Add HasStatus instance for Headers (that defers StatusOf to underlying value) (#1649)

* Add HasStatus instance for Headers (that defers StatusOf to underlying value)

* changelog.d/1649

.github/workflows/master.yml

@@ -20,6 +20,7 @@ jobs:
           - "8.10.7"
           - "9.0.2"
           - "9.2.2"
+          - "9.4.2"
 
     steps:
     - uses: actions/checkout@v2
@@ -75,40 +76,40 @@ jobs:
         (cd servant-conduit && eval $DOCTEST)
         (cd servant-pipes && eval $DOCTEST)
 
-  stack:
-    name: stack / ghc ${{ matrix.ghc }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        stack: ["2.7.5"]
-        ghc: ["8.10.7"]
+  # stack:
+  #   name: stack / ghc ${{ matrix.ghc }}
+  #   runs-on: ubuntu-latest
+  #   strategy:
+  #     matrix:
+  #       stack: ["2.7.5"]
+  #       ghc: ["8.10.7"]
 
-    steps:
-    - uses: actions/checkout@v2
+  #   steps:
+  #   - uses: actions/checkout@v2
 
-    - uses: haskell/actions/setup@v1
-      name: Setup Haskell Stack
-      with:
-        ghc-version: ${{ matrix.ghc }}
-        stack-version: ${{ matrix.stack }}
+  #   - uses: haskell/actions/setup@v1
+  #     name: Setup Haskell Stack
+  #     with:
+  #       ghc-version: ${{ matrix.ghc }}
+  #       stack-version: ${{ matrix.stack }}
 
-    - uses: actions/cache@v2.1.3
-      name: Cache ~/.stack
-      with:
-        path: ~/.stack
-        key: ${{ runner.os }}-${{ matrix.ghc }}-stack
+  #   - uses: actions/cache@v2.1.3
+  #     name: Cache ~/.stack
+  #     with:
+  #       path: ~/.stack
+  #       key: ${{ runner.os }}-${{ matrix.ghc }}-stack
 
-    - name: Install dependencies
-      run: |
-        stack build --system-ghc --test --bench --no-run-tests --no-run-benchmarks --only-dependencies
+  #   - name: Install dependencies
+  #     run: |
+  #       stack build --system-ghc --test --bench --no-run-tests --no-run-benchmarks --only-dependencies
 
-    - name: Build
-      run: |
-        stack build --system-ghc --test --bench --no-run-tests --no-run-benchmarks
+  #   - name: Build
+  #     run: |
+  #       stack build --system-ghc --test --bench --no-run-tests --no-run-benchmarks
 
-    - name: Test
-      run: |
-        stack test --system-ghc
+  #   - name: Test
+  #     run: |
+  #       stack test --system-ghc
 
   ghcjs:
     name: ubuntu-latest / ghcjs 8.6

cabal.project

@@ -47,6 +47,7 @@ packages:
   doc/cookbook/using-custom-monad
   doc/cookbook/using-free-client
   -- doc/cookbook/open-id-connect
+  doc/cookbook/managed-resource
 
 tests: True
 optimization: False

changelog.d/1573

@@ -0,0 +1,2 @@
+synopsis: Add API docs for ServerT
+prs: #1573

changelog.d/1580

@@ -0,0 +1,12 @@
+synopsis: Allow IO in validationKeys
+prs: #1580
+issues: #1579
+
+description: {
+
+Currently validationKeys are a fixed JWKSet. This does not work with OIDC
+providers such as AWS Cognito or Okta, which regularly fetching jwks_uri to
+discover new and expired keys.
+
+This change alters the type of validationKeys from JWKSet to IO JWKSet.
+}

changelog.d/1589

@@ -0,0 +1,2 @@
+synopsis: Only include question mark for nonempty query strings
+prs: 1589

changelog.d/1595

@@ -0,0 +1,2 @@
+synopsis: Run ClientEnv's makeClientRequest in IO.
+prs: #1595

changelog.d/1606

@@ -0,0 +1,10 @@
+synopsis: Handle Cookies correctly for RunStreamingClient
+prs: #1606
+issues: #1605
+
+description: {
+
+Makes performWithStreamingRequest take into consideration the
+CookieJar, which it previously didn't.
+
+}

changelog.d/1638

@@ -0,0 +1,2 @@
+synopsis: Add Functor instance to AuthHandler.
+prs: #1638

changelog.d/1649

@@ -0,0 +1,8 @@
+synopsis: Add HasStatus instance for Headers (that defers StatusOf to underlying value)
+prs: #1649
+
+description: {
+
+Adds a new HasStatus (Headers hs a) instance (StatusOf (Headers hs a) = StatusOf a)
+
+}

doc/cookbook/index.rst

@@ -37,3 +37,4 @@ you name it!
   sentry/Sentry.lhs
   testing/Testing.lhs
   open-id-connect/OpenIdConnect.lhs
+  managed-resource/ManagedResource.lhs

doc/cookbook/managed-resource/ManagedResource.lhs

@@ -0,0 +1,114 @@
+# Request-lifetime Managed Resources
+
+Let's see how we can write a handle that uses a resource managed by Servant. The resource is created automatically by Servant when the server recieves a request, and the resource is automatically destroyed when the server is finished handling a request.
+
+As usual, we start with a little bit of throat clearing.
+
+
+``` haskell
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeOperators #-}
+import Control.Concurrent
+import Control.Exception (bracket, throwIO)
+import Control.Monad.IO.Class
+import Control.Monad.Trans.Resource
+import Data.Acquire
+import Network.HTTP.Client (newManager, defaultManagerSettings)
+import Network.Wai.Handler.Warp
+import Servant
+import Servant.Client
+import System.IO
+```
+
+Here we define an API type that uses the `WithResource` combinator. The server handler for an endpoint with a `WithResource res` component will receive a value of that type as an argument.
+
+``` haskell
+type API = WithResource Handle :> ReqBody '[PlainText] String :> Post '[JSON] NoContent
+
+api :: Proxy API
+api = Proxy
+```
+
+But this resource value has to come from somewhere. Servant obtains the value using an Acquire provided in the context. The Acquire knows how to both create and destroy resources of a particular type.
+
+``` haskell
+appContext :: Context '[Acquire Handle]
+appContext = acquireHandle :. EmptyContext
+
+acquireHandle :: Acquire Handle
+acquireHandle = mkAcquire newHandle closeHandle
+
+newHandle :: IO Handle
+newHandle = do
+  putStrLn "opening file"
+  h <- openFile "test.txt" AppendMode
+  putStrLn "opened file"
+  return h
+
+closeHandle :: Handle -> IO ()
+closeHandle h = do
+  putStrLn "closing file"
+  hClose h
+  putStrLn "closed file"
+```
+
+Now we create the handler which will use this resource. This handler will write the request message to the System.IO.Handle which was provided to us. In some situations the handler will succeed, but in some in will fail. In either case, Servant will clean up the resource for us.
+
+``` haskell
+server :: Server API
+server = writeToFile
+
+  where writeToFile :: (ReleaseKey, Handle) -> String -> Handler NoContent
+        writeToFile (_, h) msg = case msg of
+          "illegal" -> error "wait, that's illegal!"
+          legalMsg -> liftIO $ do
+            putStrLn "writing file"
+            hPutStrLn h legalMsg
+            putStrLn "wrote file"
+            return NoContent
+```
+
+Finally we run the server in the background while we post messages to it.
+
+``` haskell
+runApp :: IO ()
+runApp = run 8080 (serveWithContext api appContext $ server)
+
+postMsg :: String -> ClientM NoContent
+postMsg = client api
+
+main :: IO ()
+main = do
+  mgr <- newManager defaultManagerSettings
+  bracket (forkIO $ runApp) killThread $ \_ -> do
+    ms <- flip runClientM (mkClientEnv mgr (BaseUrl Http "localhost" 8080 "")) $ do
+      liftIO $ putStrLn "sending hello message"
+      _ <- postMsg "hello"
+      liftIO $ putStrLn "sending illegal message"
+      _ <- postMsg "illegal"
+      liftIO $ putStrLn "done"
+    print ms
+```
+
+This program prints
+
+```
+sending hello message
+opening file
+opened file
+writing file
+wrote file
+closing file
+closed file
+sending illegal message
+opening file
+opened file
+closing file
+closed file
+wait, that's illegal!
+CallStack (from HasCallStack):
+  error, called at ManagedResource.lhs:63:24 in main:Main
+Left (FailureResponse (Request {requestPath = (BaseUrl {baseUrlScheme = Http, baseUrlHost = "localhost", baseUrlPort = 8080, baseUrlPath = ""},""), requestQueryString = fromList [], requestBody = Just ((),text/plain;charset=utf-8), requestAccept = fromList [], requestHeaders = fromList [], requestHttpVersion = HTTP/1.1, requestMethod = "POST"}) (Response {responseStatusCode = Status {statusCode = 500, statusMessage = "Internal Server Error"}, responseHeaders = fromList [("Transfer-Encoding","chunked"),("Date","Thu, 24 Nov 2022 21:04:47 GMT"),("Server","Warp/3.3.23"),("Content-Type","text/plain; charset=utf-8")], responseHttpVersion = HTTP/1.1, responseBody = "Something went wrong"}))
+```
+
+and appends to a file called `test.txt`. We can see from the output that when a legal message is sent, the file is opened, written to, and closed. We can also see that when an illegal message is sent, the file is opened but not written to. Crucially, it is still closed even though the handler threw an exception.

doc/cookbook/managed-resource/managed-resource.cabal

@@ -0,0 +1,30 @@
+cabal-version:       2.2
+name:                cookbook-managed-resource
+version:             0.1
+synopsis:            Simple managed resource cookbook example
+homepage:            http://docs.servant.dev/
+license:             BSD-3-Clause
+license-file:        ../../../servant/LICENSE
+author:              Servant Contributors
+maintainer:          haskell-servant-maintainers@googlegroups.com
+build-type:          Simple
+tested-with:         GHC==9.4.2
+
+executable cookbook-managed-resource
+  main-is:             ManagedResource.lhs
+  build-depends:       base == 4.*
+                     , text >= 1.2
+                     , aeson >= 1.2
+                     , servant
+                     , servant-client
+                     , servant-server
+                     , warp >= 3.2
+                     , wai >= 3.2
+                     , http-types >= 0.12
+                     , markdown-unlit >= 0.4
+                     , http-client >= 0.5
+                     , transformers
+                     , resourcet
+  default-language:    Haskell2010
+  ghc-options:         -Wall -pgmL markdown-unlit
+  build-tool-depends: markdown-unlit:markdown-unlit

doc/cookbook/open-id-connect/OpenIdConnect.lhs

@@ -330,7 +330,7 @@ data Customer = Customer {
 ```
 
 Here is the code that displays the homepage.
-It should contain a link to the the `/login` URL.
+It should contain a link to the `/login` URL.
 When the user clicks on this link it will be redirected to Google login page
 with some generated information.
 

doc/cookbook/using-free-client/UsingFreeClient.lhs

@@ -119,7 +119,7 @@ Now we can use `servant-client`'s internals to convert servant's `Request`
 to http-client's `Request`, and we can inspect it:
 
