Revert "Separable module configurations (#22588)" (#23674)

This reverts commit cefbe48c89209dc3df654795644973b1885cdea4.

34 files changed, 208 insertions, 521 deletions

diff --git a/etc/spack/defaults/config.yaml b/etc/spack/defaults/config.yaml
index 2400686e60..61c23f42df 100644
--- a/etc/spack/defaults/config.yaml
+++ b/etc/spack/defaults/config.yaml
@@ -33,6 +33,13 @@ config:
   template_dirs:
     - $spack/share/spack/templates
 
+
+  # Locations where different types of modules should be installed.
+  module_roots:
+    tcl:    $spack/share/spack/modules
+    lmod:   $spack/share/spack/lmod
+
+
   # Temporary locations Spack can try to use for builds.
   #
   # Recommended options are given below.
diff --git a/etc/spack/defaults/darwin/modules.yaml b/etc/spack/defaults/darwin/modules.yaml
index 3bfca8c613..a90cc24c60 100644
--- a/etc/spack/defaults/darwin/modules.yaml
+++ b/etc/spack/defaults/darwin/modules.yaml
@@ -14,9 +14,8 @@
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
 modules:
-  default:
-    prefix_inspections:
-      lib:
-        - DYLD_FALLBACK_LIBRARY_PATH
-      lib64:
-        - DYLD_FALLBACK_LIBRARY_PATH
+  prefix_inspections:
+    lib:
+      - DYLD_FALLBACK_LIBRARY_PATH
+    lib64:
+      - DYLD_FALLBACK_LIBRARY_PATH
diff --git a/etc/spack/defaults/linux/modules.yaml b/etc/spack/defaults/linux/modules.yaml
index 353a6ea9ab..a86a4794f1 100644
--- a/etc/spack/defaults/linux/modules.yaml
+++ b/etc/spack/defaults/linux/modules.yaml
@@ -14,9 +14,8 @@
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
 modules:
-  default:
-    prefix_inspections:
-      lib:
-        - LD_LIBRARY_PATH
-      lib64:
-        - LD_LIBRARY_PATH
+  prefix_inspections:
+    lib:
+      - LD_LIBRARY_PATH
+    lib64:
+      - LD_LIBRARY_PATH
diff --git a/etc/spack/defaults/modules.yaml b/etc/spack/defaults/modules.yaml
index 4539dbc9c2..d6d245930c 100644
--- a/etc/spack/defaults/modules.yaml
+++ b/etc/spack/defaults/modules.yaml
@@ -14,7 +14,8 @@
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
 modules:
-  # Paths to check when creating modules for all module sets
+  enable:
+    - tcl
   prefix_inspections:
     bin:
       - PATH
@@ -33,17 +34,6 @@ modules:
     '':
       - CMAKE_PREFIX_PATH
 
-  # These are configurations for the module set named "default"
-  default:
-    # Where to install modules
-    roots:
-      tcl:    $spack/share/spack/modules
-      lmod:   $spack/share/spack/lmod
-    # What type of modules to use
-    enable:
-      - tcl
-
-    # Default configurations if lmod is enabled
-    lmod:
-      hierarchy:
-        - mpi
+  lmod:
+    hierarchy:
+      - mpi
diff --git a/lib/spack/spack/cmd/env.py b/lib/spack/spack/cmd/env.py
index c980366352..11b422a9bd 100644
--- a/lib/spack/spack/cmd/env.py
+++ b/lib/spack/spack/cmd/env.py
@@ -364,9 +364,6 @@ def env_loads_setup_parser(subparser):
     subparser.add_argument(
         'env', nargs='?', help='name of env to generate loads file for')
     subparser.add_argument(
-        '-n', '--module-set-name', default='default',
-        help='module set for which to generate load operations')
-    subparser.add_argument(
         '-m', '--module-type', choices=('tcl', 'lmod'),
         help='type of module system to generate loads for')
     spack.cmd.modules.add_loads_arguments(subparser)
diff --git a/lib/spack/spack/cmd/install.py b/lib/spack/spack/cmd/install.py
index eb126460d2..53e924cb9e 100644
--- a/lib/spack/spack/cmd/install.py
+++ b/lib/spack/spack/cmd/install.py
@@ -261,7 +261,7 @@ def install_specs(cli_args, kwargs, specs):
                     with env.write_transaction():
                         specs_to_install.append(
                             env.concretize_and_add(abstract, concrete))
-                        env.write(regenerate=False)
+                        env.write(regenerate_views=False)
 
             # Install the validated list of cli specs
             if specs_to_install:
@@ -338,7 +338,7 @@ environment variables:
 
                     # save view regeneration for later, so that we only do it
                     # once, as it can be slow.
-                    env.write(regenerate=False)
+                    env.write(regenerate_views=False)
 
             specs = env.all_specs()
             if not args.log_file and not reporter.filename:
@@ -352,9 +352,9 @@ environment variables:
             tty.debug("Regenerating environment views for {0}"
                       .format(env.name))
             with env.write_transaction():
-                # write env to trigger view generation and modulefile
-                # generation
-                env.write()
+                # It is not strictly required to synchronize view regeneration
+                # but doing so can prevent redundant work in the filesystem.
+                env.regenerate_views()
             return
         else:
             msg = "install requires a package argument or active environment"
diff --git a/lib/spack/spack/cmd/modules/__init__.py b/lib/spack/spack/cmd/modules/__init__.py
index 3d6975801f..7fbce3bb9d 100644
--- a/lib/spack/spack/cmd/modules/__init__.py
+++ b/lib/spack/spack/cmd/modules/__init__.py
@@ -13,7 +13,6 @@ import sys
 from llnl.util import filesystem, tty
 
 import spack.cmd
-import spack.config
 import spack.modules
 import spack.repo
 import spack.modules.common
@@ -26,11 +25,6 @@ level = "short"
 
 
 def setup_parser(subparser):
-    subparser.add_argument(
-        '-n', '--name',
-        action='store', dest='module_set_name', default='default',
-        help="Named module set to use from modules configuration."
-    )
     sp = subparser.add_subparsers(metavar='SUBCOMMAND', dest='subparser_name')
 
     refresh_parser = sp.add_parser('refresh', help='regenerate module files')
@@ -117,19 +111,6 @@ def one_spec_or_raise(specs):
     return specs[0]
 
 
-def check_module_set_name(name):
-    modules_config = spack.config.get('modules')
-    valid_names = set([key for key, value in modules_config.items()
-                       if isinstance(value, dict) and value.get('enable', [])])
-    if 'enable' in modules_config and modules_config['enable']:
-        valid_names.add('default')
-
-    if name not in valid_names:
-        msg = "Cannot use invalid module set %s." % name
-        msg += "    Valid module set names are %s" % list(valid_names)
-        raise spack.config.ConfigError(msg)
-
-
 _missing_modules_warning = (
     "Modules have been omitted for one or more specs, either"
     " because they were blacklisted or because the spec is"
@@ -140,7 +121,6 @@ _missing_modules_warning = (
 
 def loads(module_type, specs, args, out=None):
     """Prompt the list of modules associated with a list of specs"""
-    check_module_set_name(args.module_set_name)
     out = sys.stdout if out is None else out
 
