Re: Idle timers with the active minibuffer

[bojohan+news@dd.chalmers.se (Johan Bockgård)]

Juri Linkov <juri@jurta.org> writes:

> Why idle timers don't run when the minibuffer is activated?
>
> I discovered this behavior when tried using isearch in the original
> buffer after switching to it from the minibuffer without exiting it.
> The idle timer for lazy-highlighting doesn't run.  Steps to reproduce:
>
> 1. activate the minibuffer by e.g. `M-:'
> 2. switch back to the original buffer by `C-x o'
> 3. start isearch C-s and search for a string that have multiple
> occurrences in the original buffer.
>
> Other occurrences are not highlighted by lazy-highlight face.
> Putting a breakpoint on isearch-lazy-highlight-update shows
> that run-with-idle-timer from isearch-lazy-highlight-new-loop
> never runs it when the minibuffer is not yet exited.
>
> Is it an intentional behavior or a bug?

It worked in Emacs 21. The problem seems to come from the change
to command_loop_1 in the following set of changes:

revision 1.312
date: 2006-10-10 03:20:20 +0200;  author: cyd;  state: Exp;  lines: +2 -5;
	* dispnew.c (sit_for): Sit forever if TIMEOUT is t.

	* keyboard.c (command_loop_1): Handle non-number values of
	`minibuffer-message-timeout'.
	(Fexecute_extended_command): Fix typo.

	* minibuf.c (temp_echo_area_glyphs): Sit for
	`minibuffer-message-timeout' seconds.

The change in question was this:

--- keyboard.c	15 Sep 2006 07:19:14 -0000	1.877
+++ keyboard.c	10 Oct 2006 01:20:20 -0000	1.878
@@ -1546,15 +1546,17 @@
 
       if (minibuf_level
 	  && !NILP (echo_area_buffer[0])
-	  && EQ (minibuf_window, echo_area_window)
-	  && NUMBERP (Vminibuffer_message_timeout))
+	  && EQ (minibuf_window, echo_area_window))
 	{
 	  /* Bind inhibit-quit to t so that C-g gets read in
 	     rather than quitting back to the minibuffer.  */
 	  int count = SPECPDL_INDEX ();
 	  specbind (Qinhibit_quit, Qt);
 
-	  sit_for (Vminibuffer_message_timeout, 0, 2);
+	  if (NUMBERP (Vminibuffer_message_timeout))
+	    sit_for (Vminibuffer_message_timeout, 0, 2);
+	  else
+	    sit_for (Qt, 0, 2);
 
 	  /* Clear the echo area.  */
 	  message2 (0, 0, 0);

I thinks it was made in response to this bug report

[minibuffer-message-timeout has no effect]
http://lists.gnu.org/archive/html/emacs-devel/2006-10/msg00216.html

Reverting the change fixes the isearch problem. The bug report contained
no test case, but the following example works correctly without the
change to command_loop_1 (the fix to temp_echo_area_glyphs is enough).

    (defun foo ()
      (interactive)
      (let ((minibuffer-message-timeout 0.2))
        (minibuffer-message "foo")))

    (global-set-key [f7] 'foo)

    ;; M-: <f7>

-- 
Johan Bockgård