--- a/lisp/ChangeLog	Fri Mar 11 20:40:01 2011 +0000
+++ b/lisp/ChangeLog	Sat Mar 12 13:11:31 2011 +0000
@@ -1,3 +1,16 @@
+2011-03-12  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* isearch-mode.el (isearch-mode-map):
+	Document why we bind the ASCII characters to isearch-printing-char
+	in more detail.
+	* isearch-mode.el (isearch-maybe-frob-keyboard-macros):
+	If `this-command' is nil and the keys typed would normally be
+	bound to `self-insert-command' in the global map, force
+	`isearch-printing-char' to be called with an appropriate value for
+	last-command-event. Addresses an issue where searching for
+	characters generated from x-compose.el and XIM threw errors for me
+	in dired.
+
 2011-03-10  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* etags.el (buffer-tag-table-list):

--- a/lisp/isearch-mode.el	Fri Mar 11 20:40:01 2011 +0000
+++ b/lisp/isearch-mode.el	Sat Mar 12 13:11:31 2011 +0000
@@ -239,10 +239,18 @@
   (let ((map (make-keymap)))
     (set-keymap-name map 'isearch-mode-map)
 
-    ;; Bind all printing characters to `isearch-printing-char'.
-    ;; This isn't normally necessary, but if a printing character were
-    ;; bound to something other than self-insert-command in global-map,
-    ;; then it would terminate the search and be executed without this.
+    ;; Bind ASCII printing characters to `isearch-printing-char'.  This
+    ;; isn't normally necessary, but if a printing character were bound to
+    ;; something other than self-insert-command in global-map, then it would
+    ;; terminate the search and be executed without this.
+
+    ;; This is also relevant when other modes (notably dired and gnus) call
+    ;; `suppress-keymap' on their major mode maps; this means that
+    ;; `isearch-maybe-frob-keyboard-macros' won't pick up that the command
+    ;; that would normally be executed is `self-insert-command' and do its
+    ;; thing of transforming that to `isearch-printing-char'. This is less
+    ;; of an issue for the non-ASCII characters, because they rarely have
+    ;; specific bindings in major modes.
     (let ((i 32)
 	  (str (make-string 1 0)))
       (while (< i 127)
@@ -1609,8 +1617,27 @@
 	       last-command-char (and (stringp this-command)
 				      (aref this-command 0))
 	       this-command 'isearch-printing-char))
-	))
-
+	((and (null this-command)
+              (eq 'key-press (event-type last-command-event))
+              (current-local-map)
+              (let* ((this-command-keys (this-command-keys))
+                     (this-command-keys (or (lookup-key function-key-map
+                                                        this-command-keys)
+                                            this-command-keys))
+                     (lookup-key (lookup-key global-map this-command-keys)))
+                (and (eq 'self-insert-command lookup-key)
+                     ;; The feature here that a modification of
+                     ;; last-command-event is respected is undocumented, and
+                     ;; only applies when this-command is nil. The design
+                     ;; isn't reat, and I welcome suggestions for a better
+                     ;; one.
+                     (setq last-command-event
+                           (find-if 'key-press-event-p this-command-keys
+                                    :from-end t)
+                           last-command-char
+                           (event-to-character last-command-event)
+                           this-command 'isearch-printing-char)))))))
+                           
 
 ;;;========================================================
 ;;; Highlighting

--- a/src/ChangeLog	Fri Mar 11 20:40:01 2011 +0000
+++ b/src/ChangeLog	Sat Mar 12 13:11:31 2011 +0000
@@ -1,3 +1,14 @@
+2011-03-12  Aidan Kehoe  <kehoea@parhasard.net>
+
+	* event-stream.c (Fdispatch_event):
+	As documented, allow pre-command-hook to usefully modify
+	this-command even when this-command is nil (that is, we would
+	normally throw an undefined-keystroke-sequence error). Don't throw
+	that error if this-command was modified, instead try to execute
+	the new value.
+	Allow pre-command-hook to modify last-command-event in this
+	specific context. Don't document this, for the moment.
+
 2011-03-11  Aidan Kehoe  <kehoea@parhasard.net>
 
 	* bytecode.c (optimize_byte_code):

--- a/src/event-stream.c	Fri Mar 11 20:40:01 2011 +0000
+++ b/src/event-stream.c	Sat Mar 12 13:11:31 2011 +0000
@@ -4445,6 +4445,7 @@
       {
 	Lisp_Object leaf = lookup_command_event (command_builder, event, 1);
 
+      lookedup:
 	if (KEYMAPP (leaf))
 	  /* Incomplete key sequence */
 	  break;
@@ -4524,6 +4525,22 @@
 		GCPRO1 (keys);
 		pre_command_hook ();
 		UNGCPRO;
+
+                if (!NILP (Vthis_command))
+                  {
+                    /* Allow pre-command-hook to change the command to
+                       something more useful, and avoid barfing. */
+                    leaf = Vthis_command;
+                    if (!EQ (command_builder->most_current_event,
+                             Vlast_command_event))
+                      {
+                        reset_current_events (command_builder);
+                        command_builder_append_event (command_builder,
+                                                      Vlast_command_event);
+                      }
+                    goto lookedup;
+                  }
+
 		/* The post-command-hook doesn't run. */
 		Fsignal (Qundefined_keystroke_sequence, list1 (keys));
 	      }