*** /usr/lib/python2.4/posixpath.py	2007-01-10 17:26:10.000000000 +0100
--- posixpath.py	2007-07-06 17:50:39.893615000 +0200
***************
*** 339,345 ****
  
  _varprog = None
  
! def expandvars(path):
      """Expand shell variables of form $var and ${var}.  Unknown variables
      are left unchanged."""
      global _varprog
--- 339,345 ----
  
  _varprog = None
  
! def expandvars(path, getenvFunc=os.getenv):
      """Expand shell variables of form $var and ${var}.  Unknown variables
      are left unchanged."""
      global _varprog
***************
*** 357,365 ****
          name = m.group(1)
          if name.startswith('{') and name.endswith('}'):
              name = name[1:-1]
!         if name in os.environ:
              tail = path[j:]
!             path = path[:i] + os.environ[name]
              i = len(path)
              path += tail
          else:
--- 357,366 ----
          name = m.group(1)
          if name.startswith('{') and name.endswith('}'):
              name = name[1:-1]
!         envValue = getenvFunc(name)
!         if envValue is not None:
              tail = path[j:]
!             path = path[:i] + envValue
              i = len(path)
              path += tail
          else:
*** /usr/lib/python2.4/ntpath.py	2007-01-10 17:26:10.000000000 +0100
--- ntpath.py	2007-07-06 17:51:40.873067000 +0200
***************
*** 378,384 ****
  # XXX With COMMAND.COM you can use any characters in a variable name,
  # XXX except '^|<>='.
  
! def expandvars(path):
      """Expand shell variables of form $var and ${var}.
  
      Unknown variables are left unchanged."""
--- 378,384 ----
  # XXX With COMMAND.COM you can use any characters in a variable name,
  # XXX except '^|<>='.
  
! def expandvars(path, getenvFunc=os.getenv):
      """Expand shell variables of form $var and ${var}.
  
      Unknown variables are left unchanged."""
***************
*** 410,417 ****
                  try:
                      index = path.index('}')
                      var = path[:index]
!                     if var in os.environ:
!                         res = res + os.environ[var]
                  except ValueError:
                      res = res + path
                      index = pathlen - 1
--- 410,418 ----
                  try:
                      index = path.index('}')
                      var = path[:index]
!                     value = getenvFunc(var)
!                     if value is not None:
!                         res = res + value
                  except ValueError:
                      res = res + path
                      index = pathlen - 1
***************
*** 423,430 ****
                      var = var + c
                      index = index + 1
                      c = path[index:index + 1]
!                 if var in os.environ:
!                     res = res + os.environ[var]
                  if c != '':
                      res = res + c
          else:
--- 424,432 ----
                      var = var + c
                      index = index + 1
                      c = path[index:index + 1]
!                 envValue = getenvFunc(var)
!                 if envValue is not None:
!                     res = res + envValue
                  if c != '':
                      res = res + c
          else: