.listdir(spack.stage_path):
-            path = join_path(spack.stage_path, file)
-            if os.path.islink(path):
-                real_path = os.path.realpath(path)
-                if not os.path.exists(path):
-                    os.unlink(path)
 
     def _need_to_create_path(self):
         """Makes sure nothing weird has happened since the last time we
@@ -132,8 +191,8 @@ class Stage(object):
             real_tmp = os.path.realpath(self.tmp_root)
 
             if spack.use_tmp_stage:
-                # If we're using a tmp dir, it's a link, and it points at the right spot,
-                # then keep it.
+                # If we're using a tmp dir, it's a link, and it points at the
+                # right spot, then keep it.
                 if (real_path.startswith(real_tmp) and os.path.exists(real_path)):
                     return False
                 else:
@@ -148,54 +207,6 @@ class Stage(object):
 
         return False
 
-    def _setup(self):
-        """Creates the stage directory.
-           If spack.use_tmp_stage is False, the stage directory is created
-           directly under spack.stage_path.
-
-           If spack.use_tmp_stage is True, this will attempt to create a
-           stage in a temporary directory and link it into spack.stage_path.
-           Spack will use the first writable location in spack.tmp_dirs to
-           create a stage.  If there is no valid location in tmp_dirs, fall
-           back to making the stage inside spack.stage_path.
-        """
-        # Create the top-level stage directory
-        mkdirp(spack.stage_path)
-        self._cleanup_dead_links()
-
-        # If this is a named stage, then construct a named path.
-        if self.name is not None:
-            self.path = join_path(spack.stage_path, self.name)
-
-        # If this is a temporary stage, them make the temp directory
-        tmp_dir = None
-        if self.tmp_root:
-            if self.name is None:
-                # Unnamed tmp root.  Link the path in
-                tmp_dir = tempfile.mkdtemp('', STAGE_PREFIX, self.tmp_root)
-                self.name = os.path.basename(tmp_dir)
-                self.path = join_path(spack.stage_path, self.name)
-                if self._need_to_create_path():
-                    os.symlink(tmp_dir, self.path)
-
-            else:
-                if self._need_to_create_path():
-                    tmp_dir = tempfile.mkdtemp('', STAGE_PREFIX, self.tmp_root)
-                    os.symlink(tmp_dir, self.path)
-
-        # if we're not using a tmp dir, create the stage directly in the
-        # stage dir, rather than linking to it.
-        else:
-            if self.name is None:
-                self.path = tempfile.mkdtemp('', STAGE_PREFIX, spack.stage_path)
-                self.name = os.path.basename(self.path)
-            else:
-                if self._need_to_create_path():
-                    mkdirp(self.path)
-
-        # Make sure we can actually do something with the stage we made.
-        ensure_access(self.path)
-
     @property
     def archive_file(self):
         """Path to the source archive within this stage directory."""
@@ -214,13 +225,22 @@ class Stage(object):
 
     @property
     def source_path(self):
-        """Returns the path to the expanded/checked out source code
-           within this fetch strategy's path.
+        """Returns the path to the expanded/checked out source code.
+
+        To find the source code, this method searches for the first
+        subdirectory of the stage that it can find, and returns it.
+        This assumes nothing besides the archive file will be in the
+        stage path, but it has the advantage that we don't need to
+        know the name of the archive or its contents.
 
-           This assumes nothing else is going ot be put in the
-           FetchStrategy's path.  It searches for the first
-           subdirectory of the path it can find, then returns that.
+        If the fetch strategy is not supposed to expand the downloaded
+        file, it will just return the stage path. If the archive needs
+        to be expanded, it will return None when no archive is found.
         """
+        if isinstance(self.fetcher, fs.URLFetchStrategy):
+            if not self.fetcher.expand_archive:
+                return self.path
+
         for p in [os.path.join(self.path, f) for f in os.listdir(self.path)]:
             if os.path.isdir(p):
                 return p
@@ -231,7 +251,7 @@ class Stage(object):
         if os.path.isdir(self.path):
             os.chdir(self.path)
         else:
-            tty.die("Setup failed: no such directory: " + self.path)
+            raise ChdirError("Setup failed: no such directory: " + self.path)
 
     def fetch(self, mirror_only=False):
         """Downloads an archive or checks out code from a repository."""
@@ -276,7 +296,7 @@ class Stage(object):
                 self.fetcher = fetcher
                 self.fetcher.fetch()
                 break
-            except spack.error.SpackError, e:
+            except spack.error.SpackError as e:
                 tty.msg("Fetching from %s failed." % fetcher)
                 tty.debug(e)
                 continue
@@ -306,9 +326,9 @@ class Stage(object):
         archive_dir = self.source_path
         if not archive_dir:
             self.fetcher.expand()
-            tty.msg("Created stage in %s." % self.path)
+            tty.msg("Created stage in %s" % self.path)
         else:
-            tty.msg("Already staged %s in %s." % (self.name, self.path))
+            tty.msg("Already staged %s in %s" % (self.name, self.path))
 
     def chdir_to_source(self):
         """Changes directory to the expanded archive directory.
@@ -328,8 +348,35 @@ class Stage(object):
         """
         self.fetcher.reset()
 
+    def create(self):
+        """
+        Creates the stage directory
+
+        If self.tmp_root evaluates to False, the stage directory is
+        created directly under spack.stage_path, otherwise this will
+        attempt to create a stage in a temporary directory and link it
+        into spack.stage_path.
+
+        Spack will use the first writable location in spack.tmp_dirs
+        to create a stage. If there is no valid location in tmp_dirs,
+        fall back to making the stage inside spack.stage_path.
+        """
+        # Create the top-level stage directory
+        mkdirp(spack.stage_path)
+        remove_dead_links(spack.stage_path)
+        # If a tmp_root exists then create a directory there and then link it in the stage area,
+        # otherwise create the stage directory in self.path
+        if self._need_to_create_path():
+            if self.tmp_root:
+                tmp_dir = tempfile.mkdtemp('', STAGE_PREFIX, self.tmp_root)
+                os.symlink(tmp_dir, self.path)
+            else:
+                mkdirp(self.path)
+        # Make sure we can actually do something with the stage we made.
+        ensure_access(self.path)
+
     def destroy(self):
-        """Remove this stage directory."""
+        """Removes this stage directory."""
         remove_linked_tree(self.path)
 
         # Make sure we don't end up in a removed directory
@@ -374,13 +421,28 @@ class ResourceStage(Stage):
                 shutil.move(source_path, destination_path)
 
