Comment 1 for bug 86919

bzr no longer indirects through control_files for IO-type operations, which was the original purpose of this bug. The main purpose of LockableFiles as it currently exists is to coordinate a transaction object with the state of the lock. It also still provides the _find_modes method.

_find_modes is already softly deprecated in favor of BzrDir._find_creation_modes; if/when the class as a whole is deprecated the attributes that it creates will be gone. Alternatively we could turn them into deprecated properties.

If this reasoning is correct, then Branch, which does not use get_transaction, should never need a control_files. (Removing it may strictly be a compatibility break for Branch though.)

There are also quite a large number of methods on Branch that just forward to the control_files, that can go to a CountedLock instead.