Merge remote-tracking branch 'upstream/develop' into pkg-numdiff

lib/spack/spack/build_environment.py

@@ -3,7 +3,7 @@
 build environment.  All of this is set up by package.py just before
 install() is called.
 
-There are two parts to the bulid environment:
+There are two parts to the build environment:
 
 1. Python build environment (i.e. install() method)
 
@@ -13,7 +13,7 @@
    the package's module scope.  Ths allows package writers to call
    them all directly in Package.install() without writing 'self.'
    everywhere.  No, this isn't Pythonic.  Yes, it makes the code more
-   readable and more like the shell script from whcih someone is
+   readable and more like the shell script from which someone is
    likely porting.
 
 2. Build execution environment
@@ -27,17 +27,18 @@
 Skimming this module is a nice way to get acquainted with the types of
 calls you can make from within the install() function.
 """
-import os
-import sys
-import shutil
 import multiprocessing
+import os
 import platform
-from llnl.util.filesystem import *
+import shutil
+import sys
 
 import spack
-import spack.compilers as compilers
+import llnl.util.tty as tty
-from spack.util.executable import Executable, which
+from llnl.util.filesystem import *
+from spack.environment import EnvironmentModifications, validate
 from spack.util.environment import *
+from spack.util.executable import Executable, which
 
 #
 # This can be set by the user to globally disable parallel builds.
@@ -83,85 +84,88 @@ def __call__(self, *args, **kwargs):
         return super(MakeExecutable, self).__call__(*args, **kwargs)
 
 
-def set_compiler_environment_variables(pkg):
+def set_compiler_environment_variables(pkg, env):
-    assert(pkg.spec.concrete)
+    assert pkg.spec.concrete
-    compiler = pkg.compiler
-
     # Set compiler variables used by CMake and autotools
-    assert all(key in pkg.compiler.link_paths
+    assert all(key in pkg.compiler.link_paths for key in ('cc', 'cxx', 'f77', 'fc'))
-               for key in ('cc', 'cxx', 'f77', 'fc'))
 
+    # Populate an object with the list of environment modifications
+    # and return it
+    # TODO : add additional kwargs for better diagnostics, like requestor, ttyout, ttyerr, etc.
     link_dir = spack.build_env_path
-    os.environ['CC']  = join_path(link_dir, pkg.compiler.link_paths['cc'])
+    env.set('CC', join_path(link_dir, pkg.compiler.link_paths['cc']))
-    os.environ['CXX'] = join_path(link_dir, pkg.compiler.link_paths['cxx'])
+    env.set('CXX', join_path(link_dir, pkg.compiler.link_paths['cxx']))
-    os.environ['F77'] = join_path(link_dir, pkg.compiler.link_paths['f77'])
+    env.set('F77', join_path(link_dir, pkg.compiler.link_paths['f77']))
-    os.environ['FC']  = join_path(link_dir, pkg.compiler.link_paths['fc'])
+    env.set('FC', join_path(link_dir, pkg.compiler.link_paths['fc']))
 
     # Set SPACK compiler variables so that our wrapper knows what to call
+    compiler = pkg.compiler
     if compiler.cc:
-        os.environ['SPACK_CC']  = compiler.cc
+        env.set('SPACK_CC', compiler.cc)
     if compiler.cxx:
-        os.environ['SPACK_CXX'] = compiler.cxx
+        env.set('SPACK_CXX', compiler.cxx)
     if compiler.f77:
-        os.environ['SPACK_F77'] = compiler.f77
+        env.set('SPACK_F77', compiler.f77)
     if compiler.fc:
-        os.environ['SPACK_FC']  = compiler.fc
+        env.set('SPACK_FC', compiler.fc)
 
-    os.environ['SPACK_COMPILER_SPEC']  = str(pkg.spec.compiler)
+    env.set('SPACK_COMPILER_SPEC', str(pkg.spec.compiler))
+    return env
 
 
-def set_build_environment_variables(pkg):
+def set_build_environment_variables(pkg, env):
-    """This ensures a clean install environment when we build packages.
+    """
+    This ensures a clean install environment when we build packages
     """
     # Add spack build environment path with compiler wrappers first in
     # the path. We add both spack.env_path, which includes default
     # wrappers (cc, c++, f77, f90), AND a subdirectory containing
     # compiler-specific symlinks.  The latter ensures that builds that
     # are sensitive to the *name* of the compiler see the right name
-    # when we're building wtih the wrappers.
+    # when we're building with the wrappers.
     #
     # Conflicts on case-insensitive systems (like "CC" and "cc") are
     # handled by putting one in the <build_env_path>/case-insensitive
     # directory.  Add that to the path too.
     env_paths = []
-    def add_env_path(path):
+    for item in [spack.build_env_path, join_path(spack.build_env_path, pkg.compiler.name)]:
-        env_paths.append(path)
+        env_paths.append(item)
-        ci = join_path(path, 'case-insensitive')
+        ci = join_path(item, 'case-insensitive')
-        if os.path.isdir(ci): env_paths.append(ci)
+        if os.path.isdir(ci):
-    add_env_path(spack.build_env_path)
+            env_paths.append(ci)
-    add_env_path(join_path(spack.build_env_path, pkg.compiler.name))
 
-    path_put_first("PATH", env_paths)
+    for item in reversed(env_paths):
-    path_set(SPACK_ENV_PATH, env_paths)
+        env.prepend_path('PATH', item)
+    env.set_path(SPACK_ENV_PATH, env_paths)
 
-    # Prefixes of all of the package's dependencies go in
+    # Prefixes of all of the package's dependencies go in SPACK_DEPENDENCIES
-    # SPACK_DEPENDENCIES
     dep_prefixes = [d.prefix for d in pkg.spec.traverse(root=False)]
-    path_set(SPACK_DEPENDENCIES, dep_prefixes)
+    env.set_path(SPACK_DEPENDENCIES, dep_prefixes)
+    env.set_path('CMAKE_PREFIX_PATH', dep_prefixes)  # Add dependencies to CMAKE_PREFIX_PATH
 
     # Install prefix
-    os.environ[SPACK_PREFIX] = pkg.prefix
+    env.set(SPACK_PREFIX, pkg.prefix)
 
     # Install root prefix
-    os.environ[SPACK_INSTALL] = spack.install_path
+    env.set(SPACK_INSTALL, spack.install_path)
 
     # Remove these vars from the environment during build because they
     # can affect how some packages find libraries.  We want to make
     # sure that builds never pull in unintended external dependencies.
-    pop_keys(os.environ, "LD_LIBRARY_PATH", "LD_RUN_PATH", "DYLD_LIBRARY_PATH")
+    env.unset('LD_LIBRARY_PATH')
+    env.unset('LD_RUN_PATH')
+    env.unset('DYLD_LIBRARY_PATH')
 
