text: # Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
  # Spack Project Developers. See the top-level COPYRIGHT file for details.
  #
  # SPDX-License-Identifier: (Apache-2.0 OR MIT)
  
  """This is where most of the action happens in Spack.
  
  The spack package class structure is based strongly on Homebrew
  (http://brew.sh/), mainly because Homebrew makes it very easy to create
  packages.
  """
  
  import base64
  import collections
  import contextlib
  import copy
  import functools
  import glob
  import hashlib
  import inspect
  import os
  import re
  import shutil
  import sys
  import textwrap
  import time
  import traceback
  import types
  from typing import Any, Callable, Dict, List, Optional  # novm
  
  import six
  
  import llnl.util.filesystem as fsys
  import llnl.util.tty as tty
  from llnl.util.lang import memoized
  from llnl.util.link_tree import LinkTree
  
  import spack.compilers
  import spack.config
  import spack.dependency
  import spack.directives
  import spack.directory_layout
  import spack.environment
  import spack.error
  import spack.fetch_strategy as fs
  import spack.hooks
  import spack.mirror
  import spack.mixins
  import spack.multimethod
  import spack.paths
  import spack.repo
  import spack.store
  import spack.url
  import spack.util.environment
  import spack.util.web
  from spack.filesystem_view import YamlFilesystemView
  from spack.install_test import TestFailure, TestSuite
  from spack.installer import InstallError, PackageInstaller
  from spack.stage import ResourceStage, Stage, StageComposite, stage_prefix
  from spack.util.executable import ProcessError, which
  from spack.util.package_hash import package_hash
  from spack.util.prefix import Prefix
  from spack.version import Version
  
  """Allowed URL schemes for spack packages."""
  _ALLOWED_URL_SCHEMES = ["http", "https", "ftp", "file", "git"]
  
  
  # Filename for the Spack build/install log.
  _spack_build_logfile = 'spack-build-out.txt'
  
  # Filename for the Spack build/install environment file.
  _spack_build_envfile = 'spack-build-env.txt'
  
  # Filename for the Spack build/install environment modifications file.
  _spack_build_envmodsfile = 'spack-build-env-mods.txt'
  
  # Filename of json with total build and phase times (seconds)
  _spack_times_log = 'install_times.json'
  
  # Filename for the Spack configure args file.
  _spack_configure_argsfile = 'spack-configure-args.txt'
  
  
  def preferred_version(pkg):
      """
      Returns a sorted list of the preferred versions of the package.
  
      Arguments:
          pkg (Package): The package whose versions are to be assessed.
      """
      # Here we sort first on the fact that a version is marked
      # as preferred in the package, then on the fact that the
      # version is not develop, then lexicographically
      key_fn = lambda v: (pkg.versions[v].get('preferred', False),
                          not v.isdevelop(),
                          v)
      return sorted(pkg.versions, key=key_fn).pop()
  
  
  class InstallPhase(object):
      """Manages a single phase of the installation.
  
      This descriptor stores at creation time the name of the method it should
      search for execution. The method is retrieved at __get__ time, so that
      it can be overridden by subclasses of whatever class declared the phases.
  
      It also provides hooks to execute arbitrary callbacks before and after
      the phase.
      """
  
      def __init__(self, name):
          self.name = name
          self.run_before = []
          self.run_after = []
  
      def __get__(self, instance, owner):
          # The caller is a class that is trying to customize
          # my behavior adding something
          if instance is None:
              return self
          # If instance is there the caller wants to execute the
          # install phase, thus return a properly set wrapper
          phase = getattr(instance, self.name)
  
          @functools.wraps(phase)
          def phase_wrapper(spec, prefix):
              # Check instance attributes at the beginning of a phase
              self._on_phase_start(instance)
              # Execute phase pre-conditions,
              # and give them the chance to fail
              for callback in self.run_before:
                  callback(instance)
              phase(spec, prefix)
              # Execute phase sanity_checks,
              # and give them the chance to fail
              for callback in self.run_after:
                  callback(instance)
              # Check instance attributes at the end of a phase
              self._on_phase_exit(instance)
          return phase_wrapper
  
      def _on_phase_start(self, instance):
          # If a phase has a matching stop_before_phase attribute,
          # stop the installation process raising a StopPhase
          if getattr(instance, 'stop_before_phase', None) == self.name:
              from spack.build_environment import StopPhase
              raise StopPhase('Stopping before \'{0}\' phase'.format(self.name))
  
      def _on_phase_exit(self, instance):
          # If a phase has a matching last_phase attribute,
          # stop the installation process raising a StopPhase
          if getattr(instance, 'last_phase', None) == self.name:
              from spack.build_environment import StopPhase
              raise StopPhase('Stopping at \'{0}\' phase'.format(self.name))
  
      def copy(self):
          try:
              return copy.deepcopy(self)
          except TypeError:
              # This bug-fix was not back-ported in Python 2.6
              # http://bugs.python.org/issue1515
              other = InstallPhase(self.name)
              other.run_before.extend(self.run_before)
              other.run_after.extend(self.run_after)
              return other
  
  
  #: Registers which are the detectable packages, by repo and package name
  #: Need a pass of package repositories to be filled.
  detectable_packages = collections.defaultdict(list)
  
  
  class DetectablePackageMeta(object):
      """Check if a package is detectable and add default implementations
      for the detection function.
      """
      def __init__(cls, name, bases, attr_dict):
          # If a package has the executables attribute then it's
          # assumed to be detectable
          if hasattr(cls, 'executables'):
              @classmethod
              def determine_spec_details(cls, prefix, exes_in_prefix):
                  """Allow ``spack external find ...`` to locate installations.
  
                  Args:
                      prefix (str): the directory containing the executables
                      exes_in_prefix (set): the executables that match the regex
  
                  Returns:
                      The list of detected specs for this package
                  """
                  exes_by_version = collections.defaultdict(list)
                  # The default filter function is the identity function for the
                  # list of executables
                  filter_fn = getattr(cls, 'filter_detected_exes',
                                      lambda x, exes: exes)
                  exes_in_prefix = filter_fn(prefix, exes_in_prefix)
                  for exe in exes_in_prefix:
                      try:
                          version_str = cls.determine_version(exe)
                          if version_str:
                              exes_by_version[version_str].append(exe)
                      except Exception as e:
                          msg = ('An error occurred when trying to detect '
                                 'the version of "{0}" [{1}]')
                          tty.debug(msg.format(exe, str(e)))
  
                  specs = []
                  for version_str, exes in exes_by_version.items():
                      variants = cls.determine_variants(exes, version_str)
                      # Normalize output to list
                      if not isinstance(variants, list):
                          variants = [variants]
  
                      for variant in variants:
                          if isinstance(variant, six.string_types):
                              variant = (variant, {})
                          variant_str, extra_attributes = variant
                          spec_str = '{0}@{1} {2}'.format(
                              cls.name, version_str, variant_str
                          )
  
                          # Pop a few reserved keys from extra attributes, since
                          # they have a different semantics
                          external_path = extra_attributes.pop('prefix', None)
                          external_modules = extra_attributes.pop(
                              'modules', None
                          )
                          try:
                              spec = spack.spec.Spec(
                                  spec_str,
                                  external_path=external_path,
                                  external_modules=external_modules
                              )
                          except Exception as e:
                              msg = 'Parsing failed [spec_str="{0}", error={1}]'
                              tty.debug(msg.format(spec_str, str(e)))
                          else:
                              specs.append(spack.spec.Spec.from_detection(
                                  spec, extra_attributes=extra_attributes
                              ))
  
                  return sorted(specs)
  
              @classmethod
              def determine_variants(cls, exes, version_str):
                  return ''
  
              # Register the class as a detectable package
              detectable_packages[cls.namespace].append(cls.name)
  
              # Attach function implementations to the detectable class
              default = False
              if not hasattr(cls, 'determine_spec_details'):
                  default = True
                  cls.determine_spec_details = determine_spec_details
  
              if default and not hasattr(cls, 'determine_version'):
                  msg = ('the package "{0}" in the "{1}" repo needs to define'
                         ' the "determine_version" method to be detectable')
                  NotImplementedError(msg.format(cls.name, cls.namespace))
  
              if default and not hasattr(cls, 'determine_variants'):
                  cls.determine_variants = determine_variants
  
          super(DetectablePackageMeta, cls).__init__(name, bases, attr_dict)
  
  
  class PackageMeta(
      DetectablePackageMeta,
      spack.directives.DirectiveMeta,
      spack.mixins.PackageMixinsMeta,
      spack.multimethod.MultiMethodMeta
  ):
      """
      Package metaclass for supporting directives (e.g., depends_on) and phases
      """
      phase_fmt = '_InstallPhase_{0}'
  
      # These are accessed only through getattr, by name
      _InstallPhase_run_before = {}  # type: Dict[str, List[Callable]]
      _InstallPhase_run_after = {}  # type: Dict[str, List[Callable]]
  
      def __new__(cls, name, bases, attr_dict):
          """
          Instance creation is preceded by phase attribute transformations.
  
          Conveniently transforms attributes to permit extensible phases by
          iterating over the attribute 'phases' and creating / updating private
          InstallPhase attributes in the class that will be initialized in
          __init__.
          """
          if 'phases' in attr_dict:
              # Turn the strings in 'phases' into InstallPhase instances
              # and add them as private attributes
              _InstallPhase_phases = [PackageMeta.phase_fmt.format(x) for x in attr_dict['phases']]  # NOQA: ignore=E501
              for phase_name, callback_name in zip(_InstallPhase_phases, attr_dict['phases']):  # NOQA: ignore=E501
                  attr_dict[phase_name] = InstallPhase(callback_name)
              attr_dict['_InstallPhase_phases'] = _InstallPhase_phases
  
          def _flush_callbacks(check_name):
              # Name of the attribute I am going to check it exists
              check_attr = PackageMeta.phase_fmt.format(check_name)
              checks = getattr(cls, check_attr)
              if checks:
                  for phase_name, funcs in checks.items():
                      phase_attr = PackageMeta.phase_fmt.format(phase_name)
                      try:
                          # Search for the phase in the attribute dictionary
                          phase = attr_dict[phase_attr]
                      except KeyError:
                          # If it is not there it's in the bases
                          # and we added a check. We need to copy
                          # and extend
                          for base in bases:
                              phase = getattr(base, phase_attr, None)
                              if phase is not None:
                                  break
  
                          phase = attr_dict[phase_attr] = phase.copy()
                      getattr(phase, check_name).extend(funcs)
                  # Clear the attribute for the next class
                  setattr(cls, check_attr, {})
  
          _flush_callbacks('run_before')
          _flush_callbacks('run_after')
  
          # Reset names for packages that inherit from another
          # package with a different name
          attr_dict['_name'] = None
  
          return super(PackageMeta, cls).__new__(cls, name, bases, attr_dict)
  
      @staticmethod
      def register_callback(check_type, *phases):
          def _decorator(func):
              attr_name = PackageMeta.phase_fmt.format(check_type)
              check_list = getattr(PackageMeta, attr_name)
              for item in phases:
                  checks = check_list.setdefault(item, [])
                  checks.append(func)
              setattr(PackageMeta, attr_name, check_list)
              return func
          return _decorator
  
      @property
      def package_dir(self):
          """Directory where the package.py file lives."""
          return os.path.abspath(os.path.dirname(self.module.__file__))
  
      @property
      def module(self):
          """Module object (not just the name) that this package is defined in.
  