 
-@pattern.composite(method_list=['fetch', 'check', 'expand_archive', 'restage', 'destroy'])
+@pattern.composite(method_list=['fetch', 'create', 'check', 'expand_archive',  'restage', 'destroy'])
 class StageComposite:
     """
     Composite for Stage type objects. The first item in this composite is considered to be the root package, and
     operations that return a value are forwarded to it.
     """
-
+    #
+    # __enter__ and __exit__ delegate to all stages in the composite.
+    #
+    def __enter__(self):
+        for item in self:
+            item.__enter__()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        for item in reversed(self):
+            item.keep = getattr(self, 'keep', False)
+            item.__exit__(exc_type, exc_val, exc_tb)
+
+    #
+    # Below functions act only on the *first* stage in the composite.
+    #
     @property
     def source_path(self):
         return self[0].source_path
@@ -392,6 +454,10 @@ class StageComposite:
     def chdir_to_source(self):
         return self[0].chdir_to_source()
 
+    @property
+    def archive_file(self):
+        return self[0].archive_file
+
 
 class DIYStage(object):
     """Simple class that allows any directory to be a spack stage."""
@@ -405,12 +471,16 @@ class DIYStage(object):
         if os.path.isdir(self.path):
             os.chdir(self.path)
         else:
-            tty.die("Setup failed: no such directory: " + self.path)
+            raise ChdirError("Setup failed: no such directory: " + self.path)
+
+    # DIY stages do nothing as context managers.
+    def __enter__(self): pass
+    def __exit__(self, exc_type, exc_val, exc_tb): pass
 
     def chdir_to_source(self):
         self.chdir()
 
-    def fetch(self):
+    def fetch(self, mirror_only):
         tty.msg("No need to fetch for DIY.")
 
     def check(self):
@@ -439,19 +509,6 @@ def ensure_access(file=spack.stage_path):
         tty.die("Insufficient permissions for %s" % file)
 
 
-def remove_linked_tree(path):
-    """Removes a directory and its contents.  If the directory is a symlink,
-       follows the link and reamoves the real directory before removing the
-       link.
-    """
-    if os.path.exists(path):
-        if os.path.islink(path):
-            shutil.rmtree(os.path.realpath(path), True)
-            os.unlink(path)
-        else:
-            shutil.rmtree(path, True)
-
-
 def purge():
     """Remove all build directories in the top-level stage path."""
     if os.path.isdir(spack.stage_path):
@@ -480,19 +537,15 @@ def find_tmp_root():
 
 
 class StageError(spack.error.SpackError):
-    def __init__(self, message, long_message=None):
-        super(self, StageError).__init__(message, long_message)
+    """"Superclass for all errors encountered during staging."""
 
 
 class RestageError(StageError):
-    def __init__(self, message, long_msg=None):
-        super(RestageError, self).__init__(message, long_msg)
+    """"Error encountered during restaging."""
 
 
 class ChdirError(StageError):
-    def __init__(self, message, long_msg=None):
-        super(ChdirError, self).__init__(message, long_msg)
-
+    """Raised when Spack can't change directories."""
 
 # Keep this in namespace for convenience
 FailedDownloadError = fs.FailedDownloadError
diff --git a/lib/spack/spack/test/__init__.py b/lib/spack/spack/test/__init__.py
index 4b9a361d4b..d5d8b64765 100644
--- a/lib/spack/spack/test/__init__.py
+++ b/lib/spack/spack/test/__init__.py
@@ -65,7 +65,8 @@ test_names = ['versions',
               'lock',
               'database',
               'namespace_trie',
-              'yaml']
+              'yaml',
+              'sbang']
 
 
 def list_tests():
@@ -87,20 +88,20 @@ def run(names, outputDir, verbose=False):
                           "Valid names are:")
                 colify(sorted(test_names), indent=4)
                 sys.exit(1)
-    
+
     tally = Tally()
     for test in names:
         module = 'spack.test.' + test
         print module
-        
+
         tty.msg("Running test: %s" % test)
-        
+
         runOpts = ["--with-%s" % spack.test.tally_plugin.Tally.name]
-        
+
         if outputDir:
             xmlOutputFname = "unittests-{0}.xml".format(test)
             xmlOutputPath = join_path(outputDir, xmlOutputFname)
-            runOpts += ["--with-xunit", 
+            runOpts += ["--with-xunit",
                 "--xunit-file={0}".format(xmlOutputPath)]
         argv = [""] + runOpts + [module]
         result = nose.run(argv=argv, addplugins=[tally])
diff --git a/lib/spack/spack/test/cc.py b/lib/spack/spack/test/cc.py
index 905af28a06..f3f6d4a22e 100644
--- a/lib/spack/spack/test/cc.py
+++ b/lib/spack/spack/test/cc.py
@@ -39,11 +39,11 @@ test_command = [
     'arg1',
     '-Wl,--start-group',
     'arg2',
-    '-Wl,-rpath=/first/rpath', 'arg3', '-Wl,-rpath', '-Wl,/second/rpath',
+    '-Wl,-rpath,/first/rpath', 'arg3', '-Wl,-rpath', '-Wl,/second/rpath',
     '-llib1', '-llib2',
     'arg4',
     '-Wl,--end-group',
-    '-Xlinker,-rpath', '-Xlinker,/third/rpath', '-Xlinker,-rpath=/fourth/rpath',
+    '-Xlinker', '-rpath', '-Xlinker', '/third/rpath', '-Xlinker', '-rpath', '-Xlinker', '/fourth/rpath',
     '-llib3', '-llib4',
     'arg5', 'arg6']
 
@@ -95,13 +95,13 @@ class CompilerTest(unittest.TestCase):
     def test_ccld_mode(self):
         self.check_cc('dump-mode', [], "ccld")
         self.check_cc('dump-mode', ['foo.c', '-o', 'foo'], "ccld")
-        self.check_cc('dump-mode', ['foo.c', '-o', 'foo', '-Wl,-rpath=foo'], "ccld")
-        self.check_cc('dump-mode', ['foo.o', 'bar.o', 'baz.o', '-o', 'foo', '-Wl,-rpath=foo'], "ccld")
+        self.check_cc('dump-mode', ['foo.c', '-o', 'foo', '-Wl,-rpath,foo'], "ccld")
+        self.check_cc('dump-mode', ['foo.o', 'bar.o', 'baz.o', '-o', 'foo', '-Wl,-rpath,foo'], "ccld")
 
 
     def test_ld_mode(self):
         self.check_ld('dump-mode', [], "ld")
-        self.check_ld('dump-mode', ['foo.o', 'bar.o', 'baz.o', '-o', 'foo', '-Wl,-rpath=foo'], "ld")
+        self.check_ld('dump-mode', ['foo.o', 'bar.o', 'baz.o', '-o', 'foo', '-Wl,-rpath,foo'], "ld")
 
 
     def test_includes(self):
diff --git a/lib/spack/spack/test/concretize.py b/lib/spack/spack/test/concretize.py
index 7f2938aec5..794344fb6a 100644
--- a/lib/spack/spack/test/concretize.py
+++ b/lib/spack/spack/test/concretize.py
@@ -22,8 +22,6 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
-
 import spack
 from spack.spec import Spec, CompilerSpec
 from spack.test.mock_packages_test import *
diff --git a/lib/spack/spack/test/config.py b/lib/spack/spack/test/config.py
index d8be5a855b..0562d2d620 100644
--- a/lib/spack/spack/test/config.py
+++ b/lib/spack/spack/test/config.py
@@ -22,13 +22,13 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
-import shutil
 import os
+import shutil
 from tempfile import mkdtemp
-from ordereddict_backport import OrderedDict
+
 import spack
 import spack.config
+from ordereddict_backport import OrderedDict
 from spack.test.mock_packages_test import *
 