     # Add bin directories from dependencies to the PATH for the build.
-    bin_dirs = ['%s/bin' % prefix for prefix in dep_prefixes]
+    bin_dirs = reversed(filter(os.path.isdir, ['%s/bin' % prefix for prefix in dep_prefixes]))
-    path_put_first('PATH', [bin for bin in bin_dirs if os.path.isdir(bin)])
+    for item in bin_dirs:
+        env.prepend_path('PATH', item)
 
     # Working directory for the spack command itself, for debug logs.
     if spack.debug:
-        os.environ[SPACK_DEBUG] = "TRUE"
+        env.set(SPACK_DEBUG, 'TRUE')
-    os.environ[SPACK_SHORT_SPEC] = pkg.spec.short_spec
+    env.set(SPACK_SHORT_SPEC, pkg.spec.short_spec)
-    os.environ[SPACK_DEBUG_LOG_DIR] = spack.spack_working_dir
+    env.set(SPACK_DEBUG_LOG_DIR, spack.spack_working_dir)
-
-    # Add dependencies to CMAKE_PREFIX_PATH
-    path_set("CMAKE_PREFIX_PATH", dep_prefixes)
 
     # Add any pkgconfig directories to PKG_CONFIG_PATH
     pkg_config_dirs = []
@@ -170,10 +174,12 @@ def add_env_path(path):
             pcdir = join_path(p, libdir, 'pkgconfig')
             if os.path.isdir(pcdir):
                 pkg_config_dirs.append(pcdir)
-    path_set("PKG_CONFIG_PATH", pkg_config_dirs)
+    env.set_path('PKG_CONFIG_PATH', pkg_config_dirs)
+
+    return env
 
 
-def set_module_variables_for_package(pkg, m):
+def set_module_variables_for_package(pkg, module):
     """Populate the module scope of install() with some useful functions.
        This makes things easier for package writers.
     """
@@ -183,6 +189,8 @@ def set_module_variables_for_package(pkg, m):
         jobs = 1
     elif pkg.make_jobs:
         jobs = pkg.make_jobs
+
+    m = module
     m.make_jobs = jobs
 
     # TODO: make these build deps that can be installed if not found.
@@ -264,8 +272,11 @@ def parent_class_modules(cls):
 
 def setup_package(pkg):
     """Execute all environment setup routines."""
-    set_compiler_environment_variables(pkg)
+    spack_env = EnvironmentModifications()
-    set_build_environment_variables(pkg)
+    run_env   = EnvironmentModifications()
+
+    set_compiler_environment_variables(pkg, spack_env)
+    set_build_environment_variables(pkg, spack_env)
 
     # If a user makes their own package repo, e.g.
     # spack.repos.mystuff.libelf.Libelf, and they inherit from
@@ -276,10 +287,22 @@ def setup_package(pkg):
     for mod in modules:
         set_module_variables_for_package(pkg, mod)
 
-    # Allow dependencies to set up environment as well.
+    # Allow dependencies to modify the module
-    for dep_spec in pkg.spec.traverse(root=False):
+    for dependency_spec in pkg.spec.traverse(root=False):
-        dep_spec.package.setup_dependent_environment(
+        dpkg = dependency_spec.package
-            pkg.module, dep_spec, pkg.spec)
+        dpkg.setup_dependent_python_module(pkg.module, pkg.spec)
+
+    # Allow dependencies to set up environment as well
+    for dependency_spec in pkg.spec.traverse(root=False):
+        dpkg = dependency_spec.package
+        dpkg.setup_dependent_environment(spack_env, run_env, pkg.spec)
+
+    # Allow the package to apply some settings.
+    pkg.setup_environment(spack_env, run_env)
+
+    # Make sure nothing's strange about the Spack environment.
+    validate(spack_env, tty.warn)
+    spack_env.apply_modifications()
 
 
 def fork(pkg, function):
@@ -296,9 +319,9 @@ def child_fun():
            # do stuff
        build_env.fork(pkg, child_fun)
 
-    Forked processes are run with the build environemnt set up by
+    Forked processes are run with the build environment set up by
     spack.build_environment.  This allows package authors to have
-    full control over the environment, etc. without offecting
+    full control over the environment, etc. without affecting
     other builds that might be executed in the same spack call.
 
     If something goes wrong, the child process is expected to print
@@ -308,11 +331,11 @@ def child_fun():
     """
     try:
         pid = os.fork()
-    except OSError, e:
+    except OSError as e:
         raise InstallError("Unable to fork build process: %s" % e)
 
     if pid == 0:
-        # Give the child process the package's build environemnt.
+        # Give the child process the package's build environment.
         setup_package(pkg)
 
         try:
@@ -323,7 +346,7 @@ def child_fun():
             # which interferes with unit tests.
             os._exit(0)
 
-        except spack.error.SpackError, e:
+        except spack.error.SpackError as e:
             e.die()
 
         except:
@@ -338,8 +361,7 @@ def child_fun():
         # message.  Just make the parent exit with an error code.
         pid, returncode = os.waitpid(pid, 0)
         if returncode != 0:
-            raise InstallError("Installation process had nonzero exit code."
+            raise InstallError("Installation process had nonzero exit code.".format(str(returncode)))
-                .format(str(returncode)))
 
 
 class InstallError(spack.error.SpackError):

lib/spack/spack/cmd/module.py

@@ -80,7 +80,7 @@ def module_find(mtype, spec_array):
     if not os.path.isfile(mod.file_name):
         tty.die("No %s module is installed for %s" % (mtype, spec))
 
-    print mod.use_name
+    print(mod.use_name)
 
 
 def module_refresh():

lib/spack/spack/cmd/uninstall.py

@@ -22,6 +22,7 @@
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
+from __future__ import print_function
 import sys
 import argparse
 
@@ -63,12 +64,12 @@ def uninstall(parser, args):
             matching_specs = spack.installed_db.query(spec)
             if not args.all and len(matching_specs) > 1:
                 tty.error("%s matches multiple packages:" % spec)
-                print
+                print()
                 display_specs(matching_specs, long=True)
-                print
+                print()
-                print "You can either:"
+                print("You can either:")
-                print "  a) Use a more specific spec, or"
+                print("  a) Use a more specific spec, or")
-                print "  b) use spack uninstall -a to uninstall ALL matching specs."
+                print("  b) use spack uninstall -a to uninstall ALL matching specs.")
                 sys.exit(1)
 
             if len(matching_specs) == 0:
@@ -79,7 +80,7 @@ def uninstall(parser, args):
                 try:
                     # should work if package is known to spack
                     pkgs.append(s.package)
-                except spack.repository.UnknownPackageError, e:
+                except spack.repository.UnknownPackageError as e:
                     # The package.py file has gone away -- but still
                     # want to uninstall.
                     spack.Package(s).do_uninstall(force=True)
@@ -94,11 +95,11 @@ def num_installed_deps(pkg):
         for pkg in pkgs:
             try:
                 pkg.do_uninstall(force=args.force)
-            except PackageStillNeededError, e:
+            except PackageStillNeededError as e:
                 tty.error("Will not uninstall %s" % e.spec.format("$_$@$%@$#", color=True))
-                print
+                print('')
-                print "The following packages depend on it:"
+                print("The following packages depend on it:")
                 display_specs(e.dependents, long=True)
-                print
+                print('')
-                print "You can use spack uninstall -f to force this action."
+                print("You can use spack uninstall -f to force this action.")
                 sys.exit(1)

lib/spack/spack/concretize.py

@@ -241,7 +241,7 @@ def concretize_compiler(self, spec):
             return False
 