          We use this to add variables to package modules.  This makes
          install() methods easier to write (e.g., can call configure())
          """
          return __import__(self.__module__, fromlist=[self.__name__])
  
      @property
      def namespace(self):
          """Spack namespace for the package, which identifies its repo."""
          namespace, dot, module = self.__module__.rpartition('.')
          prefix = '%s.' % spack.repo.repo_namespace
          if namespace.startswith(prefix):
              namespace = namespace[len(prefix):]
          return namespace
  
      @property
      def fullname(self):
          """Name of this package, including the namespace"""
          return '%s.%s' % (self.namespace, self.name)
  
      @property
      def name(self):
          """The name of this package.
  
          The name of a package is the name of its Python module, without
          the containing module names.
          """
          if self._name is None:
              self._name = self.module.__name__
              if '.' in self._name:
                  self._name = self._name[self._name.rindex('.') + 1:]
          return self._name
  
  
  def run_before(*phases):
      """Registers a method of a package to be run before a given phase"""
      return PackageMeta.register_callback('run_before', *phases)
  
  
  def run_after(*phases):
      """Registers a method of a package to be run after a given phase"""
      return PackageMeta.register_callback('run_after', *phases)
  
  
  def on_package_attributes(**attr_dict):
      """Decorator: executes instance function only if object has attr valuses.
  
      Executes the decorated method only if at the moment of calling the
      instance has attributes that are equal to certain values.
  
      Args:
          attr_dict (dict): dictionary mapping attribute names to their
              required values
      """
      def _execute_under_condition(func):
  
          @functools.wraps(func)
          def _wrapper(instance, *args, **kwargs):
              # If all the attributes have the value we require, then execute
              has_all_attributes = all(
                  [hasattr(instance, key) for key in attr_dict]
              )
              if has_all_attributes:
                  has_the_right_values = all(
                      [getattr(instance, key) == value for key, value in attr_dict.items()]  # NOQA: ignore=E501
                  )
                  if has_the_right_values:
                      func(instance, *args, **kwargs)
          return _wrapper
  
      return _execute_under_condition
  
  
  class PackageViewMixin(object):
      """This collects all functionality related to adding installed Spack
      package to views. Packages can customize how they are added to views by
      overriding these functions.
      """
      def view_source(self):
          """The source root directory that will be added to the view: files are
          added such that their path relative to the view destination matches
          their path relative to the view source.
          """
          return self.spec.prefix
  
      def view_destination(self, view):
          """The target root directory: each file is added relative to this
          directory.
          """
          return view.get_projection_for_spec(self.spec)
  
      def view_file_conflicts(self, view, merge_map):
          """Report any files which prevent adding this package to the view. The
          default implementation looks for any files which already exist.
          Alternative implementations may allow some of the files to exist in
          the view (in this case they would be omitted from the results).
          """
          return set(dst for dst in merge_map.values() if os.path.exists(dst))
  
      def add_files_to_view(self, view, merge_map):
          """Given a map of package files to destination paths in the view, add
          the files to the view. By default this adds all files. Alternative
          implementations may skip some files, for example if other packages
          linked into the view already include the file.
          """
          for src, dst in merge_map.items():
              if not os.path.exists(dst):
                  view.link(src, dst, spec=self.spec)
  
      def remove_files_from_view(self, view, merge_map):
          """Given a map of package files to files currently linked in the view,
          remove the files from the view. The default implementation removes all
          files. Alternative implementations may not remove all files. For
          example if two packages include the same file, it should only be
          removed when both packages are removed.
          """
          view.remove_files(merge_map.values())
  
  
  def test_log_pathname(test_stage, spec):
      """Build the pathname of the test log file
  
      Args:
          test_stage (str): path to the test stage directory
          spec (spack.spec.Spec): instance of the spec under test
  
      Returns:
          (str): the pathname of the test log file
      """
      return os.path.join(test_stage,
                          'test-{0}-out.txt'.format(TestSuite.test_pkg_id(spec)))
  
  
  class PackageBase(six.with_metaclass(PackageMeta, PackageViewMixin, object)):
      """This is the superclass for all spack packages.
  
      ***The Package class***
  
      At its core, a package consists of a set of software to be installed.
      A package may focus on a piece of software and its associated software
      dependencies or it may simply be a set, or bundle, of software.  The
      former requires defining how to fetch, verify (via, e.g., sha256), build,
      and install that software and the packages it depends on, so that
      dependencies can be installed along with the package itself.   The latter,
      sometimes referred to as a ``no-source`` package, requires only defining
      the packages to be built.
  
      Packages are written in pure Python.
  
      There are two main parts of a Spack package:
  
        1. **The package class**.  Classes contain ``directives``, which are
           special functions, that add metadata (versions, patches,
           dependencies, and other information) to packages (see
           ``directives.py``). Directives provide the constraints that are
           used as input to the concretizer.
  
        2. **Package instances**. Once instantiated, a package is
           essentially a software installer.  Spack calls methods like
           ``do_install()`` on the ``Package`` object, and it uses those to
           drive user-implemented methods like ``patch()``, ``install()``, and
           other build steps.  To install software, an instantiated package
           needs a *concrete* spec, which guides the behavior of the various
           install methods.
  
      Packages are imported from repos (see ``repo.py``).
  
      **Package DSL**
  
      Look in ``lib/spack/docs`` or check https://spack.readthedocs.io for
      the full documentation of the package domain-specific language.  That
      used to be partially documented here, but as it grew, the docs here
      became increasingly out of date.
  
      **Package Lifecycle**
  
      A package's lifecycle over a run of Spack looks something like this:
  
      .. code-block:: python
  
         p = Package()             # Done for you by spack
  
         p.do_fetch()              # downloads tarball from a URL (or VCS)
         p.do_stage()              # expands tarball in a temp directory
         p.do_patch()              # applies patches to expanded source
         p.do_install()            # calls package's install() function
         p.do_uninstall()          # removes install directory
  
      although packages that do not have code have nothing to fetch so omit
      ``p.do_fetch()``.
  
      There are also some other commands that clean the build area:
  
      .. code-block:: python
  
         p.do_clean()              # removes the stage directory entirely
         p.do_restage()            # removes the build directory and
                                   # re-expands the archive.
  
      The convention used here is that a ``do_*`` function is intended to be
      called internally by Spack commands (in ``spack.cmd``).  These aren't for
      package writers to override, and doing so may break the functionality
      of the Package class.
  
      Package creators have a lot of freedom, and they could technically
      override anything in this class.  That is not usually required.
  
      For most use cases.  Package creators typically just add attributes
      like ``homepage`` and, for a code-based package, ``url``, or functions
      such as ``install()``.
      There are many custom ``Package`` subclasses in the
      ``spack.build_systems`` package that make things even easier for
      specific build systems.
  
      """
      #
      # These are default values for instance variables.
      #
  
      #: A list or set of build time test functions to be called when tests
      #: are executed or 'None' if there are no such test functions.
      build_time_test_callbacks = None  # type: Optional[List[str]]
  
      #: By default, packages are not virtual
      #: Virtual packages override this attribute
      virtual = False
  
      #: Most Spack packages are used to install source or binary code while
      #: those that do not can be used to install a set of other Spack packages.
      has_code = True
  
      #: A list or set of install time test functions to be called when tests
      #: are executed or 'None' if there are no such test functions.
      install_time_test_callbacks = None  # type: Optional[List[str]]
  
      #: By default we build in parallel.  Subclasses can override this.
      parallel = True
  
      #: By default do not run tests within package's install()
      run_tests = False
  
      # FIXME: this is a bad object-oriented design, should be moved to Clang.
      #: By default do not setup mockup XCode on macOS with Clang
      use_xcode = False
  
      #: Most packages are NOT extendable. Set to True if you want extensions.
      extendable = False
  
      #: When True, add RPATHs for the entire DAG. When False, add RPATHs only
      #: for immediate dependencies.
      transitive_rpaths = True
  
      #: List of prefix-relative file paths (or a single path). If these do
      #: not exist after install, or if they exist but are not files,
      #: sanity checks fail.
      sanity_check_is_file = []  # type: List[str]
  
      #: List of prefix-relative directory paths (or a single path). If
      #: these do not exist after install, or if they exist but are not
      #: directories, sanity checks will fail.
      sanity_check_is_dir = []  # type: List[str]
  
      #: List of glob expressions. Each expression must either be
      #: absolute or relative to the package source path.
      #: Matching artifacts found at the end of the build process will be
      #: copied in the same directory tree as _spack_build_logfile and
      #: _spack_build_envfile.
      archive_files = []  # type: List[str]
  
      #: Boolean. Set to ``True`` for packages that require a manual download.
      #: This is currently used by package sanity tests and generation of a
      #: more meaningful fetch failure error.
      manual_download = False
  
      #: Set of additional options used when fetching package versions.
      fetch_options = {}  # type: Dict[str, Any]
  
      #
      # Set default licensing information
      #
      #: Boolean. If set to ``True``, this software requires a license.
      #: If set to ``False``, all of the ``license_*`` attributes will
      #: be ignored. Defaults to ``False``.
      license_required = False
  
      #: String. Contains the symbol used by the license manager to denote
      #: a comment. Defaults to ``#``.
      license_comment = '#'
  
      #: List of strings. These are files that the software searches for when
      #: looking for a license. All file paths must be relative to the
      #: installation directory. More complex packages like Intel may require
      #: multiple licenses for individual components. Defaults to the empty list.
      license_files = []  # type: List[str]
  
      #: List of strings. Environment variables that can be set to tell the
      #: software where to look for a license if it is not in the usual location.
      #: Defaults to the empty list.
      license_vars = []  # type: List[str]
  
      #: String. A URL pointing to license setup instructions for the software.
      #: Defaults to the empty string.
      license_url = ''
  
      #: Verbosity level, preserved across installs.
      _verbose = None
  
      #: index of patches by sha256 sum, built lazily
      _patches_by_hash = None
  
      #: Package homepage where users can find more information about the package
      homepage = None  # type: str
  
      #: Default list URL (place to find available versions)
      list_url = None  # type: str
  
      #: Link depth to which list_url should be searched for new versions
      list_depth = 0
  
      #: List of strings which contains GitHub usernames of package maintainers.
      #: Do not include @ here in order not to unnecessarily ping the users.
      maintainers = []  # type: List[str]
  
      #: List of attributes to be excluded from a package's hash.
      metadata_attrs = [
          "homepage",
          "url",
          "urls",
          "list_url",
          "extendable",
          "parallel",
          "make_jobs",
          "maintainers",
          "tags",
      ]
  
      #: Boolean. If set to ``True``, the smoke/install test requires a compiler.
      #: This is currently used by smoke tests to ensure a compiler is available
      #: to build a custom test code.
      test_requires_compiler = False
  
      #: List of test failures encountered during a smoke/install test run.
      test_failures = None
  
      #: TestSuite instance used to manage smoke/install tests for one or more
      #: specs.
      test_suite = None
  
      def __init__(self, spec):
          # this determines how the package should be built.
          self.spec = spec
  
          # Allow custom staging paths for packages
          self.path = None
  
          # Keep track of whether or not this package was installed from
          # a binary cache.
          self.installed_from_binary_cache = False
  
          # Ensure that only one of these two attributes are present
          if getattr(self, 'url', None) and getattr(self, 'urls', None):
              msg = "a package can have either a 'url' or a 'urls' attribute"
              msg += " [package '{0.name}' defines both]"
              raise ValueError(msg.format(self))
  
          # init internal variables
          self._stage = None
          self._fetcher = None
  
          # Set up timing variables
          self._fetch_time = 0.0
  
          if self.is_extension:
              spack.repo.get(self.extendee_spec)._check_extendable()
  
          super(PackageBase, self).__init__()
  
      @property
      def installed_upstream(self):
          if not hasattr(self, '_installed_upstream'):
              upstream, record = spack.store.db.query_by_spec_hash(
                  self.spec.dag_hash())
              self._installed_upstream = upstream
  
          return self._installed_upstream
  
      @classmethod
      def possible_dependencies(
              cls, transitive=True, expand_virtuals=True, deptype='all',
              visited=None, missing=None, virtuals=None):
          """Return dict of possible dependencies of this package.
  
