# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 1495349354 25200
# Node ID f44ea253ffe25a63b69d0c81a7093de137954d7e
# Parent  20c9f3ecc192ae5bfab5c425560da1febb2dcb33
match: optimize visitdir() for when no explicit files are listed

In patternmatcher, we used to say that all directories should be
visited if no explicit files were listed, because the case of empty
_files usually implied that no patterns were given (which in turns
meant that everything should match). However, this made e.g. "hg files
-r .  rootfilesin:."  slower than necessary, because that also ended
up with an empty list in _files. Now that patternmatcher does not
handle includes, the only remaining case where its _files/_fileset
fields will be empty is when it's matching everything. We can
therefore treat the always-case specially and stop treating the empty
_files case specially. This makes the case mentioned above faster on
treemanifest repos.

diff -r 20c9f3ecc192 -r f44ea253ffe2 mercurial/match.py
--- a/mercurial/match.py	Fri May 19 11:50:01 2017 -0700
+++ b/mercurial/match.py	Sat May 20 23:49:14 2017 -0700
@@ -377,10 +377,11 @@
         return set(util.dirs(self._fileset)) | {'.'}
 
     def visitdir(self, dir):
+        if self.always():
+            return 'all'
         if self.prefix() and dir in self._fileset:
             return 'all'
-        return (not self._fileset or
-                '.' in self._fileset or
+        return ('.' in self._fileset or
                 dir in self._fileset or
                 dir in self._dirs or
                 any(parentdir in self._fileset