debian: support additional suites

[nmeyerhans]

This is a proposed solution to the ability to specify a repository suite in the Debian configuration, in addition to the components currently specified. The optional suite is specified as a prefix to the component name in the Repositories= config setting, e.g.

Repositories=
    non-free-firmware
    trixie-backports:main
    trixie-backports:non-free-firmware

The trixie-backports: lines above would generate the following content in the resulting trixie.sources file:

Types: deb deb-src
URIs: http://deb.debian.org/debian
Suites: trixie-backports
Components: main non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg

Fixes #1755

[behrmann]

This is not very large, but it's very specialised to Debian. The canonical way to do this is to just put these files into a package tree, since we can't really add options for everything a package manager does into mkosi itself.

[nmeyerhans]

This is not very large, but it's very specialised to Debian.

Well yes, it fixes a Debian-specific issue in a Debian-specific source file. Though theoretically the same issue impacts Ubuntu. It may be reasonable to refactor the apt repository handling code further to extract common code in such a way that it can be shared between ubuntu.py and debian.py, but that's out of scope for the original issue and for my use case, so I didn't do that here.

The canonical way to do this is to just put these files into a package tree, since we can't really add options for everything a package manager does into mkosi itself.

The existence of #1755 suggests that this is desirable functionality to have in mkosi. Configuring the package manager to retrieve directly from a repository avoids a number of potential issues with package trees (stale packages, missing dependencies, etc).

[bketelsen]

brilliant! I need this.

[behrmann]

Configuring the package manager to retrieve directly from a repository avoids a number of potential issues with package trees (stale packages, missing dependencies, etc).

Maybe I've been a bit unclear earlier, because I used an older term no longer used in our docs, but is there a reason you can't use a SandboxTree=? You can put arbitrary apt config files in there.