[issue14847] AttributeError: NoneType has no attribute 'utf_8_decode'
Amaury Forgeot d'Arc
report at bugs.python.org
Fri May 18 10:44:27 CEST 2012
Amaury Forgeot d'Arc <amauryfa at gmail.com> added the comment:
Reproducing the issue is not too hard, see the example below. Does your program play with sys.modules?
import locale; del locale.encodings # Not necessary with python2
del sys.modules['encodings.utf_8'], sys.modules['encodings']
If we want to make make codecs more robust against sys.modules manipulation I can see several paths:
#1 Somehow clear interp->codec_search_cache (used in Python/codecs.c) when the encodings module is cleared (by using weak references?)
#2 Make sure that functions returned in CodecInfo objects don't rely on global module state. For example in utf_8.py:
def decode(input, errors='strict', _codecs=codecs):
return _codecs.utf_8_decode(input, errors, True)
#3 Capture utf_8.globals() in the CodecInfo, and run decode() with these captured globals.
#4 Get rid of module.__del__ clearing the module globals, and rely on the cyclic garbage collector to clear modules at interpreter shutdown.
Item #2 is the easiest one, but must be implemented in each codec. We could fix the most important ones though.
Item #4 is the most far-reaching one, and would probably be an improvement to other parts of Python...
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