GNU bug report logs - #73446
29.1; Curious behaviour with with-current-buffer and read-string

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Al Haji-Ali <abdo.haji.ali <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 29.1; Curious behaviour with with-current-buffer and read-string 
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 easily solve this issue with `save-excursion`, but I thought this might be an unintended behaviour worth reporting.

Best regards,
-- Al

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