[PATCH stable] subrepo: fix git status false positive (issue3109)

[Eric Roshan Eisner]

# HG changeset patch
# User Eric Roshan Eisner <ede at alum.mit.edu>
# Date 1320969611 -40260
# Branch stable
# Node ID b305f153dac07ae6d9a8ac4508913188493906e2
# Parent  6eff984d8e76811f1ce129a424236abf0afaa191
subrepo: fix git status false positive (issue3109)

It turns out there's a separate command to force git to look at file contents
if the stat has changed.

diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -807,6 +807,12 @@ class gitsubrepo(abstractsubrepo):
     def _gitisbare(self):
         return self._gitcommand(['config', '--bool', 'core.bare']) == 'true'
 
+    def _gitupdatestat(self):
+        """This must be run before git diff-index.
+        diff-index only looks at changes to file stat;
+        this command looks at file contents and updates the stat."""
+        self._gitcommand(['update-index', '-q', '--refresh'])
+
     def _gitbranchmap(self):
         '''returns 2 things:
         a map from git branch to revision
@@ -876,6 +882,7 @@ class gitsubrepo(abstractsubrepo):
             # different version checked out
             return True
         # check for staged changes or modified files; ignore untracked files
+        self._gitupdatestat()
         out, code = self._gitdir(['diff-index', '--quiet', 'HEAD'])
         return code == 1
 
@@ -983,6 +990,7 @@ class gitsubrepo(abstractsubrepo):
         source, revision, kind = state
         self._fetch(source, revision)
         base = self._gitcommand(['merge-base', revision, self._state[1]])
+        self._gitupdatestat()
         out, code = self._gitdir(['diff-index', '--quiet', 'HEAD'])
 
         def mergefunc():
@@ -1090,6 +1098,7 @@ class gitsubrepo(abstractsubrepo):
             # if the repo is missing, return no results
             return [], [], [], [], [], [], []
         modified, added, removed = [], [], []
+        self._gitupdatestat()
         if rev2:
             command = ['diff-tree', rev1, rev2]
         else:
diff --git a/tests/test-subrepo-git.t b/tests/test-subrepo-git.t
--- a/tests/test-subrepo-git.t
+++ b/tests/test-subrepo-git.t
@@ -361,6 +361,15 @@ Don't crash if the .hgsubstate entry is 
   $ hg update -qC nosubstate
   $ ls s
 
+issue3109: false positives in git diff-index
+
+  $ hg update -q
+  $ touch -d 0 s/g
+  $ hg status --subrepos
+  $ touch -d 0 s/g
+  $ hg sum | grep commit
+  commit: (clean)
+
 Check hg update --clean
   $ cd $TESTTMP/ta
   $ echo  > s/g