bug#71883: [PATCH] Fix tab-bar-auto-width with customized tab-bar-tab-face-function

[Joseph Turner via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Juri Linkov <juri@linkov.net> writes:

>>> Replacing hard-coded logic with customizable variable
>>> for external packages like activities.el is needed
>>> as soon as possible on emacs-30 because hard-coded logic
>>> hinders the use of packages.
>>>
>>> However, there is no hurry to change the default behavior
>>> to match a symbol name instead of checking face names.
>>> Therefore I think better to move the existing code
>>>
>>>   (memq (get-text-property 0 'face (nth 2 item)) tab-bar-auto-width-faces)
>>>
>>> to the new predicate function on emacs-30.  Then activities.el
>>> can change it to another function that matches a symbol.
>>>
>>> Then on master the default body on the new predicate
>>> could be replaced from checking the face to match a symbol.
>>> Also changes in tab-bar--format-tab-group should be on master as well.
>>
>> Much as I'd like to use these changes asap, I think this patchset should
>> go entirely on master.  I see these changes as adding functionality
>> (making tab-bar tabs more extensible) rather than bug fixes.
>
> Are you sure there is no hurry to make tab-bar more extensible
> for activities.el?  Then let's push to master for Emacs 31.

The effect on activities.el is purely cosmetic.  I think it's fine to
wait for 31.

Thanks for thinking it through together with me!

Joseph