 # Some sample compiler config data
diff --git a/lib/spack/spack/test/configure_guess.py b/lib/spack/spack/test/configure_guess.py
index a4e8565b62..2440d120e5 100644
--- a/lib/spack/spack/test/configure_guess.py
+++ b/lib/spack/spack/test/configure_guess.py
@@ -23,20 +23,15 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import os
-import unittest
 import shutil
 import tempfile
+import unittest
 
 from llnl.util.filesystem import *
-
 from spack.cmd.create import ConfigureGuesser
 from spack.stage import Stage
-
-from spack.fetch_strategy import URLFetchStrategy
-from spack.directory_layout import YamlDirectoryLayout
-from spack.util.executable import which
 from spack.test.mock_packages_test import *
-from spack.test.mock_repo import MockArchive
+from spack.util.executable import which
 
 
 class InstallTest(unittest.TestCase):
@@ -52,8 +47,6 @@ class InstallTest(unittest.TestCase):
 
     def tearDown(self):
         shutil.rmtree(self.tmpdir, ignore_errors=True)
-        if self.stage:
-            self.stage.destroy()
         os.chdir(self.orig_dir)
 
 
@@ -64,12 +57,12 @@ class InstallTest(unittest.TestCase):
 
         url = 'file://' + join_path(os.getcwd(), 'archive.tar.gz')
         print url
-        self.stage = Stage(url)
-        self.stage.fetch()
+        with Stage(url) as stage:
+            stage.fetch()
 
-        guesser = ConfigureGuesser()
-        guesser(self.stage)
-        self.assertEqual(system, guesser.build_system)
+            guesser = ConfigureGuesser()
+            guesser(stage)
+            self.assertEqual(system, guesser.build_system)
 
 
     def test_python(self):
diff --git a/lib/spack/spack/test/database.py b/lib/spack/spack/test/database.py
index 0205f4b8ce..9a57e1f03e 100644
--- a/lib/spack/spack/test/database.py
+++ b/lib/spack/spack/test/database.py
@@ -26,19 +26,18 @@
 These tests check the database is functioning properly,
 both in memory and in its file
 """
-import tempfile
-import shutil
 import multiprocessing
-
-from llnl.util.lock import *
-from llnl.util.filesystem import join_path
+import shutil
+import tempfile
 
 import spack
+from llnl.util.filesystem import join_path
+from llnl.util.lock import *
+from llnl.util.tty.colify import colify
 from spack.database import Database
 from spack.directory_layout import YamlDirectoryLayout
 from spack.test.mock_packages_test import *
 
-from llnl.util.tty.colify import colify
 
 def _print_ref_counts():
     """Print out all ref counts for the graph used here, for debugging"""
diff --git a/lib/spack/spack/test/directory_layout.py b/lib/spack/spack/test/directory_layout.py
index 925cb648ed..d814572d4a 100644
--- a/lib/spack/spack/test/directory_layout.py
+++ b/lib/spack/spack/test/directory_layout.py
@@ -25,20 +25,17 @@
 """\
 This test verifies that the Spack directory layout works properly.
 """
-import unittest
-import tempfile
-import shutil
 import os
-
-from llnl.util.filesystem import *
+import shutil
+import tempfile
 
 import spack
-from spack.spec import Spec
-from spack.repository import RepoPath
+from llnl.util.filesystem import *
 from spack.directory_layout import YamlDirectoryLayout
+from spack.repository import RepoPath
+from spack.spec import Spec
 from spack.test.mock_packages_test import *
 
-
 # number of packages to test (to reduce test time)
 max_packages = 10
 
diff --git a/lib/spack/spack/test/git_fetch.py b/lib/spack/spack/test/git_fetch.py
index d84433176a..3578044116 100644
--- a/lib/spack/spack/test/git_fetch.py
+++ b/lib/spack/spack/test/git_fetch.py
@@ -23,19 +23,12 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import os
-import unittest
-import shutil
-import tempfile
-
-from llnl.util.filesystem import *
 
 import spack
-from spack.version import ver
-from spack.stage import Stage
-from spack.util.executable import which
-
+from llnl.util.filesystem import *
 from spack.test.mock_packages_test import *
 from spack.test.mock_repo import MockGitRepo
+from spack.version import ver
 
 
 class GitFetchTest(MockPackagesTest):
@@ -52,19 +45,15 @@ class GitFetchTest(MockPackagesTest):
         spec.concretize()
         self.pkg = spack.repo.get(spec, new=True)
 
-
     def tearDown(self):
         """Destroy the stage space used by this test."""
         super(GitFetchTest, self).tearDown()
         self.repo.destroy()
-        self.pkg.do_clean()
-
 
     def assert_rev(self, rev):
         """Check that the current git revision is equal to the supplied rev."""
         self.assertEqual(self.repo.rev_hash('HEAD'), self.repo.rev_hash(rev))
 
-
     def try_fetch(self, rev, test_file, args):
         """Tries to:
            1. Fetch the repo using a fetch strategy constructed with
@@ -76,26 +65,27 @@ class GitFetchTest(MockPackagesTest):
         """
         self.pkg.versions[ver('git')] = args
 
-        self.pkg.do_stage()
-        self.assert_rev(rev)
+        with self.pkg.stage:
+            self.pkg.do_stage()
+            self.assert_rev(rev)
 
-        file_path = join_path(self.pkg.stage.source_path, test_file)
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            file_path = join_path(self.pkg.stage.source_path, test_file)
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        os.unlink(file_path)
-        self.assertFalse(os.path.isfile(file_path))
+            os.unlink(file_path)
+            self.assertFalse(os.path.isfile(file_path))
 
-        untracked_file = 'foobarbaz'
-        touch(untracked_file)
-        self.assertTrue(os.path.isfile(untracked_file))
-        self.pkg.do_restage()
-        self.assertFalse(os.path.isfile(untracked_file))
+            untracked_file = 'foobarbaz'
+            touch(untracked_file)
+            self.assertTrue(os.path.isfile(untracked_file))
+            self.pkg.do_restage()
+            self.assertFalse(os.path.isfile(untracked_file))
 
