avoid empty commits

Annex.hs

@@ -8,7 +8,7 @@ module Annex (
 	backends,
 	backendsChange,
 	flagIsSet,
-	flagsChange,
+	flagChange,
 	Flag(..)
 ) where
 
@@ -60,8 +60,11 @@ flagIsSet :: Flag -> Annex Bool
 flagIsSet flag = do
 	state <- get
 	return $ elem flag $ Backend.flags state
-flagsChange :: [Flag] -> Annex ()
-flagsChange b = do
+flagChange :: Flag -> Bool -> Annex ()
+flagChange flag set = do
 	state <- get
-	put state { Backend.flags = b }
+	let f = filter (/= flag) $ Backend.flags state
+	if (set)
+		then put state { Backend.flags = (flag:f) }
+		else put state { Backend.flags = f }
 	return ()

BackendTypes.hs

@@ -10,7 +10,7 @@ import Data.String.Utils
 import qualified GitRepo as Git
 
 -- command-line flags
-data Flag = Force
+data Flag = Force | NeedCommit
 	deriving (Eq, Read, Show)
 
 -- git-annex's runtime state type doesn't really belong here,

Commands.hs

@@ -178,7 +178,8 @@ logStatus key status = do
 	g <- Annex.gitRepo
 	u <- getUUID g
 	f <- liftIO $ logChange g key u status
-	liftIO $ Git.run g ["add", f] -- committed at shutdown
+	liftIO $ Git.run g ["add", f]
+	Annex.flagChange NeedCommit True
 
 inBackend file yes no = do
 	r <- liftIO $ Backend.lookupFile file

Core.hs

@@ -14,7 +14,7 @@ import qualified Annex
 {- Sets up a git repo for git-annex. -}
 startup :: [Flag] -> Annex ()
 startup flags = do
-	Annex.flagsChange flags
+	mapM (\f -> Annex.flagChange f True) flags
 	g <- Annex.gitRepo
 	liftIO $ gitAttributes g
 	prepUUID
@@ -23,8 +23,11 @@ startup flags = do
 shutdown :: Annex ()
 shutdown = do
 	g <- Annex.gitRepo
-	liftIO $ Git.run g ["commit", "-m", 
-		"git-annex log update", ".git-annex"]
+	needcommit <- Annex.flagIsSet NeedCommit
+	if (needcommit)
+		then liftIO $ Git.run g ["commit", "-m", 
+			"git-annex log update", ".git-annex"]
+		else return ()
 
 {- configure git to use union merge driver on state files, if it is not
  - already -}