unify exception handling into Utility.Exception

Removed old extensible-exceptions, only needed for very old ghc.

Made webdav use Utility.Exception, to work after some changes in DAV's
exception handling.

Removed Annex.Exception. Mostly this was trivial, but note that
tryAnnex is replaced with tryNonAsync and catchAnnex replaced with
catchNonAsync. In theory that could be a behavior change, since the former
caught all exceptions, and the latter don't catch async exceptions.

However, in practice, nothing in the Annex monad uses async exceptions.
Grepping for throwTo and killThread only find stuff in the assistant,
which does not seem related.

Command.Add.undo is changed to accept a SomeException, and things
that use it for rollback now catch non-async exceptions, rather than
only IOExceptions.

Assistant/Threads/Committer.hs

@@ -27,7 +27,6 @@ import qualified Utility.Lsof as Lsof
 import qualified Utility.DirWatcher as DirWatcher
 import Types.KeySource
 import Config
-import Annex.Exception
 import Annex.Content
 import Annex.Link
 import Annex.CatFile
@@ -217,7 +216,7 @@ commitStaged :: Annex Bool
 commitStaged = do
 	{- This could fail if there's another commit being made by
 	 - something else. -}
-	v <- tryAnnex Annex.Queue.flush
+	v <- tryNonAsync Annex.Queue.flush
 	case v of
 		Left _ -> return False
 		Right _ -> do

Assistant/Threads/Cronner.hs

@@ -191,10 +191,10 @@ runActivity' urlrenderer (ScheduledSelfFsck _ d) = do
 	mapM_ reget =<< liftAnnex (dirKeys gitAnnexBadDir)
   where
 	reget k = queueTransfers "fsck found bad file; redownloading" Next k Nothing Download
-runActivity' urlrenderer (ScheduledRemoteFsck u s d) = handle =<< liftAnnex (remoteFromUUID u)
+runActivity' urlrenderer (ScheduledRemoteFsck u s d) = dispatch =<< liftAnnex (remoteFromUUID u)
   where
-	handle Nothing = debug ["skipping remote fsck of uuid without a configured remote", fromUUID u, fromSchedule s]
-	handle (Just rmt) = void $ case Remote.remoteFsck rmt of
+	dispatch Nothing = debug ["skipping remote fsck of uuid without a configured remote", fromUUID u, fromSchedule s]
+	dispatch (Just rmt) = void $ case Remote.remoteFsck rmt of
 		Nothing -> go rmt $ do
 			program <- readProgramFile
 			void $ batchCommand program $ 

Assistant/Threads/SanityChecker.hs

@@ -40,7 +40,6 @@ import Logs.Transfer
 import Config.Files
 import Utility.DiskFree
 import qualified Annex
-import Annex.Exception
 #ifdef WITH_WEBAPP
 import Assistant.WebApp.Types
 #endif
@@ -85,7 +84,7 @@ sanityCheckerStartupThread startupdelay = namedThreadUnchecked "SanityCheckerSta
 	liftIO $ fixUpSshRemotes
 
 	{- Clean up old temp files. -}
-	void $ liftAnnex $ tryAnnex $ do
+	void $ liftAnnex $ tryNonAsync $ do
 		cleanOldTmpMisc
 		cleanReallyOldTmp
 

Assistant/Threads/Watcher.hs

@@ -104,13 +104,13 @@ runWatcher = do
 		, errHook = errhook
 		}
 	scanevents <- liftAnnex $ annexStartupScan <$> Annex.getGitConfig
-	handle <- liftIO $ watchDir "." ignored scanevents hooks startup
+	h <- liftIO $ watchDir "." ignored scanevents hooks startup
 	debug [ "watching", "."]
 	
 	{- Let the DirWatcher thread run until signalled to pause it,
 	 - then wait for a resume signal, and restart. -}
 	waitFor PauseWatcher $ do
-		liftIO $ stopWatchDir handle
+		liftIO $ stopWatchDir h
 		waitFor ResumeWatcher runWatcher
   where
 	hook a = Just <$> asIO2 (runHandler a)

Assistant/Threads/XMPPClient.hs

@@ -117,7 +117,7 @@ xmppClient urlrenderer d creds xmppuuid =
 		void $ liftIO $ atomically . swapTMVar lasttraffic =<< getCurrentTime
 		inAssistant $ debug
 			["received:", show $ map logXMPPEvent l]
-		mapM_ (handle selfjid) l
+		mapM_ (handlemsg selfjid) l
 	sendpings selfjid lasttraffic = forever $ do
 		putStanza pingstanza
 
@@ -133,21 +133,21 @@ xmppClient urlrenderer d creds xmppuuid =
 		 - cause traffic, so good enough. -}
 	  	pingstanza = xmppPing selfjid
 
-	handle selfjid (PresenceMessage p) = do
+	handlemsg selfjid (PresenceMessage p) = do
 		void $ inAssistant $ 
 			updateBuddyList (updateBuddies p) <<~ buddyList
 		resendImportantMessages selfjid p
-	handle _ (GotNetMessage QueryPresence) = putStanza gitAnnexSignature
-	handle _ (GotNetMessage (NotifyPush us)) = void $ inAssistant $ pull us
-	handle selfjid (GotNetMessage (PairingNotification stage c u)) =
+	handlemsg _ (GotNetMessage QueryPresence) = putStanza gitAnnexSignature
+	handlemsg _ (GotNetMessage (NotifyPush us)) = void $ inAssistant $ pull us
+	handlemsg selfjid (GotNetMessage (PairingNotification stage c u)) =
 		maybe noop (inAssistant . pairMsgReceived urlrenderer stage u selfjid) (parseJID c)
-	handle _ (GotNetMessage m@(Pushing _ pushstage))
+	handlemsg _ (GotNetMessage m@(Pushing _ pushstage))
 		| isPushNotice pushstage = inAssistant $ handlePushNotice m
 		| isPushInitiation pushstage = inAssistant $ queuePushInitiation m
 		| otherwise = inAssistant $ storeInbox m
-	handle _ (Ignorable _) = noop
-	handle _ (Unknown _) = noop
-	handle _ (ProtocolError _) = noop
+	handlemsg _ (Ignorable _) = noop
+	handlemsg _ (Unknown _) = noop
+	handlemsg _ (ProtocolError _) = noop
 
 	resendImportantMessages selfjid (Presence { presenceFrom = Just jid }) = do
 		let c = formatJID jid