bug#71744: 29.4; SIGSEGV during completion-at-point in lsp-mode with corfu and cape

[Eli Zaretskii <eliz@gnu.org>]

> From: Matthew Rothlisberger <mattjrothlis@gmail.com>
> Date: Wed, 26 Jun 2024 19:27:00 -0400
> Cc: 71744@debbugs.gnu.org
> 
> Thanks for your reply.
> 
> > On Mon, Jun 24, 2024 at 08:28  Eli Zaretskii <eliz@gnu.org> wrote:
> > Thanks, but we need a full GDB backtrace in order to investigate this, since your use case involves a lot of
> moving parts that are not part of Emacs.
> 
> Here's GDB output after triggering the crash:
> 
> Thread 1 "emacs" received signal SIGSEGV, Segmentation fault.
> Fget (symbol=XIL(0x555555f430d0), propname=XIL(0x6a20))
>     at /usr/src/debug/emacs/emacs-29.4/src/lisp.h:1152
> 1152  return p;
> (gdb) bt full
> #0  Fget (symbol=XIL(0x555555f430d0), propname=XIL(0x6a20)) at
> /usr/src/debug/emacs/emacs-29.4/src/lisp.h:1152
>         propval = <optimized out>
>         propval = <optimized out>
> #1  Fget (symbol=XIL(0x555555f430d0), propname=XIL(0x6a20)) at
> /usr/src/debug/emacs/emacs-29.4/src/fns.c:2516
>         propval = <optimized out>
> #2  0x0000555555727621 in parse_modifiers (symbol=XIL(0x555555f430d0)) at
> /usr/src/debug/emacs/emacs-29.4/src/keyboard.c:6897
>         elements = <optimized out>
>         elements = <optimized out>
>         end = <optimized out>
>         modifiers = <optimized out>
>         unmodified = <optimized out>
>         mask = <optimized out>
> #3  parse_modifiers (symbol=XIL(0x555555f430d0)) at
> /usr/src/debug/emacs/emacs-29.4/src/keyboard.c:6888
>         elements = <optimized out>
>         end = <optimized out>
>         modifiers = <optimized out>
>         unmodified = <optimized out>
>         mask = <optimized out>
> #4  0x00005555557377b8 in reorder_modifiers (symbol=<optimized out>) at
> /usr/src/debug/emacs/emacs-29.4/src/keyboard.c:7028
>         parsed = <optimized out>
>         parsed = <optimized out>

Thanks.  I don't see any obvious reasons for the crash, sorry, not
with so many variables "optimized out".  I do notice that your build
was done with many non-default compilation and link switches, so maybe
one of them causes this in some way.

Perhaps try reproducing this in an unoptimized build, maybe this will
give us more information regarding where and why this happens.

You mentioned earlier this doesn't happen in Emacs 31, does it mean
the master branch of the Emacs Git repository doesn't have this
problem?  How about the emacs-30 release branch (which will become
Emacs 30.1)?