Re: Change of behavior of "space" display property and face property

[Visuwesh]

[செவ்வாய் அக்டோபர் 04, 2022] Eli Zaretskii wrote:

>> From: Po Lu <luangruo@yahoo.com>
>> Cc: "emacs-devel@gnu.org" <emacs-devel@gnu.org>
>> Date: Tue, 04 Oct 2022 14:34:28 +0800
>> 
>> Qiantan Hong <qthong@stanford.edu> writes:
>> 
>> > Open an empty text file, M-: (insert #(" " 0 1 (face (:underline t) 
>> > display (space :align-to right))))
>> >
>> > On Emacs 28, this produce a blank line with underline.
>> >
>> > On Emacs 29, this produce a blank line without underline. In general, 
>> > “space” display 
>> > seem to disregard any face property.
>> >
>> > Is this intended or is this a bug? “space” display respecting face 
>> > property is useful for
>> > typesetting. For example. I use it to display a horizontal separator under 
>> > my header line.
>> >
>> > Best,
>> > Qiantan
>> 
>> That is almost certainly a bug, but I cannot be certain without knowing
>> what toolkit and window system you built Emacs with.
>
> I cannot reproduce this here, on MS-Windows.  The recipe produces the
> same display for me in both Emacs 28 and Emacs 29.  So if this is
> reproducible on some system, it is most probably a bug in the
> terminal-specific display backend.

Cannot reproduce on Emacs 29 using the Lucid backend, cairo and HarfBuzz either.