Comment 4 for bug 53340

bzr 0.15 should behave better in this case.

I don't think the SFTP server should try to detect a broken branch. It has the potential to clash badly with two connections trying to push a new branch at the same time, which doesn't seem impossible or even totally unlikely (two devs independently decide to make a "bug-1234" team branch in response to a bug report, and both have slow connections from e.g. Brazil).

If the server does need more capability to help users here, then the smart server will be a much safer system to build this on.