# HG changeset patch
# User Durham Goode <durham@fb.com>
# Date 1493832657 25200
# Node ID 6dea1701f170f38f931759267d2bbd3f49de92a5
# Parent  35a69efbf190a9538c6ac4053edd0812755fc3ce
match: make subinclude construction lazy

The matcher subinclude functionality allows us to have .hgignore files that
include subdirectory hgignore files. Today it parses the entire repo at once,
even if we only need to test a file in one subdirectory. This patch makes the
subinclude tree creation lazy, which speeds up matcher creation significantly in
large repos with very large trees of ignore patterns.

diff -r 35a69efbf190 -r 6dea1701f170 mercurial/match.py
--- a/mercurial/match.py	Wed May 03 09:09:44 2017 -0700
+++ b/mercurial/match.py	Wed May 03 10:30:57 2017 -0700
@@ -52,7 +52,7 @@
     return fset, other
 
 def _expandsubinclude(kindpats, root):
-    '''Returns the list of subinclude matchers and the kindpats without the
+    '''Returns the list of subinclude matcher args and the kindpats without the
     subincludes in it.'''
     relmatchers = []
     other = []
@@ -64,12 +64,12 @@
             path = pathutil.join(sourceroot, pat)
 
             newroot = pathutil.dirname(path)
-            relmatcher = match(newroot, '', [], ['include:%s' % path])
+            matcherargs = (newroot, '', [], ['include:%s' % path])
 
             prefix = pathutil.canonpath(root, root, newroot)
             if prefix:
                 prefix += '/'
-            relmatchers.append((prefix, relmatcher))
+            relmatchers.append((prefix, matcherargs))
         else:
             other.append((kind, pat, source))
 
@@ -584,10 +584,17 @@
 
     subincludes, kindpats = _expandsubinclude(kindpats, root)
     if subincludes:
+        submatchers = {}
         def matchsubinclude(f):
-            for prefix, mf in subincludes:
-                if f.startswith(prefix) and mf(f[len(prefix):]):
-                    return True
+            for prefix, matcherargs in subincludes:
+                if f.startswith(prefix):
+                    mf = submatchers.get(prefix)
+                    if mf is None:
+                        mf = match(*matcherargs)
+                        submatchers[prefix] = mf
+
+                    if mf(f[len(prefix):]):
+                        return True
             return False
         matchfuncs.append(matchsubinclude)