Hi, I implemented more constant folding optimizations in my FAT Python project, but it looks like I made a subtle change in the Python semantic.
Replacing "not x == y" with "x != y" changes the behaviour of Python. For example, this optimization breaks test_unittest because unittest.mock._Call implements __eq__() but not __ne__(). Is it expected that "not x.__eq__(y)" can be different than "x.__ne__(y)"? Is it part of the Python semantic? IMHO it's a bug in the unittest.mock module, but it's "acceptable" because "it just works" :-) So FAT Python must not replace "not x == y" with "x != y" to not break the code. Should Python emit a warning when __eq__() is implemented but not __ne__()? Should Python be modified to call "not __eq__()" when __ne__() is not implemented? For me, it can be an annoying and sublte bug, hard to track. Victor _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
