[issue40365] argparse: action "extend" with 1 parameter splits strings into characters

[Jonathan Haigh]

Jonathan Haigh <jonathanhaigh at gmail.com> added the comment:

>> But I wonder, was this situation discussed in the original bug/issue?
>Doesn't look like it:

I was looking at the wrong PR link. This has more discussion: https://github.com/python/cpython/pull/13305.

nargs is discussed but I'm not sure it was realized that the nargs=None and nargs="?" cases would act in the way seen here rather than acting like append.

Having a default nargs of "+" was suggested but that suggestion was not addressed.

> I suggest that the default nargs for extend should be "*" or "+" and an exception should be raised if nargs is given as "?".

I'm not convinced about that any more. Using append's behaviour is probably more reasonable for nargs=None and nargs="?".

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nosy: +Anthony Sottile, BTaskaya, berker.peksag

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