GNU bug report logs - #74091
31.0.50; string-pixel-width in mode line disables region

Previous Next

Full log

View this message in rfc822 format

From: Eshel Yaron <me <at> eshelyaron.com>
To: 74091 <at> debbugs.gnu.org
Subject: bug#74091: 31.0.50; string-pixel-width in mode line disables region
Date: Tue, 29 Oct 2024 18:27:05 +0100

The new implementation of string-pixel-width has some unexpected effect
when it is called from mode-line-format, as happens for example when
mode-line-format-right-align occurs in mode-line-format:

1. emacs -Q
2. (setq-default mode-line-format
	      '("" (:eval (progn (string-pixel-width "foo") nil))))
3. C-x C-f /path/to/emacs/lisp/subr.el
4. C-SPC
5. C-n

At this point the region is expected to be active since we activated it
in step 4.  But in step 5 the mode line is updated, which calls
string-pixel-width, which in turn unexpectedly disables the region.

I'm not really sure why this happens...  Also, if I now trace
string-pixel-width, then it no longer disables the region and everything
starts working as expected.


Thanks,

Eshel

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.