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        self.assert_rev(rev)
+            self.assert_rev(rev)
 
 
     def test_fetch_master(self):
diff --git a/lib/spack/spack/test/hg_fetch.py b/lib/spack/spack/test/hg_fetch.py
index bbcb64e4c1..b8a0c1ec46 100644
--- a/lib/spack/spack/test/hg_fetch.py
+++ b/lib/spack/spack/test/hg_fetch.py
@@ -23,16 +23,12 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import os
-import unittest
-
-from llnl.util.filesystem import *
-
 import spack
+
 from spack.version import ver
-from spack.stage import Stage
-from spack.util.executable import which
-from spack.test.mock_packages_test import *
 from spack.test.mock_repo import MockHgRepo
+from llnl.util.filesystem import *
+from spack.test.mock_packages_test import *
 
 
 class HgFetchTest(MockPackagesTest):
@@ -49,13 +45,10 @@ class HgFetchTest(MockPackagesTest):
         spec.concretize()
         self.pkg = spack.repo.get(spec, new=True)
 
-
     def tearDown(self):
         """Destroy the stage space used by this test."""
         super(HgFetchTest, self).tearDown()
         self.repo.destroy()
-        self.pkg.do_clean()
-
 
     def try_fetch(self, rev, test_file, args):
         """Tries to:
@@ -68,26 +61,27 @@ class HgFetchTest(MockPackagesTest):
         """
         self.pkg.versions[ver('hg')] = args
 
-        self.pkg.do_stage()
-        self.assertEqual(self.repo.get_rev(), rev)
+        with self.pkg.stage:
+            self.pkg.do_stage()
+            self.assertEqual(self.repo.get_rev(), rev)
 
-        file_path = join_path(self.pkg.stage.source_path, test_file)
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            file_path = join_path(self.pkg.stage.source_path, test_file)
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        os.unlink(file_path)
-        self.assertFalse(os.path.isfile(file_path))
+            os.unlink(file_path)
+            self.assertFalse(os.path.isfile(file_path))
 
-        untracked = 'foobarbaz'
-        touch(untracked)
-        self.assertTrue(os.path.isfile(untracked))
-        self.pkg.do_restage()
-        self.assertFalse(os.path.isfile(untracked))
+            untracked = 'foobarbaz'
+            touch(untracked)
+            self.assertTrue(os.path.isfile(untracked))
+            self.pkg.do_restage()
+            self.assertFalse(os.path.isfile(untracked))
 
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        self.assertEqual(self.repo.get_rev(), rev)
+            self.assertEqual(self.repo.get_rev(), rev)
 
 
     def test_fetch_default(self):
diff --git a/lib/spack/spack/test/install.py b/lib/spack/spack/test/install.py
index 8863d13c42..8297893f01 100644
--- a/lib/spack/spack/test/install.py
+++ b/lib/spack/spack/test/install.py
@@ -22,18 +22,13 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import os
-import unittest
 import shutil
 import tempfile
 
-from llnl.util.filesystem import *
-
 import spack
-from spack.stage import Stage
-from spack.fetch_strategy import URLFetchStrategy, FetchStrategyComposite
+from llnl.util.filesystem import *
 from spack.directory_layout import YamlDirectoryLayout
-from spack.util.executable import which
+from spack.fetch_strategy import URLFetchStrategy, FetchStrategyComposite
 from spack.test.mock_packages_test import *
 from spack.test.mock_repo import MockArchive
 
diff --git a/lib/spack/spack/test/link_tree.py b/lib/spack/spack/test/link_tree.py
index 886b7ef4c5..ee37e765c7 100644
--- a/lib/spack/spack/test/link_tree.py
+++ b/lib/spack/spack/test/link_tree.py
@@ -24,8 +24,6 @@
 ##############################################################################
 import os
 import unittest
-import shutil
-import tempfile
 
 from llnl.util.filesystem import *
 from llnl.util.link_tree import LinkTree
@@ -38,6 +36,7 @@ class LinkTreeTest(unittest.TestCase):
 
     def setUp(self):
         self.stage = Stage('link-tree-test')
+        self.stage.create()
 
         with working_dir(self.stage.path):
             touchp('source/1')
@@ -51,10 +50,8 @@ class LinkTreeTest(unittest.TestCase):
         source_path = os.path.join(self.stage.path, 'source')
         self.link_tree = LinkTree(source_path)
 
-
     def tearDown(self):
-        if self.stage:
-            self.stage.destroy()
+        self.stage.destroy()
 
 
     def check_file_link(self, filename):
diff --git a/lib/spack/spack/test/lock.py b/lib/spack/spack/test/lock.py
index bc68df01db..3b11d18da4 100644
--- a/lib/spack/spack/test/lock.py
+++ b/lib/spack/spack/test/lock.py
@@ -25,15 +25,13 @@
 """
 These tests ensure that our lock works correctly.
 """
-import unittest
-import os
-import tempfile
 import shutil
+import tempfile
+import unittest
 from multiprocessing import Process
 
-from llnl.util.lock import *
 from llnl.util.filesystem import join_path, touch
-
+from llnl.util.lock import *
 from spack.util.multiproc import Barrier
 
 # This is the longest a failed test will take, as the barriers will
diff --git a/lib/spack/spack/test/make_executable.py b/lib/spack/spack/test/make_executable.py
index d568a28d44..a2606acf19 100644
--- a/lib/spack/spack/test/make_executable.py
+++ b/lib/spack/spack/test/make_executable.py
@@ -28,13 +28,13 @@ Tests for Spack's built-in parallel make support.
 This just tests whether the right args are getting passed to make.
 """
 import os
-import unittest
-import tempfile
 import shutil
+import tempfile
+import unittest
 
 from llnl.util.filesystem import *
-from spack.util.environment import path_put_first
 from spack.build_environment import MakeExecutable
+from spack.util.environment import path_put_first
 
 
 class MakeExecutableTest(unittest.TestCase):
diff --git a/lib/spack/spack/test/mirror.py b/lib/spack/spack/test/mirror.py
index f83cc8090c..e707adfe9d 100644
--- a/lib/spack/spack/test/mirror.py
+++ b/lib/spack/spack/test/mirror.py
@@ -23,11 +23,10 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import os
-from filecmp import dircmp
-
 import spack
 import spack.mirror
-from spack.util.compression import decompressor_for
+
+from filecmp import dircmp
 from spack.test.mock_packages_test import *
 from spack.test.mock_repo import *
 
@@ -74,14 +73,14 @@ class MirrorTest(MockPackagesTest):
 
 
     def check_mirror(self):
-        stage = Stage('spack-mirror-test')
-        mirror_root = join_path(stage.path, 'test-mirror')
+        with Stage('spack-mirror-test') as stage:
+            mirror_root = join_path(stage.path, 'test-mirror')
+
+            # register mirror with spack config
+            mirrors = { 'spack-mirror-test' : 'file://' + mirror_root }
+            spack.config.update_config('mirrors', mirrors)
 
-        # register mirror with spack config
-        mirrors = { 'spack-mirror-test' : 'file://' + mirror_root }
-        spack.config.update_config('mirrors', mirrors)
 
