bug#38802: 24.5; emacs unusable, unpredictably, with "k is undefined" for every key

[Eli Zaretskii]

> From: Samuel Wales <samologist@gmail.com>
> Date: Tue, 31 Dec 2019 22:39:37 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>, 38802@debbugs.gnu.org
> 
> i will try to post a screenshot next time.  it could be quite a long time.

That's OK.  If this problem happens to others, they might come up with
data sooner; if not, it means the problem is rare enough for it not to
be urgent.

Btw, if you can afford that, I'd suggest to upgrade to a newer version
of Emacs, because perhaps this problem was already solved.  The
current version is 26.3, and 27.1 will start its pretest soon.

> any suggestions of what to put in for a sigusr1 or sigusr2  would be
> interesting.

I'd suggest to use debug-on-event.  You can read about it in the ELisp
manual, node "Error Debugging".