bug#54450: 29.0.50; redisplay--pre-redisplay-functions issue

[Ergus via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

On Fri, Mar 18, 2022 at 08:54:00PM +0200, Eli Zaretskii wrote:
>> Date: Fri, 18 Mar 2022 20:38:18 +0200
>> From: Eli Zaretskii <eliz@gnu.org>
>> Cc: 54450@debbugs.gnu.org
>>
>> > Yes, this could solve the issue for the region, but not in general for
>> > redisplay--update-cursor-face-highlight which was the initial problem
>> > with Juri's code. Same for any other function that goes into the
>> > pre-redisplay-functions hook.
>>
>> I asked for a test case, and this is what you gave me.
>>
>> If there's another test case, please show it.
>
>But before you do, please try the alternative patch below:
>
>diff --git a/src/xdisp.c b/src/xdisp.c
>index 5cb5839..6d8d4aa 100644
>--- a/src/xdisp.c
>+++ b/src/xdisp.c
>@@ -13211,7 +13211,8 @@ prepare_menu_bars (void)
> 	      struct window *w = XWINDOW (this);
> 	      if (w->redisplay
> 		  || XFRAME (w->frame)->redisplay
>-		  || XBUFFER (w->contents)->text->redisplay)
>+		  || XBUFFER (w->contents)->text->redisplay
>+		  || w->last_point != marker_position (w->pointm))
> 		{
> 		  windows = Fcons (this, windows);
> 		}

Yes, now this seems to solve the issue for the two use cases described.

Thanks,
Ergus