Merged revisions 82039 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

........
  r82039 | r.david.murray | 2010-06-16 21:36:52 -0400 (Wed, 16 Jun 2010) | 10 lines

  #8720: fix inspect regression by teaching getsourcefile about linecache.

  The fix for issue 4050 caused a regression:  before that fix, source
  lines in the linecache would eventually be found by inspect.  After the
  fix inspect reports an error earlier, and the source isn't found.
  The fix for the fix is to have getsourcefile look in the linecache for
  the file and return the psuedo-filename if the source is there, just as
  it already returns it if there is a PEP 302 loader.
........
diff --git a/Lib/inspect.py b/Lib/inspect.py
index ea30466..d6ac4e0 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -437,7 +437,9 @@
     if info: return info[0]
 
 def getsourcefile(object):
-    """Return the Python source file an object was defined in, if it exists."""
+    """Return the filename that can be used to locate an object's source.
+    Return None if no way can be identified to get the source.
+    """
     filename = getfile(object)
     if filename[-4:].lower() in ('.pyc', '.pyo'):
         filename = filename[:-4] + '.py'
@@ -450,6 +452,9 @@
     # only return a non-existent filename if the module has a PEP 302 loader
     if hasattr(getmodule(object, filename), '__loader__'):
         return filename
+    # or it is in the linecache
+    if filename in linecache.cache:
+        return filename
 
 def getabsfile(object, _filename=None):
     """Return an absolute path to the source or compiled file for an object.