RFC: Initial branch operation order

[Andrew Bennetts]

Aaron Bentley wrote:
[…]
> On 11-04-27 12:54 AM, Robert Collins wrote:
> > Its probably possible to make the code simpler by using a null object
> > or something, but I have no passionate attachment to the object
> > creation order (with one caveat, we shouldn't show bogus objects like
> > a branch with the tip not being in the repository at any point in
> > time).
> 
> It might be interesting to have an "incomplete" state for branches.  If
> the creation was interrupted, accessing it (other than with push/branch)
> would raise a BranchIncomplete error (a subclass of NoSuchBranch).
> 
> This could be represented on disk by storing it as
> .bzr/incomplete-branch, and then renaming it to the normal location when
> complete.

We'd get a similar result by creating branch write-locked, and not
releasing the write-lock until the initial push is over (rather than
dropping it and reacquiring it as currently happens).

-Andrew.