Subject: Re: bug#79311: 31.0.50; Some characters not displayed when using standard-display-table

From: Andy Moreton <[email-masked]>
Date: Tue, 26 Aug 2025 08:57:36 +0100

On Tue 26 Aug 2025, Eli Zaretskii wrote:

>> From: Andy Moreton <[email-masked]>
>> Date: Mon, 25 Aug 2025 22:15:54 +0100
>> 
>> On Mon 25 Aug 2025, Eli Zaretskii wrote:
>> 
>> >> From: Matija Obid <[email-masked]>
>> >> Date: Mon, 25 Aug 2025 16:07:46 +0000
>> >> 
>> >> Steps to reproduce:
>> >> $ emacs -Q
>> >> #+begin_src elisp
>> >> (setq standard-display-table (make-display-table))
>> >> (aset standard-display-table ?> [?\〉])
>> >> (switch-to-buffer ">")
>> >> #+end_src
>> >
>> >> 
>> >> The buffer name in modeline is displayed as a square instead of parenthesis.
>> >
>> > Thanks, should be fixed now.
>> 
>> This seems to cause display glitches in gnus on Windows, when using
>> non-ASCII chars for the indicators in gnus-sum-thread-tree-* variables.
>> These glitches did no occur in a build from two days ago.
>> 
>> The symptom is the gnus summary buffer displays \xe2 characters, instead
>> of the expected character, e.g. WHITE SQUARE (codepoint #x25a1) which
>> has buffer code #xE2 #x96 #xA1.
>> 
>> The wrong display is transient, in that moving the cursor over the wrong
>> display fixes the glitch.
>
> Thanks, but please show a recipe starting from "emacs -Q", so I could
> look into this.

I can try, but it will take significant effort to produce such a
a restricted config.

After reverting only commit 21b072c60744 ("Fix use of display-table for
mode-line display") and rebuilding then the gnus summary buffer display
works as expected.

    AndyM