bug#73752: 29.4; Ligatures are randomly rendered with extra spaces

[Eli Zaretskii <eliz@gnu.org>]

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> Date: Mon, 28 Oct 2024 10:44:23 -0400
> Cc: visuweshm@gmail.com, luangruo@yahoo.com, 73752@debbugs.gnu.org
> From: Yixuan Chen <xuan@xlk.me>
> 
> > Is
> > that extra space a real SPC glyph or is it just that the ligature is
> > considered "wider"?  What happens if you put the cursor on the ▷
> > ligature in the "bad" display -- does the block cursor then take up
> > all the space up to the next quote?
> 
> It's not a real SPC glyph. It's a single character ▷ (or ligature/glyph 
> I should call it? the underlying text is "|||>"). I attached five 
> screenshots, where the block cursor is at ", |, |, |, >, " respectively. 
> Noticeably, the block cursor for the first | character (1_bar.png) is 
> extra wide, and the block cursors for the following characters looks 
> offset from where they are.

According to the screenshots, it actually looks like it's a real SPC
glyph or something.  What does "C-u C-x =" show when the block cursor
is shown as below?


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Actually, how about showing what "C-u C-x =" says in each of the 6
positions you show?  And then show what "C-u C-x =" says in the same 6
positions in the "good" display?