-        try:
             os.chdir(stage.path)
             spack.mirror.create(
                 mirror_root, self.repos, no_checksum=True)
@@ -97,38 +96,28 @@ class MirrorTest(MockPackagesTest):
                 files = os.listdir(subdir)
                 self.assertEqual(len(files), 1)
 
-            # Now try to fetch each package.
-            for name, mock_repo in self.repos.items():
-                spec = Spec(name).concretized()
-                pkg = spec.package
-
-                pkg._stage = None
-                saved_checksum_setting = spack.do_checksum
-                try:
-                    # Stage the archive from the mirror and cd to it.
-                    spack.do_checksum = False
-                    pkg.do_stage(mirror_only=True)
-
-                    # Compare the original repo with the expanded archive
-                    original_path = mock_repo.path
-                    if 'svn' in name:
-                        # have to check out the svn repo to compare.
-                        original_path = join_path(mock_repo.path, 'checked_out')
-                        svn('checkout', mock_repo.url, original_path)
-
-                    dcmp = dircmp(original_path, pkg.stage.source_path)
-
-                    # make sure there are no new files in the expanded tarball
-                    self.assertFalse(dcmp.right_only)
-
-                    # and that all original files are present.
-                    self.assertTrue(all(l in exclude for l in dcmp.left_only))
-
-                finally:
-                    spack.do_checksum = saved_checksum_setting
-                    pkg.do_clean()
-        finally:
-            stage.destroy()
+                # Now try to fetch each package.
+                for name, mock_repo in self.repos.items():
+                    spec = Spec(name).concretized()
+                    pkg = spec.package
+
+                    saved_checksum_setting = spack.do_checksum
+                    with pkg.stage:
+                        # Stage the archive from the mirror and cd to it.
+                        spack.do_checksum = False
+                        pkg.do_stage(mirror_only=True)
+                        # Compare the original repo with the expanded archive
+                        original_path = mock_repo.path
+                        if 'svn' in name:
+                            # have to check out the svn repo to compare.
+                            original_path = join_path(mock_repo.path, 'checked_out')
+                            svn('checkout', mock_repo.url, original_path)
+                        dcmp = dircmp(original_path, pkg.stage.source_path)
+                        # make sure there are no new files in the expanded tarball
+                        self.assertFalse(dcmp.right_only)
+                        # and that all original files are present.
+                        self.assertTrue(all(l in exclude for l in dcmp.left_only))
+                        spack.do_checksum = saved_checksum_setting
 
 
     def test_git_mirror(self):
diff --git a/lib/spack/spack/test/mock_packages_test.py b/lib/spack/spack/test/mock_packages_test.py
index e9f1f95df5..0b8867b61e 100644
--- a/lib/spack/spack/test/mock_packages_test.py
+++ b/lib/spack/spack/test/mock_packages_test.py
@@ -22,17 +22,15 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import sys
 import os
 import shutil
-import unittest
 import tempfile
-from ordereddict_backport import OrderedDict
-
-from llnl.util.filesystem import mkdirp
+import unittest
 
 import spack
 import spack.config
+from llnl.util.filesystem import mkdirp
+from ordereddict_backport import OrderedDict
 from spack.repository import RepoPath
 from spack.spec import Spec
 
diff --git a/lib/spack/spack/test/mock_repo.py b/lib/spack/spack/test/mock_repo.py
index ed94023b0e..a8bdfb5571 100644
--- a/lib/spack/spack/test/mock_repo.py
+++ b/lib/spack/spack/test/mock_repo.py
@@ -26,13 +26,9 @@ import os
 import shutil
 
 from llnl.util.filesystem import *
-
-import spack
-from spack.version import ver
 from spack.stage import Stage
 from spack.util.executable import which
 
-
 #
 # VCS Systems used by mock repo code.
 #
diff --git a/lib/spack/spack/test/multimethod.py b/lib/spack/spack/test/multimethod.py
index 7bf4ff0a0a..2d4b8cd584 100644
--- a/lib/spack/spack/test/multimethod.py
+++ b/lib/spack/spack/test/multimethod.py
@@ -25,14 +25,11 @@
 """
 Test for multi_method dispatch.
 """
-import unittest
 
 import spack
 from spack.multimethod import *
-from spack.version import *
-from spack.spec import Spec
-from spack.multimethod import when
 from spack.test.mock_packages_test import *
+from spack.version import *
 
 
 class MultiMethodTest(MockPackagesTest):
diff --git a/lib/spack/spack/test/namespace_trie.py b/lib/spack/spack/test/namespace_trie.py
index d0d809004d..2023ba6d96 100644
--- a/lib/spack/spack/test/namespace_trie.py
+++ b/lib/spack/spack/test/namespace_trie.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://llnl.github.io/spack
+# For details, see https://software.llnl.gov/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -23,6 +23,7 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import unittest
+
 from spack.util.naming import NamespaceTrie
 
 
diff --git a/lib/spack/spack/test/optional_deps.py b/lib/spack/spack/test/optional_deps.py
index ebd7281999..55f35ea4c9 100644
--- a/lib/spack/spack/test/optional_deps.py
+++ b/lib/spack/spack/test/optional_deps.py
@@ -22,10 +22,8 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
 
-import spack
-from spack.spec import Spec, CompilerSpec
+from spack.spec import Spec
 from spack.test.mock_packages_test import *
 
 class ConcretizeTest(MockPackagesTest):
diff --git a/lib/spack/spack/test/packages.py b/lib/spack/spack/test/packages.py
index 83984dc5f6..f0b5e05f3b 100644
--- a/lib/spack/spack/test/packages.py
+++ b/lib/spack/spack/test/packages.py
@@ -22,14 +22,12 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
-
-from llnl.util.filesystem import join_path
 
 import spack
+from llnl.util.filesystem import join_path
 from spack.repository import Repo
-from spack.util.naming import mod_to_class
 from spack.test.mock_packages_test import *
+from spack.util.naming import mod_to_class
 
 
 class PackagesTest(MockPackagesTest):
diff --git a/lib/spack/spack/test/python_version.py b/lib/spack/spack/test/python_version.py
index d74d3b9b7d..4294975304 100644
--- a/lib/spack/spack/test/python_version.py
+++ b/lib/spack/spack/test/python_version.py
@@ -28,12 +28,11 @@ This test ensures that all Spack files are Python version 2.6 or less.
 Spack was originally 2.7, but enough systems in 2014 are still using
 2.6 on their frontend nodes that we need 2.6 to get adopted.
 """
-import unittest
 import os
 import re
+import unittest
 
