bzr loves Ubuntu @ UDS

[Jelmer Vernooij]

On Thu, 2009-11-19 at 11:12 +1100, Robert Collins wrote: 
> On Wed, 2009-11-18 at 17:36 -0600, Jelmer Vernooij wrote:
> > Hi Vincent,
> > 
> > Thanks for writing this up.
> > 
> > On Wed, 2009-11-18 at 16:49 -0600, Vincent Ladeuil wrote: 
> > > Many discussions and sessions related to the daily builds and the source
> > > packages have happened here already.
> > > 
> > > It's a bit hard to report about them without repeating a lot of things
> > > that has been covered during our bzr sprint, so I'll try to focus on the
> > > main differences (at least in my understanding, feel free to correct
> > > me).
> > > 
> > > 1) code imports
> > > 
> > > First of all, I'll appreciate some rehash of the arguments about why
> > > code imports should be at priority #2 behind mini-grumpy.
> > > 
> > > There seem to be many problems around branches with different histories
> > > between the upstream, debian and ubuntu branches. The sooner we get the
> > > first ones via code imports the less problems of history rewriting we'll
> > > have to deal with. Is there something wrong with that reasoning ?
> > > 
> 
> > +1, it seems a lot easier to get the history right in the first place
> > than to fix it up later on.

> The reasoning we have is:
>  - we know that ~ 25% of imports fail at the moment (maybe 50% on first
> attempt, and then we whittle it down).
>  - We don't want to block users on imports. Better to have a productive
> user now with a history rewrite down the track (because we know how to
> do history rewrites), than an unproductive user until their particular
> import works.
> 
> 'imports' is a piece of string problem: its never ending and continually
> lengthening. Thats why its #2: we can deliver daily builds where we have
> the imports, and make that work well, and then every import we add
> increases the value of the daily builds. If we do it the other way
> around, no-one gets daily builds until 'all the imports are working'.
I'm not suggesting getting *all* of the imports working before doing
anything else. But getting the import for a particular project for which
you're going to do daily builds working properly before doing something
else with it seems like a better idea than fixing the branch up later.

I don't think the failure rates are as bad as 25%-50%. For bzr-git the
only real issue I'm aware of at this point are submodules (this is e.g.
problematic for kvm/qemu); for bzr-svn the two main issues seem to be
libsvn http bugs and odd history involving bzr-svn roundtripping. I
don't know what the failure rates are like for cscvs?

Cheers,

Jelmer