emacs-29 f26622b2a47: * lisp/subr.el (combine-change-calls-1): Fix bug#64989

[Stefan Monnier]

branch: emacs-29
commit f26622b2a470a6d9cfbabbaa96f6aa3966febf2f
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Commit: Stefan Monnier <monnier@iro.umontreal.ca>

    * lisp/subr.el (combine-change-calls-1): Fix bug#64989
    
    Silence the spurious warning, and improve the warning while at it.
    Do not merge to master.
---
 lisp/subr.el | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lisp/subr.el b/lisp/subr.el
index 28473f1d38c..3ad57eeef2a 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -5002,8 +5002,8 @@ the function `undo--wrap-and-run-primitive-undo'."
                        ;; Don't include a timestamp entry.
                        (setcdr ptr (cddr ptr))
                      (setq ptr (cdr ptr))))
-                 (unless (cdr ptr)
-                   (message "combine-change-calls: buffer-undo-list broken"))
+                 (unless (or (cdr ptr) (null old-bul))
+                   (message "combine-change-calls: buffer-undo-list presumably 
truncated by GC"))
                  (setcdr ptr nil)
                  (push ap-elt buffer-undo-list)
                  (setcdr buffer-undo-list old-bul)))))