--- a/mercurial/localrepo.py	Thu Mar 13 19:48:41 2014 +0900
+++ b/mercurial/localrepo.py	Wed Mar 19 01:07:41 2014 +0900
@@ -1270,6 +1270,11 @@
                 cctx._text = editor(self, cctx, subs)
             edited = (text != cctx._text)
 
+            # Save commit message in case this transaction gets rolled back
+            # (e.g. by a pretxncommit hook).  Leave the content alone on
+            # the assumption that the user will use the same editor again.
+            msgfn = self.savecommitmessage(cctx._text)
+
             # commit subs and write new state
             if subs:
                 for s in sorted(commitsubs):
@@ -1280,11 +1285,6 @@
                     newstate[s] = (newstate[s][0], sr)
                 subrepo.writestate(self, newstate)
 
-            # Save commit message in case this transaction gets rolled back
-            # (e.g. by a pretxncommit hook).  Leave the content alone on
-            # the assumption that the user will use the same editor again.
-            msgfn = self.savecommitmessage(cctx._text)
-
             p1, p2 = self.dirstate.parents()
             hookp1, hookp2 = hex(p1), (p2 != nullid and hex(p2) or '')
             try:

--- a/tests/test-commit.t	Thu Mar 13 19:48:41 2014 +0900
+++ b/tests/test-commit.t	Wed Mar 19 01:07:41 2014 +0900
@@ -284,6 +284,52 @@
   HG: removed removed
   abort: empty commit message
   [255]
+
+test saving last-message.txt
+
+  $ hg init sub
+  $ echo a > sub/a
+  $ hg -R sub add sub/a
+  $ cat > sub/.hg/hgrc <<EOF
+  > [hooks]
+  > precommit.test-saving-last-message = false
+  > EOF
+
+  $ echo 'sub = sub' > .hgsub
+  $ hg add .hgsub
+
+  $ cat > $TESTDIR/editor.sh <<EOF
+  > echo "==== before editing:"
+  > cat \$1
+  > echo "===="
+  > echo "test saving last-message.txt" >> \$1
+  > EOF
+
+  $ rm -f .hg/last-message.txt
+  $ HGEDITOR="sh $TESTDIR/editor.sh" hg commit -S -q
+  ==== before editing:
+  
+  
+  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
+  HG: Leave message empty to abort commit.
+  HG: --
+  HG: user: test
+  HG: branch 'default'
+  HG: bookmark 'currentbookmark'
+  HG: subrepo sub
+  HG: added .hgsub
+  HG: added added
+  HG: changed .hgsubstate
+  HG: changed changed
+  HG: removed removed
+  ====
+  abort: precommit.test-saving-last-message hook exited with status 1 (in subrepo sub)
+  [255]
+  $ cat .hg/last-message.txt
+  
+  
+  test saving last-message.txt
+
   $ cd ..