view tests/test-issue619.t @ 32177:8f1a2b848b52

dirstate: optimize walk() by using match.visitdir()

We already have the logic for restricting directory walks in
match.visitdir() that we use for treemanifests. We should take
advantage of it when walking the working copy as well.

This speeds up "hg st -I rootfilesin:." on the Firefox repo from
0.587s to 0.305s on warm disk (and much more on cold disk). More time
is spent reading the dirstate than walking the working copy after.

I tried to find scenarios where calling match.visitdir() would be a
noticeable overhead, but I couldn't find any. I encourage the reader
to try for themselves, since this is performance-critical code.

https://bz.mercurial-scm.org/619

  $ hg init
  $ echo a > a
  $ hg ci -Ama
  adding a

  $ echo b > b
  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -Amb
  adding b

  $ hg co -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

Fast-forward:

  $ hg merge b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -Ammerge

Bogus fast-forward should fail:

  $ hg merge b
  abort: merging with a working directory ancestor has no effect
  [255]

Even with strange revset (issue4465)

  $ hg merge ::.
  abort: merging with a working directory ancestor has no effect
  [255]