     # Get a comprehensive list of specs
@@ -162,8 +142,7 @@ def loads(module_type, specs, args, out=None):
     modules = list(
         (spec,
          spack.modules.common.get_module(
-             module_type, spec, get_full_path=False,
-             module_set_name=args.module_set_name, required=False))
+             module_type, spec, get_full_path=False, required=False))
         for spec in specs)
 
     module_commands = {
@@ -198,7 +177,6 @@ def loads(module_type, specs, args, out=None):
 
 def find(module_type, specs, args):
     """Retrieve paths or use names of module files"""
-    check_module_set_name(args.module_set_name)
 
     single_spec = one_spec_or_raise(specs)
 
@@ -212,14 +190,12 @@ def find(module_type, specs, args):
     try:
         modules = [
             spack.modules.common.get_module(
-                module_type, spec, args.full_path,
-                module_set_name=args.module_set_name, required=False)
+                module_type, spec, args.full_path, required=False)
             for spec in dependency_specs_to_retrieve]
 
         modules.append(
             spack.modules.common.get_module(
-                module_type, single_spec, args.full_path,
-                module_set_name=args.module_set_name, required=True))
+                module_type, single_spec, args.full_path, required=True))
     except spack.modules.common.ModuleNotFoundError as e:
         tty.die(e.message)
 
@@ -233,16 +209,13 @@ def rm(module_type, specs, args):
     """Deletes the module files associated with every spec in specs, for every
     module type in module types.
     """
-    check_module_set_name(args.module_set_name)
 
     module_cls = spack.modules.module_types[module_type]
-    module_exist = lambda x: os.path.exists(
-        module_cls(x, args.module_set_name).layout.filename)
+    module_exist = lambda x: os.path.exists(module_cls(x).layout.filename)
 
     specs_with_modules = [spec for spec in specs if module_exist(spec)]
 
-    modules = [module_cls(spec, args.module_set_name)
-               for spec in specs_with_modules]
+    modules = [module_cls(spec) for spec in specs_with_modules]
 
     if not modules:
         tty.die('No module file matches your query')
@@ -266,7 +239,6 @@ def refresh(module_type, specs, args):
     """Regenerates the module files for every spec in specs and every module
     type in module types.
     """
-    check_module_set_name(args.module_set_name)
 
     # Prompt a message to the user about what is going to change
     if not specs:
@@ -291,7 +263,7 @@ def refresh(module_type, specs, args):
 
     # Skip unknown packages.
     writers = [
-        cls(spec, args.module_set_name) for spec in specs
+        cls(spec) for spec in specs
         if spack.repo.path.exists(spec.name)]
 
     # Filter blacklisted packages early
diff --git a/lib/spack/spack/cmd/modules/lmod.py b/lib/spack/spack/cmd/modules/lmod.py
index 3546e2b87a..61f2fc28d8 100644
--- a/lib/spack/spack/cmd/modules/lmod.py
+++ b/lib/spack/spack/cmd/modules/lmod.py
@@ -40,8 +40,7 @@ def setdefault(module_type, specs, args):
     # https://lmod.readthedocs.io/en/latest/060_locating.html#marking-a-version-as-default
     #
     spack.cmd.modules.one_spec_or_raise(specs)
-    writer = spack.modules.module_types['lmod'](
-        specs[0], args.module_set_name)
+    writer = spack.modules.module_types['lmod'](specs[0])
 
     module_folder = os.path.dirname(writer.layout.filename)
     module_basename = os.path.basename(writer.layout.filename)
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index aa94f89f94..574902f508 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -571,17 +571,16 @@ class Configuration(object):
         YAML config file that looks like this::
 
            config:
-             install_tree:
-               root: $spack/opt/spack
-             build_stage:
-             - $tmpdir/$user/spack-stage
+             install_tree: $spack/opt/spack
+             module_roots:
+               lmod:   $spack/share/spack/lmod
 
         ``get_config('config')`` will return::
 
-           { 'install_tree': {
-                 'root': '$spack/opt/spack',
+           { 'install_tree': '$spack/opt/spack',
+             'module_roots: {
+                 'lmod': '$spack/share/spack/lmod'
              }
-             'build_stage': ['$tmpdir/$user/spack-stage']
            }
 
         """
diff --git a/lib/spack/spack/environment.py b/lib/spack/spack/environment.py
index 979e14e8c9..647352a10e 100644
--- a/lib/spack/spack/environment.py
+++ b/lib/spack/spack/environment.py
@@ -20,7 +20,6 @@ from llnl.util.tty.color import colorize
 import spack.concretize
 import spack.error
 import spack.hash_types as ht
-import spack.hooks
 import spack.repo
 import spack.schema.env
 import spack.spec
@@ -460,15 +459,12 @@ class ViewDescriptor(object):
         self.root = spack.util.path.canonicalize_path(root)
         self.projections = projections
         self.select = select
+        self.select_fn = lambda x: any(x.satisfies(s) for s in self.select)
         self.exclude = exclude
+        self.exclude_fn = lambda x: not any(x.satisfies(e)
+                                            for e in self.exclude)
         self.link = link
 
-    def select_fn(self, spec):
-        return any(spec.satisfies(s) for s in self.select)
-
-    def exclude_fn(self, spec):
-        return not any(spec.satisfies(e) for e in self.exclude)
-
     def __eq__(self, other):
         return all([self.root == other.root,
                     self.projections == other.projections,
@@ -749,7 +745,7 @@ class Environment(object):
         if not os.path.exists(self.manifest_path):
             return
 
-        self.clear(re_read=True)
+        self.clear()
         self._read()
 
     def _read(self):
@@ -847,26 +843,15 @@ class Environment(object):
             )
         }
 
-    def clear(self, re_read=False):
-        """Clear the contents of the environment
-
-        Arguments:
-            re_read (boolean): If True, do not clear ``new_specs`` nor
-                ``new_installs`` values. These values cannot be read from
-                yaml, and need to be maintained when re-reading an existing
-                environment.
-        """
+    def clear(self):
         self.spec_lists = {user_speclist_name: SpecList()}  # specs from yaml
         self.dev_specs = {}               # dev-build specs from yaml
         self.concretized_user_specs = []  # user specs from last concretize
         self.concretized_order = []       # roots of last concretize, in order
         self.specs_by_hash = {}           # concretized specs by hash
+        self.new_specs = []               # write packages for these on write()
         self._repo = None                 # RepoPath for this env (memoized)
         self._previous_active = None      # previously active environment
-        if not re_read:
-            # things that cannot be recreated from file
-            self.new_specs = []               # write packages for these on write()
-            self.new_installs = []            # write modules for these on write()
 
     @property
     def internal(self):
@@ -1603,7 +1588,6 @@ class Environment(object):
             # Ensure links are set appropriately
             for spec in specs_to_install:
                 if spec.package.installed:
-                    self.new_installs.append(spec)
                     try:
                         self._install_log_links(spec)
                     except OSError as e:
@@ -1832,16 +1816,17 @@ class Environment(object):
             self.concretized_order = [
                 old_hash_to_new.get(h, h) for h in self.concretized_order]
 
-    def write(self, regenerate=True):
+    def write(self, regenerate_views=True):
         """Writes an in-memory environment to its location on disk.
 
