merge: Avoid creating the synced/master branch.

The branch needs to be created when merging from the remote in sync,
since we diff between it and the remote's sync branch. But git annex merge
should not be creating sync branches.

Command/Sync.hs

@@ -194,10 +194,10 @@ mergeLocal (Just branch) = go =<< needmerge
 	syncbranch = syncBranch branch
 	needmerge = ifM isBareRepo
 		( return False
-		, do
-			unlessM (inRepo $ Git.Ref.exists syncbranch) $
-				inRepo $ updateBranch syncbranch
-			inRepo $ Git.Branch.changed branch syncbranch
+		, ifM (inRepo $ Git.Ref.exists syncbranch)
+			( inRepo $ Git.Branch.changed branch syncbranch
+			, return False
+			)
 		)
 	go False = stop
 	go True = do
@@ -254,7 +254,8 @@ mergeRemote remote b = ifM isBareRepo
 		Nothing -> do
 			branch <- inRepo Git.Branch.currentUnsafe
 			and <$> mapM (merge Nothing) (branchlist branch)
-		Just thisbranch ->
+		Just thisbranch -> do
+			inRepo $ updateBranch $ syncBranch thisbranch
 			and <$> (mapM (merge (Just thisbranch)) =<< tomerge (branchlist b))
 	)
   where

debian/changelog

@@ -22,6 +22,7 @@ git-annex (5.20150618) UNRELEASED; urgency=medium
   * On linux, pass --as-needed to linker to avoid linking with unused
     shared libraries including libyaml.
   * import: Fix failure of cross-device import on Windows.
+  * merge: Avoid creating the synced/master branch.
 
  -- Joey Hess <id@joeyh.name>  Thu, 02 Jul 2015 12:31:14 -0400
 

doc/forum/annex_merge_creates___34__synced__47____42____34___branches/comment_5_39009651c3f65e2ecd225e17d157c8d8._comment

@@ -0,0 +1,10 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 5"""
+ date="2015-07-07T19:20:17Z"
+ content="""
+So, I was wrong about `git annex merge` creating the synced/master branch.
+
+There's no good reason for it to do that, so I've fixed it not to create
+it.
+"""]]