[issue30907] speed up comparisons to self for built-in containers
Raymond Hettinger
report at bugs.python.org
Thu Jul 13 00:58:33 EDT 2017
Raymond Hettinger added the comment:
This seems like it optimizes an irrelevant use case, comparing a container to itself.
I don't think this is likely to benefit any existing code, so it would be better not to add more code clutter/complexity with another special case code path unless we're pretty sure that special case actually arises in practice.
FWIW, the note about identity-implies-equality is a statement about how containers implement element comparison rather than about how two containers are compared to one another (as implemented in PyObject_RichCompareBool()). Also, it isn't just an optimization, it is necessary to help us reason about containers (i.e. preserving the invariant: all(x in c for x in c)).
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type: -> performance
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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30907>
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