[issue14722] Overflow in parsing 'float' parameters in PyArg_ParseTuple*

[Mark Dickinson]

Mark Dickinson <dickinsm at gmail.com> added the comment:

I don't think this change should be made for 2.7 or 3.2, since it has potential to break existing code.

Though technically, conversion of an out-of-range double to a float gives undefined behaviour (C99 6.3.1.5p2), I'm willing to bet that most current compilers just happily return +-infinity in these cases, and there's probably code out there that would break if we changed this.

So for 2.7 or 3.2, we could just return +-inf here instead.  Though even that isn't quite right if you're picky about corner cases, since there are some values *just* outside [-FLOAT_MAX, FLOAT_MAX] that should still round to +-FLOAT_MAX under round-to-nearest.

I suggest leaving this alone for 2.7 and 3.2

For 3.3, it's not clear to me whether it's better to return +-inf or to raise here.

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nosy: +mark.dickinson

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