Bug#1089108: /usr/bin/gnome-terminal: wrongly displays unicode sequences involving combining characters

[Simon McVittie]

Control: reassign -1 fonts-inconsolata,gnome-terminal
Control: retitle -1 fonts-inconsolata: combining accents drawn incorrectly in gnome-terminal
Control: tags -1 + help

On Wed, 11 Dec 2024 at 16:27:18 +0100, Uwe Kleine-König wrote:
> On Thu, Dec 05, 2024 at 07:41:49PM +0100, Uwe Kleine-König wrote:
> > On 12/5/24 19:28, Simon McVittie wrote:
> > > On Thu, 05 Dec 2024 at 19:05:16 +0100, Uwe Kleine-König wrote:
> > > > The (e.g.) combining Acute Accent (codepoint 0x301, utf-8 representation
> > > > "\xcc\x81") is supposed to put an accent on the char just before it.
> > > > 
> > > > That is
> > > > 
> > > > 	echo -e "e\xcc\x81e" | iconv -f utf-8
> > > > 
> > > > is supposed to show two e with the first having an accent.
...
> I upgraded my system to full unstable and the problem persists after a
> reboot :-\
> 
> Then I created a new user and tried with that => problem fixed.
> 
> Then I created (with my normal user) a new Profile for Gnome Terminal =>
> problem fixed.
> 
> Then in the old profile switched from the Custom font "Inconsolata"
> (provided by package fonts-inconsolata) to Monospace => problem fixed.
> 
> The latter even works "live", that is, if I have the Terminal show the
> bogus sequence and switch the font, the display is fixed. Same in the
> other direction.

I can reproduce this by restarting gnome-terminal after installing
Inconsolata, and then configuring it to use Inconsolata. For whatever
reason, this didn't happen until I had completely exited all running
gnome-terminal windows so that its background service exited.

This seems like a problem with the rendering of the Inconsolata font -
either a bug in the content of that font, or a bug in some rendering
library (vte? pango? harfbuzz? it's anyone's guess, really) triggered by
something specific to that font.

> Fun-fact: When I switch the font in kgx to Inconsolata, it shows two e
> without accent.

I can reproduce this, too.

kgx uses GTK 4, while gnome-terminal uses GTK 3, so it's reasonable that
their behaviour is not identical.

    smcv