I have attached a rough patch implementing the get_filename.  I 
deliberately copied code from get_source method that finds the filename 
inside the zip archive  and simply prefixed that with the archive path.

I could not find any detailed discussion of what get_filename is 
supposed to do.  Pkgutil's get_filename is not documented and not unit-
tested. Google search revealed an old thread at 
<http://mail.python.org/pipermail/python-dev/2006-April/063626.html>, 
but it only says

"""

>runpy needs a get_filename() method, so it knows what to set __file__ 
too -
>currently its emulation supports that, but it isn't officially part of 
the 
>PEP
>302 API.

It sounds like maybe a new PEP is needed to document all the extensions 
to 
the importer/loader protocols.  :(
"""

I don't think a brand new PEP is needed, but an amendment to PEP 302 
would be helpful.  Nick, do you have any notes on what get_filename 
should do in various cases?

My implementation fixes one of the problems in issue4197:

$ ./python.exe testmodule.zip 
**********************************************************************
File "testmodule.zip/__main__.py", line ?, in __main__.c
Failed example:
    'line 2'
Expected nothing
Got:
    'line 2'
**********************************************************************
1 items had failures:
   1 of   1 in __main__.c
***Test Failed*** 1 failures.

Note that line number is still reported as '?', but there is no crash.