 ```haskell
-        let req' = I.defaultMakeClientRequest burl req
+        req' <- I.defaultMakeClientRequest burl req
         putStrLn $ "Making request: " ++ show req'
 ```
 

doc/cookbook/uverb/UVerb.lhs

@@ -199,7 +199,7 @@ parsers in the hope that the ones that should will always error out so
 you can try until the right one returns a value.)
 
 [servant-exceptions](https://github.com/ch1bo/servant-exceptions) is
-another shot at at the problem.  It is inspired by
+another shot at the problem.  It is inspired by
 servant-checked-exceptions, so it may be worth taking a closer look.
 The README claims that
 [cardano-sl](https://github.com/input-output-hk/cardano-sl) also has

doc/requirements.txt

@@ -1,3 +1,4 @@
 recommonmark==0.5.0
 Sphinx==1.8.4
 sphinx_rtd_theme>=0.4.2
+jinja2<3.1.0

servant-auth/servant-auth-client/servant-auth-client.cabal

@@ -31,7 +31,7 @@ library
   default-extensions: ConstraintKinds DataKinds DefaultSignatures DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable FlexibleContexts FlexibleInstances FunctionalDependencies GADTs KindSignatures MultiParamTypeClasses OverloadedStrings RankNTypes ScopedTypeVariables TypeFamilies TypeOperators
   ghc-options: -Wall
   build-depends:
-      base                >= 4.10     && < 4.17
+      base                >= 4.10     && < 4.18
     , bytestring          >= 0.10.6.0 && < 0.12
     , containers          >= 0.5.6.2  && < 0.7
     , servant-auth        == 0.4.*
@@ -74,7 +74,7 @@ test-suite spec
     , transformers         >= 0.4.2.0  && < 0.6
     , wai                  >= 3.2.1.2  && < 3.3
     , warp                 >= 3.2.25   && < 3.4
-    , jose                 >= 0.7.0.0  && < 0.10
+    , jose                 >= 0.10     && < 0.11
   other-modules:
       Servant.Auth.ClientSpec
   default-language: Haskell2010

servant-auth/servant-auth-docs/servant-auth-docs.cabal

@@ -35,11 +35,11 @@ library
   default-extensions: ConstraintKinds DataKinds DefaultSignatures DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable FlexibleContexts FlexibleInstances FunctionalDependencies GADTs KindSignatures MultiParamTypeClasses OverloadedStrings RankNTypes ScopedTypeVariables TypeFamilies TypeOperators
   ghc-options: -Wall
   build-depends:
-      base         >= 4.10    && < 4.17
+      base         >= 4.10    && < 4.18
     , servant-docs >= 0.11.2  && < 0.13
     , servant      >= 0.13    && < 0.20
     , servant-auth == 0.4.*
-    , lens         >= 4.16.1  && <5.2
+    , lens         >= 4.16.1  && <5.3
   exposed-modules:
       Servant.Auth.Docs
   default-language: Haskell2010
@@ -50,7 +50,7 @@ test-suite doctests
   build-depends:
     base,
     servant-auth-docs,
-    doctest             >= 0.16   && < 0.19,
+    doctest             >= 0.16   && < 0.21,
     QuickCheck          >= 2.11.3 && < 2.15,
     template-haskell
   ghc-options:         -Wall -threaded

servant-auth/servant-auth-server/servant-auth-server.cabal

@@ -31,7 +31,7 @@ library
   default-extensions: ConstraintKinds DataKinds DefaultSignatures DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable FlexibleContexts FlexibleInstances FunctionalDependencies GADTs KindSignatures MultiParamTypeClasses OverloadedStrings RankNTypes ScopedTypeVariables TypeFamilies TypeOperators
   ghc-options: -Wall
   build-depends:
-      base                    >= 4.10     && < 4.17
+      base                    >= 4.10     && < 4.18
     , aeson                   >= 1.0.0.1  && < 3
     , base64-bytestring       >= 1.0.0.1  && < 2
     , blaze-builder           >= 0.4.1.0  && < 0.5
@@ -41,17 +41,17 @@ library
     , data-default-class      >= 0.1.2.0  && < 0.2
     , entropy                 >= 0.4.1.3  && < 0.5
     , http-types              >= 0.12.2   && < 0.13
-    , jose                    >= 0.7.0.0  && < 0.10
-    , lens                    >= 4.16.1   && < 5.2
-    , memory                  >= 0.14.16  && < 0.18
+    , jose                    >= 0.10     && < 0.11
+    , lens                    >= 4.16.1   && < 5.3
+    , memory                  >= 0.14.16  && < 0.19
     , monad-time              >= 0.3.1.0  && < 0.4
-    , mtl                     >= 2.2.2    && < 2.3
+    , mtl                     ^>= 2.2.2   || ^>= 2.3.1
     , servant                 >= 0.13     && < 0.20
     , servant-auth            == 0.4.*
     , servant-server          >= 0.13     && < 0.20
     , tagged                  >= 0.8.4    && < 0.9
     , text                    >= 1.2.3.0  && < 2.1
-    , time                    >= 1.5.0.1  && < 1.12
+    , time                    >= 1.5.0.1  && < 1.13
     , unordered-containers    >= 0.2.9.0  && < 0.3
     , wai                     >= 3.2.1.2  && < 3.3
 

servant-auth/servant-auth-server/src/Servant/Auth/Server/Internal/ConfigTypes.hs

@@ -33,7 +33,7 @@ data JWTSettings = JWTSettings
   -- | Algorithm used to sign JWT.
   , jwtAlg          :: Maybe Jose.Alg
   -- | Keys used to validate JWT.
-  , validationKeys  :: Jose.JWKSet
+  , validationKeys  :: IO Jose.JWKSet
   -- | An @aud@ predicate. The @aud@ is a string or URI that identifies the
   -- intended recipient of the JWT.
   , audienceMatches :: Jose.StringOrURI -> IsMatch
@@ -44,7 +44,7 @@ defaultJWTSettings :: Jose.JWK -> JWTSettings
 defaultJWTSettings k = JWTSettings
    { signingKey = k
    , jwtAlg = Nothing
-   , validationKeys = Jose.JWKSet [k]
+   , validationKeys = pure $ Jose.JWKSet [k]
    , audienceMatches = const Matches }
 
 -- | The policies to use when generating cookies.

servant-auth/servant-auth-server/src/Servant/Auth/Server/Internal/Cookie.hs

@@ -2,6 +2,7 @@
 module Servant.Auth.Server.Internal.Cookie where
 
 import           Blaze.ByteString.Builder (toByteString)
+import           Control.Monad (MonadPlus(..), guard)
 import           Control.Monad.Except
 import           Control.Monad.Reader
 import qualified Crypto.JOSE              as Jose

servant-auth/servant-auth-server/src/Servant/Auth/Server/Internal/JWT.hs

@@ -1,18 +1,14 @@
 module Servant.Auth.Server.Internal.JWT where
 
 import           Control.Lens
-import           Control.Monad.Except
+import           Control.Monad (MonadPlus(..), guard)
 import           Control.Monad.Reader
 import qualified Crypto.JOSE          as Jose
 import qualified Crypto.JWT           as Jose
-import           Data.Aeson           (FromJSON, Result (..), ToJSON, fromJSON,
-                                       toJSON)
 import           Data.ByteArray       (constEq)
 import qualified Data.ByteString      as BS
 import qualified Data.ByteString.Lazy as BSL
-import qualified Data.HashMap.Strict  as HM
 import           Data.Maybe           (fromMaybe)
-import qualified Data.Text            as T
 import           Data.Time            (UTCTime)
 import           Network.Wai          (requestHeaders)
 
@@ -42,7 +38,7 @@ jwtAuthCheck jwtSettings = do
 -- token expires.
 makeJWT :: ToJWT a
   => a -> JWTSettings -> Maybe UTCTime -> IO (Either Jose.Error BSL.ByteString)
-makeJWT v cfg expiry = runExceptT $ do
+makeJWT v cfg expiry = Jose.runJOSE $ do
   bestAlg <- Jose.bestJWSAlg $ signingKey cfg
   let alg = fromMaybe bestAlg $ jwtAlg cfg
   ejwt <- Jose.signClaims (signingKey cfg)
@@ -58,14 +54,15 @@ makeJWT v cfg expiry = runExceptT $ do
 
