(Fprimitive_undo): Check that undo function does not switch buffer.

diff --git a/src/undo.c b/src/undo.c
index 86237e2..b4e16bf 100644 (file)
--- a/src/undo.c
+++ b/src/undo.c
@@ -557,6 +557,8 @@ Return what remains of the list.  */)
              else if (EQ (car, Qapply))
                {
                  /* Element (apply FUN . ARGS) means call FUN to undo.  */
+                 struct buffer *save_buffer = current_buffer;
+
                  car = Fcar (cdr);
                  cdr = Fcdr (cdr);
                  if (INTEGERP (car))
@@ -582,6 +584,9 @@ Return what remains of the list.  */)
                    }
                  else
                    apply1 (car, cdr);
+
+                 if (save_buffer != current_buffer)
+                   error ("Undo function switched buffer");
                  did_apply = 1;
                }
              else if (STRINGP (car) && INTEGERP (cdr))