         #Find the another spec that has a compiler, or the root if none do
-        other_spec = find_spec(spec, lambda(x) : x.compiler)
+        other_spec = spec if spec.compiler else find_spec(spec, lambda(x) : x.compiler)
         if not other_spec:
             other_spec = spec.root
         other_compiler = other_spec.compiler
@@ -288,7 +288,7 @@ def find_spec(spec, condition):
     if condition(spec):
         return spec
 
-    return None   # Nohting matched the condition.
+    return None   # Nothing matched the condition.
 
 
 def cmp_specs(lhs, rhs):

lib/spack/spack/directory_layout.py

@@ -150,7 +150,7 @@ def remove_install_directory(self, spec):
         if os.path.exists(path):
             try:
                 shutil.rmtree(path)
-            except exceptions.OSError, e:
+            except exceptions.OSError as e:
                 raise RemoveFailedError(spec, path, e)
 
         path = os.path.dirname(path)

lib/spack/spack/environment.py

@@ -0,0 +1,252 @@
+import os
+import os.path
+import collections
+import inspect
+
+
+class NameModifier(object):
+    def __init__(self, name, **kwargs):
+        self.name = name
+        self.args = {'name': name}
+        self.args.update(kwargs)
+
+
+class NameValueModifier(object):
+    def __init__(self, name, value, **kwargs):
+        self.name = name
+        self.value = value
+        self.args = {'name': name, 'value': value}
+        self.args.update(kwargs)
+
+
+class SetEnv(NameValueModifier):
+    def execute(self):
+        os.environ[self.name] = str(self.value)
+
+
+class UnsetEnv(NameModifier):
+    def execute(self):
+        os.environ.pop(self.name, None)  # Avoid throwing if the variable was not set
+
+
+class SetPath(NameValueModifier):
+    def execute(self):
+        string_path = concatenate_paths(self.value)
+        os.environ[self.name] = string_path
+
+
+class AppendPath(NameValueModifier):
+    def execute(self):
+        environment_value = os.environ.get(self.name, '')
+        directories = environment_value.split(':') if environment_value else []
+        directories.append(os.path.normpath(self.value))
+        os.environ[self.name] = ':'.join(directories)
+
+
+class PrependPath(NameValueModifier):
+    def execute(self):
+        environment_value = os.environ.get(self.name, '')
+        directories = environment_value.split(':') if environment_value else []
+        directories = [os.path.normpath(self.value)] + directories
+        os.environ[self.name] = ':'.join(directories)
+
+
+class RemovePath(NameValueModifier):
+    def execute(self):
+        environment_value = os.environ.get(self.name, '')
+        directories = environment_value.split(':') if environment_value else []
+        directories = [os.path.normpath(x) for x in directories if x != os.path.normpath(self.value)]
+        os.environ[self.name] = ':'.join(directories)
+
+
+class EnvironmentModifications(object):
+    """
+    Keeps track of requests to modify the current environment.
+
+    Each call to a method to modify the environment stores the extra information on the caller in the request:
+    - 'filename' : filename of the module where the caller is defined
+    - 'lineno': line number where the request occurred
+    - 'context' : line of code that issued the request that failed
+    """
+
+    def __init__(self, other=None):
+        """
+        Initializes a new instance, copying commands from other if it is not None
+
+        Args:
+            other: another instance of EnvironmentModifications from which (optional)
+        """
+        self.env_modifications = []
+        if other is not None:
+            self.extend(other)
+
+    def __iter__(self):
+        return iter(self.env_modifications)
+
+    def __len__(self):
+        return len(self.env_modifications)
+
+    def extend(self, other):
+        self._check_other(other)
+        self.env_modifications.extend(other.env_modifications)
+
+    @staticmethod
+    def _check_other(other):
+        if not isinstance(other, EnvironmentModifications):
+            raise TypeError('other must be an instance of EnvironmentModifications')
+
+    def _get_outside_caller_attributes(self):
+        stack = inspect.stack()
+        try:
+            _, filename, lineno, _, context, index = stack[2]
+            context = context[index].strip()
+        except Exception:
+            filename, lineno, context = 'unknown file', 'unknown line', 'unknown context'
+        args = {
+            'filename': filename,
+            'lineno': lineno,
+            'context': context
+        }
+        return args
+
+    def set(self, name, value, **kwargs):
+        """
+        Stores in the current object a request to set an environment variable
+
+        Args:
+            name: name of the environment variable to be set
+            value: value of the environment variable
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = SetEnv(name, value, **kwargs)
+        self.env_modifications.append(item)
+
+    def unset(self, name, **kwargs):
+        """
+        Stores in the current object a request to unset an environment variable
+
+        Args:
+            name: name of the environment variable to be set
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = UnsetEnv(name, **kwargs)
+        self.env_modifications.append(item)
+
+    def set_path(self, name, elts, **kwargs):
+        """
+        Stores a request to set a path generated from a list.
+
+        Args:
+            name: name o the environment variable to be set.
+            elts: elements of the path to set.
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = SetPath(name, elts, **kwargs)
+        self.env_modifications.append(item)
+
+    def append_path(self, name, path, **kwargs):
+        """
+        Stores in the current object a request to append a path to a path list
+
+        Args:
+            name: name of the path list in the environment
+            path: path to be appended
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = AppendPath(name, path, **kwargs)
+        self.env_modifications.append(item)
+
+    def prepend_path(self, name, path, **kwargs):
+        """
+        Same as `append_path`, but the path is pre-pended
+
+        Args:
+            name: name of the path list in the environment
+            path: path to be pre-pended
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = PrependPath(name, path, **kwargs)
+        self.env_modifications.append(item)
+
+    def remove_path(self, name, path, **kwargs):
+        """
+        Stores in the current object a request to remove a path from a path list
+
+        Args:
+            name: name of the path list in the environment
+            path: path to be removed
+        """
+        kwargs.update(self._get_outside_caller_attributes())
+        item = RemovePath(name, path, **kwargs)
+        self.env_modifications.append(item)
+
+    def group_by_name(self):
+        """
+        Returns a dict of the modifications grouped by variable name
+
+        Returns:
+            dict mapping the environment variable name to the modifications to be done on it
+        """
+        modifications = collections.defaultdict(list)
+        for item in self:
+            modifications[item.name].append(item)
+        return modifications
+
+    def clear(self):
+        """
+        Clears the current list of modifications
+        """
+        self.env_modifications.clear()
+
+    def apply_modifications(self):
+        """
+        Applies the modifications and clears the list
+        """
+        modifications = self.group_by_name()
+        # Apply the modifications to the environment variables one variable at a time
+        for name, actions in sorted(modifications.items()):
+            for x in actions:
+                x.execute()
+
+
+def concatenate_paths(paths):
+    """
+    Concatenates an iterable of paths into a  string of column separated paths
+
+    Args:
+        paths: iterable of paths
+
+    Returns:
+        string
+    """
+    return ':'.join(str(item) for item in paths)
+
+
+def set_or_unset_not_first(variable, changes, errstream):
+    """
+    Check if we are going to set or unset something after other modifications have already been requested
+    """
+    indexes = [ii for ii, item in enumerate(changes) if ii != 0 and type(item) in [SetEnv, UnsetEnv]]
+    if indexes:
+        good = '\t    \t{context} at {filename}:{lineno}'
+        nogood = '\t--->\t{context} at {filename}:{lineno}'
+        errstream('Suspicious requests to set or unset the variable \'{var}\' found'.format(var=variable))
+        for ii, item in enumerate(changes):
+            print_format = nogood if ii in indexes else good
+            errstream(print_format.format(**item.args))
+
+
+def validate(env, errstream):
+    """
+    Validates the environment modifications to check for the presence of suspicious patterns. Prompts a warning for
+    everything that was found
+
+    Current checks:
+    - set or unset variables after other changes on the same variable
+
+    Args:
+        env: list of environment modifications
+    """
+    modifications = env.group_by_name()
+    for variable, list_of_changes in sorted(modifications.items()):
+        set_or_unset_not_first(variable, list_of_changes, errstream)

