From f9cd3f6ad18ca04a1da7082c6c10215dc5435154 Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Mon, 12 Dec 2011 02:31:07 -0400
Subject: [PATCH] optimisation

avoids a useless diff from git-annex..refs/heads/git-annex
---
 Annex/Branch.hs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Annex/Branch.hs b/Annex/Branch.hs
index b108281ce7..e6c92fbe54 100644
--- a/Annex/Branch.hs
+++ b/Annex/Branch.hs
@@ -213,7 +213,7 @@ update = onceonly $ do
 	create
 	-- check what needs updating before taking the lock
 	dirty <- journalDirty
-	c <- filterM (changedBranch name . snd) =<< siblingBranches
+	c <- filterM (changedBranch fullname . snd) =<< siblingBranches
 	let (refs, branches) = unzip c
 	if (not dirty && null refs)
 		then simpleupdate
@@ -244,7 +244,9 @@ update = onceonly $ do
 {- Checks if the second branch has any commits not present on the first
  - branch. -}
 changedBranch :: Git.Branch -> Git.Branch -> Annex Bool
-changedBranch origbranch newbranch = not . L.null <$> diffs
+changedBranch origbranch newbranch
+	| origbranch == newbranch = return False
+	| otherwise = not . L.null <$> diffs
 	where
 		diffs = inRepo $ Git.pipeRead
 			[ Param "log"