 verifyJWT :: FromJWT a => JWTSettings -> BS.ByteString -> IO (Maybe a)
 verifyJWT jwtCfg input = do
-  verifiedJWT <- liftIO $ runExceptT $ do
+  keys <- validationKeys jwtCfg
+  verifiedJWT <- Jose.runJOSE $ do
     unverifiedJWT <- Jose.decodeCompact (BSL.fromStrict input)
     Jose.verifyClaims
       (jwtSettingsToJwtValidationSettings jwtCfg)
-      (validationKeys jwtCfg)
+      keys
       unverifiedJWT
   return $ case verifiedJWT of
     Left (_ :: Jose.JWTError) -> Nothing
     Right v -> case decodeJWT v of
       Left _ -> Nothing
-      Right v' -> Just v'
+      Right v' -> Just v'

servant-auth/servant-auth-server/src/Servant/Auth/Server/Internal/Types.hs

@@ -2,6 +2,7 @@
 module Servant.Auth.Server.Internal.Types where
 
 import Control.Applicative
+import Control.Monad        (MonadPlus(..), ap)
 import Control.Monad.Reader
 import Control.Monad.Time
 import Data.Monoid          (Monoid (..))

servant-auth/servant-auth-server/test/Servant/Auth/ServerSpec.hs

@@ -6,13 +6,12 @@ module Servant.Auth.ServerSpec (spec) where
 #endif
 
 import           Control.Lens
-import           Control.Monad.Except                (runExceptT)
 import           Control.Monad.IO.Class              (liftIO)
 import           Crypto.JOSE                         (Alg (HS256, None), Error,
                                                       JWK, JWSHeader,
                                                       KeyMaterialGenParam (OctGenParam),
                                                       ToCompact, encodeCompact,
-                                                      genJWK, newJWSHeader)
+                                                      genJWK, newJWSHeader, runJOSE)
 import           Crypto.JWT                          (Audience (..), ClaimsSet,
                                                       NumericDate (NumericDate),
                                                       SignedJWT,
@@ -540,7 +539,7 @@ addJwtToHeader jwt = case jwt of
     $ defaults & header "Authorization" .~ ["Bearer " <> BSL.toStrict v]
 
 createJWT :: JWK -> JWSHeader () -> ClaimsSet -> IO (Either Error Crypto.JWT.SignedJWT)
-createJWT k a b = runExceptT $ signClaims k a b
+createJWT k a b = runJOSE $ signClaims k a b
 
 addJwtToCookie :: ToCompact a => CookieSettings -> Either Error a -> IO Options
 addJwtToCookie ccfg jwt = case jwt >>= (return . encodeCompact) of

servant-auth/servant-auth-swagger/servant-auth-swagger.cabal

@@ -31,15 +31,13 @@ library
   default-extensions: ConstraintKinds DataKinds DefaultSignatures DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable FlexibleContexts FlexibleInstances FunctionalDependencies GADTs KindSignatures MultiParamTypeClasses OverloadedStrings RankNTypes ScopedTypeVariables TypeFamilies TypeOperators
   ghc-options: -Wall
   build-depends:
-      base            >= 4.10    && < 4.16
+      base            >= 4.10    && < 4.18
     , text            >= 1.2.3.0 && < 2.1
     , servant-swagger >= 1.1.5   && < 2
     , swagger2        >= 2.2.2   && < 3
     , servant         >= 0.13    && < 0.20
     , servant-auth    == 0.4.*
-    , lens            >= 4.16.1  && < 5.2
-  if impl(ghc >= 9)
-    buildable: False
+    , lens            >= 4.16.1  && < 5.3
   exposed-modules:
       Servant.Auth.Swagger
   default-language: Haskell2010
@@ -61,8 +59,6 @@ test-suite spec
     , servant
     , servant-auth
     , lens
-  if impl(ghc >= 9)
-    buildable: False
 
   -- test dependencies
   build-depends:

servant-auth/servant-auth/servant-auth.cabal

@@ -33,11 +33,11 @@ library
   default-extensions: ConstraintKinds DataKinds DefaultSignatures DeriveFoldable DeriveFunctor DeriveGeneric DeriveTraversable FlexibleContexts FlexibleInstances FunctionalDependencies GADTs KindSignatures MultiParamTypeClasses OverloadedStrings RankNTypes ScopedTypeVariables TypeFamilies TypeOperators
   ghc-options: -Wall
   build-depends:
-      base                    >= 4.10     && < 4.17
+      base                    >= 4.10     && < 4.18
     , containers              >= 0.6      && < 0.7
     , aeson                   >= 1.3.1.1  && < 3
-    , jose                    >= 0.7.0.0  && < 0.10
-    , lens                    >= 4.16.1   && < 5.2
+    , jose                    >= 0.10     && < 0.11
+    , lens                    >= 4.16.1   && < 5.3
     , servant                 >= 0.15     && < 0.20
     , text                    >= 1.2.3.0  && < 2.1
     , unordered-containers    >= 0.2.9.0  && < 0.3

servant-auth/servant-auth/src/Servant/Auth.hs

@@ -27,7 +27,7 @@ instance HasLink sub => HasLink (Auth (tag :: [*]) value :> sub) where
 
 -- ** Combinators
 
--- | A JSON Web Token (JWT) in the the Authorization header:
+-- | A JSON Web Token (JWT) in the Authorization header:
 --
 --    @Authorization: Bearer \<token\>@
 --

servant-client-core/servant-client-core.cabal

@@ -50,14 +50,14 @@ library
   --
   -- note: mtl lower bound is so low because of GHC-7.8
   build-depends:
-      base                  >= 4.9      && < 4.17
+      base                  >= 4.9      && < 4.18
     , bytestring            >= 0.10.8.1 && < 0.12
     , constraints           >= 0.2      && < 0.14
     , containers            >= 0.5.7.1  && < 0.7
     , deepseq               >= 1.4.2.0  && < 1.5
     , text                  >= 1.2.3.0  && < 2.1
-    , transformers          >= 0.5.2.0  && < 0.6
-    , template-haskell      >= 2.11.1.0 && < 2.19
+    , transformers          >= 0.5.2.0  && < 0.7
+    , template-haskell      >= 2.11.1.0 && < 2.20
 
   if !impl(ghc >= 8.2)
     build-depends:

servant-client-core/src/Servant/Client/Core/HasClient.hs

@@ -77,7 +77,7 @@ import           Servant.API
                  NoContentVerb, QueryFlag, QueryParam', QueryParams, Raw,
                  ReflectMethod (..), RemoteHost, ReqBody', SBoolI, Stream,
                  StreamBody', Summary, ToHttpApiData, ToSourceIO (..), Vault,
-                 Verb, WithNamedContext, WithStatus (..), contentType, getHeadersHList,
+                 Verb, WithNamedContext, WithResource, WithStatus (..), contentType, getHeadersHList,
                  getResponse, toEncodedUrlPiece, toUrlPiece, NamedRoutes)
 import           Servant.API.Generic
                  (GenericMode(..), ToServant, ToServantApi
@@ -776,6 +776,14 @@ instance HasClient m subapi =>
 
   hoistClientMonad pm _ f cl = hoistClientMonad pm (Proxy :: Proxy subapi) f cl
 
+instance HasClient m subapi =>
+  HasClient m (WithResource res :> subapi) where
+
+  type Client m (WithResource res :> subapi) = Client m subapi
+  clientWithRoute pm Proxy = clientWithRoute pm (Proxy :: Proxy subapi)
+
+  hoistClientMonad pm _ f cl = hoistClientMonad pm (Proxy :: Proxy subapi) f cl
+
 instance ( HasClient m api
          ) => HasClient m (AuthProtect tag :> api) where
   type Client m (AuthProtect tag :> api)
@@ -894,7 +902,7 @@ infixl 2 /:
 -- rootClient = client api
 --
 -- endpointClient :: ClientM Person
--- endpointClient = client // subApi // endpoint
+-- endpointClient = client \/\/ subApi \/\/ endpoint
 -- @
 (//) :: a -> (a -> b) -> b
 x // f = f x
@@ -927,10 +935,10 @@ x // f = f x
 -- rootClient = client api
 --
 -- hello :: String -> ClientM String