 import llnl.util.tty as tty
-
 import pyqver2
 import spack
 
diff --git a/lib/spack/spack/test/sbang.py b/lib/spack/spack/test/sbang.py
new file mode 100644
index 0000000000..825bc4be98
--- /dev/null
+++ b/lib/spack/spack/test/sbang.py
@@ -0,0 +1,93 @@
+##############################################################################
+# Copyright (c) 2013-2015, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License (as published by
+# the Free Software Foundation) version 2.1 dated February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+"""\
+Test that Spack's shebang filtering works correctly.
+"""
+import os
+import unittest
+import tempfile
+import shutil
+
+from llnl.util.filesystem import *
+from spack.hooks.sbang import filter_shebangs_in_directory
+import spack
+
+short_line = "#!/this/is/short/bin/bash\n"
+long_line  = "#!/this/" + ('x' * 200) + "/is/long\n"
+sbang_line = '#!/bin/bash %s/bin/sbang\n' % spack.spack_root
+last_line = "last!\n"
+
+class SbangTest(unittest.TestCase):
+    def setUp(self):
+        self.tempdir = tempfile.mkdtemp()
+
+        # make sure we can ignore non-files
+        directory = os.path.join(self.tempdir, 'dir')
+        mkdirp(directory)
+
+        # Script with short shebang
+        self.short_shebang = os.path.join(self.tempdir, 'short')
+        with open(self.short_shebang, 'w') as f:
+            f.write(short_line)
+            f.write(last_line)
+
+        # Script with long shebang
+        self.long_shebang = os.path.join(self.tempdir, 'long')
+        with open(self.long_shebang, 'w') as f:
+            f.write(long_line)
+            f.write(last_line)
+
+        # Script already using sbang.
+        self.has_shebang = os.path.join(self.tempdir, 'shebang')
+        with open(self.has_shebang, 'w') as f:
+            f.write(sbang_line)
+            f.write(long_line)
+            f.write(last_line)
+
+
+    def tearDown(self):
+         shutil.rmtree(self.tempdir, ignore_errors=True)
+
+
+
+    def test_shebang_handling(self):
+        filter_shebangs_in_directory(self.tempdir)
+
+        # Make sure this is untouched
+        with open(self.short_shebang, 'r') as f:
+            self.assertEqual(f.readline(), short_line)
+            self.assertEqual(f.readline(), last_line)
+
+        # Make sure this got patched.
+        with open(self.long_shebang, 'r') as f:
+            self.assertEqual(f.readline(), sbang_line)
+            self.assertEqual(f.readline(), long_line)
+            self.assertEqual(f.readline(), last_line)
+
+        # Make sure this is untouched
+        with open(self.has_shebang, 'r') as f:
+            self.assertEqual(f.readline(), sbang_line)
+            self.assertEqual(f.readline(), long_line)
+            self.assertEqual(f.readline(), last_line)
diff --git a/lib/spack/spack/test/spec_dag.py b/lib/spack/spack/test/spec_dag.py
index 632f777cde..5e6162b6e6 100644
--- a/lib/spack/spack/test/spec_dag.py
+++ b/lib/spack/spack/test/spec_dag.py
@@ -31,8 +31,6 @@ You can find the dummy packages here::
 import spack
 import spack.package
 
-from llnl.util.lang import list_modules
-
 from spack.spec import Spec
 from spack.test.mock_packages_test import *
 
diff --git a/lib/spack/spack/test/spec_semantics.py b/lib/spack/spack/test/spec_semantics.py
index 44a09cbd7f..8c33d1ff6e 100644
--- a/lib/spack/spack/test/spec_semantics.py
+++ b/lib/spack/spack/test/spec_semantics.py
@@ -22,7 +22,6 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
 from spack.spec import *
 from spack.test.mock_packages_test import *
 
diff --git a/lib/spack/spack/test/spec_syntax.py b/lib/spack/spack/test/spec_syntax.py
index 1daaa4be8f..6e08e30e13 100644
--- a/lib/spack/spack/test/spec_syntax.py
+++ b/lib/spack/spack/test/spec_syntax.py
@@ -23,9 +23,10 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 import unittest
+
 import spack.spec
-from spack.spec import *
 from spack.parse import Token
+from spack.spec import *
 
 # Sample output for a complex lexing.
 complex_lex = [Token(ID, 'mvapich_foo'),
diff --git a/lib/spack/spack/test/stage.py b/lib/spack/spack/test/stage.py
index c1b2a2a573..ea425127c4 100644
--- a/lib/spack/spack/test/stage.py
+++ b/lib/spack/spack/test/stage.py
@@ -25,15 +25,13 @@
 """\
 Test that the Stage class works correctly.
 """
-import unittest
-import shutil
 import os
-import getpass
+import shutil
+import unittest
 from contextlib import *
 
-from llnl.util.filesystem import *
-
 import spack
+from llnl.util.filesystem import *
 from spack.stage import Stage
 from spack.util.executable import which
 
@@ -192,116 +190,125 @@ class StageTest(unittest.TestCase):
 
     def test_setup_and_destroy_name_with_tmp(self):
         with use_tmp(True):
-            stage = Stage(archive_url, name=stage_name)
-            self.check_setup(stage, stage_name)
-
-            stage.destroy()
+            with Stage(archive_url, name=stage_name) as stage:
+                self.check_setup(stage, stage_name)
             self.check_destroy(stage, stage_name)
 
 
     def test_setup_and_destroy_name_without_tmp(self):
         with use_tmp(False):
-            stage = Stage(archive_url, name=stage_name)
-            self.check_setup(stage, stage_name)
-
-            stage.destroy()
+            with Stage(archive_url, name=stage_name) as stage:
+                self.check_setup(stage, stage_name)
             self.check_destroy(stage, stage_name)
 
 
     def test_setup_and_destroy_no_name_with_tmp(self):
         with use_tmp(True):
-            stage = Stage(archive_url)
-            self.check_setup(stage, None)
-
-            stage.destroy()
+            with Stage(archive_url) as stage:
+                self.check_setup(stage, None)
             self.check_destroy(stage, None)
 
 
     def test_setup_and_destroy_no_name_without_tmp(self):
         with use_tmp(False):
-            stage = Stage(archive_url)
-            self.check_setup(stage, None)
-
-            stage.destroy()
+            with Stage(archive_url) as stage:
+                self.check_setup(stage, None)
             self.check_destroy(stage, None)
 
 
     def test_chdir(self):
-        stage = Stage(archive_url, name=stage_name)
-
-        stage.chdir()
-        self.check_setup(stage, stage_name)
-        self.check_chdir(stage, stage_name)
-
-        stage.destroy()
+        with Stage(archive_url, name=stage_name) as stage:
+            stage.chdir()
+            self.check_setup(stage, stage_name)
+            self.check_chdir(stage, stage_name)
         self.check_destroy(stage, stage_name)
 
 
     def test_fetch(self):
-        stage = Stage(archive_url, name=stage_name)
-
-        stage.fetch()
-        self.check_setup(stage, stage_name)
-        self.check_chdir(stage, stage_name)
-        self.check_fetch(stage, stage_name)
-
-        stage.destroy()
+        with Stage(archive_url, name=stage_name) as stage:
+            stage.fetch()
+            self.check_setup(stage, stage_name)
+            self.check_chdir(stage, stage_name)
+            self.check_fetch(stage, stage_name)
         self.check_destroy(stage, stage_name)
 
