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Re: Popularity of bzr-builddeb and dh-make

Steve Langasek <vorlon@debian.org> writes:

> The UDD branch model used in Launchpad has three branches (not counting
> the pristine-tar objects):

>  - the upstream branch (as it exists upstream)
>  - a synthesized branch which merges from the upstream branch and tracks
>    the contents of the upstream tarball releases /as contents/
>  - the packaging branch

> AIUI, most users of pristine-tar in git don't have the second of these
> branches, which means the pristine-tar binary delta is done against the
> upstream branch - so each pristine-tar blob contains all the information
> about autogenerated files in the tarball, in a format that doesn't in
> turn compress well in the git repository.

Oh.  No, I'm fairly certain that you're wrong, since any user of
git-buildpackge will have the second.  Rather, what's normally missing
from most Git-based packaging is the *first* branch, since the
git-buildpackage workflow was designed originally around importing
upstream tarballs to create the second branch.

> And if your packaging branch actually tracks the full source package
> contents, then it would have to track the autogenerated files, so you
> might actually be storing these files twice.

Delta compression should always take care of that, no matter how you
organize your repository.

> In UDD, the delta to the autogenerated files from one upstream release to
> the next is stored like any other branch delta, and the pristine-tar blob
> only has to account for the tarball/gzip metadata itself.

This is how git-buildpackage works with --upstream-vcs-tag, which is
relatively recent.

> I believe this was done by design precisely in order to address the
> pristine-tar scalability problem; in any case, I don't hear complaints
> about pristine-tar being unusable for Ubuntu packages for the reasons
> people seem to be shunning it for Debian packages in git.

This is the first I've heard of people thinking pristine-tar doesn't
scale, and your interpretation doesn't appear to match the reality of how
git-buildpackage works, so now I'm really curious what they were thinking

Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>

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