Bug#956612: libpango-1.0-0: broken kerning since 1.44

[Cyril Brulebois]

Hey,

Tomas Janousek <tomi at nomi.cz> (2020-04-13):
> Package: libpango-1.0-0
> Version: 1.44.7-3
> Severity: important
> Tags: upstream
> 
> Since yesterday's apt full-upgrade of testing, font rendering in Gtk
> applications is very bad, kerning is broken, text is wider than
> necessary, it's very very unpleasant, I'd even say downright unuable
> without downgrading.
> 
> What I'm seeing is exactly this:
> https://gitlab.gnome.org/GNOME/pango/issues/404#note_712911
> https://gitlab.gnome.org/GNOME/pango/issues/404#note_676284
> https://github.com/harfbuzz/harfbuzz/issues/1892#issuecomment-552877664
> so I won't include additional screenshots.
> 
> I'm not sure what should Debian do provided upstream seems a bit
> dead... But breaking font rendering in Gtk apps across all Debian
> installations doesn't seem like a very good outcome either. :-(
> 
> Any ideas?
> 
> If anyone else is experiencing this, my workaround:
> 
> /etc/apt/sources.list:
> deb http://snapshot.debian.org/archive/debian/20200401T000000Z/ testing main contrib non-free
> 
> /etc/apt/preferences:
> Package: *pango*:*
> Pin: origin "snapshot.debian.org"
> Pin-Priority: 1100

I can confirm this in the Debian Installer as well (spotted early April
but only debugged right now).

Getting a little back in time and comparing what unstable used to be at
20200401T154401Z and at 20200405T084040Z, I'm seeing these changes in
the list of udebs used to build the netboot-gtk image:

    -libcrypt1-udeb_1%3a4.4.15-1_amd64.udeb
    +libcrypt1-udeb_1%3a4.4.16-1_amd64.udeb
    -libdrm2-udeb_2.4.100-4_amd64.udeb
    +libdrm2-udeb_2.4.101-1_amd64.udeb
    -libpango1.0-udeb_1.42.4-8_amd64.udeb
    +libpango1.0-udeb_1.44.7-3_amd64.udeb
    -libudev1-udeb_245.2-1_amd64.udeb
    +libudev1-udeb_245.4-2_amd64.udeb
    -udev-udeb_245.2-1_amd64.udeb
    +udev-udeb_245.4-2_amd64.udeb

Compare attached 1/2 screenshots to see the regression.

To make sure the pango update was responsible, I deb-reversion'ed its
udeb (taking the old udeb, faking a higher version so that it would be
preferred to the new udeb), and rebuilt the installer with unstable
from 20200405T084040Z, and I can confirm the regression disappears
(see 2+revert screenshot).


Cheers,
-- 
Cyril Brulebois (kibi at debian.org)            <https://debamax.com/>
D-I release manager -- Release team member -- Freelance Consultant
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