Re: emacs-29: let*: Symbol’s function definition is void: \(setf\ compat-alist-get\) with Magit

[Tassilo Horn]

Robert Pluim <rpluim@gmail.com> writes:

>     Tassilo> See https://github.com/magit/magit/issues/4836.
>
> Oops. Breaking compatibility in a package called `compat' is a bit of
> a no-no :-)

That's funny but I think we should make clear there's no sarcasm in that
statement.  What I've understood from the various bug reports is that
David Mendler has explained why that change is for the better in the
long term and he coordinated carefully with authors of packages using
the compat library.

The result of that coordination was that when API-breaking compat
appeared, those packages had the required changes in place and required
the new compat version.  On package update, first the new compat was
installed, then the packages using the compat library.

However, it seems like when a package gets updated, it's not reloaded
and thusly the packages using the compat library where compiled with the
old compat version and that's why those errors popped up.

>     Tassilo> Basically, there has been a compat (the package) change
>     Tassilo> where after updating the compat package, one has to
>     Tassilo> re-install magit (and other packages) using that new
>     Tassilo> compat version.  That is required because some macro has
>     Tassilo> been changed.
>
> Thanks for that info, I guess that means this isnʼt an Emacs bug.

Decide for yourself.  I feel it could be an emacs bug.

Bye,
Tassilo