          Args:
              transitive (bool or None): return all transitive dependencies if
                  True, only direct dependencies if False (default True)..
              expand_virtuals (bool or None): expand virtual dependencies into
                  all possible implementations (default True)
              deptype (str or tuple or None): dependency types to consider
              visited (dict or None): dict of names of dependencies visited so
                  far, mapped to their immediate dependencies' names.
              missing (dict or None): dict to populate with packages and their
                  *missing* dependencies.
              virtuals (set): if provided, populate with virtuals seen so far.
  
          Returns:
              (dict): dictionary mapping dependency names to *their*
                  immediate dependencies
  
          Each item in the returned dictionary maps a (potentially
          transitive) dependency of this package to its possible
          *immediate* dependencies. If ``expand_virtuals`` is ``False``,
          virtual package names wil be inserted as keys mapped to empty
          sets of dependencies.  Virtuals, if not expanded, are treated as
          though they have no immediate dependencies.
  
          Missing dependencies by default are ignored, but if a
          missing dict is provided, it will be populated with package names
          mapped to any dependencies they have that are in no
          repositories. This is only populated if transitive is True.
  
          Note: the returned dict *includes* the package itself.
  
          """
          deptype = spack.dependency.canonical_deptype(deptype)
  
          visited = {} if visited is None else visited
          missing = {} if missing is None else missing
  
          visited.setdefault(cls.name, set())
  
          for name, conditions in cls.dependencies.items():
              # check whether this dependency could be of the type asked for
              types = [dep.type for cond, dep in conditions.items()]
              types = set.union(*types)
              if not any(d in types for d in deptype):
                  continue
  
              # expand virtuals if enabled, otherwise just stop at virtuals
              if spack.repo.path.is_virtual(name):
                  if virtuals is not None:
                      virtuals.add(name)
                  if expand_virtuals:
                      providers = spack.repo.path.providers_for(name)
                      dep_names = [spec.name for spec in providers]
                  else:
                      visited.setdefault(cls.name, set()).add(name)
                      visited.setdefault(name, set())
                      continue
              else:
                  dep_names = [name]
  
              # add the dependency names to the visited dict
              visited.setdefault(cls.name, set()).update(set(dep_names))
  
              # recursively traverse dependencies
              for dep_name in dep_names:
                  if dep_name in visited:
                      continue
  
                  visited.setdefault(dep_name, set())
  
                  # skip the rest if not transitive
                  if not transitive:
                      continue
  
                  try:
                      dep_cls = spack.repo.path.get_pkg_class(dep_name)
                  except spack.repo.UnknownPackageError:
                      # log unknown packages
                      missing.setdefault(cls.name, set()).add(dep_name)
                      continue
  
                  dep_cls.possible_dependencies(
                      transitive, expand_virtuals, deptype, visited, missing,
                      virtuals)
  
          return visited
  
      def enum_constraints(self, visited=None):
          """Return transitive dependency constraints on this package."""
          if visited is None:
              visited = set()
          visited.add(self.name)
  
          names = []
          clauses = []
  
          for name in self.dependencies:
              if name not in visited and not spack.spec.Spec(name).virtual:
                  pkg = spack.repo.get(name)
                  dvis, dnames, dclauses = pkg.enum_constraints(visited)
                  visited |= dvis
                  names.extend(dnames)
                  clauses.extend(dclauses)
  
          return visited
  
      # package_dir and module are *class* properties (see PackageMeta),
      # but to make them work on instances we need these defs as well.
      @property
      def package_dir(self):
          """Directory where the package.py file lives."""
          return type(self).package_dir
  
      @property
      def module(self):
          """Module object that this package is defined in."""
          return type(self).module
  
      @property
      def namespace(self):
          """Spack namespace for the package, which identifies its repo."""
          return type(self).namespace
  
      @property
      def fullname(self):
          """Name of this package, including namespace: namespace.name."""
          return type(self).fullname
  
      @property
      def name(self):
          """Name of this package (the module without parent modules)."""
          return type(self).name
  
      @property
      def global_license_dir(self):
          """Returns the directory where global license files for all
             packages are stored."""
          return os.path.join(spack.paths.prefix, 'etc', 'spack', 'licenses')
  
      @property
      def global_license_file(self):
          """Returns the path where a global license file for this
             particular package should be stored."""
          if not self.license_files:
              return
          return os.path.join(self.global_license_dir, self.name,
                              os.path.basename(self.license_files[0]))
  
      @property
      def version(self):
          if not self.spec.versions.concrete:
              raise ValueError("Version requested for a package that"
                               " does not have a concrete version.")
          return self.spec.versions[0]
  
      @memoized
      def version_urls(self):
          """OrderedDict of explicitly defined URLs for versions of this package.
  
          Return:
             An OrderedDict (version -> URL) different versions of this
             package, sorted by version.
  
          A version's URL only appears in the result if it has an an
          explicitly defined ``url`` argument. So, this list may be empty
          if a package only defines ``url`` at the top level.
          """
          version_urls = collections.OrderedDict()
          for v, args in sorted(self.versions.items()):
              if 'url' in args:
                  version_urls[v] = args['url']
          return version_urls
  
      def nearest_url(self, version):
          """Finds the URL with the "closest" version to ``version``.
  
          This uses the following precedence order:
  
            1. Find the next lowest or equal version with a URL.
            2. If no lower URL, return the next *higher* URL.
            3. If no higher URL, return None.
  
          """
          version_urls = self.version_urls()
  
          if version in version_urls:
              return version_urls[version]
  
          last_url = None
          for v, u in self.version_urls().items():
              if v > version:
                  if last_url:
                      return last_url
              last_url = u
  
          return last_url
  
      def url_for_version(self, version):
          """Returns a URL from which the specified version of this package
          may be downloaded.
  
          version: class Version
              The version for which a URL is sought.
  
          See Class Version (version.py)
          """
          if not isinstance(version, Version):
              version = Version(version)
  
          # If we have a specific URL for this version, don't extrapolate.
          version_urls = self.version_urls()
          if version in version_urls:
              return version_urls[version]
  
          # If no specific URL, use the default, class-level URL
          url = getattr(self, 'url', None)
          urls = getattr(self, 'urls', [None])
          default_url = url or urls[0]
  
          # if no exact match AND no class-level default, use the nearest URL
          if not default_url:
              default_url = self.nearest_url(version)
  
              # if there are NO URLs to go by, then we can't do anything
              if not default_url:
                  raise NoURLError(self.__class__)
  
          return spack.url.substitute_version(
              default_url, self.url_version(version))
  
      def _make_resource_stage(self, root_stage, fetcher, resource):
          resource_stage_folder = self._resource_stage(resource)
          mirror_paths = spack.mirror.mirror_archive_paths(
              fetcher,
              os.path.join(self.name, "%s-%s" % (resource.name, self.version)))
          stage = ResourceStage(resource.fetcher,
                                root=root_stage,
                                resource=resource,
                                name=resource_stage_folder,
                                mirror_paths=mirror_paths,
                                path=self.path)
          return stage
  
      def _download_search(self):
          dynamic_fetcher = fs.from_list_url(self)
          return [dynamic_fetcher] if dynamic_fetcher else []
  
      def _make_root_stage(self, fetcher):
          # Construct a mirror path (TODO: get this out of package.py)
          mirror_paths = spack.mirror.mirror_archive_paths(
              fetcher,
              os.path.join(self.name, "%s-%s" % (self.name, self.version)),
              self.spec)
          # Construct a path where the stage should build..
          s = self.spec
          stage_name = "{0}{1}-{2}-{3}".format(stage_prefix, s.name, s.version,
                                               s.dag_hash())
  
          stage = Stage(fetcher, mirror_paths=mirror_paths, name=stage_name,
                        path=self.path, search_fn=self._download_search)
          return stage
  
      def _make_stage(self):
          # If it's a dev package (not transitively), use a DIY stage object
          dev_path_var = self.spec.variants.get('dev_path', None)
          if dev_path_var:
              return spack.stage.DIYStage(dev_path_var.value)
  
          # Construct a composite stage on top of the composite FetchStrategy
          composite_fetcher = self.fetcher
          composite_stage = StageComposite()
          resources = self._get_needed_resources()
          for ii, fetcher in enumerate(composite_fetcher):
              if ii == 0:
                  # Construct root stage first
                  stage = self._make_root_stage(fetcher)
              else:
                  # Construct resource stage
                  resource = resources[ii - 1]  # ii == 0 is root!
                  stage = self._make_resource_stage(composite_stage[0], fetcher,
                                                    resource)
              # Append the item to the composite
              composite_stage.append(stage)
  
          return composite_stage
  
      @property
      def stage(self):
          """Get the build staging area for this package.
  
          This automatically instantiates a ``Stage`` object if the package
          doesn't have one yet, but it does not create the Stage directory
          on the filesystem.
          """
          if not self.spec.versions.concrete:
              raise ValueError(
                  "Cannot retrieve stage for package without concrete version.")
          if self._stage is None:
              self._stage = self._make_stage()
          return self._stage
  
      @stage.setter
      def stage(self, stage):
          """Allow a stage object to be set to override the default."""
          self._stage = stage
  
      @property
      def env_path(self):
          """Return the build environment file path associated with staging."""
          # Backward compatibility: Return the name of an existing log path;
          # otherwise, return the current install env path name.
          old_filename = os.path.join(self.stage.path, 'spack-build.env')
          if os.path.exists(old_filename):
              return old_filename
          else:
              return os.path.join(self.stage.path, _spack_build_envfile)
  
      @property
      def env_mods_path(self):
          """
          Return the build environment modifications file path associated with
          staging.
          """
          return os.path.join(self.stage.path, _spack_build_envmodsfile)
  
      @property
      def metadata_dir(self):
          """Return the install metadata directory."""
          return spack.store.layout.metadata_path(self.spec)
  
      @property
      def install_env_path(self):
          """
          Return the build environment file path on successful installation.
          """
          # Backward compatibility: Return the name of an existing log path;
          # otherwise, return the current install env path name.
          old_filename = os.path.join(self.metadata_dir, 'build.env')
          if os.path.exists(old_filename):
              return old_filename
          else:
              return os.path.join(self.metadata_dir, _spack_build_envfile)
  
      @property
      def log_path(self):
          """Return the build log file path associated with staging."""
          # Backward compatibility: Return the name of an existing log path.
          for filename in ['spack-build.out', 'spack-build.txt']:
              old_log = os.path.join(self.stage.path, filename)
              if os.path.exists(old_log):
                  return old_log
  
          # Otherwise, return the current log path name.
          return os.path.join(self.stage.path, _spack_build_logfile)
  
      @property
      def phase_log_files(self):
          """Find sorted phase log files written to the staging directory"""
          logs_dir = os.path.join(self.stage.path, "spack-build-*-out.txt")
          log_files = glob.glob(logs_dir)
          log_files.sort()
          return log_files
  
      @property
      def install_log_path(self):
          """Return the build log file path on successful installation."""
          # Backward compatibility: Return the name of an existing install log.
          for filename in ['build.out', 'build.txt']:
              old_log = os.path.join(self.metadata_dir, filename)
              if os.path.exists(old_log):
                  return old_log
  
          # Otherwise, return the current install log path name.
          return os.path.join(self.metadata_dir, _spack_build_logfile)
  
      @property
      def configure_args_path(self):
          """Return the configure args file path associated with staging."""
          return os.path.join(self.stage.path, _spack_configure_argsfile)
  
      @property
      def times_log_path(self):
          """Return the times log json file."""
          return os.path.join(self.metadata_dir, _spack_times_log)
  
      @property
      def install_configure_args_path(self):
          """Return the configure args file path on successful installation."""
          return os.path.join(self.metadata_dir, _spack_configure_argsfile)
  
      @property
      def install_test_root(self):
          """Return the install test root directory."""
          return os.path.join(self.metadata_dir, 'test')
  
      def _make_fetcher(self):
          # Construct a composite fetcher that always contains at least
          # one element (the root package). In case there are resources
          # associated with the package, append their fetcher to the
          # composite.
          root_fetcher = fs.for_package_version(self, self.version)
          fetcher = fs.FetchStrategyComposite()  # Composite fetcher
          fetcher.append(root_fetcher)  # Root fetcher is always present
          resources = self._get_needed_resources()
          for resource in resources:
              fetcher.append(resource.fetcher)
          return fetcher
  
      @property
      def fetcher(self):
          if not self.spec.versions.concrete:
              raise ValueError("Cannot retrieve fetcher for"
                               " package without concrete version.")
          if not self._fetcher:
              self._fetcher = self._make_fetcher()
          return self._fetcher
  
      @fetcher.setter
      def fetcher(self, f):
          self._fetcher = f
  
      def dependencies_of_type(self, *deptypes):
          """Get dependencies that can possibly have these deptypes.
  
