[ python-Bugs-212558 ] dictionary lookup does not check exceptions

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Bugs item #212558, was opened at 2000-08-23 14:24
Message generated for change (Comment added) made by arigo
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Category: Python Interpreter Core
Group: None
Status: Closed
Resolution: Fixed
Priority: 9
Submitted By: Jeremy Hylton (jhylton)
Assigned to: Fred L. Drake, Jr. (fdrake)
Summary: dictionary lookup does not check exceptions

Initial Comment:
class BadDictKey:
    def __hash__(self):
        return hash(self.__class__)

    def __cmp__(self, other):
        if isinstance(other, self.__class__):
            print "raising error"
            raise RuntimeError, "gotcha"
        return other

The dict lookup code does not check for hash or cmp functions raising an exception.  This can lead to a variety of bogus behavior; e.g. the uncaught exception is noticed and raised for the next line.

>>> d = {}
>>> x1 = BadDictKey()
>>> x2 = BadDictKey()
>>> d[x1] = 1
>>> d[x2] = 2
raising error
>>> print d.keys()
Traceback (most recent call last):
  File "/tmp/dicterr.py", line 8, in __cmp__
    raise RuntimeError, "gotcha"
RuntimeError: gotcha


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>Comment By: Armin Rigo (arigo)
Date: 2005-12-15 10:24

Message:
Logged In: YES 
user_id=4771

For future reference, the patch number is actually #401277.

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Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2000-08-31 19:05

Message:
Fixed by patch #101277, checked in as dictobject.c revision 2.63.

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Comment By: Fred L. Drake, Jr. (fdrake)
Date: 2000-08-24 16:56

Message:
See patch #101277 for a proposed fix & discussion.

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