lib/spack/spack/modules.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
 ##############################################################################
-"""This module contains code for creating environment modules, which
+"""
-can include dotkits, tcl modules, lmod, and others.
+This module contains code for creating environment modules, which can include dotkits, tcl modules, lmod, and others.
 
-The various types of modules are installed by post-install hooks and
+The various types of modules are installed by post-install hooks and removed after an uninstall by post-uninstall hooks.
-removed after an uninstall by post-uninstall hooks.  This class
+This class consolidates the logic for creating an abstract description of the information that module systems need.
-consolidates the logic for creating an abstract description of the
+Currently that includes a number of directories to be appended to paths in the user's environment:
-information that module systems need.  Currently that includes a
-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
@@ -37,28 +35,25 @@
   * /man* and /share/man* directories for MANPATH
   * the package prefix for CMAKE_PREFIX_PATH
 
-This module also includes logic for coming up with unique names for
+This module also includes logic for coming up with unique names for the module files so that they can be found by the
-the module files so that they can be found by the various
+various shell-support files in $SPACK/share/spack/setup-env.*.
-shell-support files in $SPACK/share/spack/setup-env.*.
 
-Each hook in hooks/ implements the logic for writing its specific type
+Each hook in hooks/ implements the logic for writing its specific type of module file.
-of module file.
 """
-__all__ = ['EnvModule', 'Dotkit', 'TclModule']
-
 import os
+import os.path
 import re
-import textwrap
 import shutil
-from glob import glob
+import textwrap
 
 import llnl.util.tty as tty
-from llnl.util.filesystem import join_path, mkdirp
-
 import spack
+from llnl.util.filesystem import join_path, mkdirp
+from spack.environment import *
 
-"""Registry of all types of modules.  Entries created by EnvModule's
+__all__ = ['EnvModule', 'Dotkit', 'TclModule']
-   metaclass."""
+
+# Registry of all types of modules.  Entries created by EnvModule's metaclass
 module_types = {}
 
 
@@ -79,8 +74,43 @@ def print_help():
             "")
 
 
+def inspect_path(prefix):
+    """
+    Inspects the prefix of an installation to search for common layouts. Issues a request to modify the environment
+    accordingly when an item is found.
+
+    Args:
+        prefix: prefix of the installation
+
+    Returns:
+        instance of EnvironmentModifications containing the requested modifications
+    """
+    env = EnvironmentModifications()
+    # Inspect the prefix to check for the existence of common directories
+    prefix_inspections = {
+        'bin': ('PATH',),
+        'man': ('MANPATH',),
+        'lib': ('LIBRARY_PATH', 'LD_LIBRARY_PATH'),
+        'lib64': ('LIBRARY_PATH', 'LD_LIBRARY_PATH'),
+        'include': ('CPATH',)
+    }
+    for attribute, variables in prefix_inspections.items():
+        expected = getattr(prefix, attribute)
+        if os.path.isdir(expected):
+            for variable in variables:
+                env.prepend_path(variable, expected)
+    # PKGCONFIG
+    for expected in (join_path(prefix.lib, 'pkgconfig'), join_path(prefix.lib64, 'pkgconfig')):
+        if os.path.isdir(expected):
+            env.prepend_path('PKG_CONFIG_PATH', expected)
+    # CMake related variables
+    env.prepend_path('CMAKE_PREFIX_PATH', prefix)
+    return env
+
+
 class EnvModule(object):
     name = 'env_module'
+    formats = {}
 
     class __metaclass__(type):
         def __init__(cls, name, bases, dict):
@@ -88,66 +118,32 @@ def __init__(cls, name, bases, dict):
             if cls.name != 'env_module':
                 module_types[cls.name] = cls
 
-
     def __init__(self, spec=None):
-        # category in the modules system
-        # TODO: come up with smarter category names.
-        self.category = "spack"
-
-        # Descriptions for the module system's UI
-        self.short_description = ""
-        self.long_description = ""
-
-        # dict pathname -> list of directories to be prepended to in
-        # the module file.
-        self._paths = None
         self.spec = spec
+        self.pkg = spec.package  # Just stored for convenience
 
