New submission from Josh Rosenberg: While checking the exceptions used to compare existing behavior while investigating #20539, I noticed a weird behavior in pow() (implemented by long_pow in longobject.c). If a 3rd argument (the modulus) is provided, and the 2nd argument (the exponent) is negative, the function raises TypeError. To my knowledge, TypeError should never be used for this purpose; some functions raise OverflowError for negative values (which violates the documented purpose of OverflowError, but the documents don't match CPython's implementation), others use ValueError (which I believe is appropriate, since it's not a matter of a C type limitation, the function is just logically restricted to the range [0,Largest possible PyLong].
I recommend switching to ValueError, possibly with a deprecation notice before making the switch if people think someone might rely on this behavior. Related: #457066 ---------- components: Interpreter Core messages: 215860 nosy: josh.rosenberg priority: normal severity: normal status: open title: pow(a, b, c) should not raise TypeError when b is negative and c is provided type: behavior versions: Python 2.7, Python 3.1, Python 3.2, Python 3.3, Python 3.4, Python 3.5 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue21193> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
