Re: Emacs 25.1 RC1 - some issues

[Stefan Monnier <monnier@iro.umontreal.ca>]

SM> There's a chance this is due to the fact that Emacs-25 breaks
SM> binary compatibility with EIEIO.  More specifically, a package
SM> using EIEIO and compiled with Emacs<25 won't work on Emacs-25
SM> until you recompile it (after which it won't work with Emacs<25
SM> either).

> I could say that your supposition holds.
> I had an old CEDET subtree in site-lisp and that bytecode is quite
> old.
> Since CEDET is a builtin now, I removed my version and now everything
> goes fine.

Hmm... maybe it's a bit late to do that, but maybe it would make sense
to add code to EIEIO which tries to catch those old uses and emit a more
friendly/helpful message (it's actually difficult to fix it
automatically, so I don't think we can hope to do that).

I know there are cases where the error is "uncatchable", tho, so we'd
first have to see exactly how the error manifests in your case (i.e. at
least the full backtrace) to have a better view of how to attack
the problems and whether it's worth the trouble.


        Stefan