Rewriting Ubuntu branches

[Jelmer Vernooij]

Hi James,

Le lundi 14 décembre 2009 à 00:48 +0000, James Westby a écrit : 
> I wanted to split this out of the large mail so that we could complete
> a design of how this would work.
> 
> Here's my initial proposal based on the feedback from that thread.

> 2) We ship map files in some known location, package-import.ubuntu.com say.
>      These contain revision id pairs and file id pairs corresponding to
>      the old branches and the new branches. Is just listing plain file ids
>      safe, or do we need (revision id, file id) pairs to do this correctly.
> 
>   3) Either bzr-rewrite itself, of something based on the code in there
>      will be used to rewrite a given branch using the information in the
>      map files.
bzr-rewrite's existing rebase-foreign command can do the renames based
on paths alone, there is no need to have a file id map. I'm not sure
whether that is sufficient for what you are trying to do, but I suspect
it is.

rebase-foreign works with foreign revision ids (in this case probably
debian version strings?), and then determines which bzr revision ids are
pseudonyms based on the foreign revision ids they originate from. 

> Open questions:
> 
>   * Should we bother with file id maps, or just match based on path?
I don't think there is a risk for confusion between the identity of two
files with the same path in similar revisions.

> * Should we put the old revision ids in to revision properties of
>     the new revisions? This could be the marker for the decorated
>     commands, and make the map files smaller. It does inflate the
>     size of the branches for ever though. If we don't, what should
>     the marker be?
If you just put the debian version that a revision refers to in a
revision property, I don't think there would be that much overhead -
just around 100 bytes per revision I'd estimate. 

> How does this plan sound? Does anyone want to take on a particular part of
> it?
I'm happy to answer questions about bzr-rewrite or help add another
pseudonym mechanism in bzr-rewrite, if you decide to go that route.

Cheers,

Jelmer