--- hello name = rootClient // hello /: name
+-- hello name = rootClient \/\/ hello \/: name
 --
 -- endpointClient :: ClientM Person
--- endpointClient = client // subApi /: "foobar123" // endpoint
+-- endpointClient = client \/\/ subApi \/: "foobar123" \/\/ endpoint
 -- @
 (/:) :: (a -> b -> c) -> b -> a -> c
 (/:) = flip

servant-client-ghcjs/servant-client-ghcjs.cabal

@@ -48,7 +48,7 @@ library
     , http-media          >=0.6.2   && <0.9
     , http-types          >=0.12    && <0.13
     , monad-control       >=1.0.0.4 && <1.1
-    , mtl                 >=2.2.2   && <2.3
+    , mtl                 ^>=2.2.2  || ^>=2.3.1
     , semigroupoids       >=5.3     && <5.4
     , string-conversions  >=0.3     && <0.5
     , transformers        >=0.3     && <0.6

servant-client/servant-client.cabal

@@ -41,15 +41,15 @@ library
   -- Bundled with GHC: Lower bound to not force re-installs
   -- text and mtl are bundled starting with GHC-8.4
   build-depends:
-      base                  >= 4.9      && < 4.17
+      base                  >= 4.9      && < 4.18
     , bytestring            >= 0.10.8.1 && < 0.12
     , containers            >= 0.5.7.1  && < 0.7
     , deepseq               >= 1.4.2.0  && < 1.5
-    , mtl                   >= 2.2.2    && < 2.3
+    , mtl                   ^>= 2.2.2   || ^>= 2.3.1
     , stm                   >= 2.4.5.1  && < 2.6
     , text                  >= 1.2.3.0  && < 2.1
-    , time                  >= 1.6.0.1  && < 1.12
-    , transformers          >= 0.5.2.0  && < 0.6
+    , time                  >= 1.6.0.1  && < 1.13
+    , transformers          >= 0.5.2.0  && < 0.7
 
   if !impl(ghc >= 8.2)
     build-depends:

servant-client/src/Servant/Client/Internal/HttpClient.hs

@@ -80,7 +80,7 @@ data ClientEnv
   { manager :: Client.Manager
   , baseUrl :: BaseUrl
   , cookieJar :: Maybe (TVar Client.CookieJar)
-  , makeClientRequest :: BaseUrl -> Request -> Client.Request
+  , makeClientRequest :: BaseUrl -> Request -> IO Client.Request
   -- ^ this function can be used to customize the creation of @http-client@ requests from @servant@ requests. Default value: 'defaultMakeClientRequest'
   --   Note that:
   --      1. 'makeClientRequest' exists to allow overriding operational semantics e.g. 'responseTimeout' per request,
@@ -162,7 +162,7 @@ runClientM cm env = runExceptT $ flip runReaderT env $ unClientM cm
 performRequest :: Maybe [Status] -> Request -> ClientM Response
 performRequest acceptStatus req = do
   ClientEnv m burl cookieJar' createClientRequest <- ask
-  let clientRequest = createClientRequest burl req
+  clientRequest <- liftIO $ createClientRequest burl req
   request <- case cookieJar' of
     Nothing -> pure clientRequest
     Just cj -> liftIO $ do
@@ -229,8 +229,8 @@ clientResponseToResponse f r = Response
 -- | Create a @http-client@ 'Client.Request' from a @servant@ 'Request'
 --    The 'Client.host', 'Client.path' and 'Client.port' fields are extracted from the 'BaseUrl'
 --    otherwise the body, headers and query string are derived from the @servant@ 'Request'
-defaultMakeClientRequest :: BaseUrl -> Request -> Client.Request
-defaultMakeClientRequest burl r = Client.defaultRequest
+defaultMakeClientRequest :: BaseUrl -> Request -> IO Client.Request
+defaultMakeClientRequest burl r = return Client.defaultRequest
     { Client.method = requestMethod r
     , Client.host = fromString $ baseUrlHost burl
     , Client.port = baseUrlPort burl
@@ -289,7 +289,8 @@ defaultMakeClientRequest burl r = Client.defaultRequest
         Https -> True
 
     -- Query string builder which does not do any encoding
-    buildQueryString = ("?" <>) . foldl' addQueryParam mempty
+    buildQueryString [] = mempty
+    buildQueryString qps = "?" <> foldl' addQueryParam mempty qps
 
     addQueryParam qs (k, v) =
           qs <> (if BS.null qs then mempty else "&") <> urlEncode True k <> foldMap ("=" <>) v

servant-client/src/Servant/Client/Internal/HttpClient/Streaming.hs

@@ -24,7 +24,8 @@ import           Control.DeepSeq
                  (NFData, force)
 import           Control.Exception
                  (evaluate, throwIO)
-import           Control.Monad ()
+import           Control.Monad
+                 (unless)
 import           Control.Monad.Base
                  (MonadBase (..))
 import           Control.Monad.Codensity
@@ -140,7 +141,7 @@ performRequest :: Maybe [Status] -> Request -> ClientM Response
 performRequest acceptStatus req = do
     -- TODO: should use Client.withResponse here too
   ClientEnv m burl cookieJar' createClientRequest <- ask
-  let clientRequest = createClientRequest burl req
+  clientRequest <- liftIO $ createClientRequest burl req
   request <- case cookieJar' of
     Nothing -> pure clientRequest
     Just cj -> liftIO $ do
@@ -174,10 +175,21 @@ performRequest acceptStatus req = do
 -- | TODO: support UVerb ('acceptStatus' argument, like in 'performRequest' above).
 performWithStreamingRequest :: Request -> (StreamingResponse -> IO a) -> ClientM a
 performWithStreamingRequest req k = do
-  m <- asks manager
-  burl <- asks baseUrl
-  createClientRequest <- asks makeClientRequest
-  let request = createClientRequest burl req
+  ClientEnv m burl cookieJar' createClientRequest <- ask
+  clientRequest <- liftIO $ createClientRequest burl req
+  request <- case cookieJar' of
+    Nothing -> pure clientRequest
+    Just cj -> liftIO $ do
+      now <- getCurrentTime
+      atomically $ do
+        oldCookieJar <- readTVar cj
+        let (newRequest, newCookieJar) =
+              Client.insertCookiesIntoRequest
+                clientRequest
+                oldCookieJar
+                now
+        writeTVar cj newCookieJar
+        pure newRequest
   ClientM $ lift $ lift $ Codensity $ \k1 ->
       Client.withResponse request m $ \res -> do
           let status = Client.responseStatus res

servant-client/test/Servant/SuccessSpec.hs

@@ -162,7 +162,8 @@ successSpec = beforeAll (startWaiApp server) $ afterAll endWaiApp $ do
       mgr <- C.newManager C.defaultManagerSettings
       -- In proper situation, extra headers should probably be visible in API type.
       -- However, testing for response timeout is difficult, so we test with something which is easy to observe
-      let createClientRequest url r = (defaultMakeClientRequest url r) { C.requestHeaders = [("X-Added-Header", "XXX")] }
+      let createClientRequest url r = fmap (\req -> req { C.requestHeaders = [("X-Added-Header", "XXX")] })
+                                           (defaultMakeClientRequest url r)
           clientEnv = (mkClientEnv mgr baseUrl) { makeClientRequest = createClientRequest }
       res <- runClientM (getRawSuccessPassHeaders HTTP.methodGet) clientEnv
       case res of

servant-conduit/servant-conduit.cabal

@@ -31,8 +31,8 @@ library
       base          >=4.9      && <5
     , bytestring    >=0.10.8.1 && <0.12
     , conduit       >=1.3.1    && <1.4
-    , mtl           >=2.2.2    && <2.3
-    , resourcet     >=1.2.2    && <1.3
+    , mtl           ^>=2.2.2   || ^>=2.3.1
+    , resourcet     >=1.2.2    && <1.4
     , servant       >=0.15     && <0.20
     , unliftio-core >=0.1.2.0  && <0.3
   hs-source-dirs:      src

servant-docs/golden/comprehensive.md

@@ -530,6 +530,24 @@
 
