[Patches] [ python-Patches-1608805 ] Py_FileSystemDefaultEncoding can be non-canonical

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Patches item #1608805, was opened at 2006-12-04 17:06
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Category: Core (C code)
Group: Python 2.5
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Stephan R.A. Deibel (sdeibel)
Assigned to: Nobody/Anonymous (nobody)
Summary: Py_FileSystemDefaultEncoding can be non-canonical

Initial Comment:
On Linux/Unix it is possible for Py_FileSystemDefaultEncoding to be set to a non-canonical  encoding such as "UTF-8" instead of "utf-8".  This happens when it is set from codeset in Py_InitializeEx() in pythonrun.c.

This becomes a problem when this value is propagated through to PyUnicode_Decode() or PyUnicode_AsEncodedString() in unicodeobject.c.  One possible such code path starts in os.listdir() via PyUnicode_FromEncodedObject()).

In that case, the common case optimizations fail.  I noticed this in a case where the PyCodec_Decode() used instead was failing.  Normally I think this just amounts to broken optimization but given the likelihood of other such code being added in the future, I feel it's best to fix Py_FileSystemDefaultEncoding to always be a canonical form.

One possible way to fix it is attached as a patch.


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