bug#57439: 29.0.50; xterm.c:20623: Emacs fatal error: assertion failed: !must_free_data

[Po Lu]

Gregor Zattler <grfz@gmx.de> writes:

> Dear Emacs developers,
>
> for me Emacs crashes if build Emacs master with git HEAD on
> 9ba6a7c508cbaed5eeedd56e7df633b722bf86b7 with --with-x-toolkit=no :
>
> 1. emacs -Q
> 2. click on "Options" menu
> 3. crash
>
> originally I did this with an -O3 optimized build, then for
> a hopefully better backtrace I re-build Emacs with -O0
> (which to build took roughly three times the amount of wall
> time than building the optimized one).
>
> This is the full backtrace:

Thanks.  Should be fixed now.

(This is really a bug in Xlib, since XGetEventData shouldn't return True
if the data no longer exists.)