parameters: (dist, req)
docstring: Fetch an egg needed for building.
  
      Use pip/wheel to fetch/build a wheel.
docstring_summary: Fetch an egg needed for building.
docstring_tokens: Fetch an egg needed for building .
function: def fetch_build_egg(dist, req):  # noqa: C901  # is too complex (16)  # FIXME
      """Fetch an egg needed for building.
  
      Use pip/wheel to fetch/build a wheel."""
      warnings.warn(
          "setuptools.installer is deprecated. Requirements should "
          "be satisfied by a PEP 517 installer.",
          SetuptoolsDeprecationWarning,
      )
      # Warn if wheel is not available
      try:
          pkg_resources.get_distribution('wheel')
      except pkg_resources.DistributionNotFound:
          dist.announce('WARNING: The wheel package is not available.', log.WARN)
      # Ignore environment markers; if supplied, it is required.
      req = strip_marker(req)
      # Take easy_install options into account, but do not override relevant
      # pip environment variables (like PIP_INDEX_URL or PIP_QUIET); they'll
      # take precedence.
      opts = dist.get_option_dict('easy_install')
      if 'allow_hosts' in opts:
          raise DistutilsError('the `allow-hosts` option is not supported '
                               'when using pip to install requirements.')
      quiet = 'PIP_QUIET' not in os.environ and 'PIP_VERBOSE' not in os.environ
      if 'PIP_INDEX_URL' in os.environ:
          index_url = None
      elif 'index_url' in opts:
          index_url = opts['index_url'][1]
      else:
          index_url = None
      find_links = (
          _fixup_find_links(opts['find_links'][1])[:] if 'find_links' in opts
          else []
      )
      if dist.dependency_links:
          find_links.extend(dist.dependency_links)
      eggs_dir = os.path.realpath(dist.get_egg_cache_dir())
      environment = pkg_resources.Environment()
      for egg_dist in pkg_resources.find_distributions(eggs_dir):
          if egg_dist in req and environment.can_add(egg_dist):
              return egg_dist
      with tempfile.TemporaryDirectory() as tmpdir:
          cmd = [
              sys.executable, '-m', 'pip',
              '--disable-pip-version-check',
              'wheel', '--no-deps',
              '-w', tmpdir,
          ]
          if quiet:
              cmd.append('--quiet')
          if index_url is not None:
              cmd.extend(('--index-url', index_url))
          for link in find_links or []:
              cmd.extend(('--find-links', link))
          # If requirement is a PEP 508 direct URL, directly pass
          # the URL to pip, as `req @ url` does not work on the
          # command line.
          cmd.append(req.url or str(req))
          try:
              subprocess.check_call(cmd)
          except subprocess.CalledProcessError as e:
              raise DistutilsError(str(e)) from e
          wheel = Wheel(glob.glob(os.path.join(tmpdir, '*.whl'))[0])
          dist_location = os.path.join(eggs_dir, wheel.egg_name())
          wheel.install_as_egg(dist_location)
          dist_metadata = pkg_resources.PathMetadata(
              dist_location, os.path.join(dist_location, 'EGG-INFO'))
          dist = pkg_resources.Distribution.from_filename(
              dist_location, metadata=dist_metadata)
          return dist
function_tokens: def fetch_build_egg ( dist , req ) : # noqa: C901  # is too complex (16)  # FIXME warnings . warn ( "setuptools.installer is deprecated. Requirements should " "be satisfied by a PEP 517 installer." , SetuptoolsDeprecationWarning , ) # Warn if wheel is not available try : pkg_resources . get_distribution ( 'wheel' ) except pkg_resources . DistributionNotFound : dist . announce ( 'WARNING: The wheel package is not available.' , log . WARN ) # Ignore environment markers; if supplied, it is required. req = strip_marker ( req ) # Take easy_install options into account, but do not override relevant # pip environment variables (like PIP_INDEX_URL or PIP_QUIET); they'll # take precedence. opts = dist . get_option_dict ( 'easy_install' ) if 'allow_hosts' in opts : raise DistutilsError ( 'the `allow-hosts` option is not supported ' 'when using pip to install requirements.' ) quiet = 'PIP_QUIET' not in os . environ and 'PIP_VERBOSE' not in os . environ if 'PIP_INDEX_URL' in os . environ : index_url = None elif 'index_url' in opts : index_url = opts [ 'index_url' ] [ 1 ] else : index_url = None find_links = ( _fixup_find_links ( opts [ 'find_links' ] [ 1 ] ) [ : ] if 'find_links' in opts else [ ] ) if dist . dependency_links : find_links . extend ( dist . dependency_links ) eggs_dir = os . path . realpath ( dist . get_egg_cache_dir ( ) ) environment = pkg_resources . Environment ( ) for egg_dist in pkg_resources . find_distributions ( eggs_dir ) : if egg_dist in req and environment . can_add ( egg_dist ) : return egg_dist with tempfile . TemporaryDirectory ( ) as tmpdir : cmd = [ sys . executable , '-m' , 'pip' , '--disable-pip-version-check' , 'wheel' , '--no-deps' , '-w' , tmpdir , ] if quiet : cmd . append ( '--quiet' ) if index_url is not None : cmd . extend ( ( '--index-url' , index_url ) ) for link in find_links or [ ] : cmd . extend ( ( '--find-links' , link ) ) # If requirement is a PEP 508 direct URL, directly pass # the URL to pip, as `req @ url` does not work on the # command line. cmd . append ( req . url or str ( req ) ) try : subprocess . check_call ( cmd ) except subprocess . CalledProcessError as e : raise DistutilsError ( str ( e ) ) from e wheel = Wheel ( glob . glob ( os . path . join ( tmpdir , '*.whl' ) ) [ 0 ] ) dist_location = os . path . join ( eggs_dir , wheel . egg_name ( ) ) wheel . install_as_egg ( dist_location ) dist_metadata = pkg_resources . PathMetadata ( dist_location , os . path . join ( dist_location , 'EGG-INFO' ) ) dist = pkg_resources . Distribution . from_filename ( dist_location , metadata = dist_metadata ) return dist