Add tree diffing in HgLoaderFromDisk
Add tree diffing in HgLoaderFromDisk
By looking at differences between revisions, the repository tree is updated rather that fully rebuild for each one.
Observed load time improvement on https://www.mercurial-scm.org/repo/hg/ 1:11:02 -> 47:58
Migrated from D4540 (view on Phabricator)