Code review comment for lp:~garyvdm/bzr/get_trees_and_branches_to_diff

Seems ok. I was suprised to see that:
            bzrdir.BzrDir.open_containing_tree_or_branch(new_url)
Cannot take a 'possible_transports' parameter, which means that doing:

  bzr diff --old bzr+ssh://foo/branch1 --new bzr+ssh://foo/branch2

Will always connect 2 times.

Anyway, it doesn't specifically relate to promoting this to be a public api, or returning the branches that it does have open.

This was really meant to be a DWIM function based on the command line parameters, more than something that qdiff (or more importantly bzr-explorer) would re-use.

However, as you *are* using it, and find it useful, it seems ok to promote it.