Re: Weired side-effect of using the remap feature in keymaps

[Chong Yidong]

>         (defvar my-dummy-map (make-keymap))
>         (define-key my-dummy-map
>           (vector 'remap 'delete-backward-char) 'backward-char)
>         (switch-to-buffer (get-buffer-create "foo"))
>         (use-local-map my-dummy-map)

>      (where-is-internal 'delete-backward-char global-map)
>
>    This search seems to fail after the code above, i.e. something
>    seems to have changed in global map which should not have changed.

The trouble is that when where_is_internal checks whether the command
you entered is remapped, it does so using Fcommand_remapping, which
looks at all currently-active keymaps.  The alternative is to scan
through the provided keymaps manually.

The following patch should DTRT.

*** emacs/src/keymap.c.~1.348.~ 2007-03-24 21:19:54.000000000 -0400
--- emacs/src/keymap.c  2007-03-31 11:44:16.000000000 -0400
***************
*** 2579,2593 ****
    /* 1 means ignore all menu bindings entirely.  */
    int nomenus = !NILP (firstonly) && !EQ (firstonly, Qnon_ascii);
  
-   /* If this command is remapped, then it has no key bindings
-      of its own.  */
-   if (NILP (no_remap) && SYMBOLP (definition))
-     {
-       Lisp_Object tem;
-       if (tem = Fcommand_remapping (definition, Qnil), !NILP (tem))
-       return Qnil;
-     }
- 
    found = keymaps;
    while (CONSP (found))
      {
--- 2579,2584 ----
***************
*** 2601,2606 ****
--- 2592,2615 ----
    found = Qnil;
    sequences = Qnil;
  
+   /* If this command is remapped, then it has no key bindings
+      of its own.  */
+   if (NILP (no_remap) && SYMBOLP (definition))
+     {
+       Lisp_Object check_maps, map, remap;
+ 
+       for (check_maps = maps;
+          !NILP (check_maps);
+          check_maps = Fcdr (check_maps))
+       {
+         map = Fcdr (Fcar (maps));
+         ASET (command_remapping_vector, 1, definition);
+         remap = Flookup_key (map, command_remapping_vector, Qnil);
+         if (!NILP (remap) && !INTEGERP (remap))
+           RETURN_UNGCPRO (Qnil);
+       }
+     }
+ 
    for (; !NILP (maps); maps = Fcdr (maps))
      {
        /* Key sequence to reach map, and the map that it reaches */