 ```
 
+## GET /resource
+
+### Response:
+
+- Status code 200
+- Headers: []
+
+- Supported content types are:
+
+    - `application/json;charset=utf-8`
+    - `application/json`
+
+- Example (`application/json;charset=utf-8`, `application/json`):
+
+```javascript
+
+```
+
 ## GET /streaming
 
 ### Request:

servant-docs/servant-docs.cabal

@@ -41,7 +41,7 @@ library
   --
   -- note: mtl lower bound is so low because of GHC-7.8
   build-depends:
-      base       >= 4.9      && < 4.17
+      base       >= 4.9      && < 4.18
     , bytestring >= 0.10.8.1 && < 0.12
     , text       >= 1.2.3.0  && < 2.1
 
@@ -59,7 +59,7 @@ library
     , hashable             >= 1.2.7.0  && < 1.5
     , http-media           >= 0.7.1.3  && < 0.9
     , http-types           >= 0.12.2   && < 0.13
-    , lens                 >= 4.17     && < 5.2
+    , lens                 >= 4.17     && < 5.3
     , string-conversions   >= 0.4.0.1  && < 0.5
     , universe-base        >= 1.1.1    && < 1.2
     , unordered-containers >= 0.2.9.0  && < 0.3

servant-docs/src/Servant/Docs/Internal.hs

@@ -62,6 +62,7 @@ import           GHC.TypeLits
 import           Servant.API
 import           Servant.API.ContentTypes
 import           Servant.API.TypeLevel
+import           Servant.API.Generic
 
 import qualified Data.Universe.Helpers      as U
 
@@ -446,7 +447,7 @@ docsWith opts intros (ExtraInfo endpoints) p =
       & apiEndpoints %~ HM.unionWith (flip combineAction) endpoints
 
 
--- | Generate the docs for a given API that implements 'HasDocs' with with any
+-- | Generate the docs for a given API that implements 'HasDocs' with any
 -- number of introduction(s)
 docsWithIntros :: HasDocs api => [DocIntro] -> Proxy api -> API
 docsWithIntros intros = docsWith defaultDocOptions intros mempty
@@ -1143,6 +1144,9 @@ instance HasDocs api => HasDocs (Vault :> api) where
 instance HasDocs api => HasDocs (WithNamedContext name context api) where
   docsFor Proxy = docsFor (Proxy :: Proxy api)
 
+instance HasDocs api => HasDocs (WithResource res :> api) where
+  docsFor Proxy = docsFor (Proxy :: Proxy api)
+
 instance (ToAuthInfo (BasicAuth realm usr), HasDocs api) => HasDocs (BasicAuth realm usr :> api) where
   docsFor Proxy (endpoint, action) =
     docsFor (Proxy :: Proxy api) (endpoint, action')
@@ -1150,6 +1154,9 @@ instance (ToAuthInfo (BasicAuth realm usr), HasDocs api) => HasDocs (BasicAuth r
         authProxy = Proxy :: Proxy (BasicAuth realm usr)
         action' = over authInfo (|> toAuthInfo authProxy) action
 
