* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
@ 2024-09-24 8:19 Al Haji-Ali
2024-09-24 12:12 ` Eli Zaretskii
0 siblings, 1 reply; 6+ messages in thread
From: Al Haji-Ali @ 2024-09-24 8:19 UTC (permalink / raw)
To: 73446
Consider this code snippet:
,----
| (with-current-buffer (get-buffer "*scratch*")
| (message "START point %S %S" (current-buffer) (point))
| (goto-char 10)
| (message "BEFORE point %S %S" (current-buffer) (point))
| (with-current-buffer (get-buffer "*Messages*") ;; some random buffer
| (read-string "Test: "))
| (message "AFTER point %S %S" (current-buffer) (point)))
`----
Assuming that *scratch* has a point at something other than 10 and *is visible in a window*, I get this output in Messages
,----
| START point #<buffer *scratch*> 2952
| BEFORE point #<buffer *scratch*> 10
| AFTER point #<buffer *scratch*> 2952
`----
I was expecting (point) AFTER to be 100, as it was BEFORE.
This only happens when `read-string` is called and when `with-current-buffer` is nested, and only when *scratch* is visible in a window.
I can easily solve this issue with `save-excursion`, but I thought this might be an unintended behaviour worth reporting.
Best regards,
-- Al
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
2024-09-24 8:19 bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string Al Haji-Ali
@ 2024-09-24 12:12 ` Eli Zaretskii
2024-09-24 13:12 ` Al Haji-Ali
0 siblings, 1 reply; 6+ messages in thread
From: Eli Zaretskii @ 2024-09-24 12:12 UTC (permalink / raw)
To: Al Haji-Ali; +Cc: 73446
> From: Al Haji-Ali <abdo.haji.ali@gmail.com>
> Date: Tue, 24 Sep 2024 09:19:56 +0100
>
>
> Consider this code snippet:
>
> ,----
> | (with-current-buffer (get-buffer "*scratch*")
> | (message "START point %S %S" (current-buffer) (point))
> | (goto-char 10)
> | (message "BEFORE point %S %S" (current-buffer) (point))
> | (with-current-buffer (get-buffer "*Messages*") ;; some random buffer
> | (read-string "Test: "))
> | (message "AFTER point %S %S" (current-buffer) (point)))
> `----
>
> Assuming that *scratch* has a point at something other than 10 and *is visible in a window*, I get this output in Messages
>
> ,----
> | START point #<buffer *scratch*> 2952
> | BEFORE point #<buffer *scratch*> 10
> | AFTER point #<buffer *scratch*> 2952
> `----
>
> I was expecting (point) AFTER to be 100, as it was BEFORE.
>
> This only happens when `read-string` is called and when `with-current-buffer` is nested, and only when *scratch* is visible in a window.
I can't reproduce this, but see switch-to-buffer-preserve-window-point.
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
2024-09-24 12:12 ` Eli Zaretskii
@ 2024-09-24 13:12 ` Al Haji-Ali
2024-09-24 13:43 ` Eli Zaretskii
0 siblings, 1 reply; 6+ messages in thread
From: Al Haji-Ali @ 2024-09-24 13:12 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: 73446
> I can't reproduce this, but see switch-to-buffer-preserve-window-point.
Oh, is it maybe emacsen specific?
I have `switch-to-buffer-preserve-window-point` set to t, but setting it to `nil` gives the same result. Here's how I can reproduce the problem:
1. Open 'emacs -Q'.
2. Paste the following into the scratch buffer
(progn
(defun test-bug-73446 nil
(let ((buf1 "test1")
(buf2 "test2"))
(switch-to-buffer (get-buffer-create buf1))
(insert (make-string 20 ?H))
(goto-char 1)
(switch-to-buffer (get-buffer-create buf2))
(let ((switch-to-buffer-preserve-window-point t)
start before after)
(display-buffer buf1 'display-buffer-use-some-window)
(with-current-buffer (get-buffer buf1)
(setq start (point))
(goto-char 10)
(setq before (point))
(with-current-buffer (get-buffer buf2) ;; some random buffer
(read-string "Test: "))
(setq after (point)))
(list start before after))))
(message "%S" (test-bug-73446)))
3. Press `C-x c-e` (or call `eval-last-sexp`)
3. Press return when the prompt "Test: " appears.
4. I see the output (1 10 1), instead of (1 10 10) as I would expect.
Best regards,
-- Al
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
2024-09-24 13:12 ` Al Haji-Ali
@ 2024-09-24 13:43 ` Eli Zaretskii
2024-09-24 15:07 ` Al Haji-Ali
0 siblings, 1 reply; 6+ messages in thread
From: Eli Zaretskii @ 2024-09-24 13:43 UTC (permalink / raw)
To: Al Haji-Ali; +Cc: 73446
> From: Al Haji-Ali <abdo.haji.ali@gmail.com>
> Cc: 73446@debbugs.gnu.org
> Date: Tue, 24 Sep 2024 14:12:43 +0100
>
>
> 1. Open 'emacs -Q'.
