master 28d4952d42: Improve error trapping on X

[Po Lu]

branch: master
commit 28d4952d423a088a53a82c8e02f283fa98b7e20d
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Improve error trapping on X
    
    * xterm.c (x_uncatch_errors, x_had_errors_p): Don't sync if no
    request was made since the error trap was installed.
---
 src/xterm.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 5c59113469..3e5aaf5d4a 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -21265,7 +21265,11 @@ x_uncatch_errors (void)
       /* There is no point in making this extra sync if all requests
         are known to have been fully processed.  */
       && (LastKnownRequestProcessed (x_error_message->dpy)
-         != NextRequest (x_error_message->dpy) - 1))
+         != NextRequest (x_error_message->dpy) - 1)
+      /* Likewise if no request was made since the trap was
+        installed.  */
+      && (NextRequest (x_error_message->dpy)
+         > x_error_message->first_request))
     XSync (x_error_message->dpy, False);
 
   tmp = x_error_message;
@@ -21315,8 +21319,10 @@ x_had_errors_p (Display *dpy)
     emacs_abort ();
 
   /* Make sure to catch any errors incurred so far.  */
-  if (LastKnownRequestProcessed (dpy)
-      != NextRequest (dpy) - 1)
+  if ((LastKnownRequestProcessed (dpy)
+       != NextRequest (dpy) - 1)
+      && (NextRequest (dpy)
+         > x_error_message->first_request))
     XSync (dpy, False);
 
   return x_error_message->string[0] != 0;