The linecache module does not handle packages at all (Guido mentions here that he wrote it before Python had packages: http://mail.python.org/pipermail/python-dev/2005-September/056870.html).

This seems to cause problems with pdb and pydoc, as illustrated by this example:

$ mkdir pydoc_test
$ cd pydoc_test
$ echo "#" > __init__.py
$ pydoc logging

This gives a traceback due to an out of range index, resulting essentially from ./__init__.py being confused with logging/__init__.py. A line number from the latter is used as an index into a list of the lines from the former.

Patch attached, and a bit more explanation can be seen here:

https://bugs.launchpad.net/ubuntu/+source/python-defaults/+bug/70902

New patch upload, typo fix.
File Added: linecache.py.patch

The patch does not fix the underlying problem which is not limited to
files named '__init__.py'.

The following issues appear to be the same bug to me:

   http://bugs.python.org/issue1068477
   http://bugs.python.org/issue1309567
   http://bugs.python.org/issue1754483

and are, as of 2008-06-30, unfixed in both rel25-maint and trunk.

Hans is right, that patch isn't very good. Here's a second pass. This
one avoids joining the file basename to sys.path components, which I'd
say is wrong since it strips (presumably relevant) leading path components.

A second part of this skips out early on absolute file names, which
prevents joining them with sys.path components also. As far as I can
tell this would cause no harm, but it's not useful either.

Here's a small test script.

Even with that patch, I'm still getting backtraces similar to this:

Traceback (most recent call last):
  File "/home/user/foo/src/foo", line 83, in <module>
    foomain(sys.argv)
  File "/home/uli/foo/src/foo", line 79, in foomain
    foolib.main.cmdmain(sys.argv)
  File "./foolib/main.py", line 250, in cmdmain
  File "./foolib/main.py", line 199, in main
  File "./foolib/main.py", line 180, in __init__
  File "./foolib/main.py", line 115, in __get__
AttributeError: property--48216a94

Looks like I should write a dozen test cases I can think of on my own. :)

Test script works with patch from issue 1309567. Hans, do you have more
test cases?

Setting #1309567 as superseder.