bug#56869: 29.0.50; segfault, "assertion 'GDK_IS_DEVICE (device)' failed"

[Po Lu]

Joe Corneli <joseph.corneli@hyperreal.enterprises> writes:

> Now it’s produced the following, alongside the crash.  I’m happy to
> adapt the instrumentation further if this is not yet sufficiently
> useful!

Could you please type "coredumpctl debug emacs", and then in the
debugger prompt, type "bt", and send the complete backtrace?

In the meantime, I made an attempt to fix this on master based on some
serious guesswork.

Thanks.