How is Bazaar-NG related to Bazaar and Arch in general?

Mark Shuttleworth mark at
Thu Jun 2 07:41:21 BST 2005

ser at wrote:

>>Canonical's working on Bazaar, because they need a distributed revision
>>control system that works *now*.  They've got a bunch of infrastructure
>>that uses Arch, and they won't want to drop it all at once in favour of
>>bzr, which is still experimental and doesn't yet support their needs.
>This is what I don't understand.  They can continue *using* Bazaar without
>put resources into developing new features for it.  Adding Bazaar-NG
>support to Bazaar seems -- to me -- like a non-trivial amount of effort;
>effort that might be better invested into bringing Bazaar-NG up to the
>point where it *does* support their needs.
I'm the investor, so maybe it will help if I give some rationale for the
dual investment.

The Bazaar team is confident that they can transition to the model used
by Bazaar-NG as that stabilises. We've committed that we will be able to
migrate all data from where we are today with Baz to where Bazaar-NG
will be when it hits 1.0. As pieces of the Baz-NG model stabilise, they
get worked into Baz. In general, we make sure that Baz supports its own
data formats for two releases, and that there are perfect data migration
tools builtin to Baz to bump archives etc through the migration path,
one release at a time.

So far this is working.

I'm very pleased with the work of the baz team, baz itself feels much
more polished and behaves in a more predictable fashion than its
ancestry. That's the tool we use every day, and the tool we are using to
coordinate distro work with upstream revision control (see for scope).

Meanwhile, baz-ng lays out the future path, allows us to test new ideas
and change them rapidly without worrying too much about avast universe
of existing data.

In the end, it will be possible to use either the Python implementation
("bazaar-ng 1.0"), or the C implementation ("baz X.Y"). At that point,
we may ourselves decide to prefer one over the other, and stop investing
in both. But for the moment, it works for me to have both out there.

If you're looking for an industrial strength but slightly limited
revision control system, use baz. If you want the blue-sky for personal
projects, try baz-ng.


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