view tests/test-diff-newlines.t @ 20713:6a1a4c212d50

revset: improve head revset performance

Previously the head() revset would iterate over every item in the subset and
check if it was a head.  Since the subset is often the entire repo, this was
slow on large repos. Now we iterate over each item in the head list and check if
it's in the subset, which results in much less work.

hg log -r 'head()' on a large repo:
Before: 0.95s
After: 0.28s

  $ hg init

  $ python -c 'file("a", "wb").write("confuse str.splitlines\nembedded\rnewline\n")'
  $ hg ci -Ama -d '1 0'
  adding a

  $ echo clean diff >> a
  $ hg ci -mb -d '2 0'

  $ hg diff -r0 -r1
  diff -r 107ba6f817b5 -r 310ce7989cdc a
  --- a/a	Thu Jan 01 00:00:01 1970 +0000
  +++ b/a	Thu Jan 01 00:00:02 1970 +0000
  @@ -1,2 +1,3 @@
   confuse str.splitlines
   embedded\r (no-eol) (esc)
  newline
  +clean diff