Summary: Depends on D20838. Fixes T13414. Instead of doing coarse diffing with "PhutilEditDistanceMatrix", use hash-and-diff with "DocumentEngine".
Test Plan:
- On a large document (~3K top level blocks), saw a more sensible diff, instead of the whole thing falling back to "everything changed" mode.
- On a small document, still saw a sensible granular diff.
{F6888249}
Maniphest Tasks: T13414
Differential Revision: https://secure.phabricator.com/D20839
Summary: Depends on D20836. Ref T13414. Ref T13425. Ref T13395. Move these to "phabricator/" before trying to improve the high-level diff engine in prose diffs.
Test Plan: Ran "arc liberate", looked at a prose diff (no behavioral change).
Maniphest Tasks: T13425, T13414, T13395
Differential Revision: https://secure.phabricator.com/D20838
