bug#43780: 27.1; defvaralias and define-obsolete-variable-alias

[Drew Adams]

> Since this bug report is just about one example; and since your tried
> "fix", when it had worked, would also have had an undesired global
> effect - what would be your favorite solution?
> 
> Would it make sense if Emacs provided a file-local variable with which
> you could specify an Emacs version and the effect would be that for
> compiling that file all warnings about obsolete stuff would be
> suppressed if the obsolete declaration happened in an Emacs version
> newer than what you specified?  So like
> 
>   ;;; byte-comp-suppress-obsolete 23.1
> 
> would have the effect that only stuff that has been obsolete before 23.1
> would be reported?

Sorry, but I don't have a plan/solution.

IMHO, that variable should never have been renamed.
If the renaming (done in 27.1, for dubious reasons)
could be reverted that would be great.  Or just
remove the obsolete part - have two aliases (no big
deal, and probably the best way to repair the damage
at this point).

The previous name was better, and in any case there
was no need (no good reason) to apply such a trivial,
gratuitous renaming, even if the new name were
(mistakenly) considered better.

See https://lists.gnu.org/archive/html/emacs-devel/2020-10/msg00326.html

I have no hope that this (trivial) bug (#43780) will
be fixed, and I have no other good solution for it
(besides removing the obsolete labeling).

Any code that uses the old name will lead to a compiler
warning now.  So be it.  I really wish this kind of
thing didn't happen.  No good purpose was served.

That's really the lesson here.  If that gets learned
somehow then the bother caused by this bug will have
been worth it.