          This analyzes the package and determines which dependencies *can*
          be a certain kind of dependency. Note that they may not *always*
          be this kind of dependency, since dependencies can be optional,
          so something may be a build dependency in one configuration and a
          run dependency in another.
          """
          return dict(
              (name, conds) for name, conds in self.dependencies.items()
              if any(dt in self.dependencies[name][cond].type
                     for cond in conds for dt in deptypes))
  
      @property
      def extendee_spec(self):
          """
          Spec of the extendee of this package, or None if it is not an extension
          """
          if not self.extendees:
              return None
  
          deps = []
  
          # If the extendee is in the spec's deps already, return that.
          for dep in self.spec.traverse(deptypes=('link', 'run')):
              if dep.name in self.extendees:
                  deps.append(dep)
  
          # TODO: allow more than one active extendee.
          if deps:
              assert len(deps) == 1
              return deps[0]
  
          # if the spec is concrete already, then it extends something
          # that is an *optional* dependency, and the dep isn't there.
          if self.spec._concrete:
              return None
          else:
              # TODO: do something sane here with more than one extendee
              # If it's not concrete, then return the spec from the
              # extends() directive since that is all we know so far.
              spec, kwargs = next(iter(self.extendees.items()))
              return spec
  
      @property
      def extendee_args(self):
          """
          Spec of the extendee of this package, or None if it is not an extension
          """
          if not self.extendees:
              return None
  
          # TODO: allow multiple extendees.
          name = next(iter(self.extendees))
          return self.extendees[name][1]
  
      @property
      def is_extension(self):
          # if it is concrete, it's only an extension if it actually
          # dependes on the extendee.
          if self.spec._concrete:
              return self.extendee_spec is not None
          else:
              # If not, then it's an extension if it *could* be an extension
              return bool(self.extendees)
  
      def extends(self, spec):
          '''
          Returns True if this package extends the given spec.
  
          If ``self.spec`` is concrete, this returns whether this package extends
          the given spec.
  
          If ``self.spec`` is not concrete, this returns whether this package may
          extend the given spec.
          '''
          if spec.name not in self.extendees:
              return False
          s = self.extendee_spec
          return s and spec.satisfies(s)
  
      def is_activated(self, view):
          """Return True if package is activated."""
          if not self.is_extension:
              raise ValueError(
                  "is_activated called on package that is not an extension.")
          if self.extendee_spec.package.installed_upstream:
              # If this extends an upstream package, it cannot be activated for
              # it. This bypasses construction of the extension map, which can
              # can fail when run in the context of a downstream Spack instance
              return False
          extensions_layout = view.extensions_layout
          exts = extensions_layout.extension_map(self.extendee_spec)
          return (self.name in exts) and (exts[self.name] == self.spec)
  
      def provides(self, vpkg_name):
          """
          True if this package provides a virtual package with the specified name
          """
          return any(
              any(self.spec.satisfies(c) for c in constraints)
              for s, constraints in self.provided.items() if s.name == vpkg_name
          )
  
      @property
      def virtuals_provided(self):
          """
          virtual packages provided by this package with its spec
          """
          return [vspec for vspec, constraints in self.provided.items()
                  if any(self.spec.satisfies(c) for c in constraints)]
  
      @property
      def installed(self):
          """Installation status of a package.
  
          Returns:
              True if the package has been installed, False otherwise.
          """
          try:
              # If the spec is in the DB, check the installed
              # attribute of the record
              return spack.store.db.get_record(self.spec).installed
          except KeyError:
              # If the spec is not in the DB, the method
              #  above raises a Key error
              return False
  
      @property
      def prefix(self):
          """Get the prefix into which this package should be installed."""
          return self.spec.prefix
  
      @property  # type: ignore[misc]
      @memoized
      def compiler(self):
          """Get the spack.compiler.Compiler object used to build this package"""
          if not self.spec.concrete:
              raise ValueError("Can only get a compiler for a concrete package.")
  
          return spack.compilers.compiler_for_spec(self.spec.compiler,
                                                   self.spec.architecture)
  
      def url_version(self, version):
          """
          Given a version, this returns a string that should be substituted
          into the package's URL to download that version.
  
          By default, this just returns the version string. Subclasses may need
          to override this, e.g. for boost versions where you need to ensure that
          there are _'s in the download URL.
          """
          return str(version)
  
      def remove_prefix(self):
          """
          Removes the prefix for a package along with any empty parent
          directories
          """
          spack.store.layout.remove_install_directory(self.spec)
  
      @property
      def download_instr(self):
          """
          Defines the default manual download instructions.  Packages can
          override the property to provide more information.
  
          Returns:
              (str):  default manual download instructions
          """
          required = ('Manual download is required for {0}. '
                      .format(self.spec.name) if self.manual_download else '')
          return ('{0}Refer to {1} for download instructions.'
                  .format(required, self.spec.package.homepage))
  
      def do_fetch(self, mirror_only=False):
          """
          Creates a stage directory and downloads the tarball for this package.
          Working directory will be set to the stage directory.
          """
          if not self.has_code or self.spec.external:
              tty.debug('No fetch required for {0}'.format(self.name))
              return
  
          checksum = spack.config.get('config:checksum')
          fetch = self.stage.managed_by_spack
          if checksum and fetch and self.version not in self.versions:
              tty.warn("There is no checksum on file to fetch %s safely." %
                       self.spec.cformat('{name}{@version}'))
  
              # Ask the user whether to skip the checksum if we're
              # interactive, but just fail if non-interactive.
              ck_msg = "Add a checksum or use --no-checksum to skip this check."
              ignore_checksum = False
              if sys.stdout.isatty():
                  ignore_checksum = tty.get_yes_or_no("  Fetch anyway?",
                                                      default=False)
                  if ignore_checksum:
                      tty.debug('Fetching with no checksum. {0}'
                                .format(ck_msg))
  
              if not ignore_checksum:
                  raise FetchError("Will not fetch %s" %
                                   self.spec.format('{name}{@version}'), ck_msg)
  
          deprecated = spack.config.get('config:deprecated')
          if not deprecated and self.versions.get(
                  self.version, {}).get('deprecated', False):
              tty.warn("{0} is deprecated and may be removed in a future Spack "
                       "release.".format(
                           self.spec.format('{name}{@version}')))
  
              # Ask the user whether to install deprecated version if we're
              # interactive, but just fail if non-interactive.
              dp_msg = ("If you are willing to be a maintainer for this version "
                        "of the package, submit a PR to remove `deprecated=False"
                        "`, or use `--deprecated` to skip this check.")
              ignore_deprecation = False
              if sys.stdout.isatty():
                  ignore_deprecation = tty.get_yes_or_no("  Fetch anyway?",
                                                         default=False)
  
                  if ignore_deprecation:
                      tty.debug("Fetching deprecated version. {0}".format(
                          dp_msg))
  
              if not ignore_deprecation:
                  raise FetchError("Will not fetch {0}".format(
                      self.spec.format('{name}{@version}')), dp_msg)
  
          self.stage.create()
          err_msg = None if not self.manual_download else self.download_instr
          start_time = time.time()
          self.stage.fetch(mirror_only, err_msg=err_msg)
          self._fetch_time = time.time() - start_time
  
          if checksum and self.version in self.versions:
              self.stage.check()
  
          self.stage.cache_local()
  
          for patch in self.spec.patches:
              patch.fetch()
              if patch.stage:
                  patch.stage.cache_local()
  
      def do_stage(self, mirror_only=False):
          """Unpacks and expands the fetched tarball."""
          # Always create the stage directory at this point.  Why?  A no-code
          # package may want to use the installation process to install metadata.
          self.stage.create()
  
          # Fetch/expand any associated code.
          if self.has_code:
              self.do_fetch(mirror_only)
              self.stage.expand_archive()
  
              if not os.listdir(self.stage.path):
                  raise FetchError("Archive was empty for %s" % self.name)
          else:
              # Support for post-install hooks requires a stage.source_path
              fsys.mkdirp(self.stage.source_path)
  
      def do_patch(self):
          """Applies patches if they haven't been applied already."""
          if not self.spec.concrete:
              raise ValueError("Can only patch concrete packages.")
  
          # Kick off the stage first.  This creates the stage.
          self.do_stage()
  
          # Package can add its own patch function.
          has_patch_fun = hasattr(self, 'patch') and callable(self.patch)
  
          # Get the patches from the spec (this is a shortcut for the MV-variant)
          patches = self.spec.patches
  
          # If there are no patches, note it.
          if not patches and not has_patch_fun:
              tty.msg('No patches needed for {0}'.format(self.name))
              return
  
          # Construct paths to special files in the archive dir used to
          # keep track of whether patches were successfully applied.
          archive_dir = self.stage.source_path
          good_file = os.path.join(archive_dir, '.spack_patched')
          no_patches_file = os.path.join(archive_dir, '.spack_no_patches')
          bad_file = os.path.join(archive_dir, '.spack_patch_failed')
  
          # If we encounter an archive that failed to patch, restage it
          # so that we can apply all the patches again.
          if os.path.isfile(bad_file):
              tty.debug('Patching failed last time. Restaging.')
              self.stage.restage()
  
          # If this file exists, then we already applied all the patches.
          if os.path.isfile(good_file):
              tty.msg('Already patched {0}'.format(self.name))
              return
          elif os.path.isfile(no_patches_file):
              tty.msg('No patches needed for {0}'.format(self.name))
              return
  
          # Apply all the patches for specs that match this one
          patched = False
          for patch in patches:
              try:
                  with fsys.working_dir(self.stage.source_path):
                      patch.apply(self.stage)
                  tty.msg('Applied patch {0}'.format(patch.path_or_url))
                  patched = True
              except spack.error.SpackError as e:
                  tty.debug(e)
  
                  # Touch bad file if anything goes wrong.
                  tty.msg('Patch %s failed.' % patch.path_or_url)
                  fsys.touch(bad_file)
                  raise
  
          if has_patch_fun:
              try:
                  with fsys.working_dir(self.stage.source_path):
                      self.patch()
                  tty.msg('Ran patch() for {0}'.format(self.name))
                  patched = True
              except spack.multimethod.NoSuchMethodError:
                  # We are running a multimethod without a default case.
                  # If there's no default it means we don't need to patch.
                  if not patched:
                      # if we didn't apply a patch from a patch()
                      # directive, AND the patch function didn't apply, say
                      # no patches are needed.  Otherwise, we already
                      # printed a message for each patch.
                      tty.msg('No patches needed for {0}'.format(self.name))
              except spack.error.SpackError as e:
                  tty.debug(e)
  
                  # Touch bad file if anything goes wrong.
                  tty.msg('patch() function failed for {0}'.format(self.name))
                  fsys.touch(bad_file)
                  raise
  
          # Get rid of any old failed file -- patches have either succeeded
          # or are not needed.  This is mostly defensive -- it's needed
          # if the restage() method doesn't clean *everything* (e.g., for a repo)
          if os.path.isfile(bad_file):
              os.remove(bad_file)
  
          # touch good or no patches file so that we skip next time.
          if patched:
              fsys.touch(good_file)
          else:
              fsys.touch(no_patches_file)
  
      @classmethod
      def all_patches(cls):
          """Retrieve all patches associated with the package.
  
