bzr-git, the git map, fetching revisions, and being very slow

[Jelmer Vernooij]

On Sun, 2009-11-22 at 17:18 +0000, Russel Winder wrote: 
> On Sun, 2009-11-22 at 10:57 -0600, Jelmer Vernooij wrote:
> [ . . . ]
> > My point was that copying data from one repository in a particular
> > format into another repository in the same format is *always* going to
> > be faster than copying into a different format because there would be
> > some sort of conversion involved in the second case. It is never going
> > to be as fast.
> > 
> > Perhaps we should be telling the user that an operation is expected to
> > be slower when fetching between differing formats. 
> 
> I think this is a crucially important point and one that definitely
> needs raising with the user.
> 
> The fact that Bazaar is hiding Subversion, Git and Mercurial
> repositories behind Bazaar branches and the Bazaar UI is great.  The
> fact that Bazaar is hiding Subversion, Git and Mercurial repositories
> behind Bazaar branches and the Bazaar UI is a real pain the @rse.
Hiding isn't the right word here, we support different repository
formats. We're not hiding anything behind Bazaar branches - you can work
on Git repositories with Bazaar without using any of the Bazaar formats
in one form or another. Fetching from one git repository into another
using Bazaar is fast, fetching from a 2a repo into another 2a repo is
fast, fetching from a 2a repo into a 0.92 repo is slow and so is
fetching from a git repo into a bzr repo.

> So being able to use Bazaar to manipulate Subversion, Git and Mercurial
> repositories is seriously great, but it should always be clear and not
> hidden when a non-Bazaar storage is being used.  Not only is this
> managing user expectations, it is allowing the use transparency of
> knowledge about the system under manipulation.
I don't think this should be specific to foreign repositories - this
also applies e.g. to fetches between 0.92 and 2a bzr formats.

Cheers,

Jelmer