1  # encoding: utf-8
   2  """
   3  Context managers for adding things to sys.path temporarily.
   4  
   5  Authors:
   6  
   7  * Brian Granger
   8  """
   9  
  10  #-----------------------------------------------------------------------------
  11  #  Copyright (C) 2008-2011  The IPython Development Team
  12  #
  13  #  Distributed under the terms of the BSD License.  The full license is in
  14  #  the file COPYING, distributed as part of this software.
  15  #-----------------------------------------------------------------------------
  16  
  17  import sys
  18  import warnings
  19  
  20  
  21  class appended_to_syspath(object):
  22      """
  23      Deprecated since IPython 8.1, no replacements.
  24  
  25      A context for appending a directory to sys.path for a second."""
  26  
  27      def __init__(self, dir):
  28          warnings.warn(
  29              "`appended_to_syspath` is deprecated since IPython 8.1, and has no replacements",
  30              DeprecationWarning,
  31              stacklevel=2,
  32          )
  33          self.dir = dir
  34  
  35      def __enter__(self):
  36          if self.dir not in sys.path:
  37              sys.path.append(self.dir)
  38              self.added = True
  39          else:
  40              self.added = False
  41  
  42      def __exit__(self, type, value, traceback):
  43          if self.added:
  44              try:
  45                  sys.path.remove(self.dir)
  46              except ValueError:
  47                  pass
  48          # Returning False causes any exceptions to be re-raised.
  49          return False
  50  
  51  class prepended_to_syspath(object):
  52      """A context for prepending a directory to sys.path for a second."""
  53  
  54      def __init__(self, dir):
  55          self.dir = dir
  56  
  57      def __enter__(self):
  58          if self.dir not in sys.path:
  59              sys.path.insert(0,self.dir)
  60              self.added = True
  61          else:
  62              self.added = False
  63  
  64      def __exit__(self, type, value, traceback):
  65          if self.added:
  66              try:
  67                  sys.path.remove(self.dir)
  68              except ValueError:
  69                  pass
  70          # Returning False causes any exceptions to be re-raised.
  71          return False
  72