fixed the build

Manually tested getLiveRepoSizes and it is working correctly.

Annex/RepoSize/LiveUpdate.hs

@@ -64,16 +64,17 @@ prepareLiveUpdate mu k sc = do
   where
 	{- Wait for checkLiveUpdate to request a start, or for the
 	 - LiveUpdate to get garbage collected in the case where
-	 - it is not needed. -}
+	 - it is not needed.
+	 -
+	 - Deferring updating the database until here avoids overhead
+	 - except in cases where preferred content expressions
+	 - need live updates.
+	 -}
 	waitstart startv readyv donev h u =
 		tryNonAsync (takeMVar startv) >>= \case
 			Right () -> do
 				pid <- getCurrentPid
 				cid <- mkSizeChangeId pid
-				{- Deferring updating the database until
-				 - here avoids overhead except in cases
-				 - where preferred content expressions
-				 - need live updates. -}
 				Db.startingLiveSizeChange h u k sc cid
 				putMVar readyv ()
 				waitdone donev h u cid
@@ -82,17 +83,18 @@ prepareLiveUpdate mu k sc = do
 	{- Wait for finishedLiveUpdate to be called, or for the LiveUpdate
 	 - to get garbage collected in the case where the change didn't
 	 - actually happen. Updates the database. -}
-	waitdone donev finishv h u cid = tryNonAsync (takeMVar donev) >>= \case
+	waitdone donev h u cid = tryNonAsync (takeMVar donev) >>= \case
 		Right (Just (u', k', sc', finishv))
 			| u' == u && k' == k && sc' == sc -> do
 				Db.successfullyFinishedLiveSizeChange h u k sc cid
 				putMVar finishv ()
-			-- This can happen when eg, storing to a cluster
+			-- Not the update we were expecting. This can
+			-- happen when eg, storing to a cluster
 			-- causes fanout and so this is called with
 			-- other UUIDs.
 			| otherwise -> do
 				putMVar finishv ()
-				waitdone donev finishv h u cid
+				waitdone donev h u cid
 		Right Nothing -> abandoned h u cid
 		Left _ -> abandoned h u cid
 	abandoned h u cid = Db.removeStaleLiveSizeChange h u k sc cid

Database/RepoSize.hs

@@ -201,11 +201,6 @@ successfullyFinishedLiveSizeChange (RepoSizeHandle (Just h)) u k sc sid =
 		setSizeChangeFor u (updateRollingTotal rollingtotal sc k)
 		addRecentChange u k sc
 		removeLiveSizeChange u k sc sid
-  where
-	updaterollingtotal t = case sc of
-		AddingKey -> t + ksz
-		RemovingKey -> t - ksz
-	ksz = fromMaybe 0 $ fromKey keySize k
 successfullyFinishedLiveSizeChange (RepoSizeHandle Nothing) _ _ _ _ = noop
 
 updateRollingTotal :: FileSize -> SizeChange -> Key -> FileSize
@@ -288,20 +283,25 @@ getRecentChange u k = do
  - adding the key is used, in order to err on the side of a larger
  - RepoSize.
  -
- - Omits live changes that are redundant due to a recent change already
- - being recorded for the same change.
+ - In the case where the same live change is recorded by two different
+ - processes or threads, the first to complete will record it as a recent
+ - change. This omits live changes that are redundant due to a recent
+ - change already being recorded for the same change.
  - 
  - This is only expensive when there are a lot of live changes happening at
  - the same time.
  -}
-getLiveRepoSizes :: RepoSizeHandle -> IO (M.Map UUID RepoSize, Maybe Sha)
+getLiveRepoSizes :: RepoSizeHandle -> IO (Maybe (M.Map UUID RepoSize, Sha))
 getLiveRepoSizes (RepoSizeHandle (Just h)) = H.queryDb h $ do
-	sizechanges <- getSizeChanges
-	livechanges <- getLiveSizeChanges
-	reposizes <- getRepoSizes'
-	annexbranchsha <- getAnnexBranchCommit
-	m <- M.fromList <$> forM reposizes (go sizechanges livechanges)
-	return (m, annexbranchsha)
+	getAnnexBranchCommit >>= \case
+		Nothing -> return Nothing
+		Just annexbranchsha -> do
+			sizechanges <- getSizeChanges
+			livechanges <- getLiveSizeChanges
+			reposizes <- getRepoSizes'
+			m <- M.fromList <$> forM reposizes
+				(go sizechanges livechanges)
+			return (Just (m, annexbranchsha))
   where
 	go
 		:: M.Map UUID FileSize
@@ -310,8 +310,10 @@ getLiveRepoSizes (RepoSizeHandle (Just h)) = H.queryDb h $ do
 		-> SqlPersistM (UUID, RepoSize)
 	go sizechanges livechanges (u, RepoSize startsize) = do
 		let livechangesbykey = 
-			M.fromListWith (++) $ maybe [] (\v -> [v]) $
-				M.lookup u livechanges
+			M.fromListWith (++) $
+				map (\(k, v) -> (k, [v])) $
+					fromMaybe [] $
+						M.lookup u livechanges
 		livechanges' <- combinelikelivechanges <$> 
 			filterM (nonredundantlivechange livechangesbykey u)
 				(fromMaybe [] $ M.lookup u livechanges)
@@ -348,4 +350,4 @@ getLiveRepoSizes (RepoSizeHandle (Just h)) = H.queryDb h $ do
 		filter (\(sc', cid') -> cid /= cid' && sc' == AddingKey)
 			(fromMaybe [] $ M.lookup k livechangesbykey)
 	competinglivechanges _ _ AddingKey _ = []
-getLiveRepoSizes (RepoSizeHandle Nothing) = return mempty
+getLiveRepoSizes (RepoSizeHandle Nothing) = return Nothing

Types/RepoSize.hs

@@ -44,7 +44,7 @@ data LiveUpdate
 	| NoLiveUpdate
 
 data SizeChange = AddingKey | RemovingKey
-	deriving (Show, Eq)
+	deriving (Show, Eq, Ord)
 
 instance PersistField SizeChange where
         toPersistValue AddingKey = toPersistValue (1 :: Int)