old_contents: # Copyright 2013-2019 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)
  
  """Implementation of Spack imports that uses importlib underneath.
  
  ``importlib`` is only fully implemented in Python 3.
  """
  from importlib.machinery import SourceFileLoader
  
  
  class PrependFileLoader(SourceFileLoader):
      def __init__(self, full_name, path, prepend=None):
          super(PrependFileLoader, self).__init__(full_name, path)
          self.prepend = prepend
  
      def get_data(self, path):
          data = super(PrependFileLoader, self).get_data(path)
          if path != self.path or self.prepend is None:
              return data
          else:
              return self.prepend.encode() + b"\n" + data
  
  
  def load_source(full_name, path, prepend=None):
      """Import a Python module from source.
  
      Load the source file and add it to ``sys.modules``.
  
      Args:
          full_name (str): full name of the module to be loaded
          path (str): path to the file that should be loaded
          prepend (str, optional): some optional code to prepend to the
              loaded module; e.g., can be used to inject import statements
  
      Returns:
          (ModuleType): the loaded module
      """
      # use our custom loader
      loader = PrependFileLoader(full_name, path, prepend)
      return loader.load_module()
  
new_contents: # Copyright 2013-2019 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)
  
  """Implementation of Spack imports that uses importlib underneath.
  
  ``importlib`` is only fully implemented in Python 3.
  """
  from importlib.machinery import SourceFileLoader
  
  
  class PrependFileLoader(SourceFileLoader):
      def __init__(self, full_name, path, prepend=None):
          super(PrependFileLoader, self).__init__(full_name, path)
          self.prepend = prepend
  
      def path_stats(self, path):
          stats = super(PrependFileLoader, self).path_stats(path)
          if self.prepend:
              stats["size"] += len(self.prepend) + 1
          return stats
  
      def get_data(self, path):
          data = super(PrependFileLoader, self).get_data(path)
          if path != self.path or self.prepend is None:
              return data
          else:
              return self.prepend.encode() + b"\n" + data
  
  
  def load_source(full_name, path, prepend=None):
      """Import a Python module from source.
  
      Load the source file and add it to ``sys.modules``.
  
      Args:
          full_name (str): full name of the module to be loaded
          path (str): path to the file that should be loaded
          prepend (str, optional): some optional code to prepend to the
              loaded module; e.g., can be used to inject import statements
  
      Returns:
          (ModuleType): the loaded module
      """
      # use our custom loader
      loader = PrependFileLoader(full_name, path, prepend)
      return loader.load_module()
  
subject: make importlib_importer recognize .pyc cache (#13239)