 
     def test_expand_archive(self):
-        stage = Stage(archive_url, name=stage_name)
-
-        stage.fetch()
-        self.check_setup(stage, stage_name)
-        self.check_fetch(stage, stage_name)
-
-        stage.expand_archive()
-        self.check_expand_archive(stage, stage_name)
-
-        stage.destroy()
+        with Stage(archive_url, name=stage_name) as stage:
+            stage.fetch()
+            self.check_setup(stage, stage_name)
+            self.check_fetch(stage, stage_name)
+            stage.expand_archive()
+            self.check_expand_archive(stage, stage_name)
         self.check_destroy(stage, stage_name)
 
 
     def test_expand_archive(self):
-        stage = Stage(archive_url, name=stage_name)
+        with Stage(archive_url, name=stage_name) as stage:
+            stage.fetch()
+            self.check_setup(stage, stage_name)
+            self.check_fetch(stage, stage_name)
+            stage.expand_archive()
+            stage.chdir_to_source()
+            self.check_expand_archive(stage, stage_name)
+            self.check_chdir_to_source(stage, stage_name)
+        self.check_destroy(stage, stage_name)
 
-        stage.fetch()
-        self.check_setup(stage, stage_name)
-        self.check_fetch(stage, stage_name)
 
-        stage.expand_archive()
-        stage.chdir_to_source()
-        self.check_expand_archive(stage, stage_name)
-        self.check_chdir_to_source(stage, stage_name)
+    def test_restage(self):
+        with Stage(archive_url, name=stage_name) as stage:
+            stage.fetch()
+            stage.expand_archive()
+            stage.chdir_to_source()
+            self.check_expand_archive(stage, stage_name)
+            self.check_chdir_to_source(stage, stage_name)
+
+            # Try to make a file in the old archive dir
+            with open('foobar', 'w') as file:
+                file.write("this file is to be destroyed.")
+
+            self.assertTrue('foobar' in os.listdir(stage.source_path))
+
+            # Make sure the file is not there after restage.
+            stage.restage()
+            self.check_chdir(stage, stage_name)
+            self.check_fetch(stage, stage_name)
+            stage.chdir_to_source()
+            self.check_chdir_to_source(stage, stage_name)
+            self.assertFalse('foobar' in os.listdir(stage.source_path))
+        self.check_destroy(stage, stage_name)
 
-        stage.destroy()
+
+    def test_no_keep_without_exceptions(self):
+        with Stage(archive_url, name=stage_name, keep=False) as stage:
+            pass
         self.check_destroy(stage, stage_name)
 
 
-    def test_restage(self):
-        stage = Stage(archive_url, name=stage_name)
+    def test_keep_without_exceptions(self):
+        with Stage(archive_url, name=stage_name, keep=True) as stage:
+            pass
+        path = self.get_stage_path(stage, stage_name)
+        self.assertTrue(os.path.isdir(path))
 
-        stage.fetch()
-        stage.expand_archive()
-        stage.chdir_to_source()
-        self.check_expand_archive(stage, stage_name)
-        self.check_chdir_to_source(stage, stage_name)
 
-        # Try to make a file in the old archive dir
-        with open('foobar', 'w') as file:
-            file.write("this file is to be destroyed.")
+    def test_no_keep_with_exceptions(self):
+        try:
+            with Stage(archive_url, name=stage_name, keep=False) as stage:
+                raise Exception()
 
-        self.assertTrue('foobar' in os.listdir(stage.source_path))
+            path = self.get_stage_path(stage, stage_name)
+            self.assertTrue(os.path.isdir(path))
+        except:
+            pass # ignore here.
 
-        # Make sure the file is not there after restage.
-        stage.restage()
-        self.check_chdir(stage, stage_name)
-        self.check_fetch(stage, stage_name)
 
-        stage.chdir_to_source()
-        self.check_chdir_to_source(stage, stage_name)
-        self.assertFalse('foobar' in os.listdir(stage.source_path))
+    def test_keep_exceptions(self):
+        try:
+            with Stage(archive_url, name=stage_name, keep=True) as stage:
+                raise Exception()
 
-        stage.destroy()
-        self.check_destroy(stage, stage_name)
+            path = self.get_stage_path(stage, stage_name)
+            self.assertTrue(os.path.isdir(path))
+        except:
+            pass # ignore here.
diff --git a/lib/spack/spack/test/svn_fetch.py b/lib/spack/spack/test/svn_fetch.py
index 454a7f1d1f..1ee4ee700e 100644
--- a/lib/spack/spack/test/svn_fetch.py
+++ b/lib/spack/spack/test/svn_fetch.py
@@ -24,18 +24,12 @@
 ##############################################################################
 import os
 import re
-import unittest
-import shutil
-import tempfile
-
-from llnl.util.filesystem import *
-
 import spack
+
+from spack.test.mock_repo import svn, MockSvnRepo
 from spack.version import ver
-from spack.stage import Stage
-from spack.util.executable import which
 from spack.test.mock_packages_test import *
-from spack.test.mock_repo import svn, MockSvnRepo
+from llnl.util.filesystem import *
 
 
 class SvnFetchTest(MockPackagesTest):
@@ -51,13 +45,10 @@ class SvnFetchTest(MockPackagesTest):
         spec.concretize()
         self.pkg = spack.repo.get(spec, new=True)
 
-
     def tearDown(self):
         """Destroy the stage space used by this test."""
         super(SvnFetchTest, self).tearDown()
         self.repo.destroy()
-        self.pkg.do_clean()
-
 
     def assert_rev(self, rev):
         """Check that the current revision is equal to the supplied rev."""
@@ -70,7 +61,6 @@ class SvnFetchTest(MockPackagesTest):
                     return match.group(1)
         self.assertEqual(get_rev(), rev)
 
-
     def try_fetch(self, rev, test_file, args):
         """Tries to:
            1. Fetch the repo using a fetch strategy constructed with
@@ -82,26 +72,27 @@ class SvnFetchTest(MockPackagesTest):
         """
         self.pkg.versions[ver('svn')] = args
 
-        self.pkg.do_stage()
-        self.assert_rev(rev)
+        with self.pkg.stage:
+            self.pkg.do_stage()
+            self.assert_rev(rev)
 
-        file_path = join_path(self.pkg.stage.source_path, test_file)
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            file_path = join_path(self.pkg.stage.source_path, test_file)
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        os.unlink(file_path)
-        self.assertFalse(os.path.isfile(file_path))
+            os.unlink(file_path)
+            self.assertFalse(os.path.isfile(file_path))
 
-        untracked = 'foobarbaz'
-        touch(untracked)
-        self.assertTrue(os.path.isfile(untracked))
-        self.pkg.do_restage()
-        self.assertFalse(os.path.isfile(untracked))
+            untracked = 'foobarbaz'
+            touch(untracked)
+            self.assertTrue(os.path.isfile(untracked))
+            self.pkg.do_restage()
+            self.assertFalse(os.path.isfile(untracked))
 
