bug#61667: 29.0.60; Failure to redisplay

[Dmitry Gutov]

On 25/02/2023 09:21, Po Lu via Bug reports for GNU Emacs, the Swiss army 
knife of text editors wrote:
> Eli Zaretskii<eliz@gnu.org>  writes:
>
> > Yes.  Which means these X and GTK calls are not the direct culprit of
> > the delay.
> What happens if you add an explicit call to XFlush afterwards?
> If that makes it work, then the frame title delay is caused by some
> slowness after the call is made.
>
> An Xlib function will only place the request onto an output buffer,
> which is normally flushed when it becomes full or the next time Xlib
> decides to read input or wait for a reply from the X server.  The
> library also performs optimizations on requests inside the output
> buffer, mostly those of the Poly* type.  You have to call XFlush
> manually after making a request if you really want it to be sent.

Alas, this doesn't fix the problem:

diff --git a/src/xfns.c b/src/xfns.c
index 528ae61ca32..803a692bfbf 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -2211,6 +2211,8 @@ x_set_name_internal (struct frame *f, Lisp_Object 
name)
 #ifdef USE_GTK
         gtk_window_set_title (GTK_WINDOW (FRAME_GTK_OUTER_WIDGET (f)),
                               SSDATA (encoded_name));
+       XFlush (FRAME_X_DISPLAY (f));
+
 #else /* not USE_GTK */
        XSetWMName (FRAME_X_DISPLAY (f), FRAME_OUTER_WINDOW (f), &text);
        XChangeProperty (FRAME_X_DISPLAY (f), FRAME_OUTER_WINDOW (f),
@@ -2291,6 +2293,8 @@ x_set_name (struct frame *f, Lisp_Object name, 
bool explicit)
     name = f->title;

   x_set_name_internal (f, name);
+
+  XFlush (FRAME_X_DISPLAY (f));
 }

 /* This function should be called when the user's lisp code has
@@ -2331,6 +2335,8 @@ x_set_title (struct frame *f, Lisp_Object name, 
Lisp_Object old_name)
     CHECK_STRING (name);

   x_set_name_internal (f, name);
+
+  XFlush (FRAME_X_DISPLAY (f));
 }

 void