[Python-Dev] Relative path in co_filename for zipped modules (original) (raw)

Vitaly Murashev vitaly.murashev at gmail.com
Tue Jun 25 22:11:04 CEST 2013

Dear Python developers community,

Recently I found out that it not possible to debug python code if it is a part of zip-module. Python version being used is 3.3.0

Well known GUI debuggers like Eclipse+PyDev or PyCharm are unable to start debugging and give the following warning:

pydev debugger: CRITICAL WARNING: This version of python seems to be incorrectly compiled (internal generated filenames are not absolute) pydev debugger: The debugger may still function, but it will work slower and may miss breakpoints.

So I started my own investigation of this issue and results are the following.

At first I took traditional python debugger 'pdb' to analyze how it behaves during debugging of zipped module. 'pdb' showed me some backtaces and filename part for stack entries looks malformed. I expected something like 'full-path-to-zip-dir/my_zipped_module.zip/subdir/test_module.py' but realy it looks like 'full-path-to-current-dir/subdir/test_module.py'

Source code in pdb.py and bdb.py (which one are a part of python stdlib) gave me the answer why it happens.

The root cause are inside Bdb.format_stack_entry() + Bdb.canonic()

Please take a look at the following line inside 'format_stack_entry' method:

filename = self.canonic(frame.f_code.co_filename)

For zipped module variable 'frame.f_code.co_filename' holds relative file path started from the root of zip archive like 'subdir/test_module.py' And as result Bdb.canonic() method gives what we have - 'full-path-to-current-dir/subdir/test_module.py'

So my final question. Could anyone confirm that it is a bug in python core subsystem which one is responsible for loading zipped modules, or something is wrong with my zipped module ?

If it is a bug could you please submit it into official python bugtracker ? I never did it before and afraid to do something wrong.

Thanks, Vitaly Murashev

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