          Retrieves patches on the package itself as well as patches on the
          dependencies of the package."""
          patches = []
          for _, patch_list in cls.patches.items():
              for patch in patch_list:
                  patches.append(patch)
  
          pkg_deps = cls.dependencies
          for dep_name in pkg_deps:
              for _, dependency in pkg_deps[dep_name].items():
                  for _, patch_list in dependency.patches.items():
                      for patch in patch_list:
                          patches.append(patch)
  
          return patches
  
      def content_hash(self, content=None):
          """Create a hash based on the sources and logic used to build the
          package. This includes the contents of all applied patches and the
          contents of applicable functions in the package subclass."""
          if not self.spec.concrete:
              err_msg = ("Cannot invoke content_hash on a package"
                         " if the associated spec is not concrete")
              raise spack.error.SpackError(err_msg)
  
          hash_content = list()
          try:
              source_id = fs.for_package_version(self, self.version).source_id()
          except fs.ExtrapolationError:
              source_id = None
          if not source_id:
              # TODO? in cases where a digest or source_id isn't available,
              # should this attempt to download the source and set one? This
              # probably only happens for source repositories which are
              # referenced by branch name rather than tag or commit ID.
              env = spack.environment.active_environment()
              from_local_sources = env and env.is_develop(self.spec)
              if not self.spec.external and not from_local_sources:
                  message = 'Missing a source id for {s.name}@{s.version}'
                  tty.warn(message.format(s=self))
              hash_content.append(''.encode('utf-8'))
          else:
              hash_content.append(source_id.encode('utf-8'))
          hash_content.extend(':'.join((p.sha256, str(p.level))).encode('utf-8')
                              for p in self.spec.patches)
          hash_content.append(package_hash(self.spec, source=content).encode('utf-8'))
  
          b32_hash = base64.b32encode(
              hashlib.sha256(bytes().join(
                  sorted(hash_content))).digest()).lower()
  
          # convert from bytes if running python 3
          if sys.version_info[0] >= 3:
              b32_hash = b32_hash.decode('utf-8')
  
          return b32_hash
  
      def _has_make_target(self, target):
          """Checks to see if 'target' is a valid target in a Makefile.
  
          Parameters:
              target (str): the target to check for
  
          Returns:
              bool: True if 'target' is found, else False
          """
          # Prevent altering LC_ALL for 'make' outside this function
          make = copy.deepcopy(inspect.getmodule(self).make)
  
          # Use English locale for missing target message comparison
          make.add_default_env('LC_ALL', 'C')
  
          # Check if we have a Makefile
          for makefile in ['GNUmakefile', 'Makefile', 'makefile']:
              if os.path.exists(makefile):
                  break
          else:
              tty.debug('No Makefile found in the build directory')
              return False
  
          # Check if 'target' is a valid target.
          #
          # `make -n target` performs a "dry run". It prints the commands that
          # would be run but doesn't actually run them. If the target does not
          # exist, you will see one of the following error messages:
          #
          # GNU Make:
          #     make: *** No rule to make target `test'.  Stop.
          #           *** No rule to make target 'test'.  Stop.
          #
          # BSD Make:
          #     make: don't know how to make test. Stop
          missing_target_msgs = [
              "No rule to make target `{0}'.  Stop.",
              "No rule to make target '{0}'.  Stop.",
              "don't know how to make {0}. Stop",
          ]
  
          kwargs = {
              'fail_on_error': False,
              'output': os.devnull,
              'error': str,
          }
  
          stderr = make('-n', target, **kwargs)
  
          for missing_target_msg in missing_target_msgs:
              if missing_target_msg.format(target) in stderr:
                  tty.debug("Target '{0}' not found in {1}"
                            .format(target, makefile))
                  return False
  
          return True
  
      def _if_make_target_execute(self, target, *args, **kwargs):
          """Runs ``make target`` if 'target' is a valid target in the Makefile.
  
          Parameters:
              target (str): the target to potentially execute
          """
          if self._has_make_target(target):
              # Execute target
              inspect.getmodule(self).make(target, *args, **kwargs)
  
      def _has_ninja_target(self, target):
          """Checks to see if 'target' is a valid target in a Ninja build script.
  
          Parameters:
              target (str): the target to check for
  
          Returns:
              bool: True if 'target' is found, else False
          """
          ninja = inspect.getmodule(self).ninja
  
          # Check if we have a Ninja build script
          if not os.path.exists('build.ninja'):
              tty.debug('No Ninja build script found in the build directory')
              return False
  
          # Get a list of all targets in the Ninja build script
          # https://ninja-build.org/manual.html#_extra_tools
          all_targets = ninja('-t', 'targets', 'all', output=str).split('\n')
  
          # Check if 'target' is a valid target
          matches = [line for line in all_targets
                     if line.startswith(target + ':')]
  
          if not matches:
              tty.debug("Target '{0}' not found in build.ninja"
                        .format(target))
              return False
  
          return True
  
      def _if_ninja_target_execute(self, target, *args, **kwargs):
          """Runs ``ninja target`` if 'target' is a valid target in the Ninja
          build script.
  
          Parameters:
              target (str): the target to potentially execute
          """
          if self._has_ninja_target(target):
              # Execute target
              inspect.getmodule(self).ninja(target, *args, **kwargs)
  
      def _get_needed_resources(self):
          resources = []
          # Select the resources that are needed for this build
          if self.spec.concrete:
              for when_spec, resource_list in self.resources.items():
                  if when_spec in self.spec:
                      resources.extend(resource_list)
          else:
              for when_spec, resource_list in self.resources.items():
                  # Note that variant checking is always strict for specs where
                  # the name is not specified. But with strict variant checking,
                  # only variants mentioned in 'other' are checked. Here we only
                  # want to make sure that no constraints in when_spec
                  # conflict with the spec, so we need to invoke
                  # when_spec.satisfies(self.spec) vs.
                  # self.spec.satisfies(when_spec)
                  if when_spec.satisfies(self.spec, strict=False):
                      resources.extend(resource_list)
          # Sorts the resources by the length of the string representing their
          # destination. Since any nested resource must contain another
          # resource's name in its path, it seems that should work
          resources = sorted(resources, key=lambda res: len(res.destination))
          return resources
  
      def _resource_stage(self, resource):
          pieces = ['resource', resource.name, self.spec.dag_hash()]
          resource_stage_folder = '-'.join(pieces)
          return resource_stage_folder
  
      @contextlib.contextmanager
      def _stage_and_write_lock(self):
          """Prefix lock nested in a stage."""
          with self.stage:
              with spack.store.db.prefix_write_lock(self.spec):
                  yield
  
      def do_install(self, **kwargs):
          """Called by commands to install a package and or its dependencies.
  
          Package implementations should override install() to describe
          their build process.
  
          Args:
              cache_only (bool): Fail if binary package unavailable.
              dirty (bool): Don't clean the build environment before installing.
              explicit (bool): True if package was explicitly installed, False
                  if package was implicitly installed (as a dependency).
              fail_fast (bool): Fail if any dependency fails to install;
                  otherwise, the default is to install as many dependencies as
                  possible (i.e., best effort installation).
              fake (bool): Don't really build; install fake stub files instead.
              force (bool): Install again, even if already installed.
              install_deps (bool): Install dependencies before installing this
                  package
              install_source (bool): By default, source is not installed, but
                  for debugging it might be useful to keep it around.
              keep_prefix (bool): Keep install prefix on failure. By default,
                  destroys it.
              keep_stage (bool): By default, stage is destroyed only if there
                  are no exceptions during build. Set to True to keep the stage
                  even with exceptions.
              restage (bool): Force spack to restage the package source.
              skip_patch (bool): Skip patch stage of build if True.
              stop_before (InstallPhase): stop execution before this
                  installation phase (or None)
              stop_at (InstallPhase): last installation phase to be executed
                  (or None)
              tests (bool or list or set): False to run no tests, True to test
                  all packages, or a list of package names to run tests for some
              use_cache (bool): Install from binary package, if available.
              verbose (bool): Display verbose build output (by default,
                  suppresses it)
          """
          # Non-transitive dev specs need to keep the dev stage and be built from
          # source every time. Transitive ones just need to be built from source.
          dev_path_var = self.spec.variants.get('dev_path', None)
          if dev_path_var:
              kwargs['keep_stage'] = True
  
          builder = PackageInstaller([(self, kwargs)])
          builder.install()
  
      def cache_extra_test_sources(self, srcs):
          """Copy relative source paths to the corresponding install test subdir
  
          This method is intended as an optional install test setup helper for
          grabbing source files/directories during the installation process and
          copying them to the installation test subdirectory for subsequent use
          during install testing.
  