-
+        # short description default is just the package + version
-    @property
+        # packages can provide this optional attribute
-    def paths(self):
+        self.short_description = spec.format("$_ $@")
-        if self._paths is None:
+        if hasattr(self.pkg, 'short_description'):
-            self._paths = {}
+            self.short_description = self.pkg.short_description
-
-            def add_path(path_name, directory):
-                path = self._paths.setdefault(path_name, [])
-                path.append(directory)
-
-            # Add paths if they exist.
-            for var, directory in [
-                    ('PATH', self.spec.prefix.bin),
-                    ('MANPATH', self.spec.prefix.man),
-                    ('MANPATH', self.spec.prefix.share_man),
-                    ('LIBRARY_PATH', self.spec.prefix.lib),
-                    ('LIBRARY_PATH', self.spec.prefix.lib64),
-                    ('LD_LIBRARY_PATH', self.spec.prefix.lib),
-                    ('LD_LIBRARY_PATH', self.spec.prefix.lib64),
-                    ('CPATH', self.spec.prefix.include),
-                    ('PKG_CONFIG_PATH', join_path(self.spec.prefix.lib, 'pkgconfig')),
-                    ('PKG_CONFIG_PATH', join_path(self.spec.prefix.lib64, 'pkgconfig'))]:
-
-                if os.path.isdir(directory):
-                    add_path(var, directory)
-
-            # Add python path unless it's an actual python installation
-            # TODO: is there a better way to do this?
-            if self.spec.name != 'python':
-                site_packages = glob(join_path(self.spec.prefix.lib, "python*/site-packages"))
-                if site_packages:
-                    add_path('PYTHONPATH', site_packages[0])
-
-            if self.spec.package.extends(spack.spec.Spec('ruby')):
-              add_path('GEM_PATH', self.spec.prefix)
-
-            # short description is just the package + version
-            # TODO: maybe packages can optionally provide it.
-            self.short_description = self.spec.format("$_ $@")
 
         # long description is the docstring with reduced whitespace.
+        self.long_description = None
         if self.spec.package.__doc__:
             self.long_description = re.sub(r'\s+', ' ', self.spec.package.__doc__)
 
-        return self._paths
+
+    @property
+    def category(self):
+        # Anything defined at the package level takes precedence
+        if hasattr(self.pkg, 'category'):
+            return self.pkg.category
+        # Extensions
+        for extendee in self.pkg.extendees:
+            return '{extendee} extension'.format(extendee=extendee)
+        # Not very descriptive fallback
+        return 'spack installed package'
 
 
     def write(self):
@@ -156,18 +152,41 @@ def write(self):
         if not os.path.exists(module_dir):
             mkdirp(module_dir)
 
-        # If there are no paths, no need for a dotkit.
+        # Environment modifications guessed by inspecting the
-        if not self.paths:
+        # installation prefix
+        env = inspect_path(self.spec.prefix)
+
+        # Let the extendee modify their extensions before asking for
+        # package-specific modifications
+        for extendee in self.pkg.extendees:
+            extendee_spec = self.spec[extendee]
+            extendee_spec.package.modify_module(
+                self.pkg.module, extendee_spec, self.spec)
+
+        # Package-specific environment modifications
+        spack_env = EnvironmentModifications()
+        self.spec.package.setup_environment(spack_env, env)
+
+        # TODO : implement site-specific modifications and filters
+        if not env:
             return
 
         with open(self.file_name, 'w') as f:
-            self._write(f)
+            self.write_header(f)
+            for line in self.process_environment_command(env):
+                f.write(line)
 
-
+    def write_header(self, stream):
-    def _write(self, stream):
-        """To be implemented by subclasses."""
         raise NotImplementedError()
 
+    def process_environment_command(self, env):
+        for command in env:
+            try:
+                yield self.formats[type(command)].format(**command.args)
+            except KeyError:
+                tty.warn('Cannot handle command of type {command} : skipping request'.format(command=type(command)))
+                tty.warn('{context} at {filename}:{lineno}'.format(**command.args))
+
 
     @property
     def file_name(self):
@@ -175,14 +194,12 @@ def file_name(self):
            where this module lives."""
         raise NotImplementedError()
 
-
     @property
     def use_name(self):
         """Subclasses should implement this to return the name the
            module command uses to refer to the package."""
         raise NotImplementedError()
 
-
     def remove(self):
         mod_file = self.file_name
         if os.path.exists(mod_file):
@@ -193,10 +210,14 @@ class Dotkit(EnvModule):
     name = 'dotkit'
     path = join_path(spack.share_path, "dotkit")
 
+    formats = {
+        PrependPath: 'dk_alter {name} {value}\n',
+        SetEnv: 'dk_setenv {name} {value}\n'
+    }
+
     @property
     def file_name(self):
-        return join_path(Dotkit.path, self.spec.architecture,
+        return join_path(Dotkit.path, self.spec.architecture, '%s.dk' % self.use_name)
-                         '%s.dk' % self.use_name)
 
     @property
     def use_name(self):
@@ -205,7 +226,7 @@ def use_name(self):
                                  self.spec.compiler.version,
                                  self.spec.dag_hash())
 
-    def _write(self, dk_file):
+    def write_header(self, dk_file):
         # Category
         if self.category:
             dk_file.write('#c %s\n' % self.category)
@@ -219,24 +240,23 @@ def _write(self, dk_file):
             for line in textwrap.wrap(self.long_description, 72):
                 dk_file.write("#h %s\n" % line)
 
-        # Path alterations
-        for var, dirs in self.paths.items():
-            for directory in dirs:
-                dk_file.write("dk_alter %s %s\n" % (var, directory))
-
-        # Let CMake find this package.
-        dk_file.write("dk_alter CMAKE_PREFIX_PATH %s\n" % self.spec.prefix)
-
 
 class TclModule(EnvModule):
     name = 'tcl'
     path = join_path(spack.share_path, "modules")
 
+    formats = {
+        PrependPath: 'prepend-path {name} \"{value}\"\n',
+        AppendPath: 'append-path {name} \"{value}\"\n',
+        RemovePath: 'remove-path {name} \"{value}\"\n',
+        SetEnv: 'setenv {name} \"{value}\"\n',
+        UnsetEnv: 'unsetenv {name}\n'
+    }
+
     @property
     def file_name(self):
         return join_path(TclModule.path, self.spec.architecture, self.use_name)
 
-
     @property
     def use_name(self):
       return "%s-%s-%s-%s-%s" % (self.spec.name, self.spec.version,
@@ -244,25 +264,17 @@ def use_name(self):
                                  self.spec.compiler.version,
                                  self.spec.dag_hash())
 
-
+    def write_header(self, module_file):
-    def _write(self, m_file):
+        # TCL Modulefile header
-        # TODO: cateogry?
+        module_file.write('#%Module1.0\n')
-        m_file.write('#%Module1.0\n')
+        # TODO : category ?
-
         # Short description
         if self.short_description:
-            m_file.write('module-whatis \"%s\"\n\n' % self.short_description)
+            module_file.write('module-whatis \"%s\"\n\n' % self.short_description)
 
