display alert for inotify/kqueue errors

Assistant/Alert.hs

@@ -27,7 +27,7 @@ data AlertPriority = Filler | Low | Medium | High | Pinned
 
 {- An alert can have an name, which is used to combine it with other similar
  - alerts. -}
-data AlertName = FileAlert TenseChunk | DownloadFailedAlert | SanityCheckFixAlert
+data AlertName = FileAlert TenseChunk | SanityCheckFixAlert | WarningAlert String
 	deriving (Eq)
 
 {- The first alert is the new alert, the second is an old alert.
@@ -180,6 +180,20 @@ baseActivityAlert = Alert
 	, alertName = Nothing
 	}
 
+warningAlert :: String -> String -> Alert
+warningAlert name msg = Alert
+	{ alertClass = Warning
+	, alertHeader = Just $ tenseWords ["warning"]
+	, alertMessageRender = tenseWords
+	, alertData = [UnTensed $ T.pack msg]
+	, alertBlockDisplay = True
+	, alertClosable = True
+	, alertPriority = High
+	, alertIcon = Just "exclamation-sign"
+	, alertCombiner = Just $ dataCombiner (++)
+	, alertName = Just $ WarningAlert name
+	}
+
 activityAlert :: Maybe TenseText -> [TenseChunk] -> Alert
 activityAlert header dat = baseActivityAlert
 	{ alertHeader = header

Assistant/Threads/Watcher.hs

@@ -235,10 +235,11 @@ onDelDir threadname dir _ _dstatus _ = do
 		[Params "--quiet -r --cached --ignore-unmatch --"] [dir]
 	madeChange dir RmDirChange
 
-{- Called when there's an error with inotify. -}
+{- Called when there's an error with inotify or kqueue. -}
 onErr :: Handler
-onErr _ msg _ _dstatus _ = do
+onErr _ msg _ dstatus _ = do
 	warning msg
+	void $ liftIO $ addAlert dstatus $ warningAlert "watcher" msg
 	return Nothing
 
 {- Adds a symlink to the index, without ever accessing the actual symlink

doc/design/assistant/webapp.mdwn

@@ -23,8 +23,8 @@ The webapp is a web server that displays a shiny interface.
 
 * there could be a UI to export a file, which would make it be served up
   over http by the web app
-* Display any relevant warning messages. One is the `inotify max_user_watches`
-  exceeded message.
+* Display the `inotify max_user_watches` exceeded message. **done**
+* Display something sane when kqueue runs out of file descriptors.
 * possibly add a desktop file to the top of the repository that can be used
   to open the webapp (rather than using the menus). Would be complicated
   some by the path to git-annex sometimes needing to be hardcoded and varying