[Python-ideas] Mutable default function parameter warning

[Sérgio Surkamp]

Hello list,

The documentation states that the default value of function parameter,
if mutable, can change it's default value at runtime due to be
evaluated only once on function object creation.

I would like to suggest the inclusion of an default language warning
when this kind of construction is used, as it's Python specific
behavior and can lead to "strange behavior" or misuse by programmers
that are migrating from other languages to Python.

This proposal was first open as a suggestion issue in bug track, but,
as a request from Mr. Peterson, I'm rewriting it to this list.
http://bugs.python.org/issue9646

Regards,
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