> 2. Paste the following into the scratch buffer
>
> (progn
> (defun test-bug-73446 nil
> (let ((buf1 "test1")
> (buf2 "test2"))
> (switch-to-buffer (get-buffer-create buf1))
> (insert (make-string 20 ?H))
> (goto-char 1)
> (switch-to-buffer (get-buffer-create buf2))
>
> (let ((switch-to-buffer-preserve-window-point t)
> start before after)
> (display-buffer buf1 'display-buffer-use-some-window)
>
> (with-current-buffer (get-buffer buf1)
> (setq start (point))
> (goto-char 10)
> (setq before (point))
> (with-current-buffer (get-buffer buf2) ;; some random buffer
> (read-string "Test: "))
> (setq after (point)))
> (list start before after))))
> (message "%S" (test-bug-73446)))
>
> 3. Press `C-x c-e` (or call `eval-last-sexp`)
> 3. Press return when the prompt "Test: " appears.
> 4. I see the output (1 10 1), instead of (1 10 10) as I would expect.
If this is what you do, then it's the expected behavior: test1 is
displayed in another window, and so its window-point overrides what
you do. See the node "Window Point" in the ELisp manual.
This is not a bug.
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
2024-09-24 13:43 ` Eli Zaretskii
@ 2024-09-24 15:07 ` Al Haji-Ali
2024-09-24 15:50 ` Eli Zaretskii
0 siblings, 1 reply; 6+ messages in thread
From: Al Haji-Ali @ 2024-09-24 15:07 UTC (permalink / raw)
To: Eli Zaretskii; +Cc: 73446
On 24/09/2024, Eli Zaretskii wrote:
> If this is what you do, then it's the expected behavior: test1 is
> displayed in another window, and so its window-point overrides what
> you do. See the node "Window Point" in the ELisp manual.
>
> This is not a bug.
Ah I see. It is interesting that even if the window displaying the
buffer is shown but seemingly not selected (since the focus is on the
minibuffer during `read-string`), the point gets reset to the
window-point when Emacs waits for user input.
I vote to close this issue and apologies for the noise.
Best regards,
-- Al
^ permalink raw reply [flat|nested] 6+ messages in thread
* bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string
2024-09-24 15:07 ` Al Haji-Ali
@ 2024-09-24 15:50 ` Eli Zaretskii
0 siblings, 0 replies; 6+ messages in thread
From: Eli Zaretskii @ 2024-09-24 15:50 UTC (permalink / raw)
To: Al Haji-Ali; +Cc: 73446-done
> From: Al Haji-Ali <abdo.haji.ali@gmail.com>
> Cc: 73446@debbugs.gnu.org
> Date: Tue, 24 Sep 2024 16:07:42 +0100
>
>
> On 24/09/2024, Eli Zaretskii wrote:
> > If this is what you do, then it's the expected behavior: test1 is
> > displayed in another window, and so its window-point overrides what
> > you do. See the node "Window Point" in the ELisp manual.
> >
> > This is not a bug.
>
> Ah I see. It is interesting that even if the window displaying the
> buffer is shown but seemingly not selected (since the focus is on the
> minibuffer during `read-string`), the point gets reset to the
> window-point when Emacs waits for user input.
>
> I vote to close this issue and apologies for the noise.
Thanks, I'm closing it. But there's no need to apologize: Emacs is a
very complex beast, and no one knows all of its subtleties by heart.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-09-24 15:50 UTC | newest]
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-- links below jump to the message on this page --
2024-09-24 8:19 bug#73446: 29.1; Curious behaviour with with-current-buffer and read-string Al Haji-Ali
2024-09-24 12:12 ` Eli Zaretskii
2024-09-24 13:12 ` Al Haji-Ali
2024-09-24 13:43 ` Eli Zaretskii
2024-09-24 15:07 ` Al Haji-Ali
2024-09-24 15:50 ` Eli Zaretskii
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