configure branches to build in addition to default branch

[steveej]

i'm working on repositories that have continuous delivery pipelines based on multiple branches. for this to work with buildbot-nix there needs to be an option that takes a list of branch names that buildbot will consider acting upon exactly in the same way it does for the default branch.

[Mic92]

I think a list of regexes in the nixos configuration would be the best. Pull requests welcome.

[Mic92]

After checking again, we actually shouldn't make it a list but a single regex. So just make this property configurable: https://github.com/nix-community/buildbot-nix/blob/d2dd93e4d12be7a05ef7640c7375c58739263d8d/buildbot_nix/__init__.py#L1257

You will need to extend this object: https://github.com/nix-community/buildbot-nix/blob/d2dd93e4d12be7a05ef7640c7375c58739263d8d/buildbot_nix/models.py#L175 and add a nixos option similar to other configuration.

Use (gh-readonly-queue/.*|staging|trying) as the default value

We have checks for "default_branch" in several places, you might need to grep and see if we need to allow also non-default branches that matches the regex or not.

[MagicRB]

Will tackle this now and tomorrow

[MagicRB]

I'm tackling this in a way where we split branches into 3 groups:

• PR branches, get built automatically but don't trigger output writing (currently)
• primary branches, concrete list (regex) of branches, behave exactly the same as the default branch which is implicitly part of this list
• secondary branches, concrete list (regex) of branches, behave exactly as PR branches just that their hardcoded

not sure if the primary/secondary split is needed, but not hard to do, we can rip it out later. (we'll have to rewrite this anyway, i really do not like that this is global for the whole instance. I think we should prioritize per repo configs finally )

[MagicRB]

@steveej #312 is a thing now, can you check the master.nix changes whether the semantics satisfy your needs?