Merge request friendly handling of debian/changelog

[Bastian Blank <waldi@debian.org>]

Moin

In Debian most people prefer to have changelog entries with all changes,
so changes always contain a modification to debian/changelog.

If we also start to use merge requests on Salsa, all those changes will
contain modifications to debian/changelog, which will usualy conflict
with each other.  Or worse, are applied to an old changelog entry.  This
for example happens on the linux packaging project.

I don't think we already have a way to get around this?  Do we need
some?

There is "gbp dch", which ignores merge commits (so no really good for
merge requests), but I don't consider it to have enough control over the
content of the changelog.

The way that for example GitLab chooses in many locations is to create
split files and merge them together in the final release process.  They
now not only use that for the core software changelog[1], but also for
stuff like release posts.

So one rough idea could be:
- "dch $message" writes a dummy entry to debian/changelog if it does not
  exist and the entry to debian/changelog-unreleased/$hash.
- "dch --release" collects the snippets and creates one large entry.

Regards,
Bastian

[1]: https://docs.gitlab.com/ee/development/changelog.html
-- 
One does not thank logic.
		-- Sarek, "Journey to Babel", stardate 3842.4