dirstate-tree: Remove newly-empty nodes after removing a `DirstateEntry`...
dirstate-tree: Remove newly-empty nodes after removing a `DirstateEntry`
This is actually necessary to make `DirstateMap::has_dir` correct, since it
assumes that a node without a `DirstateEntry` has at least one descedant node
with a `DirstateEntry`.
This bug would become apparent when a later changeset persists tree nodes
on disk in the "dirstate-v2" format.
Differential Revision:
https://phab.mercurial-scm.org/D10706
