Bug#1030000: fontconfig: after upgrade from 2.13.1-4.5 to 2.14.1-3 subpixel is enabled

[Andreas Henriksson]

Hello Thorsten Glaser,

Thanks for your bug report.

On Mon, Jan 30, 2023 at 03:32:02AM +0100, Thorsten Glaser wrote:
> Package: fontconfig
> Version: 2.14.1-3
> Severity: serious
> Justification: Policy 10.7.3
> X-Debbugs-Cc: tg at mirbsd.de
> 
> > * local changes must be preserved during a package upgrade, and
> 
> After an upgrade, etckeeper reports that
> /etc/fonts/conf.d/10-sub-pixel-rgb.conf
> shows up again, despite the local admin
> choice to not have blurry fonts.

Ouch, no relevant changes to maintainer scripts has been done.
Have you experienced this problem in previous upgrades?
Can you reproduce the problem at all?

> 
> Running dpkg-reconfigure -plow fontconfig-config
> shows that the debconf database correctly remembers
> the admin-provided setting (subpixel disabled was
> pre-selected),

By 'disabled' I assume you mean 'Never', right?

> and just pressing Enter on every
> question makes it remove that file, 

Did it also create 10-no-sub-pixel.conf ?
(Which would be consistent with 'Never'.
If neither file exists, that's the 'Automatic' option
which is also the default.)

> so I believe that some maintainer script errorneously forcibly
> creates that file overriding local configuration.

Is there any chance you can try to find some additional information
on what happened on your system?

It sounds weird that you would end up with 'Always' option somehow
when default is 'Automatic' and you supposedly selected 'Never'.


The relevant code is here:
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.postinst/#L93-L116

Note that this is protected by:
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.postinst/#L32
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.postinst/#L13-L23
(Thus it should not have run at all on upgrade.)

See also:
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.config/#L49-L64


Possibly 'Always' option could have come from here:
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.config/#L56
But then again, the initial/re-configure should not have been run at all
because of
https://sources.debian.org/src/fontconfig/2.14.1-3/debian/fontconfig-config.postinst/#L32
as mentioned earlier.



Regards,
Andreas Henriksson