         Write out package files for each newly concretized spec.  Also
-        regenerate any views associated with the environment and run post-write
-        hooks, if regenerate is True.
+        regenerate any views associated with the environment, if
+        regenerate_views is True.
 
         Arguments:
-            regenerate (bool): regenerate views and run post-write hooks as
-                well as writing if True.
+            regenerate_views (bool): regenerate views as well as
+                writing if True.
+
         """
         # Intercept environment not using the latest schema format and prevent
         # them from being modified
@@ -1877,6 +1862,7 @@ class Environment(object):
 
                     fs.mkdirp(pkg_dir)
                     spack.repo.path.dump_provenance(dep, pkg_dir)
+            self.new_specs = []
 
             # write the lock file last
             with fs.write_tmp_and_move(self.lock_path) as f:
@@ -1892,16 +1878,9 @@ class Environment(object):
         # call.  But, having it here makes the views consistent witht the
         # concretized environment for most operations.  Which is the
         # special case?
-        if regenerate:
+        if regenerate_views:
             self.regenerate_views()
 
-            # Run post_env_hooks
-            spack.hooks.post_env_write(self)
-
-        # new specs and new installs reset at write time
-        self.new_specs = []
-        self.new_installs = []
-
     def _update_and_write_manifest(self, raw_yaml_dict, yaml_dict):
         """Update YAML manifest for this environment based on changes to
         spec lists and views and write it.
diff --git a/lib/spack/spack/hooks/__init__.py b/lib/spack/spack/hooks/__init__.py
index d4b8cd8eca..3c15b978d3 100644
--- a/lib/spack/spack/hooks/__init__.py
+++ b/lib/spack/spack/hooks/__init__.py
@@ -22,7 +22,6 @@ Currently the following hooks are supported:
     * on_phase_error(pkg, phase_name, log_file)
     * on_phase_error(pkg, phase_name, log_file)
     * on_analyzer_save(pkg, result)
-    * post_env_write(env)
 
 This can be used to implement support for things like module
 systems (e.g. modules, lmod, etc.) or to add other custom
@@ -92,6 +91,3 @@ on_install_failure = _HookRunner('on_install_failure')
 
 # Analyzer hooks
 on_analyzer_save = _HookRunner('on_analyzer_save')
-
-# Environment hooks
-post_env_write = _HookRunner('post_env_write')
diff --git a/lib/spack/spack/hooks/module_file_generation.py b/lib/spack/spack/hooks/module_file_generation.py
index 99d149f29c..363654efc4 100644
--- a/lib/spack/spack/hooks/module_file_generation.py
+++ b/lib/spack/spack/hooks/module_file_generation.py
@@ -11,37 +11,24 @@ import llnl.util.tty as tty
 
 def _for_each_enabled(spec, method_name):
     """Calls a method for each enabled module"""
-    for name in spack.config.get('modules', {}):
-        enabled = spack.config.get('modules:%s:enable' % name)
-        if not enabled:
-            tty.debug('NO MODULE WRITTEN: list of enabled module files is empty')
-            return
-
-        for type in enabled:
-            generator = spack.modules.module_types[type](spec, name)
-            try:
-                getattr(generator, method_name)()
-            except RuntimeError as e:
-                msg = 'cannot perform the requested {0} operation on module files'
-                msg += ' [{1}]'
-                tty.warn(msg.format(method_name, str(e)))
+    enabled = spack.config.get('modules:enable')
+    if not enabled:
+        tty.debug('NO MODULE WRITTEN: list of enabled module files is empty')
+        return
 
+    for name in enabled:
+        generator = spack.modules.module_types[name](spec)
+        try:
+            getattr(generator, method_name)()
+        except RuntimeError as e:
+            msg = 'cannot perform the requested {0} operation on module files'
+            msg += ' [{1}]'
+            tty.warn(msg.format(method_name, str(e)))
 
-def post_install(spec):
-    import spack.environment  # break import cycle
-    if spack.environment.get_env({}, ''):
-        # If the installed through an environment, we skip post_install
-        # module generation and generate the modules on env_write so Spack
-        # can manage interactions between env views and modules
-        return
 
+def post_install(spec):
     _for_each_enabled(spec, 'write')
 
 
 def post_uninstall(spec):
     _for_each_enabled(spec, 'remove')
-
-
-def post_env_write(env):
-    for spec in env.new_installs:
-        _for_each_enabled(spec, 'write')
diff --git a/lib/spack/spack/main.py b/lib/spack/spack/main.py
index fa1406be14..6359d6dacf 100644
--- a/lib/spack/spack/main.py
+++ b/lib/spack/spack/main.py
@@ -647,9 +647,7 @@ def print_setup_info(*info):
         'tcl': list(),
         'lmod': list()
     }
-    module_roots = spack.config.get('modules:default:roots', {})
-    module_roots = spack.config.merge_yaml(
-        module_roots, spack.config.get('config:module_roots', {}))
+    module_roots = spack.config.get('config:module_roots')
     module_roots = dict(
         (k, v) for k, v in module_roots.items() if k in module_to_roots
     )
diff --git a/lib/spack/spack/modules/common.py b/lib/spack/spack/modules/common.py
index ae67ea5143..ed843e03af 100644
--- a/lib/spack/spack/modules/common.py
+++ b/lib/spack/spack/modules/common.py
@@ -40,7 +40,6 @@ import llnl.util.filesystem
 from llnl.util.lang import dedupe
 import llnl.util.tty as tty
 import spack.build_environment as build_environment
-import spack.environment as ev
 import spack.error
 import spack.paths
 import spack.schema.environment
@@ -53,13 +52,8 @@ import spack.util.spack_yaml as syaml
 
 
 #: config section for this file
-def configuration(module_set_name):
-    config_path = 'modules:%s' % module_set_name
-    config = spack.config.get(config_path, {})
-    if not config and module_set_name == 'default':
-        # return old format for backward compatibility
-        return spack.config.get('modules', {})
-    return config
+def configuration():
+    return spack.config.get('modules', {})
 
 
 #: Valid tokens for naming scheme and env variable names
@@ -210,23 +204,17 @@ def merge_config_rules(configuration, spec):
     return spec_configuration
 
 
-def root_path(name, module_set_name):
+def root_path(name):
     """Returns the root folder for module file installation.
 
     Args:
         name: name of the module system to be used (e.g. 'tcl')
-        module_set_name: name of the set of module configs to use
 
     Returns:
         root folder for module file installation
     """
     # Root folders where the various module files should be written
-    roots = spack.config.get('modules:%s:roots' % module_set_name, {})
-
-    # For backwards compatibility, read the old module roots for default set
-    if module_set_name == 'default':
-        roots = spack.config.merge_yaml(
-            spack.config.get('config:module_roots', {}), roots)
+    roots = spack.config.get('config:module_roots', {})
     path = roots.get(name, os.path.join(spack.paths.share_path, name))
     return spack.util.path.canonicalize_path(path)
 
@@ -338,10 +326,7 @@ class UpstreamModuleIndex(object):
             return None
 
 
-def get_module(
-        module_type, spec, get_full_path,
-        module_set_name='default', required=True
-):
+def get_module(module_type, spec, get_full_path, required=True):
     """Retrieve the module file for a given spec and module type.
 
