# HG changeset patch
# User Durham Goode <durham@fb.com>
# Date 1455240190 28800
# Node ID 19424f960bf5891a1a84e8bd1bc1ccbcdfb913d1
# Parent  0b7ce0b16d8a629cee8610c62c16307ccefa5893
checkunknown: audit path before checking if it's a file or link

Previously we would lstat the file to see if it was a file or a link before
attempting to process it. If the file happened to exist across a symlink, and if
that symlink was pointing to a network file system, that check could be very
expensive.

The new logic audit's the path to avoid symlinks before performing the lstat on
the file itself.

In our situation, this shaved 10 minutes off of certain hg updates.
300 files * (2 seconds - the network filesystem lookup time)

diff -r 0b7ce0b16d8a -r 19424f960bf5 mercurial/merge.py
--- a/mercurial/merge.py	Thu Feb 11 17:04:33 2016 -0800
+++ b/mercurial/merge.py	Thu Feb 11 17:23:10 2016 -0800
@@ -598,8 +598,8 @@
 def _checkunknownfile(repo, wctx, mctx, f, f2=None):
     if f2 is None:
         f2 = f
-    return (repo.wvfs.isfileorlink(f)
-        and repo.wvfs.audit.check(f)
+    return (repo.wvfs.audit.check(f)
+        and repo.wvfs.isfileorlink(f)
         and repo.dirstate.normalize(f) not in repo.dirstate
         and mctx[f2].cmp(wctx[f]))