Add test on handler priority

Web/Scotty/Action.hs

@@ -94,7 +94,7 @@
 import           Numeric.Natural
 
 import           Web.Scotty.Internal.Types
 import           Web.Scotty.Util (mkResponse, addIfNotPresent, add, replace, lazyTextToStrictByteString, decodeUtf8Lenient)
 import           UnliftIO.Exception (Handler(..), catch, catches, throwIO)
 
 import Network.Wai.Internal (ResponseReceived(..))
@@ -111,9 +111,9 @@
           -> m (Maybe Response)
 runAction mh env action = do
   ok <- flip runReaderT env $ runAM $ tryNext $ action `catches` concat
-    [ [actionErrorHandler]
+    [ [actionErrorHandler, statusErrorHandler, scottyExceptionHandler]
     , maybeToList mh
-    , [statusErrorHandler, scottyExceptionHandler, someExceptionHandler]
+    , [someExceptionHandler]
     ]
   res <- getResponse env
   return $ bool Nothing (Just $ mkResponse res) ok
@@ -121,7 +121,7 @@
 -- | Catches 'StatusError' and produces an appropriate HTTP response.
 statusErrorHandler :: MonadIO m => ErrorHandler m
 statusErrorHandler = Handler $ \case
   StatusError s e -> do
     status s
     let code = T.pack $ show $ statusCode s
     let msg = decodeUtf8Lenient $ statusMessage s
@@ -188,7 +188,7 @@
 --
 -- Uncaught exceptions turn into HTTP responses corresponding to the given status.
 raiseStatus :: Monad m => Status -> T.Text -> ActionT m a
 raiseStatus s = E.throw . StatusError s
 {-# DEPRECATED raiseStatus "Use status, text, and finish instead" #-}
 
 -- | Throw an exception which can be caught within the scope of the current Action with 'catch'.

test/Web/ScottySpec.hs

@@ -65,7 +65,7 @@ spec = do
             makeRequest "/:paramName" `shouldRespondWith` ":paramName"
           it ("captures route parameters for " ++ method ++ " requests with url encoded '/' in path") $ do
             makeRequest "/a%2Fb" `shouldRespondWith` "a/b"
-            
+
     describe "addroute" $ do
       forM_ availableMethods $ \method -> do
         withApp (addroute method "/scotty" $ html "") $ do
@@ -108,9 +108,13 @@ spec = do
       withApp (do
                   let h = Handler (\(_ :: E.SomeException) -> setHeader "Location" "/c" >> status status500)
                   defaultHandler h
-                  Scotty.get "/a" (redirect "/b")) $ do
+                  Scotty.get "/a" (redirect "/b")
+                  Scotty.get "/d" (raiseStatus status404 "d not found")) $ do
         it "should give priority to actionErrorHandlers" $ do
           get "/a" `shouldRespondWith` 302 { matchHeaders = ["Location" <:> "/b"] }
+          get "/d"
+            `shouldRespondWith`
+            "<h1>404 Not Found</h1>d not found" { matchStatus = 404 }
 
       context "when not specified" $ do
         withApp (Scotty.get "/" $ throw E.DivideByZero) $ do