Re: question about markers, replace-match, and undo

[Richard Stallman]

    I have some text, with a marker before it and a marker after it. For
    instance, the first marker is at position 41, just before `m', and the
    second is at position 48, just after `s':

      41     48
        mnopqrs

    I match this text, and then call (replace-match "ABC"), with the result that
    the first marker is still at position 41 and the second marker is now at
    position 44, just after `C', which is what I would expect and what I want:

      41 44
        ABC

    I use `undo', and the result is that both markers are now at position 41:

      41
      41
        mnopqrs

That is definitely a bug.  Does this fix it?

*** insdel.c    02 Mar 2007 03:28:13 -0500      1.190
--- insdel.c    27 Apr 2007 23:55:23 -0400      
***************
*** 1603,1610 ****
  
    if (! EQ (current_buffer->undo_list, Qt))
      {
        record_delete (from, deletion);
-       record_insert (from, inschars);
      }
  
    GAP_SIZE -= outgoing_insbytes;
--- 1603,1614 ----
  
    if (! EQ (current_buffer->undo_list, Qt))
      {
+       /* Record the insertion first, so that when we undo,
+        the deletion will be undone first.  Thus, undo
+        will insert before deleting, and thus will keep
+        the markers before and after this text separate.  */
+       record_insert (from + SCHARS (deletion), inschars);
        record_delete (from, deletion);
      }
  
    GAP_SIZE -= outgoing_insbytes;