[ python-Bugs-1180193 ] broken pyc files

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Bugs item #1180193, was opened at 2005-04-10 15:10
Message generated for change (Comment added) made by loewis
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Category: Python Interpreter Core
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Armin Rigo (arigo)
Assigned to: Nobody/Anonymous (nobody)
Summary: broken pyc files

Initial Comment:
In a number of situations, the .pyc files can become "corrupted" in a subtle way: the co_filename attribute of the code objects it contains become wrong.  This can occur if we move or rename directories, or if we access the same set of files from two different locations (e.g. over NFS).

This corruption doesn't prevent the .pyc files from working, but the interpreter looses the reference to the source file.  It causes trouble in tracebacks, in the inspect module, etc.

A simple fix would be to use the following logic when importing a .py file: if there is a corresponding .pyc file, in addition to checking the timestamp, check the co_filename attribute of the loaded object.  If it doesn't point to the original .py file, discard the code object and ignore the .pyc file.

Alternatively, we could force all co_filenames to point to the .py file when loading the .pyc file.

I'll write a patch for whichever alternative seems better.

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>Comment By: Martin v. Löwis (loewis)
Date: 2007-03-28 14:01

Message:
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I fail to see the corruption. It is quite desirable and normal to only
ship pyc files - that the file name they refer to is actually present is
not a requirement at all.

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