sync, merge: Bug fix: Don't try to merge into master when in a bare repo.

Command/Sync.hs

@@ -101,10 +101,13 @@ mergeLocal :: Git.Ref -> CommandStart
 mergeLocal branch = go =<< needmerge
   where
 	syncbranch = syncBranch branch
-	needmerge = do
-		unlessM (inRepo $ Git.Ref.exists syncbranch) $
-			inRepo $ updateBranch syncbranch
-		inRepo $ Git.Branch.changed branch syncbranch
+	needmerge = ifM isBareRepo
+		( return False
+		, do
+			unlessM (inRepo $ Git.Ref.exists syncbranch) $
+				inRepo $ updateBranch syncbranch
+			inRepo $ Git.Branch.changed branch syncbranch
+		)
 	go False = stop
 	go True = do
 		showStart "merge" $ Git.Ref.describe syncbranch

debian/changelog

@@ -3,6 +3,7 @@ git-annex (4.20130816) UNRELEASED; urgency=low
   * Debian: Run the builtin test suite as an autopkgtest.
   * Debian: Recommend ssh-askpass, which ssh will use when the assistant
     is run w/o a tty. Closes: #719832
+  * sync, merge: Bug fix: Don't try to merge into master when in a bare repo.
 
  -- Joey Hess <joeyh@debian.org>  Thu, 15 Aug 2013 15:47:52 +0200