Removed adding a space into empty docstrings.

[MarkCBell]

Resolves #2168 by disabling the insertion of a " " when the docstring is entirely empty.

Note that this PR is focussed only on the case of empty docstrings. In particular this does not make any changes to the behaviour that a " " is inserted if a non-empty docstring begins with the quoting character. That is, black still prefers:

""" "something" """

to:

""""something" """

and that:

""""Something""""

is not a legal docstring.

[JelleZijlstra]

Thanks, I agree we should do this. Can we still make it output a single space if the original docspace is nonempty?

[JelleZijlstra]

Looks good to me. With the change to preserve docstrings that already contain a space, this shouldn't cause thrash for people who applied the formatting from the current release, while preserving completely empty docstrings for those who need them.

[ichard26]

I don't see anything wrong with this and this is a good pragmatic change. Thanks!

[johnthagen]

Can we still make it output a single space if the original docspace is nonempty?

Does this mean if I reformatted the code with the previous black I need to hunt through and find the docstrings """ """ and fix them manually again?

[ichard26]

Does this mean if I reformatted the code with the previous black I need to hunt through and find the docstrings """ """ and fix them manually again?

Yes. It's not great for docstrings that were erroneously (like for sphinx docs) changed to """ """ but the main reason why is reduce churn by not effectively flip-flopping the original rule. Why the original rule? IIRC it was to indicate to users about the (probably) wrong empty or whitespace only docstring (it turns out an empty docstring isn't always wrong, unfortunately we didn't know this until after we got a report).