Re: master 9ade7ea: Fix Eldoc problem when loading on Emacs 26.3

[João Távora]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>>> Maybe come up with a better idea, or maybe, like Stefan suggests, don't
>>> make it an alias at all, just deprecate it and keep using it instead of
>>> eldoc-documentation-strategy when we find it to be bound.
>>
>> That sort of works, but it forces extensions that do want to
>> "Package-Require" eldoc to remember to unbind
>> eldoc-documentation-function if they are loaded on older Emacs versions,
>> which is undesirable.
>
> Maybe use a rule like:
>
>     (if (and (buffer-local-p 'eldoc-documentation-function)
>              (not (buffer-local-p 'eldoc-documentation-functions)))
>         <Use `eldoc-documentation-function`>
>       <Use `eldoc-documentation-functions`>

Sounds a bit complicated for me, especially since there's already a
eldoc--supported-p which does similar heuristics.  Wouldn't it break in
some older Emacs version that loads the new Eldoc and has some global
value in eldoc-documentation-functions (say, a spell-checking eldoc
backend)?

For now, I'd like to go with the alias/reverse-alias technique, which is
the simplest, I think, for this simple problem.  I've tested it and it
works correctly.  Have you seen the patch?  Do you see any blockers
there?  We can move on to some more sophisticated version later.

João