Re: git interface to snapshot.debian.org

[Ian Jackson <ijackson@chiark.greenend.org.uk>]

Joachim Breitner writes ("git interface to snapshot.debian.org"):
> this is a follow-up to my question after the dgit talk today: It would
> be great to have a git view of the a package’s history in Debian. There
> is some possible overlap with dgit in the sense that if everyone had
> been using dgit from the start, then we would have that, but dgit’s
> objectives are slightly different, so maybe my question could be posed
> and answered separately.

Hi.  I'm sorry that we didn't manage to talk about this idea of yours
properly at DC.  I think it is a good idea.

> If the answer is „Nothing is stopping, just that someone has to do it“,
> then I’m volunteering, as long as I can do most of it during DebConf.

There are two problems that are stopping us doing this right away:

  - Maybe the amount of data is too big to suddenly dump in the dgit
    git server (we should talk to DSA)

  - There is nothing which currently automatically updates the
    server-side dgit history when non-dgit uploads are made.  Such a
    thing could be produced, but I think it is essential to have it
    before we embark on a historical import.

There are some things that you would need my help (as admin of
dgit.d.o) with:

  - your histories would have to be stitched into the dgit git history
    for packages with existing dgit history

  - your ref updates can't be done by DDs in general, because the dgit
    git server only accepts updates made with dgit push.  So you would
    need me with my admin hat on to do the updates.


Your details seem largely sound:

>  * Every source package from snapshots.d.o becomes, extracted with 
>    dpkg-source -x as usual, produces a git tree object.
>    I’d probably simply ignore empty directories.

Right.

>    - Parents: This is the interesting bit
>      The set of parents should be the commits corresponding to any 
>      version mentioned in debian/changelog, pruned by those that
>      are transitively reachable.

Nice idea.

>  * Every suite (unstable, jessie...) becomes a branch, pointing to the
>    corresponding commit

s/unstable/sid/, but yes.

>  * Optionally: One tag per version pointing to the corresponding
>    commit, for each version. Although maybe that would produce too
>    many tags...

We definitely want this.  The tag should be in DEP-14 format, which
makes it identical to existing dgit git tags.

Thanks,
Ian.