* src/lisp.h (last_undo_boundary): Declare new var.

* src/keyboard.c (command_loop_1): Set it.
* src/cmds.c (Fself_insert_command): Use it to only remove boundaries that
were auto-added by the command loop.

Fixes: debbugs:11774

1 files changed, 4 insertions, 1 deletions

diff --git a/src/cmds.c b/src/cmds.c
index d617c7f81d9..a7a2eb6f528 100644
--- a/src/cmds.c
+++ b/src/cmds.c
@@ -296,7 +296,10 @@ At the end, it runs `post-self-insert-hook'.  */)
 
   if (remove_boundary
       && CONSP (BVAR (current_buffer, undo_list))
-      && NILP (XCAR (BVAR (current_buffer, undo_list))))
+      && NILP (XCAR (BVAR (current_buffer, undo_list)))
+      /* Only remove auto-added boundaries, not boundaries
+         added be explicit calls to undo-boundary.  */
+      && EQ (BVAR (current_buffer, undo_list), last_undo_boundary))
     /* Remove the undo_boundary that was just pushed.  */
     BVAR (current_buffer, undo_list) = XCDR (BVAR (current_buffer, undo_list));