Execute handlers sequentially.

Network/IRC/Client/Events.hs

@@ -11,7 +11,8 @@
 -- Portability : CPP, OverloadedStrings, RankNTypes
 --
 -- Events and event handlers. When a message is received from the
--- server, all matching handlers are executed concurrently.
+-- server, all matching handlers are executed sequentially in the
+-- order that they appear in the 'handlers' list.
 module Network.IRC.Client.Events
   ( -- * Handlers
     EventHandler(..)

Network/IRC/Client/Internal.hs

@@ -148,8 +148,7 @@ forgetful = awaitForever go where
   go (Left  _) = return ()
   go (Right b) = yield b
 
--- | Block on receiving a message and invoke all matching handlers
--- concurrently.
+-- | Block on receiving a message and invoke all matching handlers.
 eventSink :: MonadIO m => IORef UTCTime -> IRCState s -> Consumer (Event ByteString) m ()
 eventSink lastReceived ircstate = go where
   go = await >>= maybe (return ()) (\event -> do
@@ -164,7 +163,7 @@ eventSink lastReceived ircstate = go where
       iconf <- snapshot instanceConfig ircstate
       forM_ (get handlers iconf) $ \(EventHandler matcher handler) ->
         maybe (pure ())
-              (void . forkIO . flip runIRCAction ircstate . handler (_source event'))
+              (void . flip runIRCAction ircstate . handler (_source event'))
               (matcher event')
 
     -- If disconnected, do not loop.

Network/IRC/Client/Internal/Types.hs

@@ -113,7 +113,8 @@ data InstanceConfig s = InstanceConfig
   -- ^ The version is sent in response to the CTCP \"VERSION\" request by
   -- the default event handlers.
   , _handlers :: [EventHandler s]
-  -- ^ The registered event handlers
+  -- ^ The registered event handlers. The order in this list is the
+  -- order in which they are executed.
   , _ignore   :: [(Text, Maybe Text)]
   -- ^ List of nicks (optionally restricted to channels) to ignore
   -- messages from. 'Nothing' ignores globally.