         # Long description
         if self.long_description:
-            m_file.write('proc ModulesHelp { } {\n')
+            module_file.write('proc ModulesHelp { } {\n')
             doc = re.sub(r'"', '\"', self.long_description)
-            m_file.write("puts stderr \"%s\"\n" % doc)
+            module_file.write("puts stderr \"%s\"\n" % doc)
-            m_file.write('}\n\n')
+            module_file.write('}\n\n')
-
-        # Path alterations
-        for var, dirs in self.paths.items():
-            for directory in dirs:
-                m_file.write("prepend-path %s \"%s\"\n" % (var, directory))
-
-        m_file.write("prepend-path CMAKE_PREFIX_PATH \"%s\"\n" % self.spec.prefix)

lib/spack/spack/package.py

@@ -34,40 +34,34 @@
 README.
 """
 import os
-import errno
 import re
-import shutil
-import time
-import itertools
-import subprocess
-import platform as py_platform
-import multiprocessing
-from urlparse import urlparse, urljoin
 import textwrap
-from StringIO import StringIO
+import time
+import glob
 
 import llnl.util.tty as tty
-from llnl.util.tty.log import log_output
-from llnl.util.link_tree import LinkTree
-from llnl.util.filesystem import *
-from llnl.util.lang import *
-
 import spack
-import spack.error
-import spack.compilers
-import spack.mirror
-import spack.hooks
-import spack.directives
-import spack.repository
 import spack.build_environment
+import spack.compilers
+import spack.directives
+import spack.error
+import spack.fetch_strategy as fs
+import spack.hooks
+import spack.mirror
+import spack.repository
 import spack.url
 import spack.util.web
-import spack.fetch_strategy as fs
+from StringIO import StringIO
-from spack.version import *
+from llnl.util.filesystem import *
+from llnl.util.lang import *
+from llnl.util.link_tree import LinkTree
+from llnl.util.tty.log import log_output
 from spack.stage import Stage, ResourceStage, StageComposite
-from spack.util.compression import allowed_archive, extension
+from spack.util.compression import allowed_archive
-from spack.util.executable import ProcessError
 from spack.util.environment import dump_environment
+from spack.util.executable import ProcessError
+from spack.version import *
+from urlparse import urlparse
 
 """Allowed URL schemes for spack packages."""
 _ALLOWED_URL_SCHEMES = ["http", "https", "ftp", "file", "git"]
@@ -1008,38 +1002,127 @@ def module(self):
         return __import__(self.__class__.__module__,
                           fromlist=[self.__class__.__name__])
 
+    def setup_environment(self, spack_env, run_env):
+        """Set up the compile and runtime environemnts for a package.
 
-    def setup_dependent_environment(self, module, spec, dependent_spec):
+        `spack_env` and `run_env` are `EnvironmentModifications`
-        """Called before the install() method of dependents.
+        objects.  Package authors can call methods on them to alter
+        the environment within Spack and at runtime.
+
+        Both `spack_env` and `run_env` are applied within the build
+        process, before this package's `install()` method is called.
+
+        Modifications in `run_env` will *also* be added to the
+        generated environment modules for this package.
 
         Default implementation does nothing, but this can be
-        overridden by an extendable package to set up the install
+        overridden if the package needs a particular environment.
-        environment for its extensions.  This is useful if there are
-        some common steps to installing all extensions for a
-        certain package.
 
-        Some examples:
+        Examples:
 
-        1. Installing python modules generally requires PYTHONPATH to
+            1. Qt extensions need `QTDIR` set.
-           point to the lib/pythonX.Y/site-packages directory in the
-           module's install prefix.  This could set that variable.
 
-        2. Extensions often need to invoke the 'python' interpreter
+        Args:
-           from the Python installation being extended.  This routine can
+            spack_env (EnvironmentModifications): list of
-           put a 'python' Execuable object in the module scope for the
+                modifications to be applied when this package is built
-           extension package to simplify extension installs.
+                within Spack.
 
-        3. A lot of Qt extensions need QTDIR set.  This can be used to do that.
+            run_env (EnvironmentModifications): list of environment
+                changes to be applied when this package is run outside
+                of Spack.
 
         """
         pass
 
 
+    def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
+        """Set up the environment of packages that depend on this one.
+
+        This is similar to `setup_environment`, but it is used to
+        modify the compile and runtime environments of packages that
+        *depend* on this one. This gives packages like Python and
+        others that follow the extension model a way to implement
+        common environment or compile-time settings for dependencies.
+
+        By default, this delegates to self.setup_environment()
+
+        Example :
+
+            1. Installing python modules generally requires
+              `PYTHONPATH` to point to the lib/pythonX.Y/site-packages
+              directory in the module's install prefix.  This could
+              set that variable.
+
+        Args:
+
+            spack_env (EnvironmentModifications): list of
+                modifications to be applied when the dependent package
+                is bulit within Spack.
+
+            run_env (EnvironmentModifications): list of environment
+                changes to be applied when the dependent package is
+                run outside of Spack.
+
+            dependent_spec (Spec): The spec of the dependent package
+                about to be built. This allows the extendee (self) to
+                query the dependent's state. Note that *this*
+                package's spec is available as `self.spec`.
+
+        This is useful if there are some common steps to installing
+        all extensions for a certain package.
+
+        """
+        self.setup_environment(spack_env, run_env)
+
+
+    def setup_dependent_python_module(self, module, dependent_spec):
+        """Set up Python module-scope variables for dependent packages.
+
+        Called before the install() method of dependents.
+
+        Default implementation does nothing, but this can be
+        overridden by an extendable package to set up the module of
+        its extensions. This is useful if there are some common steps
+        to installing all extensions for a certain package.
+
+        Example :
+
+            1. Extensions often need to invoke the `python`
+               interpreter from the Python installation being
+               extended.  This routine can put a 'python' Executable
+               object in the module scope for the extension package to
+               simplify extension installs.
+
+            2. MPI compilers could set some variables in the
+               dependent's scope that point to `mpicc`, `mpicxx`,
+               etc., allowing them to be called by common names
+               regardless of which MPI is used.
+
+            3. BLAS/LAPACK implementations can set some variables
+               indicating the path to their libraries, since these
+               paths differ by BLAS/LAPACK implementation.
+
+        Args:
+
+            module (module): The Python `module` object of the
+                dependent package. Packages can use this to set
+                module-scope variables for the dependent to use.
+
+            dependent_spec (Spec): The spec of the dependent package
+                about to be built. This allows the extendee (self) to
+                query the dependent's state.  Note that *this*
+                package's spec is available as `self.spec`.
+
+        This is useful if there are some common steps to installing
+        all extensions for a certain package.
+
+        """
+        pass
+
     def install(self, spec, prefix):
         """Package implementations override this with their own build configuration."""
         raise InstallError("Package %s provides no install method!" % self.name)
 
-
     def do_uninstall(self, force=False):
         if not self.installed:
             raise InstallError(str(self.spec) + " is not installed.")

