D1224: merge: cache unknown dir checks (issue5716)

[sid0 (Siddharth Agarwal)]

sid0 added a comment.


  Could you make this a class with unknowndircache and missingdircache being private members?
  
  How much do you think writing some of this code in native code (e.g. Rust) would help?

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D1224

To: mbthomas, #hg-reviewers
Cc: sid0, krbullock, mercurial-devel