Steven D'Aprano schrieb:
Sometimes it seems that barely a day goes by without some newbie, or not-
so-newbie, getting confused by the behaviour of functions with mutable
default arguments. No sooner does one thread finally, and painfully, fade
away than another one starts up.
I suggest that Python should raise warnings.RuntimeWarning (or similar?)
when a function is defined with a default argument consisting of a list,
dict or set. (This is not meant as an exhaustive list of all possible
mutable types, but as the most common ones that I expect will trip up
newbies.) The warning should refer to the relevant FAQ or section in the
docs.
I just suggested a documentation enhancement in one of the plethora of
threads... so I'm certainly +1 for any enhancement in this area.
Diez
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