     Retrieve the module file for the given spec if it is available. If the
@@ -357,8 +342,6 @@ def get_module(
             then an exception is raised (regardless of whether it is required)
         get_full_path: if ``True``, this returns the full path to the module.
             Otherwise, this returns the module name.
-        module_set_name: the named module configuration set from modules.yaml
-            for which to retrieve the module.
 
     Returns:
         The module name or path. May return ``None`` if the module is not
@@ -379,7 +362,7 @@ def get_module(
         else:
             return module.use_name
     else:
-        writer = spack.modules.module_types[module_type](spec, module_set_name)
+        writer = spack.modules.module_types[module_type](spec)
         if not os.path.isfile(writer.layout.filename):
             if not writer.conf.blacklisted:
                 err_msg = "No module available for package {0} at {1}".format(
@@ -406,22 +389,20 @@ class BaseConfiguration(object):
     default_projections = {
         'all': '{name}-{version}-{compiler.name}-{compiler.version}'}
 
-    def __init__(self, spec, module_set_name):
+    def __init__(self, spec):
         # Module where type(self) is defined
         self.module = inspect.getmodule(self)
         # Spec for which we want to generate a module file
         self.spec = spec
-        self.name = module_set_name
         # Dictionary of configuration options that should be applied
         # to the spec
-        self.conf = merge_config_rules(
-            self.module.configuration(self.name), self.spec)
+        self.conf = merge_config_rules(self.module.configuration(), self.spec)
 
     @property
     def projections(self):
         """Projection from specs to module names"""
         # backwards compatiblity for naming_scheme key
-        conf = self.module.configuration(self.name)
+        conf = self.module.configuration()
         if 'naming_scheme' in conf:
             default = {'all': conf['naming_scheme']}
         else:
@@ -479,7 +460,7 @@ class BaseConfiguration(object):
         """
         # A few variables for convenience of writing the method
         spec = self.spec
-        conf = self.module.configuration(self.name)
+        conf = self.module.configuration()
 
         # Compute the list of whitelist rules that match
         wlrules = conf.get('whitelist', [])
@@ -541,7 +522,7 @@ class BaseConfiguration(object):
     def _create_list_for(self, what):
         whitelist = []
         for item in self.conf[what]:
-            conf = type(self)(item, self.name)
+            conf = type(self)(item)
             if not conf.blacklisted:
                 whitelist.append(item)
         return whitelist
@@ -570,10 +551,11 @@ class BaseFileLayout(object):
         """Spec under consideration"""
         return self.conf.spec
 
-    def dirname(self):
+    @classmethod
+    def dirname(cls):
         """Root folder for module files of this type."""
-        module_system = str(self.conf.module.__name__).split('.')[-1]
-        return root_path(module_system, self.conf.name)
+        module_system = str(inspect.getmodule(cls).__name__).split('.')[-1]
+        return root_path(module_system)
 
     @property
     def use_name(self):
@@ -673,30 +655,10 @@ class BaseContext(tengine.Context):
     @tengine.context_property
     def environment_modifications(self):
         """List of environment modifications to be processed."""
-        # Modifications guessed by inspecting the spec prefix
-        std_prefix_inspections = spack.config.get(
-            'modules:prefix_inspections', {})
-        set_prefix_inspections = spack.config.get(
-            'modules:%s:prefix_inspections' % self.conf.name, {})
-        prefix_inspections = spack.config.merge_yaml(
-            std_prefix_inspections, set_prefix_inspections)
-
-        use_view = spack.config.get(
-            'modules:%s:use_view' % self.conf.name, False)
-
-        spec = self.spec.copy()  # defensive copy before setting prefix
-        if use_view:
-            if use_view is True:
-                use_view = ev.default_view_name
-
-            env = ev.get_env({}, 'post_env_write_hook', required=True)
-            view = env.views[use_view].view()
-
-            spec.prefix = view.get_projection_for_spec(spec)
-
+        # Modifications guessed inspecting the spec prefix
         env = spack.util.environment.inspect_path(
-            spec.prefix,
-            prefix_inspections,
+            self.spec.prefix,
+            spack.config.get('modules:prefix_inspections', {}),
             exclude=spack.util.environment.is_system_path
         )
 
@@ -704,12 +666,12 @@ class BaseContext(tengine.Context):
         # before asking for package-specific modifications
         env.extend(
             build_environment.modifications_from_dependencies(
-                spec, context='run'
+                self.spec, context='run'
             )
         )
         # Package specific modifications
-        build_environment.set_module_variables_for_package(spec.package)
-        spec.package.setup_run_environment(env)
+        build_environment.set_module_variables_for_package(self.spec.package)
+        self.spec.package.setup_run_environment(env)
 
         # Modifications required from modules.yaml
         env.extend(self.conf.env)
@@ -724,17 +686,17 @@ class BaseContext(tengine.Context):
         # tokens uppercase.
         transform = {}
         for token in _valid_tokens:
-            transform[token] = lambda s, string: str.upper(string)
+            transform[token] = lambda spec, string: str.upper(string)
 
         for x in env:
             # Ensure all the tokens are valid in this context
             msg = 'some tokens cannot be expanded in an environment variable name'  # noqa: E501
             _check_tokens_are_valid(x.name, message=msg)
             # Transform them
-            x.name = spec.format(x.name, transform=transform)
+            x.name = self.spec.format(x.name, transform=transform)
             try:
                 # Not every command has a value
-                x.value = spec.format(x.value)
+                x.value = self.spec.format(x.value)
             except AttributeError:
                 pass
             x.name = str(x.name).replace('-', '_')
@@ -752,8 +714,7 @@ class BaseContext(tengine.Context):
 
     def _create_module_list_of(self, what):
         m = self.conf.module
-        name = self.conf.name
-        return [m.make_layout(x, name).use_name
+        return [m.make_layout(x).use_name
                 for x in getattr(self.conf, what)]
 
     @tengine.context_property
@@ -763,7 +724,7 @@ class BaseContext(tengine.Context):
 
 
 class BaseModuleFileWriter(object):
-    def __init__(self, spec, module_set_name):
+    def __init__(self, spec):
         self.spec = spec
 
         # This class is meant to be derived. Get the module of the
@@ -772,9 +733,9 @@ class BaseModuleFileWriter(object):
         m = self.module
 
         # Create the triplet of configuration/layout/context
-        self.conf = m.make_configuration(spec, module_set_name)
-        self.layout = m.make_layout(spec, module_set_name)
-        self.context = m.make_context(spec, module_set_name)
+        self.conf = m.make_configuration(spec)
+        self.layout = m.make_layout(spec)
+        self.context = m.make_context(spec)
 
         # Check if a default template has been defined,
         # throw if not found
diff --git a/lib/spack/spack/modules/lmod.py b/lib/spack/spack/modules/lmod.py
index bc47761421..bb4476a7b0 100644
--- a/lib/spack/spack/modules/lmod.py
+++ b/lib/spack/spack/modules/lmod.py
@@ -22,42 +22,36 @@ from .common import BaseContext, BaseModuleFileWriter
 
 
 #: lmod specific part of the configuration
-def configuration(module_set_name):
-    config_path = 'modules:%s:lmod' % module_set_name
-    config = spack.config.get(config_path, {})
-    if not config and module_set_name == 'default':
-        # return old format for backward compatibility
-        return spack.config.get('modules:lmod', {})
-    return config
+def configuration():
+    return spack.config.get('modules:lmod', {})
 