lib/spack/spack/test/__init__.py

@@ -66,7 +66,8 @@
               'database',
               'namespace_trie',
               'yaml',
-              'sbang']
+              'sbang',
+              'environment']
 
 
 def list_tests():

lib/spack/spack/test/concretize.py

@@ -309,3 +309,10 @@ def test_find_spec_none(self):
                       Spec('d')),
                  Spec('e'))
         self.assertEqual(None, find_spec(s['b'], lambda s: '+foo' in s))
+
+
+    def test_compiler_child(self):
+        s = Spec('mpileaks%clang ^dyninst%gcc')
+        s.concretize()
+        self.assertTrue(s['mpileaks'].satisfies('%clang'))
+        self.assertTrue(s['dyninst'].satisfies('%gcc'))

lib/spack/spack/test/database.py

@@ -26,6 +26,7 @@
 These tests check the database is functioning properly,
 both in memory and in its file
 """
+import os.path
 import multiprocessing
 import shutil
 import tempfile

lib/spack/spack/test/environment.py

@@ -0,0 +1,73 @@
+import unittest
+import os
+from spack.environment import EnvironmentModifications
+
+
+class EnvironmentTest(unittest.TestCase):
+    def setUp(self):
+        os.environ.clear()
+        os.environ['UNSET_ME'] = 'foo'
+        os.environ['EMPTY_PATH_LIST'] = ''
+        os.environ['PATH_LIST'] = '/path/second:/path/third'
+        os.environ['REMOVE_PATH_LIST'] = '/a/b:/duplicate:/a/c:/remove/this:/a/d:/duplicate/:/f/g'
+
+    def test_set(self):
+        env = EnvironmentModifications()
+        env.set('A', 'dummy value')
+        env.set('B', 3)
+        env.apply_modifications()
+        self.assertEqual('dummy value', os.environ['A'])
+        self.assertEqual(str(3), os.environ['B'])
+
+    def test_unset(self):
+        env = EnvironmentModifications()
+        self.assertEqual('foo', os.environ['UNSET_ME'])
+        env.unset('UNSET_ME')
+        env.apply_modifications()
+        self.assertRaises(KeyError, os.environ.__getitem__, 'UNSET_ME')
+
+    def test_set_path(self):
+        env = EnvironmentModifications()
+        env.set_path('A', ['foo', 'bar', 'baz'])
+        env.apply_modifications()
+        self.assertEqual('foo:bar:baz', os.environ['A'])
+
+    def test_path_manipulation(self):
+        env = EnvironmentModifications()
+
+        env.append_path('PATH_LIST', '/path/last')
+        env.prepend_path('PATH_LIST', '/path/first')
+
+        env.append_path('EMPTY_PATH_LIST', '/path/middle')
+        env.append_path('EMPTY_PATH_LIST', '/path/last')
+        env.prepend_path('EMPTY_PATH_LIST', '/path/first')
+
+        env.append_path('NEWLY_CREATED_PATH_LIST', '/path/middle')
+        env.append_path('NEWLY_CREATED_PATH_LIST', '/path/last')
+        env.prepend_path('NEWLY_CREATED_PATH_LIST', '/path/first')
+
+        env.remove_path('REMOVE_PATH_LIST', '/remove/this')
+        env.remove_path('REMOVE_PATH_LIST', '/duplicate/')
+
+        env.apply_modifications()
+        self.assertEqual('/path/first:/path/second:/path/third:/path/last', os.environ['PATH_LIST'])
+        self.assertEqual('/path/first:/path/middle:/path/last', os.environ['EMPTY_PATH_LIST'])
+        self.assertEqual('/path/first:/path/middle:/path/last', os.environ['NEWLY_CREATED_PATH_LIST'])
+        self.assertEqual('/a/b:/a/c:/a/d:/f/g', os.environ['REMOVE_PATH_LIST'])
+
+    def test_extra_arguments(self):
+        env = EnvironmentModifications()
+        env.set('A', 'dummy value', who='Pkg1')
+        for x in env:
+            assert 'who' in x.args
+        env.apply_modifications()
+        self.assertEqual('dummy value', os.environ['A'])
+
+    def test_extend(self):
+        env = EnvironmentModifications()
+        env.set('A', 'dummy value')
+        env.set('B', 3)
+        copy_construct = EnvironmentModifications(env)
+        self.assertEqual(len(copy_construct), 2)
+        for x, y in zip(env, copy_construct):
+            assert x is y

lib/spack/spack/util/environment.py

@@ -59,12 +59,6 @@ def path_put_first(var_name, directories):
     path_set(var_name, new_path)
 
 
-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:

var/spack/repos/builtin/packages/mpich/package.py

@@ -25,6 +25,7 @@
 from spack import *
 import os
 
+
 class Mpich(Package):
     """MPICH is a high performance and widely portable implementation of
        the Message Passing Interface (MPI) standard."""
@@ -46,14 +47,16 @@ class Mpich(Package):
     provides('mpi@:3.0', when='@3:')
     provides('mpi@:1.3', when='@1:')
 
-    def setup_dependent_environment(self, module, spec, dep_spec):
+    def setup_dependent_environment(self, env, dependent_spec):
-        """For dependencies, make mpicc's use spack wrapper."""
+        env.set('MPICH_CC', spack_cc)
-        os.environ['MPICH_CC']  = os.environ['CC']
+        env.set('MPICH_CXX', spack_cxx)
-        os.environ['MPICH_CXX'] = os.environ['CXX']
+        env.set('MPICH_F77', spack_f77)
-        os.environ['MPICH_F77'] = os.environ['F77']
+        env.set('MPICH_F90', spack_f90)
-        os.environ['MPICH_F90'] = os.environ['FC']
+        env.set('MPICH_FC', spack_fc)
-        os.environ['MPICH_FC'] = os.environ['FC']
 
+    def setup_dependent_python_module(self, module, spec, dep_spec):
+        """For dependencies, make mpicc's use spack wrapper."""
+        # FIXME : is this necessary ? Shouldn't this be part of a contract with MPI providers?
         module.mpicc = join_path(self.prefix.bin, 'mpicc')
 
     def install(self, spec, prefix):

var/spack/repos/builtin/packages/mvapich2/package.py

@@ -123,7 +123,7 @@ def set_network_type(self, spec, configure_args):
                 count += 1
         if count > 1:
             raise RuntimeError('network variants are mutually exclusive (only one can be selected at a time)')
-
+        network_options = []
         # From here on I can suppose that only one variant has been selected
         if self.enabled(Mvapich2.PSM) in spec:
             network_options = ["--with-device=ch3:psm"]

var/spack/repos/builtin/packages/netlib-scalapack/package.py

@@ -1,5 +1,4 @@
 from spack import *
-import sys
 
 class NetlibScalapack(Package):
     """ScaLAPACK is a library of high-performance linear algebra routines for parallel distributed memory machines"""
@@ -41,11 +40,10 @@ def install(self, spec, prefix):
             make()
             make("install")
 