          Args:
              srcs (str or list): relative path for files and or
                  subdirectories located in the staged source path that are to
                  be copied to the corresponding location(s) under the install
                  testing directory.
          """
          paths = [srcs] if isinstance(srcs, six.string_types) else srcs
  
          for path in paths:
              src_path = os.path.join(self.stage.source_path, path)
              dest_path = os.path.join(self.install_test_root, path)
              if os.path.isdir(src_path):
                  fsys.install_tree(src_path, dest_path)
              else:
                  fsys.mkdirp(os.path.dirname(dest_path))
                  fsys.copy(src_path, dest_path)
  
      def do_test(self, dirty=False, externals=False):
          if self.test_requires_compiler:
              compilers = spack.compilers.compilers_for_spec(
                  self.spec.compiler, arch_spec=self.spec.architecture)
              if not compilers:
                  tty.error('Skipping tests for package %s\n' %
                            self.spec.format('{name}-{version}-{hash:7}') +
                            'Package test requires missing compiler %s' %
                            self.spec.compiler)
                  return
  
          # Clear test failures
          self.test_failures = []
          self.test_log_file = self.test_suite.log_file_for_spec(self.spec)
          self.tested_file = self.test_suite.tested_file_for_spec(self.spec)
          fsys.touch(self.test_log_file)  # Otherwise log_parse complains
  
          kwargs = {
              'dirty': dirty, 'fake': False, 'context': 'test',
              'externals': externals
          }
          if tty.is_verbose():
              kwargs['verbose'] = True
          spack.build_environment.start_build_process(self, test_process, kwargs)
  
      def test(self):
          # Defer tests to virtual and concrete packages
          pass
  
      def run_test(self, exe, options=[], expected=[], status=0,
                   installed=False, purpose='', skip_missing=False,
                   work_dir=None):
          """Run the test and confirm the expected results are obtained
  
          Log any failures and continue, they will be re-raised later
  
          Args:
              exe (str): the name of the executable
              options (str or list): list of options to pass to the runner
              expected (str or list): list of expected output strings.
                  Each string is a regex expected to match part of the output.
              status (int or list): possible passing status values
                  with 0 meaning the test is expected to succeed
              installed (bool): if ``True``, the executable must be in the
                  install prefix
              purpose (str): message to display before running test
              skip_missing (bool): skip the test if the executable is not
                  in the install prefix bin directory or the provided work_dir
              work_dir (str or None): path to the smoke test directory
          """
          wdir = '.' if work_dir is None else work_dir
          with fsys.working_dir(wdir, create=True):
              try:
                  runner = which(exe)
                  if runner is None and skip_missing:
                      return
                  assert runner is not None, \
                      "Failed to find executable '{0}'".format(exe)
  
                  self._run_test_helper(
                      runner, options, expected, status, installed, purpose)
                  print("PASSED")
                  return True
              except BaseException as e:
                  # print a summary of the error to the log file
                  # so that cdash and junit reporters know about it
                  exc_type, _, tb = sys.exc_info()
                  print('FAILED: {0}'.format(e))
                  import traceback
  
                  # remove the current call frame to exclude the extract_stack
                  # call from the error
                  stack = traceback.extract_stack()[:-1]
  
                  # Package files have a line added at import time, so we re-read
                  # the file to make line numbers match. We have to subtract two
                  # from the line number because the original line number is
                  # inflated once by the import statement and the lines are
                  # displaced one by the import statement.
                  for i, entry in enumerate(stack):
                      filename, lineno, function, text = entry
                      if spack.repo.is_package_file(filename):
                          with open(filename, 'r') as f:
                              lines = f.readlines()
                          new_lineno = lineno - 2
                          text = lines[new_lineno]
                          stack[i] = (filename, new_lineno, function, text)
  
                  # Format the stack to print and print it
                  out = traceback.format_list(stack)
                  for line in out:
                      print(line.rstrip('\n'))
  
                  if exc_type is spack.util.executable.ProcessError:
                      out = six.StringIO()
                      spack.build_environment.write_log_summary(
                          out, 'test', self.test_log_file, last=1)
                      m = out.getvalue()
                  else:
                      # We're below the package context, so get context from
                      # stack instead of from traceback.
                      # The traceback is truncated here, so we can't use it to
                      # traverse the stack.
                      m = '\n'.join(
                          spack.build_environment.get_package_context(tb)
                      )
  
                  exc = e  # e is deleted after this block
  
                  # If we fail fast, raise another error
                  if spack.config.get('config:fail_fast', False):
                      raise TestFailure([(exc, m)])
                  else:
                      self.test_failures.append((exc, m))
                  return False
  
      def _run_test_helper(self, runner, options, expected, status, installed,
                           purpose):
          status = [status] if isinstance(status, six.integer_types) else status
          expected = [expected] if isinstance(expected, six.string_types) else \
              expected
          options = [options] if isinstance(options, six.string_types) else \
              options
  
          if purpose:
              tty.msg(purpose)
          else:
              tty.debug('test: {0}: expect command status in {1}'
                        .format(runner.name, status))
  
          if installed:
              msg = "Executable '{0}' expected in prefix".format(runner.name)
              msg += ", found in {0} instead".format(runner.path)
              assert runner.path.startswith(self.spec.prefix), msg
  
          try:
              output = runner(*options, output=str.split, error=str.split)
  
              assert 0 in status, \
                  'Expected {0} execution to fail'.format(runner.name)
          except ProcessError as err:
              output = str(err)
              match = re.search(r'exited with status ([0-9]+)', output)
              if not (match and int(match.group(1)) in status):
                  raise
  
          for check in expected:
              cmd = ' '.join([runner.name] + options)
              msg = "Expected '{0}' to match output of `{1}`".format(check, cmd)
              msg += '\n\nOutput: {0}'.format(output)
              assert re.search(check, output), msg
  
      def unit_test_check(self):
          """Hook for unit tests to assert things about package internals.
  
          Unit tests can override this function to perform checks after
          ``Package.install`` and all post-install hooks run, but before
          the database is updated.
  
          The overridden function may indicate that the install procedure
          should terminate early (before updating the database) by
          returning ``False`` (or any value such that ``bool(result)`` is
          ``False``).
  
          Return:
              (bool): ``True`` to continue, ``False`` to skip ``install()``
          """
          return True
  
      def sanity_check_prefix(self):
          """This function checks whether install succeeded."""
  
          def check_paths(path_list, filetype, predicate):
              if isinstance(path_list, six.string_types):
                  path_list = [path_list]
  
              for path in path_list:
                  abs_path = os.path.join(self.prefix, path)
                  if not predicate(abs_path):
                      raise InstallError(
                          "Install failed for %s. No such %s in prefix: %s" %
                          (self.name, filetype, path))
  
          check_paths(self.sanity_check_is_file, 'file', os.path.isfile)
          check_paths(self.sanity_check_is_dir, 'directory', os.path.isdir)
  
          installed = set(os.listdir(self.prefix))
          installed.difference_update(
              spack.store.layout.hidden_file_regexes)
          if not installed:
              raise InstallError(
                  "Install failed for %s.  Nothing was installed!" % self.name)
  
      def apply_macos_rpath_fixups(self):
          """On Darwin, make installed libraries more easily relocatable.
  
          Some build systems (handrolled, autotools, makefiles) can set their own
          rpaths that are duplicated by spack's compiler wrapper. This fixup
          interrogates, and postprocesses if necessary, all libraries installed
          by the code.
  
          It should be added as a @run_after to packaging systems (or individual
          packages) that do not install relocatable libraries by default.
          """
          if 'platform=darwin' not in self.spec:
              return
  
          from spack.relocate import fixup_macos_rpaths
          fixup_macos_rpaths(self.spec)
  
      @property
      def build_log_path(self):
          """
          Return the expected (or current) build log file path.  The path points
          to the staging build file until the software is successfully installed,
          when it points to the file in the installation directory.
          """
          return self.install_log_path if self.installed else self.log_path
  
      @classmethod
      def inject_flags(cls, name, flags):
          """
          flag_handler that injects all flags through the compiler wrapper.
          """
          return (flags, None, None)
  
      @classmethod
      def env_flags(cls, name, flags):
          """
          flag_handler that adds all flags to canonical environment variables.
          """
          return (None, flags, None)
  
      @classmethod
      def build_system_flags(cls, name, flags):
          """
          flag_handler that passes flags to the build system arguments.  Any
          package using `build_system_flags` must also implement
          `flags_to_build_system_args`, or derive from a class that
          implements it.  Currently, AutotoolsPackage and CMakePackage
          implement it.
          """
          return (None, None, flags)
  
      def _get_legacy_environment_method(self, method_name):
          legacy_fn = getattr(self, method_name, None)
          name_prefix = method_name.split('_environment')[0]
          if legacy_fn:
              msg = '[DEPRECATED METHOD]\n"{0}" ' \
                    'still defines the deprecated method "{1}" ' \
                    '[should be split into "{2}_build_environment" and ' \
                    '"{2}_run_environment"]'
              tty.debug(msg.format(self.name, method_name, name_prefix))
          return legacy_fn
  
      def setup_build_environment(self, env):
          """Sets up the build environment for a package.
  
          This method will be called before the current package prefix exists in
          Spack's store.
  
          Args:
              env (spack.util.environment.EnvironmentModifications): environment
                  modifications to be applied when the package is built. Package authors
                  can call methods on it to alter the build environment.
          """
          legacy_fn = self._get_legacy_environment_method('setup_environment')
          if legacy_fn:
              _ = spack.util.environment.EnvironmentModifications()
              legacy_fn(env, _)
  
      def setup_run_environment(self, env):
          """Sets up the run environment for a package.
  
          Args:
              env (spack.util.environment.EnvironmentModifications): environment
                  modifications to be applied when the package is run. Package authors
                  can call methods on it to alter the run environment.
          """
          legacy_fn = self._get_legacy_environment_method('setup_environment')
          if legacy_fn:
              _ = spack.util.environment.EnvironmentModifications()
              legacy_fn(_, env)
  
      def setup_dependent_build_environment(self, env, dependent_spec):
          """Sets up the build environment of packages that depend on this one.
  
          This is similar to ``setup_build_environment``, but it is used to
          modify the build 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.
  
          This method will be called before the dependent package prefix exists
          in Spack's store.
  
          Examples:
              1. Installing python modules generally requires ``PYTHONPATH``
              to point to the ``lib/pythonX.Y/site-packages`` directory in the
              module's install prefix. This method could be used to set that
              variable.
  
          Args:
              env (spack.util.environment.EnvironmentModifications): environment
                  modifications to be applied when the dependent package is built.
                  Package authors can call methods on it to alter the build environment.
  
              dependent_spec (spack.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``
          """
          legacy_fn = self._get_legacy_environment_method(
              'setup_dependent_environment'
          )
          if legacy_fn:
              _ = spack.util.environment.EnvironmentModifications()
              legacy_fn(env, _, dependent_spec)
  
      def setup_dependent_run_environment(self, env, dependent_spec):
          """Sets up the run environment of packages that depend on this one.
  
          This is similar to ``setup_run_environment``, but it is used to
          modify the run 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 run-time settings
          for dependencies.
  
          Args:
              env (spack.util.environment.EnvironmentModifications): environment
                  modifications to be applied when the dependent package is run.
                  Package authors can call methods on it to alter the build environment.
  
              dependent_spec (spack.spec.Spec): The spec of the dependent package
                  about to be run. This allows the extendee (self) to query
                  the dependent's state. Note that *this* package's spec is
                  available as ``self.spec``
          """
          legacy_fn = self._get_legacy_environment_method(
              'setup_dependent_environment'
          )
          if legacy_fn:
              _ = spack.util.environment.EnvironmentModifications()
              legacy_fn(_, env, dependent_spec)
  
      def setup_dependent_package(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.
  
