Make function-key-map apply when key is bound to `undefined'.

* src/keyboard.c (test_undefined): New function.
(read_key_sequence): Use it to detect when a key is bound to `undefined'.

Fixes: debbugs:9751

2 files changed, 19 insertions, 2 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index cee48bd1731..52581be2863 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2011-10-25  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * keyboard.c (test_undefined): New function (bug#9751).
+        (read_key_sequence): Use it to detect when a key is bound to `undefined'.
+
 2011-10-25  Enami Tsugutomo  <tsugutomo.enami@jp.sony.com>
 
         * sysdep.c (init_sys_modes): Fix the check for the controlling
diff --git a/src/keyboard.c b/src/keyboard.c
index 6f3bfd8c1e7..eb316947dcb 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -8902,6 +8902,14 @@ keyremap_step (Lisp_Object *keybuf, int bufsize, volatile keyremap *fkey,
   return 0;
 }
 
+static int
+test_undefined (Lisp_Object binding)
+{
+  return (EQ (binding, Qundefined)
+          || (!NILP (binding) && SYMBOLP (binding)
+              && EQ (Fcommand_remapping (binding, Qnil, Qnil), Qundefined)));
+}
+
 /* Read a sequence of keys that ends with a non prefix character,
    storing it in KEYBUF, a buffer of size BUFSIZE.
    Prompt with PROMPT.
@@ -9852,7 +9860,9 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
             }
         }
 
-      if (first_binding < nmaps && NILP (submaps[first_binding])
+      if (first_binding < nmaps
+          && NILP (submaps[first_binding])
+          && !test_undefined (defs[first_binding])
           && indec.start >= t)
         /* There is a binding and it's not a prefix.
            (and it doesn't have any input-decode-map translation pending).
@@ -9879,7 +9889,9 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
                                   /* If there's a binding (i.e.
                                      first_binding >= nmaps) we don't want
                                      to apply this function-key-mapping.  */
-                                  fkey.end + 1 == t && first_binding >= nmaps,
+                                  fkey.end + 1 == t
+                                  && (first_binding >= nmaps
+                                      || test_undefined (defs[first_binding])),
                                   &diff, prompt);
             UNGCPRO;
             if (done)