+instance HasDocs (ToServantApi api) => HasDocs (NamedRoutes api) where
+  docsFor Proxy = docsFor (Proxy :: Proxy (ToServantApi api))
+
 -- ToSample instances for simple types
 instance ToSample NoContent
 instance ToSample Bool

servant-foreign/servant-foreign.cabal

@@ -41,7 +41,7 @@ library
   --
   -- note: mtl lower bound is so low because of GHC-7.8
   build-depends:
-      base        >= 4.9     && < 4.17
+      base        >= 4.9     && < 4.18
     , text        >= 1.2.3.0 && < 2.1
 
   -- Servant dependencies
@@ -52,7 +52,7 @@ library
   -- Here can be exceptions if we really need features from the newer versions.
   build-depends:
       base-compat >= 0.10.5  && < 0.13
-    , lens        >= 4.17    && < 5.2
+    , lens        >= 4.17    && < 5.3
     , http-types  >= 0.12.2  && < 0.13
 
   hs-source-dirs:      src

servant-foreign/src/Servant/Foreign/Internal.hs

@@ -487,6 +487,13 @@ instance HasForeign lang ftype api =>
 
   foreignFor lang ftype Proxy = foreignFor lang ftype (Proxy :: Proxy api)
 
+instance HasForeign lang ftype api =>
+  HasForeign lang ftype (WithResource res :> api) where
+
+  type Foreign ftype (WithResource res :> api) = Foreign ftype api
+
+  foreignFor lang ftype Proxy = foreignFor lang ftype (Proxy :: Proxy api)
+
 instance HasForeign lang ftype api
   => HasForeign lang ftype (HttpVersion :> api) where
   type Foreign ftype (HttpVersion :> api) = Foreign ftype api

servant-http-streams/servant-http-streams.cabal

@@ -38,14 +38,14 @@ library
   -- Bundled with GHC: Lower bound to not force re-installs
   -- text and mtl are bundled starting with GHC-8.4
   build-depends:
-      base                  >= 4.9      && < 4.17
+      base                  >= 4.9      && < 4.18
     , bytestring            >= 0.10.8.1 && < 0.12
     , containers            >= 0.5.7.1  && < 0.7
     , deepseq               >= 1.4.2.0  && < 1.5
-    , mtl                   >= 2.2.2    && < 2.3
+    , mtl                   ^>= 2.2.2   || ^>= 2.3.1
     , text                  >= 1.2.3.0  && < 2.1
-    , time                  >= 1.6.0.1  && < 1.12
-    , transformers          >= 0.5.2.0  && < 0.6
+    , time                  >= 1.6.0.1  && < 1.13
+    , transformers          >= 0.5.2.0  && < 0.7
 
   if !impl(ghc >= 8.2)
     build-depends:

servant-machines/servant-machines.cabal

@@ -31,7 +31,7 @@ library
       base          >=4.9      && <5
     , bytestring    >=0.10.8.1 && <0.12
     , machines      >=0.6.4    && <0.8
-    , mtl           >=2.2.2    && <2.3
+    , mtl           ^>=2.2.2   || ^>=2.3.1
     , servant       >=0.15     && <0.20
   hs-source-dirs:      src
   default-language:    Haskell2010

servant-pipes/servant-pipes.cabal

@@ -32,7 +32,7 @@ library
     , bytestring    >=0.10.8.1 && <0.12
     , pipes         >=4.3.9    && <4.4
     , pipes-safe    >=2.3.1    && <2.4
-    , mtl           >=2.2.2    && <2.3
+    , mtl           ^>=2.2.2   || ^>=2.3.1
     , monad-control >=1.0.2.3  && <1.1
     , servant       >=0.15     && <0.20
   hs-source-dirs:      src

servant-server/CHANGELOG.md

@@ -3,11 +3,17 @@
 
 Package versions follow the [Package Versioning Policy](https://pvp.haskell.org/): in A.B.C, bumps to either A or B represent major versions.
 
+0.19.2
+------
+
+Compatibility with GHC 9.4, see [PR #1592](https://github.com/haskell-servant/servant/pull/1592).
+
 0.19.1
 ------
 
 - Add `MonadFail` instance for `Handler` wrt [#1545](https://github.com/haskell-servant/servant/issues/1545)
 - Support GHC 9.2 [#1525](https://github.com/haskell-servant/servant/issues/1525)
+- Add capture hints in `Router` type for debug and display purposes [PR #1556] (https://github.com/haskell-servant/servant/pull/1556)
 
 0.19
 ----

servant-server/servant-server.cabal

@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                servant-server
-version:             0.19.1
+version:             0.19.2
 
 synopsis:            A family of combinators for defining webservices APIs and serving them
 category:            Servant, Web
@@ -23,7 +23,7 @@ author:              Servant Contributors
 maintainer:          haskell-servant-maintainers@googlegroups.com
 copyright:           2014-2016 Zalora South East Asia Pte Ltd, 2016-2019 Servant Contributors
 build-type:          Simple
-tested-with: GHC ==8.6.5 || ==8.8.4 || ==8.10.2 || ==9.0.1
+tested-with: GHC ==8.6.5 || ==8.8.4 || ==8.10.7 || ==9.0.2 || ==9.2.4 || ==9.4.3
 
 extra-source-files:
   CHANGELOG.md
@@ -60,20 +60,20 @@ library
   -- Bundled with GHC: Lower bound to not force re-installs
   -- text and mtl are bundled starting with GHC-8.4
   build-depends:
-      base                >= 4.9      && < 4.17
+      base                >= 4.9      && < 4.18
     , bytestring          >= 0.10.8.1 && < 0.12
     , constraints         >= 0.2      && < 0.14
     , containers          >= 0.5.7.1  && < 0.7
-    , mtl                 >= 2.2.2    && < 2.3
+    , mtl                 ^>= 2.2.2   || ^>= 2.3.1
     , text                >= 1.2.3.0  && < 2.1
-    , transformers        >= 0.5.2.0  && < 0.6
+    , transformers        >= 0.5.2.0  && < 0.7
     , filepath            >= 1.4.1.1  && < 1.5
 
   -- Servant dependencies
   -- strict dependency as we re-export 'servant' things.
   build-depends:
       servant             >= 0.19     && < 0.20
-    , http-api-data       >= 0.4.1    && < 0.4.4
+    , http-api-data       >= 0.4.1    && < 0.5.1
 
