obsutil: maintain a homogenous list when computing successors...
obsutil: maintain a homogenous list when computing successors
In practice, this wasn't a problem because of an internal check for an empty
list, but it avoids the following pytype error:
File "/mnt/c/Users/Matt/hg/mercurial/obsutil.py", line 823, in successorsandmarkers: No attribute 'markers' on List[nothing] [attribute-error]
In Union[Any, List[nothing], _succs]
Differential Revision:
https://phab.mercurial-scm.org/D10213