          Examples:
  
          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 name 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 (spack.package.PackageBase.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 (spack.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``.
          """
          pass
  
      flag_handler = inject_flags
      # The flag handler method is called for each of the allowed compiler flags.
      # It returns a triple of inject_flags, env_flags, build_system_flags.
      # The flags returned as inject_flags are injected through the spack
      #  compiler wrappers.
      # The flags returned as env_flags are passed to the build system through
      #  the environment variables of the same name.
      # The flags returned as build_system_flags are passed to the build system
      #  package subclass to be turned into the appropriate part of the standard
      #  arguments. This is implemented for build system classes where
      #  appropriate and will otherwise raise a NotImplementedError.
  
      def flags_to_build_system_args(self, flags):
          # Takes flags as a dict name: list of values
          if any(v for v in flags.values()):
              msg = 'The {0} build system'.format(self.__class__.__name__)
              msg += ' cannot take command line arguments for compiler flags'
              raise NotImplementedError(msg)
  
      @staticmethod
      def uninstall_by_spec(spec, force=False, deprecator=None):
          if not os.path.isdir(spec.prefix):
              # prefix may not exist, but DB may be inconsistent. Try to fix by
              # removing, but omit hooks.
              specs = spack.store.db.query(spec, installed=True)
              if specs:
                  if deprecator:
                      spack.store.db.deprecate(specs[0], deprecator)
                      tty.debug('Deprecating stale DB entry for {0}'
                                .format(spec.short_spec))
                  else:
                      spack.store.db.remove(specs[0])
                      tty.debug('Removed stale DB entry for {0}'
                                .format(spec.short_spec))
                  return
              else:
                  raise InstallError(str(spec) + " is not installed.")
  
          if not force:
              dependents = spack.store.db.installed_relatives(
                  spec, 'parents', True)
              if dependents:
                  raise PackageStillNeededError(spec, dependents)
  
          # Try to get the package for the spec
          try:
              pkg = spec.package
          except spack.repo.UnknownEntityError:
              pkg = None
  
          # Pre-uninstall hook runs first.
          with spack.store.db.prefix_write_lock(spec):
  
              if pkg is not None:
                  try:
                      spack.hooks.pre_uninstall(spec)
                  except Exception as error:
                      if force:
                          error_msg = (
                              "One or more pre_uninstall hooks have failed"
                              " for {0}, but Spack is continuing with the"
                              " uninstall".format(str(spec)))
                          if isinstance(error, spack.error.SpackError):
                              error_msg += (
                                  "\n\nError message: {0}".format(str(error)))
                          tty.warn(error_msg)
                          # Note that if the uninstall succeeds then we won't be
                          # seeing this error again and won't have another chance
                          # to run the hook.
                      else:
                          raise
  
              # Uninstalling in Spack only requires removing the prefix.
              if not spec.external:
                  msg = 'Deleting package prefix [{0}]'
                  tty.debug(msg.format(spec.short_spec))
                  # test if spec is already deprecated, not whether we want to
                  # deprecate it now
                  deprecated = bool(spack.store.db.deprecator(spec))
                  spack.store.layout.remove_install_directory(spec, deprecated)
              # Delete DB entry
              if deprecator:
                  msg = 'deprecating DB entry [{0}] in favor of [{1}]'
                  tty.debug(msg.format(spec.short_spec, deprecator.short_spec))
                  spack.store.db.deprecate(spec, deprecator)
              else:
                  msg = 'Deleting DB entry [{0}]'
                  tty.debug(msg.format(spec.short_spec))
                  spack.store.db.remove(spec)
  
          if pkg is not None:
              try:
                  spack.hooks.post_uninstall(spec)
              except Exception:
                  # If there is a failure here, this is our only chance to do
                  # something about it: at this point the Spec has been removed
                  # from the DB and prefix, so the post-uninstallation hooks
                  # will not have another chance to run.
                  error_msg = (
                      "One or more post-uninstallation hooks failed for"
                      " {0}, but the prefix has been removed (if it is not"
                      " external).".format(str(spec)))
                  tb_msg = traceback.format_exc()
                  error_msg += "\n\nThe error:\n\n{0}".format(tb_msg)
                  tty.warn(error_msg)
  
          tty.msg('Successfully uninstalled {0}'.format(spec.short_spec))
  
      def do_uninstall(self, force=False):
          """Uninstall this package by spec."""
          # delegate to instance-less method.
          Package.uninstall_by_spec(self.spec, force)
  
      def do_deprecate(self, deprecator, link_fn):
          """Deprecate this package in favor of deprecator spec"""
          spec = self.spec
  
          # Check whether package to deprecate has active extensions
          if self.extendable:
              view = spack.filesystem_view.YamlFilesystemView(spec.prefix,
                                                              spack.store.layout)
              active_exts = view.extensions_layout.extension_map(spec).values()
              if active_exts:
                  short = spec.format('{name}/{hash:7}')
                  m = "Spec %s has active extensions\n" % short
                  for active in active_exts:
                      m += '        %s\n' % active.format('{name}/{hash:7}')
                      m += "Deactivate extensions before deprecating %s" % short
                  tty.die(m)
  
          # Check whether package to deprecate is an active extension
          if self.is_extension:
              extendee = self.extendee_spec
              view = spack.filesystem_view.YamlFilesystemView(extendee.prefix,
                                                              spack.store.layout)
  
              if self.is_activated(view):
                  short = spec.format('{name}/{hash:7}')
                  short_ext = extendee.format('{name}/{hash:7}')
                  msg = "Spec %s is an active extension of %s\n" % (short,
                                                                    short_ext)
                  msg += "Deactivate %s to be able to deprecate it" % short
                  tty.die(msg)
  
          # Install deprecator if it isn't installed already
          if not spack.store.db.query(deprecator):
              deprecator.package.do_install()
  
          old_deprecator = spack.store.db.deprecator(spec)
          if old_deprecator:
              # Find this specs yaml file from its old deprecation
              self_yaml = spack.store.layout.deprecated_file_path(spec,
                                                                  old_deprecator)
          else:
              self_yaml = spack.store.layout.spec_file_path(spec)
  
          # copy spec metadata to "deprecated" dir of deprecator
          depr_yaml = spack.store.layout.deprecated_file_path(spec,
                                                              deprecator)
          fsys.mkdirp(os.path.dirname(depr_yaml))
          shutil.copy2(self_yaml, depr_yaml)
  
          # Any specs deprecated in favor of this spec are re-deprecated in
          # favor of its new deprecator
          for deprecated in spack.store.db.specs_deprecated_by(spec):
              deprecated.package.do_deprecate(deprecator, link_fn)
  
          # Now that we've handled metadata, uninstall and replace with link
          Package.uninstall_by_spec(spec, force=True, deprecator=deprecator)
          link_fn(deprecator.prefix, spec.prefix)
  
      def _check_extendable(self):
          if not self.extendable:
              raise ValueError("Package %s is not extendable!" % self.name)
  
      def _sanity_check_extension(self):
          if not self.is_extension:
              raise ActivationError("This package is not an extension.")
  
          extendee_package = self.extendee_spec.package
          extendee_package._check_extendable()
  
          if not extendee_package.installed:
              raise ActivationError(
                  "Can only (de)activate extensions for installed packages.")
          if not self.installed:
              raise ActivationError("Extensions must first be installed.")
          if self.extendee_spec.name not in self.extendees:
              raise ActivationError("%s does not extend %s!" %
                                    (self.name, self.extendee.name))
  
      def do_activate(self, view=None, with_dependencies=True, verbose=True):
          """Called on an extension to invoke the extendee's activate method.
  
          Commands should call this routine, and should not call
          activate() directly.
          """
          if verbose:
              tty.msg('Activating extension {0} for {1}'.format(
                  self.spec.cshort_spec, self.extendee_spec.cshort_spec))
  
          self._sanity_check_extension()
          if not view:
              view = YamlFilesystemView(
                  self.extendee_spec.prefix, spack.store.layout)
  
          extensions_layout = view.extensions_layout
  
          try:
              extensions_layout.check_extension_conflict(
                  self.extendee_spec, self.spec)
          except spack.directory_layout.ExtensionAlreadyInstalledError as e:
              # already installed, let caller know
              tty.msg(e.message)
              return
  
          # Activate any package dependencies that are also extensions.
          if with_dependencies:
              for spec in self.dependency_activations():
                  if not spec.package.is_activated(view):
                      spec.package.do_activate(
                          view, with_dependencies=with_dependencies,
                          verbose=verbose)
  
          self.extendee_spec.package.activate(
              self, view, **self.extendee_args)
  
          extensions_layout.add_extension(self.extendee_spec, self.spec)
  
          if verbose:
              tty.debug('Activated extension {0} for {1}'.format(
                  self.spec.cshort_spec, self.extendee_spec.cshort_spec))
  
      def dependency_activations(self):
          return (spec for spec in self.spec.traverse(root=False, deptype='run')
                  if spec.package.extends(self.extendee_spec))
  
      def activate(self, extension, view, **kwargs):
          """
          Add the extension to the specified view.
  
          Package authors can override this function to maintain some
          centralized state related to the set of activated extensions
          for a package.
  
          Spack internals (commands, hooks, etc.) should call
          do_activate() method so that proper checks are always executed.
          """
          view.merge(extension.spec, ignore=kwargs.get('ignore', None))
  
      def do_deactivate(self, view=None, **kwargs):
          """Remove this extension package from the specified view. Called
          on the extension to invoke extendee's deactivate() method.
  
          `remove_dependents=True` deactivates extensions depending on this
          package instead of raising an error.
          """
          self._sanity_check_extension()
          force = kwargs.get('force', False)
          verbose = kwargs.get('verbose', True)
          remove_dependents = kwargs.get('remove_dependents', False)
  
          if verbose:
              tty.msg('Deactivating extension {0} for {1}'.format(
                  self.spec.cshort_spec, self.extendee_spec.cshort_spec))
  
          if not view:
              view = YamlFilesystemView(
                  self.extendee_spec.prefix, spack.store.layout)
          extensions_layout = view.extensions_layout
  
          # Allow a force deactivate to happen.  This can unlink
          # spurious files if something was corrupted.
          if not force:
              extensions_layout.check_activated(
                  self.extendee_spec, self.spec)
  
              activated = extensions_layout.extension_map(
                  self.extendee_spec)
              for name, aspec in activated.items():
                  if aspec == self.spec:
                      continue
                  for dep in aspec.traverse(deptype='run'):
                      if self.spec == dep:
                          if remove_dependents:
                              aspec.package.do_deactivate(**kwargs)
                          else:
                              msg = ('Cannot deactivate {0} because {1} is '
                                     'activated and depends on it')
                              raise ActivationError(msg.format(
                                  self.spec.cshort_spec, aspec.cshort_spec))
  
          self.extendee_spec.package.deactivate(
              self, view, **self.extendee_args)
  
          # redundant activation check -- makes SURE the spec is not
          # still activated even if something was wrong above.
          if self.is_activated(view):
              extensions_layout.remove_extension(
                  self.extendee_spec, self.spec)
  
          if verbose:
              tty.debug('Deactivated extension {0} for {1}'.format(
                  self.spec.cshort_spec, self.extendee_spec.cshort_spec))
  
      def deactivate(self, extension, view, **kwargs):
          """
          Remove all extension files from the specified view.
  
          Package authors can override this method to support other
          extension mechanisms.  Spack internals (commands, hooks, etc.)
          should call do_deactivate() method so that proper checks are
          always executed.
          """
          view.unmerge(extension.spec, ignore=kwargs.get('ignore', None))
  
      def view(self):
          """Create a view with the prefix of this package as the root.
          Extensions added to this view will modify the installation prefix of
          this package.
          """
          return YamlFilesystemView(self.prefix, spack.store.layout)
  
      def do_restage(self):
          """Reverts expanded/checked out source to a pristine state."""
          self.stage.restage()
  
      def do_clean(self):
          """Removes the package's build stage and source tarball."""
          for patch in self.spec.patches:
              patch.clean()
  
          self.stage.destroy()
  
      def format_doc(self, **kwargs):
          """Wrap doc string at 72 characters and format nicely"""
          indent = kwargs.get('indent', 0)
  
          if not self.__doc__:
              return ""
  
          doc = re.sub(r'\s+', ' ', self.__doc__)
          lines = textwrap.wrap(doc, 72)
          results = six.StringIO()
          for line in lines:
              results.write((" " * indent) + line + "\n")
          return results.getvalue()
  
      @property
      def all_urls(self):
          """A list of all URLs in a package.
  
          Check both class-level and version-specific URLs.
  
          Returns:
              list: a list of URLs
          """
          urls = []
          if hasattr(self, 'url') and self.url:
              urls.append(self.url)
  
          # fetch from first entry in urls to save time
          if hasattr(self, 'urls') and self.urls:
              urls.append(self.urls[0])
  
          for args in self.versions.values():
              if 'url' in args:
                  urls.append(args['url'])
          return urls
  
      def fetch_remote_versions(self, concurrency=128):
          """Find remote versions of this package.
  
