Re: [PATCH] On the nasty "ghost key" problem on NS

[Kai Ma]

On Nov 4, 2022, at 17:29, Po Lu <luangruo@yahoo.com> wrote:

Kai Ma <justksqsf@gmail.com> writes:

Yes and no. Emacs still responds to new key events, but a previous
call is stuck and does not return. Presumably in another thread. To be
more clear: changing that code to be

 static int enter_cnt, leave_cnt;
 enter_cnt++;
 [referenced piece of code]
 leave_cnt++;
 /* (Or just count the return/leave counts of (ns-in-echo-area).) */

leave_cnt can be less than enter_cnt. I’ve confirmed re-entrance to
[firstRectForCharacterRange] leads to the problem.

I'm going to guess what actually happened is that ns-in-echo-area
signalled.

What happens if you replace ns-in-echo-area with:

 safe_call (0, Qns_in_echo_area)

?

Yes, this indeed is related to signals, but it’s not (ns-in-echo-area) that signals. It seems that there are problems in nsterm.m regarding waiting_for_input, which caused aborts for me ([eval.c:signal_or_quit] asserts !waiting_for_input). It’s also observed that inhibit-quit must be set, or the bug persists.

I believe the attached patch fixes this bug, but I don’t know why Vthrow_on_input is not correctly handled by safe_call. 

fix-ghost-key-v2.patch
Description: Binary data