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

[Tassilo Horn <tsdh@gnu.org>]

Robert Pluim <rpluim@gmail.com> writes:

>>>>>> On Wed, 18 Jan 2023 19:39:54 +0100, Tassilo Horn <tsdh@gnu.org> said:
>
>     Tassilo> The result of that coordination was that when API-breaking compat
>     Tassilo> appeared, those packages had the required changes in place and
>     Tassilo> required
>     Tassilo> the new compat version.  On package update, first the new compat
>     Tassilo> was
>     Tassilo> installed, then the packages using the compat library.
>
>     Tassilo> However, it seems like when a package gets updated, it's not
>     Tassilo> reloaded
>     Tassilo> and thusly the packages using the compat library where compiled
>     Tassilo> with the
>     Tassilo> 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.
>
> That could or could not be an Emacs bug. I guess weʼd need a recipe
> from 'emacs -Q' to be sure.

How would one create a recipe with emacs -Q when one is interested in
package updates?  I guess one would rather use emacs -q in a testuser
account with no ~/.emacs.

I think what one has to do would create fake packages

  macro-1.0
  use-macro-1.0 requires macro-1.0

and install use-macro-1.0, macro-1.0 as a dependency.  Then make a
breaking change in macro leading to macro-2.0 required by use-macro-2.0
which will error if use-macro-2.0 was compiled with macro-1.0 instead of
2.0.

Bye,
Tassilo