 
 #: Caches the configuration {spec_hash: configuration}
 configuration_registry = {}  # type: Dict[str, Any]
 
 
-def make_configuration(spec, module_set_name):
+def make_configuration(spec):
     """Returns the lmod configuration for spec"""
-    key = (spec.dag_hash(), module_set_name)
+    key = spec.dag_hash()
     try:
         return configuration_registry[key]
     except KeyError:
-        return configuration_registry.setdefault(
-            key, LmodConfiguration(spec, module_set_name))
+        return configuration_registry.setdefault(key, LmodConfiguration(spec))
 
 
-def make_layout(spec, module_set_name):
+def make_layout(spec):
     """Returns the layout information for spec """
-    conf = make_configuration(spec, module_set_name)
+    conf = make_configuration(spec)
     return LmodFileLayout(conf)
 
 
-def make_context(spec, module_set_name):
+def make_context(spec):
     """Returns the context information for spec"""
-    conf = make_configuration(spec, module_set_name)
+    conf = make_configuration(spec)
     return LmodContext(conf)
 
 
-def guess_core_compilers(name, store=False):
+def guess_core_compilers(store=False):
     """Guesses the list of core compilers installed in the system.
 
     Args:
@@ -87,12 +81,11 @@ def guess_core_compilers(name, store=False):
         # in the default modify scope (i.e. within the directory hierarchy
         # of Spack itself)
         modules_cfg = spack.config.get(
-            'modules:' + name, {}, scope=spack.config.default_modify_scope()
+            'modules', scope=spack.config.default_modify_scope()
         )
         modules_cfg.setdefault('lmod', {})['core_compilers'] = core_compilers
         spack.config.set(
-            'modules:' + name, modules_cfg,
-            scope=spack.config.default_modify_scope()
+            'modules', modules_cfg, scope=spack.config.default_modify_scope()
         )
 
     return core_compilers or None
@@ -111,9 +104,9 @@ class LmodConfiguration(BaseConfiguration):
                 specified in the configuration file or the sequence
                 is empty
         """
-        value = configuration(self.name).get(
+        value = configuration().get(
             'core_compilers'
-        ) or guess_core_compilers(self.name, store=True)
+        ) or guess_core_compilers(store=True)
 
         if not value:
             msg = 'the key "core_compilers" must be set in modules.yaml'
@@ -123,14 +116,14 @@ class LmodConfiguration(BaseConfiguration):
     @property
     def core_specs(self):
         """Returns the list of "Core" specs"""
-        return configuration(self.name).get('core_specs', [])
+        return configuration().get('core_specs', [])
 
     @property
     def hierarchy_tokens(self):
         """Returns the list of tokens that are part of the modulefile
         hierarchy. 'compiler' is always present.
         """
-        tokens = configuration(self.name).get('hierarchy', [])
+        tokens = configuration().get('hierarchy', [])
 
         # Check if all the tokens in the hierarchy are virtual specs.
         # If not warn the user and raise an error.
@@ -414,7 +407,7 @@ class LmodContext(BaseContext):
     @tengine.context_property
     def unlocked_paths(self):
         """Returns the list of paths that are unlocked unconditionally."""
-        layout = make_layout(self.spec, self.conf.name)
+        layout = make_layout(self.spec)
         return [os.path.join(*parts) for parts in layout.unlocked_paths[None]]
 
     @tengine.context_property
@@ -422,7 +415,7 @@ class LmodContext(BaseContext):
         """Returns the list of paths that are unlocked conditionally.
         Each item in the list is a tuple with the structure (condition, path).
         """
-        layout = make_layout(self.spec, self.conf.name)
+        layout = make_layout(self.spec)
         value = []
         conditional_paths = layout.unlocked_paths
         conditional_paths.pop(None)
diff --git a/lib/spack/spack/modules/tcl.py b/lib/spack/spack/modules/tcl.py
index d2f980bbc7..e1d2ac7fe3 100644
--- a/lib/spack/spack/modules/tcl.py
+++ b/lib/spack/spack/modules/tcl.py
@@ -20,38 +20,32 @@ from .common import BaseContext, BaseModuleFileWriter
 
 
 #: TCL specific part of the configuration
-def configuration(module_set_name):
-    config_path = 'modules:%s:tcl' % module_set_name
-    config = spack.config.get(config_path, {})
-    if not config and module_set_name == 'default':
-        # return old format for backward compatibility
-        return spack.config.get('modules:tcl', {})
-    return config
+def configuration():
+    return spack.config.get('modules:tcl', {})
 
 
 #: Caches the configuration {spec_hash: configuration}
 configuration_registry = {}  # type: Dict[str, Any]
 
 
-def make_configuration(spec, module_set_name):
+def make_configuration(spec):
     """Returns the tcl configuration for spec"""
-    key = (spec.dag_hash(), module_set_name)
+    key = spec.dag_hash()
     try:
         return configuration_registry[key]
     except KeyError:
-        return configuration_registry.setdefault(
-            key, TclConfiguration(spec, module_set_name))
+        return configuration_registry.setdefault(key, TclConfiguration(spec))
 
 
-def make_layout(spec, module_set_name):
+def make_layout(spec):
     """Returns the layout information for spec """
-    conf = make_configuration(spec, module_set_name)
+    conf = make_configuration(spec)
     return TclFileLayout(conf)
 
 
-def make_context(spec, module_set_name):
+def make_context(spec):
     """Returns the context information for spec"""
-    conf = make_configuration(spec, module_set_name)
+    conf = make_configuration(spec)
     return TclContext(conf)
 
 
diff --git a/lib/spack/spack/schema/modules.py b/lib/spack/spack/schema/modules.py
index 07a495af13..39db0bf9a7 100644
--- a/lib/spack/spack/schema/modules.py
+++ b/lib/spack/spack/schema/modules.py
@@ -20,10 +20,6 @@ spec_regex = r'(?!hierarchy|core_specs|verbose|hash_length|whitelist|' \
              r'blacklist|projections|naming_scheme|core_compilers|all)' \
              r'(^\w[\w-]*)'
 
-#: Matches a valid name for a module set
-# Banned names are valid entries at that level in the previous schema
-set_regex = r'(?!enable|lmod|tcl|dotkit|prefix_inspections)^\w[\w-]*'
-
 #: Matches an anonymous spec, i.e. a spec without a root name
 anonymous_spec_regex = r'^[\^@%+~]'
 
