Buildbot docker latent container name not unique PROD | DEV

Bug identified after migrating PROD to container.

How to reproduce

You start a docker latent builder in DEV, let's say tarball-docker and you get a conflict.
https://buildbot.dev.mariadb.org/#/builders/110/builds/99/steps/0/logs/err_html

The container name "/buildbot-hz-bbw1-docker-tarball-debian-12-15cc21" is already in use by container

causing the worker to RETRY and sometimes it will block Production builder, stuck in Preparing worker.

Why?

Because now the master names are the SAME in both DEV and PROD
and when the same builder is started on the SAME worker host at the same time, the above error will occur.

Details

This is how Buildbot gives "unique" names to containers on a worker HOST

(f'buildbot-{self.workername}-{self.masterhash}').replace("_", "-")

Example of container name on worker host: buildbot-hz-bbw1-docker-tarball-debian-12-15cc21
The last part is important i.e. self.masterhash (15cc21)

How buildbot calculate this hash

self.name = f"{self.hostname}:{os.path.abspath(self.basedir or '.')}"

masterName = unicde2bytes(self.master.name)

self.masterhash = hashlib.sha1(masterName).hexdigest()[:6]

For example:

self.hostname = autogen_aarch64-master-0 # name of the master container

os.path.abspath(self.basedir or '.') = /srv/buildbot/master/autogen/aarch64-master-0 # path to master config in container

Resulting in autogen_aarch64-master-0:/srv/buildbot/master/autogen/aarch64-master-0
The masterhash is the SAME in both DEV and PROD.

Proposed solution

Change hostname of master containers in DEV

Definition of done

Let's take for example tarball-docker running on master-protected-branches.
It will always render:

buildbot-hz-bbw1-docker-tarball-debian-12-15cc21

or

buildbot-hz-bbw4-docker-tarball-debian-12-15cc21

which is the same on both DEV and PROD.
Changing the master name should render something else than -15cc21