[Bug 2051313] [NEW] font-config confilcts ubuntustudio-default-settings upgrading from 22.04 to 24.04

[Daniel Tang]

Public bug reported:

This bug was migrated from https://askubuntu.com/q/1501240/1004020 .

A nearly identical bug is
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/2005124 . It
fixed things for `kubuntu-settings-desktop` but not `ubuntustudio-
default-settings`. Please add an analogous fix.

A similar but potentially unrelated bug is
https://bugs.launchpad.net/ubuntu/+source/ubuntustudio-default-
settings/+bug/2037471 .

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System
-> About Ubuntu

Not my computer.

2) The version of the package you are using, via 'apt-cache policy
pkgname' or by checking in Software Center

Not my computer.

3) What you expected to happen

The AskUbuntu user's upgrade from 22.04 to 24.04 to complete
successfully.

4) What happened instead

The upgrade failed and they posted to AskUbuntu.

# Copy of their question body

After an upgrade to 
```
Distributor ID: Ubuntu
Description:Ubuntu Noble Numbat (development branch)
Release: 24.04
Codename:noble 

```
apt won't update bcs of unmet dependencies.

``` 
The following packages have unmet dependencies:
 libfontconfig1 : Depends: fontconfig-config (>= 2.14.2-6ubuntu1)
 libfontconfig1:i386 : Depends: fontconfig-config:i386 (>= 2.14.2-6ubuntu1)
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution). 
```
I've tried: 

``` 
apt --fix-broken install

```
```
dpkg: error processing archive /var/cache/apt/archives/fontconfig-config_2.14.2-6ubuntu1_amd64.deb (--unpack):
 trying to overwrite '/etc/fonts/conf.d/10-sub-pixel-rgb.conf', which is also in package ubuntustudio-default-settings 22.04.26.3
dpkg-query: package 'fontconfig-config' is not installed
Use dpkg --contents (= dpkg-deb --contents) to list archive files contents.
dpkg-query: package 'fontconfig-config' is not installed
Use dpkg --contents (= dpkg-deb --contents) to list archive files contents.
dpkg-query: package 'fontconfig-config' is not installed
Use dpkg --contents (= dpkg-deb --contents) to list archive files contents.
Errors were encountered while processing:
 /var/cache/apt/archives/fontconfig-config_2.14.2-6ubuntu1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
```

# Copy of workaround in my answer body

The problem is that 24.04 moved `/etc/fonts/conf.d/10-sub-pixel-
rgb.conf` out of `ubuntustudio-default-settings`
([before](https://packages.ubuntu.com/jammy/all/ubuntustudio-default-
settings/filelist),
[after](https://packages.ubuntu.com/noble/all/ubuntustudio-default-
settings/filelist)) and into [`fontconfig-
config`](https://packages.ubuntu.com/noble/all/fontconfig-
config/filelist). The `ubuntustudio-default-settings` package needs to
be updated first but the maintainers forgot to add an automatic
`Conflicts:` line.

You can retry installing the package in the correct order by running
`sudo apt install --upgrade ubuntustudio-default-settings`. If that does
not work, you need to forcibly reinstall things in the correct order:

```bash
sudo -i

apt update
apt download ubuntustudio-default-settings
apt download fontconfig-config

# Temporarily force-uninstall only ubuntustudio-default-settings
# so that we DON'T uninstall ubuntustudio-desktop
dpkg --force-all -r ubuntustudio-default-settings
dpkg --force-all -i ./fontconfig-config_*
dpkg --force-all -i ./ubuntustudio-default-settings_*

dpkg --configure -a
apt --fix-broken install
apt upgrade
apt dist-upgrade
```

# Analysis

Please apply an analogous fix. Where I mentioned `Conflicts:` on
AskUbuntu, a `Pre-Depends:` may be necessary instead as I read somewhere
on Launchpad.

** Affects: fontconfig (Ubuntu)
     Importance: Undecided
         Status: Confirmed

** Affects: ubuntustudio-default-settings (Ubuntu)
     Importance: Undecided
         Status: Confirmed

** Also affects: fontconfig (Ubuntu)
   Importance: Undecided
       Status: New

** Changed in: fontconfig (Ubuntu)
       Status: New => Confirmed

** Changed in: ubuntustudio-default-settings (Ubuntu)
       Status: New => Confirmed

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https://bugs.launchpad.net/bugs/2051313

Title:
  font-config confilcts ubuntustudio-default-settings upgrading from
  22.04 to 24.04

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