@@ -116,105 +112,74 @@ module_type_configuration = {
 }
 
 
-#: The "real" module properties -- the actual configuration parameters.
-#: They are separate from ``properties`` because they can appear both
-#: at the top level of a Spack ``modules:`` config (old, deprecated format),
-#: and within a named module set (new format with multiple module sets).
-module_config_properties = {
-    'use_view': {'anyOf': [
-        {'type': 'string'},
-        {'type': 'boolean'}
-    ]},
-    'prefix_inspections': {
-        'type': 'object',
-        'additionalProperties': False,
-        'patternProperties': {
-            # prefix-relative path to be inspected for existence
-            r'^[\w-]*': array_of_strings
-        }
-    },
-    'roots': {
-        'type': 'object',
-        'properties': {
-            'tcl': {'type': 'string'},
-            'lmod': {'type': 'string'},
-        },
-    },
-    'enable': {
-        'type': 'array',
-        'default': [],
-        'items': {
-            'type': 'string',
-            'enum': ['tcl', 'dotkit', 'lmod']
-        },
-        'deprecatedProperties': {
-            'properties': ['dotkit'],
-            'message': 'cannot enable "dotkit" in modules.yaml '
-            '[support for "dotkit" has been dropped '
-            'in v0.13.0]',
-            'error': False
-        },
-    },
-    'lmod': {
-        'allOf': [
-            # Base configuration
-            module_type_configuration,
-            {
-                'type': 'object',
-                'properties': {
-                    'core_compilers': array_of_strings,
-                    'hierarchy': array_of_strings,
-                    'core_specs': array_of_strings,
-                },
-            }  # Specific lmod extensions
-        ]
-    },
-    'tcl': {
-        'allOf': [
-            # Base configuration
-            module_type_configuration,
-            {}  # Specific tcl extensions
-        ]
-    },
-    'dotkit': {
-        'allOf': [
-            # Base configuration
-            module_type_configuration,
-            {}  # Specific dotkit extensions
-        ]
-    },
-}
-
-
 # Properties for inclusion into other schemas (requires definitions)
 properties = {
     'modules': {
         'type': 'object',
-        'patternProperties': {
-            set_regex: {
+        'default': {},
+        'additionalProperties': False,
+        'properties': {
+            'prefix_inspections': {
                 'type': 'object',
-                'default': {},
-                'additionalProperties': False,
-                'properties': module_config_properties,
+                'patternProperties': {
+                    # prefix-relative path to be inspected for existence
+                    r'\w[\w-]*': array_of_strings
+                }
+            },
+            'enable': {
+                'type': 'array',
+                'default': [],
+                'items': {
+                    'type': 'string',
+                    'enum': ['tcl', 'dotkit', 'lmod']
+                },
                 'deprecatedProperties': {
                     'properties': ['dotkit'],
-                    'message': 'the "dotkit" section in modules.yaml has no effect'
-                    ' [support for "dotkit" has been dropped in v0.13.0]',
+                    'message': 'cannot enable "dotkit" in modules.yaml '
+                               '[support for "dotkit" has been dropped '
+                               'in v0.13.0]',
                     'error': False
-                }
+                },
+            },
+            'lmod': {
+                'allOf': [
+                    # Base configuration
+                    module_type_configuration,
+                    {
+                        'type': 'object',
+                        'properties': {
+                            'core_compilers': array_of_strings,
+                            'hierarchy': array_of_strings,
+                            'core_specs': array_of_strings,
+                        },
+                    }  # Specific lmod extensions
+                ]
+            },
+            'tcl': {
+                'allOf': [
+                    # Base configuration
+                    module_type_configuration,
+                    {}  # Specific tcl extensions
+                ]
+            },
+            'dotkit': {
+                'allOf': [
+                    # Base configuration
+                    module_type_configuration,
+                    {}  # Specific dotkit extensions
+                ]
             },
         },
-        # Available here for backwards compatibility
-        'properties': module_config_properties,
         'deprecatedProperties': {
             'properties': ['dotkit'],
             'message': 'the "dotkit" section in modules.yaml has no effect'
-            ' [support for "dotkit" has been dropped in v0.13.0]',
+                       ' [support for "dotkit" has been dropped in v0.13.0]',
             'error': False
-        }
-    }
+        },
+    },
 }
 
+
 #: Full schema with metadata
 schema = {
     '$schema': 'http://json-schema.org/schema#',
diff --git a/lib/spack/spack/subprocess_context.py b/lib/spack/spack/subprocess_context.py
index 0b41d796fa..3eee2125d2 100644
--- a/lib/spack/spack/subprocess_context.py
+++ b/lib/spack/spack/subprocess_context.py
@@ -65,25 +65,19 @@ class PackageInstallContext(object):
     needs to be transmitted to a child process.
     """
     def __init__(self, pkg):
-        import spack.environment as ev  # break import cycle
         if _serialize:
             self.serialized_pkg = serialize(pkg)
-            self.serialized_env = serialize(ev._active_environment)
         else:
             self.pkg = pkg
-            self.env = ev._active_environment
         self.spack_working_dir = spack.main.spack_working_dir
         self.test_state = TestState()
 
     def restore(self):
-        import spack.environment as ev  # break import cycle
         self.test_state.restore()
         spack.main.spack_working_dir = self.spack_working_dir
         if _serialize:
-            ev._active_environment = pickle.load(self.serialized_env)
             return pickle.load(self.serialized_pkg)
         else:
-            ev._active_environment = self.env
             return self.pkg
 
 
diff --git a/lib/spack/spack/test/cmd/env.py b/lib/spack/spack/test/cmd/env.py
index 002bd14c0f..f6933dc349 100644
--- a/lib/spack/spack/test/cmd/env.py
+++ b/lib/spack/spack/test/cmd/env.py
@@ -2,7 +2,7 @@
 # Spack Project Developers. See the top-level COPYRIGHT file for details.
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
-import glob
+
 import os
 from six import StringIO
 
@@ -2484,80 +2484,3 @@ def test_custom_version_concretize_together(tmpdir):
     e.concretize()
 
     assert any('hdf5@myversion' in spec for _, spec in e.concretized_specs())
-
-
-def test_modules_relative_to_views(tmpdir, install_mockery, mock_fetch):
-    spack_yaml = """
-spack:
-  specs:
-  - trivial-install-test-package
-  modules:
-    default:
-      enable:: [tcl]
-      use_view: true
-      roots:
-        tcl: modules
-"""
-    _env_create('test', StringIO(spack_yaml))
-
-    with ev.read('test') as e:
-        install()
-
-        spec = e.specs_by_hash[e.concretized_order[0]]
-        view_prefix = e.default_view.view().get_projection_for_spec(spec)
-        modules_glob = '%s/modules/**/*' % e.path
-        modules = glob.glob(modules_glob)
-        assert len(modules) == 1
-        module = modules[0]
-
-    with open(module, 'r') as f:
-        contents = f.read()
-
-    assert view_prefix in contents
-    assert spec.prefix not in contents
-
-
-def test_multiple_modules_post_env_hook(tmpdir, install_mockery, mock_fetch):
-    spack_yaml = """
-spack:
-  specs:
-  - trivial-install-test-package
-  modules:
-    default:
-      enable:: [tcl]
-      use_view: true
-      roots:
-        tcl: modules
-    full:
-      enable:: [tcl]
-      roots:
-        tcl: full_modules
-"""
-    _env_create('test', StringIO(spack_yaml))
-
-    with ev.read('test') as e:
-        install()
-
-        spec = e.specs_by_hash[e.concretized_order[0]]
-        view_prefix = e.default_view.view().get_projection_for_spec(spec)
-        modules_glob = '%s/modules/**/*' % e.path
-        modules = glob.glob(modules_glob)
-        assert len(modules) == 1
-        module = modules[0]
-
-        full_modules_glob = '%s/full_modules/**/*' % e.path
-        full_modules = glob.glob(full_modules_glob)
-        assert len(full_modules) == 1
-        full_module  = full_modules[0]
-
-    with open(module, 'r') as f:
-        contents = f.read()
-
-    with open(full_module, 'r') as f:
-        full_contents = f.read()
-
-    assert view_prefix in contents
-    assert spec.prefix not in contents
-
-    assert view_prefix not in full_contents
-    assert spec.prefix in full_contents
diff --git a/lib/spack/spack/test/cmd/module.py b/lib/spack/spack/test/cmd/module.py
index 7b281eeba3..9acb21fdef 100644
--- a/lib/spack/spack/test/cmd/module.py
+++ b/lib/spack/spack/test/cmd/module.py
@@ -32,7 +32,7 @@ def ensure_module_files_are_there(
 def _module_files(module_type, *specs):
     specs = [spack.spec.Spec(x).concretized() for x in specs]
     writer_cls = spack.modules.module_types[module_type]
-    return [writer_cls(spec, 'default').layout.filename for spec in specs]
+    return [writer_cls(spec).layout.filename for spec in specs]
 
