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Mon Jan 27 14:13:01 CET 2014 · https://mail.python.org/pipermail/python-dev/2014-January/132141.html

On 01/27/2014 04:56 AM, Steven D'Aprano wrote (rearranged slightly so I 
could make my points in order):
> I'm confused... you seem to be saying that you are *against* changing
> the behaviour of repeat so that:
>
>      repeat(x, -1)
>
> and
>
>      repeat(x, times=-1)
>
> behave the same. Is that actually what you mean, or have I
> misunderstood?

I apologize for not making myself clear.  But that's part of what I 
meant, yes: we should preserve the existing behavior of times=-1 when 
passed in by position or by keyword.  However, we should *also* add a 
deprecation warning when passing times=-1 by keyword, suggesting that 
they use times=None instead.  The idea is that we could eventually 
remove the PyTuple_Size check and make times=-1 always behave like 
times=0.  In practice it'd be okay with me if we never did, or at least 
not until Python 4.

> Are you rejecting the idea that the current behaviour is an out and out
> buggy, and therefore fixing these things can and should occur in a
> bug-fix release?

While it's a bug, it's a very minor bug.  As Python 3.4 release manager, 
my position is: Python 3.4 is in beta, so let's not change semantics for 
purity's sakes now.  I'm -0.5 on adding times=None right now, and until 
we do we can't deprecate the old behavior.

> Are there any other functions in the standard library where the
> behaviour differs depending on whether an argument is given positionally
> or by keyword?

Not that I know of.  This instance seems to be purely unintentional; see 
my latest message on the relevant issue, where I went back and figured 
out why itertools.repeat behaves like this in the first place:

    http://bugs.python.org/issue19145#msg209440

Cheers,

//arry/
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[Python-Dev] Negative times behaviour in itertools.repeat for Python maintenance releases (2.7, 3.3 and maybe 3.4)