Subject: bug#3938 closed by "Drew Adams" <[email-masked]> (bug#3938: 23.0.96; regression: minibuffer-message interferes with C-u)

From: [email-masked] (Emacs bug Tracking System)
Date: Tue, 28 Jul 2009 20:20:06 +0000

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#3938: 23.0.96; regression: minibuffer-message interferes with C-u

It has been closed by "Drew Adams" <[email-masked]>.

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If this explanation is unsatisfactory and you have not received a
better one in a separate message then please contact "Drew Adams" <[email-masked]> by
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3938: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=3938
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Subject: bug#3938: 23.0.96; regression: minibuffer-message interferes with C-u
From: "Drew Adams" <[email-masked]>
To: "'Chong Yidong'" <[email-masked]>
Cc: <[email-masked]>
Date: Tue, 28 Jul 2009 13:14:19 -0700

> The function `sit-for', which `minibuffer-message' uses, treats C-u
> specially.  It's easy to get your code to work; just put the call to
> `minibuffer-message' after `ensure-overriding-map-is-bound':
> 
> (defun test-univ-arg ()
>   (interactive)
>   (setq prefix-arg                     (list 4)
>         universal-argument-num-events  (length (this-command-keys)))
>   (ensure-overriding-map-is-bound)
>   (minibuffer-message "FOO"))

Actually, I already had the call to `minibuffer-message' last, in my own code.

I pared down my original code again, and discovered that the problem of the
regression is elsewhere. (Note, BTW, that the definition of `sit-for' has not
changed in Emacs 23 wrt Emacs 22, and this bug is a regression from Emacs 22.)

emacs -Q

(define-key minibuffer-local-must-match-map "\C-f" 'test2)
(define-key minibuffer-local-must-match-map
  (vector 'remap 'universal-argument) 'test-univ-arg)

(defun test2 () (interactive) (describe-function '+))

(defun test-univ-arg ()
  (interactive)
  (setq prefix-arg                     (list 4)
        universal-argument-num-events  (length (this-command-keys)))
  (my-ensure-overriding-map-is-bound)
  (minibuffer-message "FOO"))

;; Same as `ensure-overriding-map-is-bound', but with
;; `my-universal-argument-map' instead of `universal-argument-map'.
(defun my-ensure-overriding-map-is-bound ()
  (unless overriding-map-is-bound
    (setq saved-overriding-map           overriding-terminal-local-map
          overriding-terminal-local-map  my-universal-argument-map
          overriding-map-is-bound        t)))

;; Exact copy of `universal-argument-map'.
(defvar my-universal-argument-map
  (let ((map  (make-sparse-keymap)))
    (define-key map [t] 'universal-argument-other-key)
    (define-key map (vector meta-prefix-char t) 'universal-argument-other-key)
    (define-key map [switch-frame] nil)
    (define-key map [?\C-u] 'universal-argument-more)
    (define-key map [?-] 'universal-argument-minus)
    (define-key map [?0] 'digit-argument)
    (define-key map [?1] 'digit-argument)
    (define-key map [?2] 'digit-argument)
    (define-key map [?3] 'digit-argument)
    (define-key map [?4] 'digit-argument)
    (define-key map [?5] 'digit-argument)
    (define-key map [?6] 'digit-argument)
    (define-key map [?7] 'digit-argument)
    (define-key map [?8] 'digit-argument)
    (define-key map [?9] 'digit-argument)
    (define-key map [kp-0] 'digit-argument)
    (define-key map [kp-1] 'digit-argument)
    (define-key map [kp-2] 'digit-argument)
    (define-key map [kp-3] 'digit-argument)
    (define-key map [kp-4] 'digit-argument)
    (define-key map [kp-5] 'digit-argument)
    (define-key map [kp-6] 'digit-argument)
    (define-key map [kp-7] 'digit-argument)
    (define-key map [kp-8] 'digit-argument)
    (define-key map [kp-9] 'digit-argument)
    (define-key map [kp-subtract] 'universal-argument-minus)
    map))

IOW, we use an exact copy of `universal-argument-map' instead of
`universal-argument-map' itself. That's the only change from vanilla Emacs (the
definition of `my-ensure-overriding-map-is-bound' just reflects the vanilla
definition).

Same instructions as before: M-x C-u C-f, hitting C-f right after C-u (no delay)
vs waiting until the 2-sec delay for `minibuffer-message' has elapsed.

Compare the same test using Emacs 22.

With Emacs 23, the delay must elapse entirely - the user input event of hitting
`C-f' does not seem to interrupt it (`sit-for' should be interrupted by an input
event). So the effect, in Emacs 23, is that you need to hit `C-f' twice (or wait
before hitting it). In Emacs 22, hitting `C-f' just once works immediately. In
Emacs 23, the first `C-f' just has the effect of clearing "FOO" from the
minibuffer.

[Also, if instead of using `my-universal-argument-map' you use (copy-keymap
universal-argument-map) the result is the same. Using
`my-universal-argument-map' is a better test, since `copy-keymap' doesn't copy
recursively.]

Subject: 23.0.96; regression: minibuffer-message interferes with C-u
From: "Drew Adams" <[email-masked]>
To: <[email-masked]>
Date: Sun, 26 Jul 2009 16:30:44 -0700

emacs -Q
 
Eval these:

(defun test-univ-arg ()
  (interactive)
  (setq prefix-arg                     (list 4)
        universal-argument-num-events  (length (this-command-keys)))
  (minibuffer-message "FOO") ; NO GOOD. OK ONLY IF THIS IS REMOVED
  (ensure-overriding-map-is-bound))
 
(defun test2 () (interactive) (describe-function '+))
 
(define-key minibuffer-local-completion-map "\C-f" 'test2)
(define-key minibuffer-local-completion-map
  (vector 'remap 'universal-argument) 'test-univ-arg)
 
Note that the definition of `test-univ-arg' is identical to the
definition of `universal-argument', except for the addition of the
call to `minibuffer-message'.

1. Now do this, without waiting for the 2-sec delay after C-u.
That is, hit C-f immediately after C-u.
 
M-x C-u C-f
 
2. Now do `M-x C-u C-f' again, this time waiting for the delay,
so the minibuffer message `FOO' is no longer displayed, before
hitting `C-f'.
 
#2 has the correct behavior: the input event `C-f' interrupts the
minibuffer message and immediately executes the `C-f' command (the
particular command used is immaterial; I use `describe-function'
just to easily see whether it is executed).
 
In Emacs 23, #1 has this incorrect effect: After C-u, the minibuffer
message FOO is erased, but the `C-f' is not picked up. You must
repeat `C-f' a second time, to get it to be picked up.

Note that if you hit C-f twice even very quickly, then the second
`C-f' is picked up (but not the first). IOW, the problem doesn't
seem to be that the delay has not passed. It seems to be that
only the first input event is ignored if the delay has not
expired. It's hard to hit C-f twice quickly, so I'm not certain
about this, but it seems to be the case.

In Emacs prior to Emacs 23, #1 also had the correct behavior of #2.
IOW, this is a regression.

In GNU Emacs 23.0.96.1 (i386-mingw-nt5.1.2600)
 of 2009-07-09 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4)'