          Uses ``list_url`` and any other URLs listed in the package file.
  
          Returns:
              dict: a dictionary mapping versions to URLs
          """
          if not self.all_urls:
              return {}
  
          try:
              return spack.util.web.find_versions_of_archive(
                  self.all_urls,
                  self.list_url,
                  self.list_depth,
                  concurrency,
                  reference_package=self,
              )
          except spack.util.web.NoNetworkConnectionError as e:
              tty.die("Package.fetch_versions couldn't connect to:", e.url,
                      e.message)
  
      @property
      def rpath(self):
          """Get the rpath this package links with, as a list of paths."""
          rpaths = [self.prefix.lib, self.prefix.lib64]
          deps = self.spec.dependencies(deptype='link')
          rpaths.extend(d.prefix.lib for d in deps
                        if os.path.isdir(d.prefix.lib))
          rpaths.extend(d.prefix.lib64 for d in deps
                        if os.path.isdir(d.prefix.lib64))
          return rpaths
  
      @property
      def rpath_args(self):
          """
          Get the rpath args as a string, with -Wl,-rpath, for each element
          """
          return " ".join("-Wl,-rpath,%s" % p for p in self.rpath)
  
      @on_package_attributes(run_tests=True)
      def _run_default_build_time_test_callbacks(self):
          """Tries to call all the methods that are listed in the attribute
          ``build_time_test_callbacks`` if ``self.run_tests is True``.
  
          If ``build_time_test_callbacks is None`` returns immediately.
          """
          if self.build_time_test_callbacks is None:
              return
  
          for name in self.build_time_test_callbacks:
              try:
                  fn = getattr(self, name)
              except AttributeError:
                  msg = 'RUN-TESTS: method not implemented [{0}]'
                  tty.warn(msg.format(name))
              else:
                  tty.msg('RUN-TESTS: build-time tests [{0}]'.format(name))
                  fn()
  
      @on_package_attributes(run_tests=True)
      def _run_default_install_time_test_callbacks(self):
          """Tries to call all the methods that are listed in the attribute
          ``install_time_test_callbacks`` if ``self.run_tests is True``.
  
          If ``install_time_test_callbacks is None`` returns immediately.
          """
          if self.install_time_test_callbacks is None:
              return
  
          for name in self.install_time_test_callbacks:
              try:
                  fn = getattr(self, name)
              except AttributeError:
                  msg = 'RUN-TESTS: method not implemented [{0}]'
                  tty.warn(msg.format(name))
              else:
                  tty.msg('RUN-TESTS: install-time tests [{0}]'.format(name))
                  fn()
  
  
  def has_test_method(pkg):
      """Returns True if the package defines its own stand-alone test method."""
      if not inspect.isclass(pkg):
          tty.die('{0}: is not a class, it is {1}'.format(pkg, type(pkg)))
  
      return (
          (issubclass(pkg, PackageBase) and pkg.test != PackageBase.test) or
          (isinstance(pkg, PackageBase) and pkg.test.__func__ != PackageBase.test)
      )
  
  
  def print_test_message(logger, msg, verbose):
      if verbose:
          with logger.force_echo():
              print(msg)
      else:
          print(msg)
  
  
  def test_process(pkg, kwargs):
      verbose = kwargs.get('verbose', False)
      externals = kwargs.get('externals', False)
      with tty.log.log_output(pkg.test_log_file, verbose) as logger:
          with logger.force_echo():
              tty.msg('Testing package {0}'
                      .format(pkg.test_suite.test_pkg_id(pkg.spec)))
  
          if pkg.spec.external and not externals:
              print_test_message(logger, 'Skipped external package', verbose)
              return
  
          # use debug print levels for log file to record commands
          old_debug = tty.is_debug()
          tty.set_debug(True)
  
          # run test methods from the package and all virtuals it
          # provides virtuals have to be deduped by name
          v_names = list(set([vspec.name
                              for vspec in pkg.virtuals_provided]))
  
          # hack for compilers that are not dependencies (yet)
          # TODO: this all eventually goes away
          c_names = ('gcc', 'intel', 'intel-parallel-studio', 'pgi')
          if pkg.name in c_names:
              v_names.extend(['c', 'cxx', 'fortran'])
          if pkg.spec.satisfies('llvm+clang'):
              v_names.extend(['c', 'cxx'])
  
          test_specs = [pkg.spec] + [spack.spec.Spec(v_name)
                                     for v_name in sorted(v_names)]
  
          ran_actual_test_function = False
          try:
              with fsys.working_dir(
                      pkg.test_suite.test_dir_for_spec(pkg.spec)):
                  for spec in test_specs:
                      pkg.test_suite.current_test_spec = spec
                      # Fail gracefully if a virtual has no package/tests
                      try:
                          spec_pkg = spec.package
                      except spack.repo.UnknownPackageError:
                          continue
  
                      # copy installed test sources cache into test cache dir
                      if spec.concrete:
                          cache_source = spec_pkg.install_test_root
                          cache_dir = pkg.test_suite.current_test_cache_dir
                          if (os.path.isdir(cache_source) and
                                  not os.path.exists(cache_dir)):
                              fsys.install_tree(cache_source, cache_dir)
  
                      # copy test data into test data dir
                      data_source = Prefix(spec_pkg.package_dir).test
                      data_dir = pkg.test_suite.current_test_data_dir
                      if (os.path.isdir(data_source) and
                              not os.path.exists(data_dir)):
                          # We assume data dir is used read-only
                          # maybe enforce this later
                          shutil.copytree(data_source, data_dir)
  
                      # grab the function for each method so we can call
                      # it with the package
                      test_fn = spec_pkg.__class__.test
                      if not isinstance(test_fn, types.FunctionType):
                          test_fn = test_fn.__func__
  
                      # Skip any test methods consisting solely of 'pass'
                      # since they do not contribute to package testing.
                      source = (inspect.getsource(test_fn)).splitlines()[1:]
                      lines = (ln.strip() for ln in source)
                      statements = [ln for ln in lines if not ln.startswith('#')]
                      if len(statements) > 0 and statements[0] == 'pass':
                          continue
  
                      # Run the tests
                      ran_actual_test_function = True
                      test_fn(pkg)
  
              # If fail-fast was on, we error out above
              # If we collect errors, raise them in batch here
              if pkg.test_failures:
                  raise TestFailure(pkg.test_failures)
  
          finally:
              # reset debug level
              tty.set_debug(old_debug)
  
              # flag the package as having been tested (i.e., ran one or more
              # non-pass-only methods
              if ran_actual_test_function:
                  fsys.touch(pkg.tested_file)
              else:
                  print_test_message(logger, 'No tests to run',  verbose)
  
  
  inject_flags = PackageBase.inject_flags
  env_flags = PackageBase.env_flags
  build_system_flags = PackageBase.build_system_flags
  
  
  class BundlePackage(PackageBase):
      """General purpose bundle, or no-code, package class."""
      #: There are no phases by default but the property is required to support
      #: post-install hooks (e.g., for module generation).
      phases = []  # type: List[str]
      #: This attribute is used in UI queries that require to know which
      #: build-system class we are using
      build_system_class = 'BundlePackage'
  
      #: Bundle packages do not have associated source or binary code.
      has_code = False
  
  
  class Package(PackageBase):
      """General purpose class with a single ``install``
      phase that needs to be coded by packagers.
      """
      #: The one and only phase
      phases = ['install']
      #: This attribute is used in UI queries that require to know which
      #: build-system class we are using
      build_system_class = 'Package'
      # This will be used as a registration decorator in user
      # packages, if need be
      run_after('install')(PackageBase.sanity_check_prefix)
      # On macOS, force rpaths for shared library IDs and remove duplicate rpaths
      run_after('install')(PackageBase.apply_macos_rpath_fixups)
  
  
  def install_dependency_symlinks(pkg, spec, prefix):
      """
      Execute a dummy install and flatten dependencies.
  
      This routine can be used in a ``package.py`` definition by setting
      ``install = install_dependency_symlinks``.
  
      This feature comes in handy for creating a common location for the
      the installation of third-party libraries.
      """
      flatten_dependencies(spec, prefix)
  
  
  def use_cray_compiler_names():
      """Compiler names for builds that rely on cray compiler names."""
      os.environ['CC'] = 'cc'
      os.environ['CXX'] = 'CC'
      os.environ['FC'] = 'ftn'
      os.environ['F77'] = 'ftn'
  
  
  def flatten_dependencies(spec, flat_dir):
      """Make each dependency of spec present in dir via symlink."""
      for dep in spec.traverse(root=False):
          name = dep.name
  
          dep_path = spack.store.layout.path_for_spec(dep)
          dep_files = LinkTree(dep_path)
  
          os.mkdir(flat_dir + '/' + name)
  
          conflict = dep_files.find_conflict(flat_dir + '/' + name)
          if conflict:
              raise DependencyConflictError(conflict)
  
          dep_files.merge(flat_dir + '/' + name)
  
  
  def possible_dependencies(*pkg_or_spec, **kwargs):
      """Get the possible dependencies of a number of packages.
  
      See ``PackageBase.possible_dependencies`` for details.
      """
      packages = []
      for pos in pkg_or_spec:
          if isinstance(pos, PackageMeta):
              packages.append(pos)
              continue
  
          if not isinstance(pos, spack.spec.Spec):
              pos = spack.spec.Spec(pos)
  
          if spack.repo.path.is_virtual(pos.name):
              packages.extend(
                  p.package_class
                  for p in spack.repo.path.providers_for(pos.name)
              )
              continue
          else:
              packages.append(pos.package_class)
  
      visited = {}
      for pkg in packages:
          pkg.possible_dependencies(visited=visited, **kwargs)
  
      return visited
  
  
  class FetchError(spack.error.SpackError):
      """Raised when something goes wrong during fetch."""
  
      def __init__(self, message, long_msg=None):
          super(FetchError, self).__init__(message, long_msg)
  
  
  class PackageStillNeededError(InstallError):
      """Raised when package is still needed by another on uninstall."""
      def __init__(self, spec, dependents):
          super(PackageStillNeededError, self).__init__("Cannot uninstall %s" %
                                                        spec)
          self.spec = spec
          self.dependents = dependents
  
  
  class PackageError(spack.error.SpackError):
      """Raised when something is wrong with a package definition."""
      def __init__(self, message, long_msg=None):
          super(PackageError, self).__init__(message, long_msg)
  
  
  class PackageVersionError(PackageError):
      """Raised when a version URL cannot automatically be determined."""
      def __init__(self, version):
          super(PackageVersionError, self).__init__(
              "Cannot determine a URL automatically for version %s" % version,
              "Please provide a url for this version in the package.py file.")
  
  
  class NoURLError(PackageError):
      """Raised when someone tries to build a URL for a package with no URLs."""
  
      def __init__(self, cls):
          super(NoURLError, self).__init__(
              "Package %s has no version with a URL." % cls.__name__)
  
  
  class InvalidPackageOpError(PackageError):
      """Raised when someone tries perform an invalid operation on a package."""
  
  
  class ExtensionError(PackageError):
      """Superclass for all errors having to do with extension packages."""
  
  
  class ActivationError(ExtensionError):
      """Raised when there are problems activating an extension."""
      def __init__(self, msg, long_msg=None):
          super(ActivationError, self).__init__(msg, long_msg)
  
  
  class DependencyConflictError(spack.error.SpackError):
      """Raised when the dependencies cannot be flattened as asked for."""
      def __init__(self, conflict):
          super(DependencyConflictError, self).__init__(
              "%s conflicts with another file in the flattened directory." % (
                  conflict))
  