Bugs item #1174712, was opened at 2005-04-01 10:22
Message generated for change (Comment added) made by mwh
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1174712&group_id=5470
Category: Python Interpreter Core
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Armin Rigo (arigo)
Assigned to: Nobody/Anonymous (nobody)
Summary: subclassing ModuleType and another built-in type
Initial Comment:
class X(types.ModuleType, str): pass
X('name')
-> segfault
This buggy subclassing goes through typeobject.c's checks because
PyModuleObject looks exactly like a user-defined subclass of 'object': it has a
PyObject_HEAD followed only by the dict, as specified by tp_dictoffset.
A fix would be to forbid any subclassing to move the tp_dictoffset of a
non-heap type.
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>Comment By: Michael Hudson (mwh)
Date: 2005-04-03 14:39
Message:
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> This might point to the need for cleaning up typeobject.c's
> darker corners...
No kidding. Maybe Samuele, you and I can gang up on Guido at
EuroPython (is he sprinting? Perhaps we should ask).
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Comment By: Armin Rigo (arigo)
Date: 2005-04-02 13:27
Message:
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The proposed fix is not good enough. If another built-in C type similar to
PyModuleObject is defined (say by a C extension module), then it would become
possible to subclass both this new type and ModuleType. This might lead to
unwanted behavior if e.g. one parent class allows rebinding __dict__ and the
other not (and crashes if __dict__ is rebound).
This might point to the need for cleaning up typeobject.c's darker corners...
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You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1174712&group_id=5470
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