-        self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
-        self.assertTrue(os.path.isfile(file_path))
+            self.assertTrue(os.path.isdir(self.pkg.stage.source_path))
+            self.assertTrue(os.path.isfile(file_path))
 
-        self.assert_rev(rev)
+            self.assert_rev(rev)
 
 
     def test_fetch_default(self):
diff --git a/lib/spack/spack/test/tally_plugin.py b/lib/spack/spack/test/tally_plugin.py
index 9ca898c47c..4163ab95dd 100644
--- a/lib/spack/spack/test/tally_plugin.py
+++ b/lib/spack/spack/test/tally_plugin.py
@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://scalability-llnl.github.io/spack
+# For details, see https://scalability-software.llnl.gov/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify
@@ -22,10 +22,10 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-from nose.plugins import Plugin
-
 import os
 
+from nose.plugins import Plugin
+
 class Tally(Plugin):
     name = 'tally'
 
@@ -34,7 +34,7 @@ class Tally(Plugin):
         self.successCount = 0
         self.failCount = 0
         self.errorCount = 0
-    
+
     @property
     def numberOfTestsRun(self):
         """Excludes skipped tests"""
@@ -48,10 +48,10 @@ class Tally(Plugin):
 
     def addSuccess(self, test):
         self.successCount += 1
-        
+
     def addError(self, test, err):
         self.errorCount += 1
-            
+
     def addFailure(self, test, err):
         self.failCount += 1
 
diff --git a/lib/spack/spack/test/unit_install.py b/lib/spack/spack/test/unit_install.py
index ccc409dd60..18615b7efe 100644
--- a/lib/spack/spack/test/unit_install.py
+++ b/lib/spack/spack/test/unit_install.py
@@ -22,10 +22,11 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
-import unittest
 import itertools
+import unittest
 
 import spack
+
 test_install = __import__("spack.cmd.test-install",
     fromlist=["BuildId", "create_test_output", "TestResult"])
 
diff --git a/lib/spack/spack/test/url_extrapolate.py b/lib/spack/spack/test/url_extrapolate.py
index 87adf89401..068a335b49 100644
--- a/lib/spack/spack/test/url_extrapolate.py
+++ b/lib/spack/spack/test/url_extrapolate.py
@@ -25,10 +25,7 @@
 """\
 Tests ability of spack to extrapolate URL versions from existing versions.
 """
-import spack
 import spack.url as url
-from spack.spec import Spec
-from spack.version import ver
 from spack.test.mock_packages_test import *
 
 
diff --git a/lib/spack/spack/test/url_parse.py b/lib/spack/spack/test/url_parse.py
index efde7c0c73..561d4658a1 100644
--- a/lib/spack/spack/test/url_parse.py
+++ b/lib/spack/spack/test/url_parse.py
@@ -27,8 +27,8 @@ This file has a bunch of versions tests taken from the excellent version
 detection in Homebrew.
 """
 import unittest
+
 import spack.url as url
-from pprint import pprint
 
 
 class UrlParseTest(unittest.TestCase):
diff --git a/lib/spack/spack/test/url_substitution.py b/lib/spack/spack/test/url_substitution.py
index aec8baf4ea..2be38af0d3 100644
--- a/lib/spack/spack/test/url_substitution.py
+++ b/lib/spack/spack/test/url_substitution.py
@@ -27,7 +27,6 @@ This test does sanity checks on substituting new versions into URLs
 """
 import unittest
 
-import spack
 import spack.url as url
 
 
diff --git a/lib/spack/spack/test/versions.py b/lib/spack/spack/test/versions.py
index 108450e098..2732006eb3 100644
--- a/lib/spack/spack/test/versions.py
+++ b/lib/spack/spack/test/versions.py
@@ -28,6 +28,7 @@ We try to maintain compatibility with RPM's version semantics
 where it makes sense.
 """
 import unittest
+
 from spack.version import *
 
 
diff --git a/lib/spack/spack/test/yaml.py b/lib/spack/spack/test/yaml.py
index 5a357b8e69..b930c022f2 100644
--- a/lib/spack/spack/test/yaml.py
+++ b/lib/spack/spack/test/yaml.py
@@ -26,6 +26,7 @@
 Test Spack's custom YAML format.
 """
 import unittest
+
 import spack.util.spack_yaml as syaml
 
 test_file = """\
diff --git a/lib/spack/spack/url.py b/lib/spack/spack/url.py
index 02c0b83e26..ad551a6ded 100644
--- a/lib/spack/spack/url.py
+++ b/lib/spack/spack/url.py
@@ -225,7 +225,7 @@ def parse_version_offset(path):
         (r'_((\d+\.)+\d+[a-z]?)[.]orig$', stem),
 
         # e.g. http://www.openssl.org/source/openssl-0.9.8s.tar.gz
-        (r'-([^-]+(-alpha|-beta)?)', stem),
+        (r'-v?([^-]+(-alpha|-beta)?)', stem),
 
         # e.g. astyle_1.23_macosx.tar.gz
         (r'_([^_]+(_alpha|_beta)?)', stem),
diff --git a/lib/spack/spack/util/environment.py b/lib/spack/spack/util/environment.py
index cd413dcfbc..ae8e5708be 100644
--- a/lib/spack/spack/util/environment.py
+++ b/lib/spack/spack/util/environment.py
@@ -63,3 +63,10 @@ def pop_keys(dictionary, *keys):
     for key in keys:
         if key in dictionary:
             dictionary.pop(key)
+
+
+def dump_environment(path):
+    """Dump the current environment out to a file."""
+    with open(path, 'w') as env_file:
+        for key,val in sorted(os.environ.items()):
+            env_file.write("%s=%s\n" % (key, val))
diff --git a/lib/spack/spack/util/web.py b/lib/spack/spack/util/web.py
index e26daef296..73f4858b02 100644
--- a/lib/spack/spack/util/web.py
+++ b/lib/spack/spack/util/web.py
@@ -86,12 +86,12 @@ def _spider(args):
 
         if not "Content-type" in resp.headers:
             tty.debug("ignoring page " + url)
-            return pages
+            return pages, links
 
         if not resp.headers["Content-type"].startswith('text/html'):
             tty.debug("ignoring page " + url + " with content type " +
                       resp.headers["Content-type"])
-            return pages
+            return pages, links
 
         # Do the real GET request when we know it's just HTML.
         req.get_method = lambda: "GET"
@@ -173,7 +173,7 @@ def spider(root_url, **kwargs):
        performance over a sequential fetch.
     """
     max_depth = kwargs.setdefault('depth', 1)
-    pages, links =  _spider((root_url, set(), root_url, None, 1, max_depth, False))
+    pages, links = _spider((root_url, set(), root_url, None, 1, max_depth, False))
     return pages, links