RFC: Initial branch operation order

[Martin Pool]

On 27 April 2011 17:20, John Arbash Meinel <john at arbash-meinel.com> wrote:
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> At the moment, our code is a bit cluttered with fetch-like operations,
> leading to bugs like:
>  https://bugs.launchpad.net/bzr/+bug/771255
>
> (initial branch doesn't copy tags)
>
> I'm thinking about improving that a bit, but my idea goes against an old
> design from Robert, that I'd like to talk through a bit.
>
> Specifically, BzrDir.sprout() re-implements a lot of Branch.pull (except
> now it doesn't have the tag-fetching code). At least a partial reason is
> because Robert didn't want us to create a proper Branch at the target
> until we had the revisions for it already copied into its Repository. So
> people wouldn't see a new Branch that had no revisions (tip ==
> 'null:'),they would just see NoSuchBranch until the fetch finished.
>
> The biggest reason for the change is that I think it would simplify the
> model (you would always use InterBranch.get() for exchanging the
> revisions, etc.)

That makes sense to me.  I think it would remove some cruft and I
can't think of any problems at the moment.  I think seeing a branch
that then later updates to point to the right value is in some ways
cleaner, and it might avoid some problems with interrupted operations,
or improve them.

Martin