 
 @pytest.fixture(
@@ -200,10 +200,8 @@ def test_setdefault_command(
     spack.spec.Spec(preferred).concretized().package.do_install(fake=True)
 
     writers = {
-        preferred: writer_cls(
-            spack.spec.Spec(preferred).concretized(), 'default'),
-        other_spec: writer_cls(
-            spack.spec.Spec(other_spec).concretized(), 'default')
+        preferred: writer_cls(spack.spec.Spec(preferred).concretized()),
+        other_spec: writer_cls(spack.spec.Spec(other_spec).concretized())
     }
 
     # Create two module files for the same software
diff --git a/lib/spack/spack/test/config.py b/lib/spack/spack/test/config.py
index 3e21bddbd6..d47851462a 100644
--- a/lib/spack/spack/test/config.py
+++ b/lib/spack/spack/test/config.py
@@ -374,9 +374,9 @@ def test_substitute_config_variables(mock_low_high_config, monkeypatch):
 
     # relative paths with source information are relative to the file
     spack.config.set(
-        'modules:default', {'roots': {'lmod': 'foo/bar/baz'}}, scope='low')
+        'config:module_roots', {'lmod': 'foo/bar/baz'}, scope='low')
     spack.config.config.clear_caches()
-    path = spack.config.get('modules:default:roots:lmod')
+    path = spack.config.get('config:module_roots:lmod')
     assert spack_path.canonicalize_path(path) == os.path.normpath(
         os.path.join(mock_low_high_config.scopes['low'].path,
                      'foo/bar/baz'))
@@ -987,9 +987,8 @@ def test_bad_config_yaml(tmpdir):
         check_schema(spack.schema.config.schema, """\
 config:
     verify_ssl: False
-    install_tree:
-      root:
-        extra_level: foo
+    module_roots:
+        fmod: /some/fake/location
 """)
 
 
diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index b76cd1be1b..6cc3ad16db 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -763,11 +763,11 @@ class MockConfig(object):
         self._configuration = configuration
         self.writer_key = writer_key
 
-    def configuration(self, module_set_name):
+    def configuration(self):
         return self._configuration
 
-    def writer_configuration(self, module_set_name):
-        return self.configuration(module_set_name)[self.writer_key]
+    def writer_configuration(self):
+        return self.configuration()[self.writer_key]
 
 
 class ConfigUpdate(object):
@@ -780,9 +780,7 @@ class ConfigUpdate(object):
     def __call__(self, filename):
         file = os.path.join(self.root_for_conf, filename + '.yaml')
         with open(file) as f:
-            config_settings = syaml.load_config(f)
-        spack.config.set('modules:default', config_settings)
-        mock_config = MockConfig(config_settings, self.writer_key)
+            mock_config = MockConfig(syaml.load_config(f), self.writer_key)
 
         self.monkeypatch.setattr(
             spack.modules.common,
diff --git a/lib/spack/spack/test/data/config/config.yaml b/lib/spack/spack/test/data/config/config.yaml
index d5c5f914fb..09ab7709a3 100644
--- a/lib/spack/spack/test/data/config/config.yaml
+++ b/lib/spack/spack/test/data/config/config.yaml
@@ -14,3 +14,6 @@ config:
   checksum: true
   dirty: false
   concretizer: {0}
+  module_roots:
+    tcl: {1}
+    lmod: {2}
diff --git a/lib/spack/spack/test/data/config/modules.yaml b/lib/spack/spack/test/data/config/modules.yaml
index e2ddd841c5..f610087fb1 100644
--- a/lib/spack/spack/test/data/config/modules.yaml
+++ b/lib/spack/spack/test/data/config/modules.yaml
@@ -14,9 +14,8 @@
 #   ~/.spack/modules.yaml
 # -------------------------------------------------------------------------
 modules:
-  default:
-    enable:
-      - tcl
+  enable:
+    - tcl
   prefix_inspections:
     bin:
       - PATH
diff --git a/lib/spack/spack/test/data/modules/lmod/alter_environment.yaml b/lib/spack/spack/test/data/modules/lmod/alter_environment.yaml
index 314dd1ddf5..f61c94362e 100644
--- a/lib/spack/spack/test/data/modules/lmod/alter_environment.yaml
+++ b/lib/spack/spack/test/data/modules/lmod/alter_environment.yaml
@@ -9,7 +9,7 @@ lmod:
 
   all:
     filter:
-      environment_blacklist:
+      environment_blacklist':
         - CMAKE_PREFIX_PATH
     environment:
       set:
diff --git a/lib/spack/spack/test/data/modules/lmod/with_view.yaml b/lib/spack/spack/test/data/modules/lmod/with_view.yaml
deleted file mode 100644
index 28220fe445..0000000000
--- a/lib/spack/spack/test/data/modules/lmod/with_view.yaml
+++ /dev/null
@@ -1,6 +0,0 @@
-enable:
-  - lmod
-use_view: default
-lmod:
-  core_compilers:
-    - 'clang@3.3'
diff --git a/lib/spack/spack/test/data/modules/tcl/alter_environment.yaml b/lib/spack/spack/test/data/modules/tcl/alter_environment.yaml
index 74d9724695..ecb0f56254 100644
--- a/lib/spack/spack/test/data/modules/tcl/alter_environment.yaml
+++ b/lib/spack/spack/test/data/modules/tcl/alter_environment.yaml
@@ -3,7 +3,7 @@ enable:
 tcl:
   all:
     filter:
-      environment_blacklist:
+      environment_blacklist':
         - CMAKE_PREFIX_PATH
     environment:
       set:
diff --git a/lib/spack/spack/test/data/modules/tcl/invalid_token_in_env_var_name.yaml b/lib/spack/spack/test/data/modules/tcl/invalid_token_in_env_var_name.yaml
index 6012a2d3b0..bed866fe90 100644
--- a/lib/spack/spack/test/data/modules/tcl/invalid_token_in_env_var_name.yaml
+++ b/lib/spack/spack/test/data/modules/tcl/invalid_token_in_env_var_name.yaml
@@ -3,7 +3,7 @@ enable:
 tcl:
   all:
     filter:
-      environment_blacklist:
+      environment_blacklist':
         - CMAKE_PREFIX_PATH
     environment:
       set:
diff --git a/lib/spack/spack/test/modules/common.py b/lib/spack/spack/test/modules/common.py
index 8270b01c71..0918cf2dfd 100644
--- a/lib/spack/spack/test/modules/common.py
+++ b/lib/spack/spack/test/modules/common.py
@@ -70,7 +70,7 @@ def test_modules_written_with_proper_permissions(mock_module_filename,
 
