subrepo: avoid sanitizing ".hg/hgrc" in meta data area for non-hg subrepos

Before this patch, sanitizing ".hg/hgrc" scans directories and files
also in meta data area for non-hg subrepos: under ".svn" for
Subversion subrepo, for example.

This may cause not only performance impact (especially in large scale
subrepos) but also unexpected removing meta data files.

This patch avoids sanitizing ".hg/hgrc" in meta data area for non-hg
subrepos.

This patch stops checking "ignore" target at the first
(case-insensitive) appearance of it, because continuation of scanning
is meaningless in almost all cases.

mercurial/subrepo.py

@@ -314,8 +314,12 b' def _abssource(repo, push=False, abort=T'
     if abort:
         raise util.Abort(_("default path for subrepository not found"))
 
-def _sanitize(ui, path):
+def _sanitize(ui, path, ignore):
     for dirname, dirs, names in os.walk(path):
+        for i, d in enumerate(dirs):
+            if d.lower() == ignore:
+                del dirs[i]
+                break
         if os.path.basename(dirname).lower() != '.hg':
             continue
         for f in names:
@@ -1050,7 +1054,7 b' class svnsubrepo(abstractsubrepo):'
         # update to a directory which has since been deleted and recreated.
         args.append('%s@%s' % (state[0], state[1]))
         status, err = self._svncommand(args, failok=True)
-        _sanitize(self._ui, self._ctx._repo.wjoin(self._path))
+        _sanitize(self._ui, self._ctx._repo.wjoin(self._path), '.svn')
         if not re.search('Checked out revision [0-9]+.', status):
             if ('is already a working copy for a different URL' in err
                 and (self._wcchanged()[:2] == (False, False))):
@@ -1343,7 +1347,7 b' class gitsubrepo(abstractsubrepo):'
                 self._gitcommand(['reset', 'HEAD'])
                 cmd.append('-f')
             self._gitcommand(cmd + args)
-            _sanitize(self._ui, self._abspath)
+            _sanitize(self._ui, self._abspath, '.git')
 
         def rawcheckout():
             # no branch to checkout, check it out with no branch
@@ -1392,7 +1396,7 b' class gitsubrepo(abstractsubrepo):'
             if tracking[remote] != self._gitcurrentbranch():
                 checkout([tracking[remote]])
             self._gitcommand(['merge', '--ff', remote])
-            _sanitize(self._ui, self._abspath)
+            _sanitize(self._ui, self._abspath, '.git')
         else:
             # a real merge would be required, just checkout the revision
             rawcheckout()
@@ -1428,7 +1432,7 b' class gitsubrepo(abstractsubrepo):'
                 self.get(state) # fast forward merge
             elif base != self._state[1]:
                 self._gitcommand(['merge', '--no-commit', revision])
-            _sanitize(self._ui, self._abspath)
+            _sanitize(self._ui, self._abspath, '.git')
 
         if self.dirty():
             if self._gitstate() != revision:

tests/test-subrepo-git.t

@@ -658,4 +658,13 b' additional test for "git merge --ff" rou'
   $ cat s/sub/.hg/hgrc
   cat: s/sub/.hg/hgrc: No such file or directory
   [1]
+
+Test that sanitizing is omitted in meta data area:
+
+  $ mkdir s/.git/.hg
+  $ echo '.hg/hgrc in git metadata area' > s/.git/.hg/hgrc
+  $ hg update -q -C af6d2edbb0d3
+  checking out detached HEAD in subrepo s
+  check out a git branch if you intend to make changes
+
   $ cd ..

tests/test-subrepo-svn.t

@@ -676,4 +676,10 b' Test sanitizing ".hg/hgrc" in subrepo'
   cat: s/sub/.hg/hgrc: No such file or directory
   [1]
 
+Test that sanitizing is omitted in meta data area:
+
+  $ mkdir s/.svn/.hg
+  $ echo '.hg/hgrc in svn metadata area' > s/.svn/.hg/hgrc
+  $ hg update -q -C '.^1'
+
   $ cd ../..