bug#61667: 29.0.60; Failure to redisplay

[Dmitry Gutov <dgutov@yandex.ru>]

On 17/04/2023 05:31, Eli Zaretskii wrote:
>> Date: Mon, 17 Apr 2023 01:26:28 +0300
>> Cc: 61667@debbugs.gnu.org
>> From: Dmitry Gutov <dgutov@yandex.ru>
>>
>>> Dmitry, does this happen with Emacs 28?
>>
>> Actually, this one might be a master-only problem.
> 
> I wasn't aware of that; the Subject says 29.  I tried on the release
> branch and in the installed 29.0.90.

The behavior is very similar to the one originally reported in this bug.

At first the news was that the Lucid build doesn't help (on emacs-29 or 
master), because this scenario manifests when using it.

Then I've tried a build with xdbe=off, and now I can't quite remember 
from which branch it was. When doing subsequent testing, I think I've 
seen this problem once (probably just once) on branches emacs-29 and 
emacs-28, but neither was repeatable, so we might chalk that up to my 
faulty memory/cognition.

>> But it's pretty easy to repro on master. I'll try to bisect and report back.

Finished now. It was a pain because the offending commit predated the 
two commits that fixed the build without XDBE (4dc1f2b9a01e and 
f1c838980601), so I had to dump them as patch files and apply when 
building older commits.

ae4ff4f25fbf704446f8f38d8e818f223b79042b is the first bad commit
commit ae4ff4f25fbf704446f8f38d8e818f223b79042b
Author: Po Lu <luangruo@yahoo.com>
Date:   Sun Feb 12 19:55:28 2023 +0800

     Support input method ``text conversion'' on X Windows

     * configure.ac (HAVE_TEXT_CONVERSION): Define on X.
     * etc/NEWS: Announce new change.
     * src/emacs.c (main): Always call init_xterm.
     * src/frame.c (do_switch_frame): Use `fset_selected_window'.
     * src/insdel.c (struct safe_del_range_context): New structure.
     (safe_del_range_1, safe_del_range_2, safe_del_range): New
     functions.
     * src/lisp.h: Export new functions.
     * src/window.c (run_window_change_functions): Report selected
     window and buffer changes so that the input method can be reset.
     * src/xfns.c (XICCallback, Xxic_preedit_caret_callback)
     (Xxic_preedit_done_callback, Xxic_preedit_start_callback)
     (Xxic_preedit_draw_callback): Fix coding style.
     (Xxic_string_conversion_callback): New callback.
     (create_frame_xic): Register string conversion callback.
     (struct x_xim_text_conversion_data): New field `size'.
     (x_encode_xim_text_1, x_encode_xim_text): New functions.
     (xic_string_conversion_callback): New function.
     * src/xterm.c (x_reset_conversion): New function.
     (text_conversion_interface): New variable.
     (init_xterm): Initialize text conversion interface.

(Together with the next one, 9510e8ad68271f58b4, which it doesn't build 
without).

I've double checked that 9510e8ad682 exhibits the problem (with Lucid 
and xdbe=off), whereas ae4ff4f25fbf's parent (50140585a29) does not.