Subject: bug#74437: 30.0.92; completion-preview-idle-delay is delayed by flyspell

From: Eshel Yaron <[email-masked]>
Date: Fri, 22 Nov 2024 08:26:42 +0100

Eli Zaretskii <[email-masked]> writes:

>> From: Eshel Yaron <[email-masked]>
>> Cc: [email-masked],  [email-masked]
>> Date: Wed, 20 Nov 2024 16:52:49 +0100
>> 
>> Eli Zaretskii <[email-masked]> writes:
>> 
>> >> From: Eshel Yaron <[email-masked]>
>> >> Cc: [email-masked],  [email-masked]
>> >> Date: Tue, 19 Nov 2024 21:16:56 +0100
>> >
>> >> > Also, what happens if there are other async
>> >> > subprocesses running in parallel, like maybe Grep or compilation or
>> >> > url-retrieve?
>> >> 
>> >> They make progress, which seems to work as expected, at least with Grep.
>> >> That is if we use the previous patch, with the one below we pass non-nil
>> >> JUST-THIS-ONE argument to accept-process-output when called from a timer
>> >> so other processes shouldn't see new output during this call.  Either
>> >> way works, AFAICT.
>> >
>> > The question is: what do users expect to happen in those cases?
>> 
>> I don't know
>
> Neither do I.  I didn't say something was wrong with either of these
> implementations, I'm just saying they should be well tested by users
> before we have enough basis to make the decisions whether the idea is
> generally good and whether it should probably become the default in
> some future version.

Sounds good.  So here's a full patch that keeps the current
implementation as the default:

>From 0dfa6f8b4aaa825a2587fa36f30bf9f55918ff3d Mon Sep 17 00:00:00 2001
From: Eshel Yaron <[email-masked]>
Date: Fri, 22 Nov 2024 08:17:25 +0100
Subject: [PATCH] New option 'flyspell-delay-use-timer'

* lisp/textmodes/flyspell.el (flyspell-delay-use-timer):
New user option.
(flyspell--timer): New variable.
(flyspell-check-word-p): Use them.
(flyspell-post-command-hook): Disable timer.
(flyspell-word): Pass non-nil SECONDS argument to
'accept-process-output' to permit quitting.  (bug#74437)
---
 lisp/textmodes/flyspell.el | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/lisp/textmodes/flyspell.el b/lisp/textmodes/flyspell.el
index 09d4e8a8d1a..5fcb83efb57 100644
--- a/lisp/textmodes/flyspell.el
+++ b/lisp/textmodes/flyspell.el
@@ -810,6 +810,18 @@ flyspell-check-changed-word-p
              (let ((pos (point)))
                (or (>= pos start) (<= pos stop) (= pos (1+ stop))))))))
 
+(defcustom flyspell-delay-use-timer nil
+  "Whether Flyspell should use a timer for waiting after a delayed command.
+
+If this is non-nil, Flyspell sets up a timer for checking the word at
+point `flyspell-delay' seconds after you invoke a delayed command.
+Otherwise, if this option is nil, Flyspell uses `sit-for' to wait for
+that duration instead."
+  :type 'boolean
+  :version "31.1")
+
+(defvar flyspell--timer nil)
+
 ;;*---------------------------------------------------------------------*/
 ;;*    flyspell-check-word-p ...                                        */
 ;;*---------------------------------------------------------------------*/
@@ -844,7 +856,16 @@ flyspell-check-word-p
 	;; The current command is not delayed, that
 	;; is that we must check the word now.
 	(and (not unread-command-events)
-	     (sit-for flyspell-delay)))
+             (if (not flyspell-delay-use-timer)
+                 (sit-for flyspell-delay)
+               (setq flyspell--timer
+                     (run-with-idle-timer
+                      flyspell-delay nil
+                      (lambda (buffer)
+                        (when (eq (current-buffer) buffer)
+                          (flyspell-word nil nil t)))
+                      (current-buffer)))
+               nil)))
        (t t)))
      (t t))))
 
@@ -955,6 +976,7 @@ flyspell-debug-signal-changed-checked
 (defun flyspell-post-command-hook ()
   "The `post-command-hook' used by flyspell to check a word on-the-fly."
   (interactive)
+  (when (timerp flyspell--timer) (cl-callf cancel-timer flyspell--timer))
   (when flyspell-mode
     (with-local-quit
       (let ((command this-command)
@@ -1179,7 +1201,7 @@ flyspell-word
 		  (set-process-query-on-exit-flag ispell-process nil)
                   ;; Wait until ispell has processed word.
                   (while (progn
-                           (accept-process-output ispell-process)
+                           (accept-process-output ispell-process 1)
                            (not (string= "" (car ispell-filter)))))
                   ;; (ispell-send-string "!\n")
                   ;; back to terse mode.
-- 
2.46.2