[Python-Dev] Very Strange Argument Handling Behavior

[Mark Dickinson]

On Fri, Apr 16, 2010 at 3:33 PM, Guido van Rossum <guido at python.org> wrote:
> On Fri, Apr 16, 2010 at 7:15 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
>> I would agree with leaving it implementation defined - I don't think
>> either PyPy or CPython should be forced to change their current
>> behaviour in relation to this. A minor note in the language reference to
>> that effect may be worthwhile just to make that stance official.
>
> That is just going to cause some programs to have a portability
> surprise. I think one or the other should be fixed. I am fine with
> declaring dict({}, **{1:3}) illegal, since after all it is abuse of
> the ** mechanism. We should deprecate it in at least one version
> though.

Okay;  I'll open an issue for deprecation in 3.2 and removal in 3.3.

Can this sneak in under the 'incorrect language semantics' exemption
for PEP 3003 (the moratorium PEP)?  If not, then deprecation
presumably has to wait for 3.3.

Mark