-    def setup_dependent_environment(self, module, spec, dependent_spec):
+    def setup_dependent_python_module(self, module, spec, dependent_spec):
         lib_dsuffix = '.dylib' if sys.platform == 'darwin' else '.so'
         lib_suffix = lib_dsuffix if '+shared' in spec['scalapack'] else '.a'
 
         spec['scalapack'].fc_link = '-L%s -lscalapack' % spec['scalapack'].prefix.lib
         spec['scalapack'].cc_link = spec['scalapack'].fc_link
-        spec['scalapack'].libraries = [join_path(spec['scalapack'].prefix.lib,
+        spec['scalapack'].libraries = [join_path(spec['scalapack'].prefix.lib, 'libscalapack%s' % lib_suffix)]
-                                                 'libscalapack%s' % lib_suffix)]

var/spack/repos/builtin/packages/openmpi/package.py

@@ -41,12 +41,13 @@ class Openmpi(Package):
     def url_for_version(self, version):
         return "http://www.open-mpi.org/software/ompi/v%s/downloads/openmpi-%s.tar.bz2" % (version.up_to(2), version)
 
-    def setup_dependent_environment(self, module, spec, dep_spec):
+
-        """For dependencies, make mpicc's use spack wrapper."""
+    def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
-        os.environ['OMPI_CC'] = 'cc'
+        spack_env.set('OMPI_CC', spack_cc)
-        os.environ['OMPI_CXX'] = 'c++'
+        spack_env.set('OMPI_CXX', spack_cxx)
-        os.environ['OMPI_FC'] = 'f90'
+        spack_env.set('OMPI_FC', spack_fc)
-        os.environ['OMPI_F77'] = 'f77'
+        spack_env.set('OMPI_F77', spack_f77)
+
 
     def install(self, spec, prefix):
         config_args = ["--prefix=%s" % prefix,

var/spack/repos/builtin/packages/paraview/package.py

@@ -16,9 +16,9 @@ class Paraview(Package):
 
     variant('osmesa', default=False, description='Enable OSMesa support')
     variant('qt', default=False, description='Enable Qt support')
-    variant('opengl2', default=False, description='Enable OPengl2 backend')
+    variant('opengl2', default=False, description='Enable OpenGL2 backend')
 
-    depends_on('python', when='+python')
+    depends_on('python@2:2.7', when='+python')
     depends_on('py-numpy', when='+python')
     depends_on('py-matplotlib', when='+python')
     depends_on('tcl', when='+tcl')

var/spack/repos/builtin/packages/py-nose/package.py

@@ -1,5 +1,6 @@
 from spack import *
 
+
 class PyNose(Package):
     """nose extends the test loading and running features of unittest,
     making it easier to write, find and run tests."""

var/spack/repos/builtin/packages/python/package.py

@@ -1,11 +1,14 @@
+import functools
+import glob
+import inspect
 import os
 import re
 from contextlib import closing
-from llnl.util.lang import match_predicate
-from spack.util.environment import *
 
-from spack import *
 import spack
+from llnl.util.lang import match_predicate
+from spack import *
+from spack.util.environment import *
 
 
 class Python(Package):
@@ -90,8 +93,24 @@ def site_packages_dir(self):
         return os.path.join(self.python_lib_dir, 'site-packages')
 
 
-    def setup_dependent_environment(self, module, spec, ext_spec):
+    def setup_dependent_environment(self, spack_env, run_env, extension_spec):
-        """Called before python modules' install() methods.
+        # TODO: do this only for actual extensions.
+
+        # Set PYTHONPATH to include site-packages dir for the
+        # extension and any other python extensions it depends on.
+        python_paths = []
+        for d in extension_spec.traverse():
+            if d.package.extends(self.spec):
+                python_paths.append(os.path.join(d.prefix, self.site_packages_dir))
+
+        pythonpath = ':'.join(python_paths)
+        spack_env.set('PYTHONPATH', pythonpath)
+        run_env.set('PYTHONPATH', pythonpath)
+
+
+    def modify_module(self, module, spec, ext_spec):
+        """
+        Called before python modules' install() methods.
 
         In most cases, extensions will only need to have one line::
 
@@ -111,15 +130,6 @@ def setup_dependent_environment(self, module, spec, ext_spec):
         # Make the site packages directory if it does not exist already.
         mkdirp(module.site_packages_dir)
 
-        # Set PYTHONPATH to include site-packages dir for the
-        # extension and any other python extensions it depends on.
-        python_paths = []
-        for d in ext_spec.traverse():
-            if d.package.extends(self.spec):
-                python_paths.append(os.path.join(d.prefix, self.site_packages_dir))
-        os.environ['PYTHONPATH'] = ':'.join(python_paths)
-
-
     # ========================================================================
     # Handle specifics of activating and deactivating python modules.
     # ========================================================================

var/spack/repos/builtin/packages/qt/package.py

@@ -56,9 +56,12 @@ class Qt(Package):
     depends_on("libxcb")
 
 
-    def setup_dependent_environment(self, module, spec, dep_spec):
+    def setup_environment(self, spack_env, env):
-        """Dependencies of Qt find it using the QTDIR environment variable."""
+        env.set('QTDIR', self.prefix)
-        os.environ['QTDIR'] = self.prefix
+
+
+    def setup_dependent_environment(self, spack_env, run_env, dspec):
+        spack_env.set('QTDIR', self.prefix)
 
 
     def patch(self):

var/spack/repos/builtin/packages/ruby/package.py

@@ -1,6 +1,5 @@
 from spack import *
-import spack
+
-import os
 
 class Ruby(Package):
     """A dynamic, open source programming language with a focus on
@@ -15,11 +14,23 @@ class Ruby(Package):
 
     def install(self, spec, prefix):
         configure("--prefix=%s" % prefix)
-
         make()
         make("install")
 
-    def setup_dependent_environment(self, module, spec, ext_spec):
+    def setup_dependent_environment(self, spack_env, run_env, extension_spec):
+        # TODO: do this only for actual extensions.
+        # Set GEM_PATH to include dependent gem directories
+        ruby_paths = []
+        for d in extension_spec.traverse():
+            if d.package.extends(self.spec):
+                ruby_paths.append(d.prefix)
+
+        spack_env.set_path('GEM_PATH', ruby_paths)
+
+        # The actual installation path for this gem
+        spack_env.set('GEM_HOME', extension_spec.prefix)
+
+    def modify_module(self, module, spec, ext_spec):
         """Called before ruby modules' install() methods.  Sets GEM_HOME
         and GEM_PATH to values appropriate for the package being built.
 
@@ -30,12 +41,3 @@ def setup_dependent_environment(self, module, spec, ext_spec):
         # Ruby extension builds have global ruby and gem functions
         module.ruby = Executable(join_path(spec.prefix.bin, 'ruby'))
         module.gem = Executable(join_path(spec.prefix.bin, 'gem'))
-
-        # Set GEM_PATH to include dependent gem directories
-        ruby_paths = []
-        for d in ext_spec.traverse():
-            if d.package.extends(self.spec):
-                ruby_paths.append(d.prefix)
-        os.environ['GEM_PATH'] = ':'.join(ruby_paths)
-        # The actual installation path for this gem
-        os.environ['GEM_HOME'] = ext_spec.prefix