     # The code tested is common to all module types, but has to be tested from
     # one. TCL picked at random
-    generator = spack.modules.tcl.TclModulefileWriter(spec, 'default')
+    generator = spack.modules.tcl.TclModulefileWriter(spec)
     generator.write()
 
     assert mock_package_perms & os.stat(
diff --git a/lib/spack/spack/test/modules/conftest.py b/lib/spack/spack/test/modules/conftest.py
index ea61a3b955..dbfac6b0bc 100644
--- a/lib/spack/spack/test/modules/conftest.py
+++ b/lib/spack/spack/test/modules/conftest.py
@@ -19,11 +19,11 @@ def modulefile_content(request):
 
     writer_cls = getattr(request.module, 'writer_cls')
 
-    def _impl(spec_str, module_set_name='default'):
+    def _impl(spec_str):
         # Write the module file
         spec = spack.spec.Spec(spec_str)
         spec.concretize()
-        generator = writer_cls(spec, module_set_name)
+        generator = writer_cls(spec)
         generator.write(overwrite=True)
 
         # Get its filename
@@ -56,9 +56,9 @@ def factory(request):
     # Class of the module file writer
     writer_cls = getattr(request.module, 'writer_cls')
 
-    def _mock(spec_string, module_set_name='default'):
+    def _mock(spec_string):
         spec = spack.spec.Spec(spec_string)
         spec.concretize()
-        return writer_cls(spec, module_set_name), spec
+        return writer_cls(spec), spec
 
     return _mock
diff --git a/lib/spack/spack/test/modules/lmod.py b/lib/spack/spack/test/modules/lmod.py
index 097aaf526f..7239c487aa 100644
--- a/lib/spack/spack/test/modules/lmod.py
+++ b/lib/spack/spack/test/modules/lmod.py
@@ -5,17 +5,12 @@
 import re
 import pytest
 
-import spack.environment as ev
-import spack.main
 import spack.modules.lmod
-import spack.spec
 
 mpich_spec_string = 'mpich@3.0.4'
 mpileaks_spec_string = 'mpileaks'
 libdwarf_spec_string = 'libdwarf arch=x64-linux'
 
-install = spack.main.SpackCommand('install')
-
 #: Class of the writer tested in this module
 writer_cls = spack.modules.lmod.LmodModulefileWriter
 
@@ -319,35 +314,3 @@ class TestLmod(object):
         assert writer.conf.projections == expected
         projection = writer.spec.format(writer.conf.projections['all'])
         assert projection in writer.layout.use_name
-
-    def test_config_backwards_compat(self, mutable_config):
-        settings = {
-            'enable': ['lmod'],
-            'lmod': {
-                'core_compilers': ['%gcc@0.0.0']
-            }
-        }
-
-        spack.config.set('modules:default', settings)
-        new_format = spack.modules.lmod.configuration('default')
-
-        spack.config.set('modules', settings)
-        old_format = spack.modules.lmod.configuration('default')
-
-        assert old_format == new_format
-        assert old_format == settings['lmod']
-
-    def test_modules_relative_to_view(
-            self, tmpdir, modulefile_content, module_configuration, install_mockery):
-        with ev.Environment(str(tmpdir), with_view=True) as e:
-            module_configuration('with_view')
-            install('cmake')
-
-            spec = spack.spec.Spec('cmake').concretized()
-
-            content = modulefile_content('cmake')
-            expected = e.default_view.view().get_projection_for_spec(spec)
-            # Rather than parse all lines, ensure all prefixes in the content
-            # point to the right one
-            assert any(expected in line for line in content)
-            assert not any(spec.prefix in line for line in content)
diff --git a/lib/spack/spack/test/modules/tcl.py b/lib/spack/spack/test/modules/tcl.py
index 464d91c278..e5f2797e39 100644
--- a/lib/spack/spack/test/modules/tcl.py
+++ b/lib/spack/spack/test/modules/tcl.py
@@ -359,14 +359,14 @@ class TestTcl(object):
         # the tests database
         mpileaks_specs = database.query('mpileaks')
         for item in mpileaks_specs:
-            writer = writer_cls(item, 'default')
+            writer = writer_cls(item)
             assert not writer.conf.blacklisted
 
         # callpath is a dependency of mpileaks, and has been pulled
         # in implicitly
         callpath_specs = database.query('callpath')
         for item in callpath_specs:
-            writer = writer_cls(item, 'default')
+            writer = writer_cls(item)
             assert writer.conf.blacklisted
 
     @pytest.mark.regression('9624')
@@ -385,22 +385,3 @@ class TestTcl(object):
         # Test the mpileaks that should NOT have the autoloaded dependencies
         content = modulefile_content('mpileaks ^mpich')
         assert len([x for x in content if 'is-loaded' in x]) == 0
-
-    def test_config_backwards_compat(self, mutable_config):
-        settings = {
-            'enable': ['tcl'],
-            'tcl': {
-                'all': {
-                    'conflict': ['{name}']
-                }
-            }
-        }
-
-        spack.config.set('modules:default', settings)
-        new_format = spack.modules.tcl.configuration('default')
-
-        spack.config.set('modules', settings)
-        old_format = spack.modules.tcl.configuration('default')
-
-        assert old_format == new_format
-        assert old_format == settings['tcl']
diff --git a/lib/spack/spack/user_environment.py b/lib/spack/spack/user_environment.py
index 15c8d2822a..7dd63dcdea 100644
--- a/lib/spack/spack/user_environment.py
+++ b/lib/spack/spack/user_environment.py
@@ -26,8 +26,8 @@ def prefix_inspections(platform):
         A dictionary mapping subdirectory names to lists of environment
             variables to modify with that directory if it exists.
     """
-    inspections = spack.config.get('modules:default:prefix_inspections', {})
-    if inspections:
+    inspections = spack.config.get('modules:prefix_inspections', None)
+    if inspections is not None:
         return inspections
 
     inspections = {
diff --git a/share/spack/spack-completion.bash b/share/spack/spack-completion.bash
index ac2727eeb9..0c17f29312 100755
--- a/share/spack/spack-completion.bash
+++ b/share/spack/spack-completion.bash
@@ -858,7 +858,7 @@ _spack_env_st() {
 _spack_env_loads() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help -n --module-set-name -m --module-type --input-only -p --prefix -x --exclude -r --dependencies"
+        SPACK_COMPREPLY="-h --help -m --module-type --input-only -p --prefix -x --exclude -r --dependencies"
     else
         _environments
     fi
@@ -1218,7 +1218,7 @@ _spack_module() {
 _spack_module_lmod() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help -n --name"
+        SPACK_COMPREPLY="-h --help"
     else
         SPACK_COMPREPLY="refresh find rm loads setdefault"
     fi
@@ -1272,7 +1272,7 @@ _spack_module_lmod_setdefault() {
 _spack_module_tcl() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help -n --name"
+        SPACK_COMPREPLY="-h --help"
     else
         SPACK_COMPREPLY="refresh find rm loads"
     fi