fix changeFile to not be partial

That led to runtime crashes, without even a warning from -Wall. Yipes!

Assistant/Threads/Committer.hs

@@ -390,7 +390,7 @@ safeToAdd delayadd pending inprocess = do
  - transfer scan does the same thing then.
  -}
 checkChangeContent :: Change -> Assistant ()
-checkChangeContent (Change { changeInfo = i , changeFile = f }) =
+checkChangeContent change@(Change { changeInfo = i }) =
 	case changeInfoKey i of
 		Nothing -> noop
 		Just k -> whenM (scanComplete <$> getDaemonStatus) $ do
@@ -399,5 +399,6 @@ checkChangeContent (Change { changeInfo = i , changeFile = f }) =
 				then queueTransfers "new file created" Next k (Just f) Upload
 				else queueTransfers "new or renamed file wanted" Next k (Just f) Download
 			handleDrops "file renamed" present k (Just f) Nothing
+  where
+	f = changeFile change
 checkChangeContent _ = noop
-

Assistant/Types/Changes.hs

@@ -24,15 +24,18 @@ changeInfoKey _ = Nothing
 
 type ChangeChan = TSet Change
 
+newChangeChan :: IO ChangeChan
+newChangeChan = atomically newTSet
+
 data Change
 	= Change 
 		{ changeTime :: UTCTime
-		, changeFile :: FilePath
+		, _changeFile :: FilePath
 		, changeInfo :: ChangeInfo
 		}
 	| PendingAddChange
 		{ changeTime ::UTCTime
-		, changeFile :: FilePath
+		, _changeFile :: FilePath
 		}
 	| InProcessAddChange
 		{ changeTime ::UTCTime
@@ -40,8 +43,10 @@ data Change
 		}
 	deriving (Show)
 
-newChangeChan :: IO ChangeChan
-newChangeChan = atomically newTSet
+changeFile :: Change -> FilePath
+changeFile (Change _ f _) = f
+changeFile (PendingAddChange _ f) = f
+changeFile (InProcessAddChange _ ks) = keyFilename ks
 
 isPendingAddChange :: Change -> Bool
 isPendingAddChange (PendingAddChange {}) = True
@@ -54,7 +59,7 @@ isInProcessAddChange _ = False
 finishedChange :: Change -> Key -> Change
 finishedChange c@(InProcessAddChange { keySource = ks }) k = Change
 	{ changeTime = changeTime c
-	, changeFile = keyFilename ks
+	, _changeFile = keyFilename ks
 	, changeInfo = AddChange k
 	}
 finishedChange c _ = c