[RFC] branch --bind

[Ian Clatworthy]

I've put together a patch extending the branch command with a --bind
option. See
https://code.edge.launchpad.net/~ian-clatworthy/bzr/branch-bind-option/+merge/16725.
The intent is that

  branch --bind X Y

is equivalent to

  branch X Y
  cd Y
  bind X
  cd -

Poolie has approved this patch. lifeless and fullermd have asked for
more discussion before this lands. Some background ...

FWIW, my short term driver for this is a better qbranch dialog. Due to
locking considerations, I can't easily add a "Bind to parent" checkbox
to qbranch without pushing the functionality down into the bzr core.

Longer term, I think our "checkout" model is broken - heavyweight and
lightweight checkouts have different semantics - and needs fixing. I'd
like to see lightweight checkouts the default with the option of a true
(history horizon) cache. That's a separate debate though. If anything,
having "branch --bind" is good because we can introduce new users to
bound branches without needing to explain all the complexity/issues
around various checkout types.

Discuss way. :-)

Ian C.