   -- Other dependencies: Lower bound around what is in the latest Stackage LTS.
   -- Here can be exceptions if we really need features from the newer versions.
@@ -88,10 +88,10 @@ library
     , network             >= 2.8      && < 3.2
     , sop-core            >= 0.4.0.0  && < 0.6
     , string-conversions  >= 0.4.0.1  && < 0.5
-    , resourcet           >= 1.2.2    && < 1.3
+    , resourcet           >= 1.2.2    && < 1.4
     , tagged              >= 0.8.6    && < 0.9
     , transformers-base   >= 0.4.5.2  && < 0.5
-    , wai                 >= 3.2.1.2  && < 3.3
+    , wai                 >= 3.2.2.1  && < 3.3
     , wai-app-static      >= 3.1.6.2  && < 3.2
     , word8               >= 0.1.3    && < 0.2
 

servant-server/src/Servant/Server/Experimental/Auth.hs

@@ -1,5 +1,6 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 {-# LANGUAGE DeriveDataTypeable    #-}
+{-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE DeriveGeneric         #-}
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE FlexibleInstances     #-}
@@ -44,7 +45,7 @@ type family AuthServerData a :: *
 -- NOTE: THIS API IS EXPERIMENTAL AND SUBJECT TO CHANGE
 newtype AuthHandler r usr = AuthHandler
   { unAuthHandler :: r -> Handler usr }
-  deriving (Generic, Typeable)
+  deriving (Functor, Generic, Typeable)
 
 -- | NOTE: THIS API IS EXPERIMENTAL AND SUBJECT TO CHANGE
 mkAuthHandler :: (r -> Handler usr) -> AuthHandler r usr

servant-server/src/Servant/Server/Internal.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE AllowAmbiguousTypes   #-}
 {-# LANGUAGE ConstraintKinds       #-}
+{-# LANGUAGE CPP                   #-}
 {-# LANGUAGE DataKinds             #-}
 {-# LANGUAGE DeriveDataTypeable    #-}
 {-# LANGUAGE FlexibleContexts      #-}
@@ -34,9 +35,10 @@ module Servant.Server.Internal
 import           Control.Monad
                  (join, when)
 import           Control.Monad.Trans
-                 (liftIO)
+                 (liftIO, lift)
 import           Control.Monad.Trans.Resource
-                 (runResourceT)
+                 (runResourceT, ReleaseKey)
+import           Data.Acquire
 import qualified Data.ByteString                            as B
 import qualified Data.ByteString.Builder                    as BB
 import qualified Data.ByteString.Char8                      as BC8
@@ -76,7 +78,7 @@ import           Servant.API
                  QueryParam', QueryParams, Raw, ReflectMethod (reflectMethod),
                  RemoteHost, ReqBody', SBool (..), SBoolI (..), SourceIO,
                  Stream, StreamBody', Summary, ToSourceIO (..), Vault, Verb,
-                 WithNamedContext, NamedRoutes)
+                 WithNamedContext, WithResource, NamedRoutes)
 import           Servant.API.Generic (GenericMode(..), ToServant, ToServantApi, GServantProduct, toServant, fromServant)
 import           Servant.API.ContentTypes
                  (AcceptHeader (..), AllCTRender (..), AllCTUnrender (..),
@@ -94,6 +96,8 @@ import           Servant.API.TypeErrors
 import           Web.HttpApiData
                  (FromHttpApiData, parseHeader, parseQueryParam, parseUrlPiece,
                  parseUrlPieces)
+import           Data.Kind
+                 (Type)
 
 import           Servant.Server.Internal.BasicAuth
 import           Servant.Server.Internal.Context
@@ -112,6 +116,10 @@ import           Servant.API.TypeLevel
                  (AtLeastOneFragment, FragmentUnique)
 
 class HasServer api context where
+  -- | The type of a server for this API, given a monad to run effects in.
+  --
+  -- Note that the result kind is @*@, so it is /not/ a monad transformer, unlike
+  -- what the @T@ in the name might suggest.
   type ServerT api (m :: * -> *) :: *
 
   route ::
@@ -241,6 +249,42 @@ instance (KnownSymbol capture, FromHttpApiData a, Typeable a
       formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
       hint = CaptureHint (T.pack $ symbolVal $ Proxy @capture) (typeRep (Proxy :: Proxy [a]))
 
+-- | If you use 'WithResource' in one of the endpoints for your API Servant
+-- will provide the handler for this endpoint an argument of the specified type.
+-- The lifespan of this resource will be automatically managed by Servant. This
+-- resource will be created before the handler starts and it will be destoyed
+-- after it ends. A new resource is created for each request to the endpoint.
+
+-- The creation and destruction are done using a 'Data.Acquire.Acquire'
+-- provided via server 'Context'.
+--
+-- Example
+--
+-- > type MyApi = WithResource Handle :> "writeToFile" :> Post '[JSON] NoContent
+-- >
+-- > server :: Server MyApi
+-- > server = writeToFile
+-- >   where writeToFile :: (ReleaseKey, Handle) -> Handler NoContent
+-- >         writeToFile (_, h) = hPutStrLn h "message"
+--
+-- In addition to the resource, the handler will also receive a 'ReleaseKey'
+-- which can be used to deallocate the resource before the end of the request
+-- if desired.
+
+instance (HasServer api ctx, HasContextEntry ctx (Acquire a))
+      => HasServer (WithResource a :> api) ctx where
+
+  type ServerT (WithResource a :> api) m = (ReleaseKey, a) -> ServerT api m
+
+  hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy @api) pc nt . s
+
+  route Proxy context d = route (Proxy @api) context (d `addParameterCheck` allocateResource)
+    where
+      allocateResource :: DelayedIO (ReleaseKey, a)
+      allocateResource = DelayedIO $ lift $ allocateAcquire (getContextEntry context)
+
+
+
 allowedMethodHead :: Method -> Request -> Bool
 allowedMethodHead method request = method == methodGet && requestMethod request == methodHead
 
@@ -821,7 +865,11 @@ instance (HasContextEntry context (NamedContext name subContext), HasServer subA
 -------------------------------------------------------------------------------
 
 -- Erroring instance for 'HasServer' when a combinator is not fully applied
-instance TypeError (PartialApplication HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
+instance TypeError (PartialApplication 
+#if __GLASGOW_HASKELL__ >= 904
+                    @(Type -> [Type] -> Constraint) 
+#endif
+                    HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
   where
     type ServerT (arr :> sub) _ = TypeError (PartialApplication (HasServer :: * -> [*] -> Constraint) arr)
     route = error "unreachable"
@@ -865,7 +913,11 @@ type HasServerArrowTypeError a b =
 -- XXX: This omits the @context@ parameter, e.g.:
 --
 -- "There is no instance for HasServer (Bool :> …)". Do we care ?
-instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub HasServer ty) => HasServer (ty :> sub) context
+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub 
+#if __GLASGOW_HASKELL__ >= 904
+                                         @(Type -> [Type] -> Constraint) 
+#endif
+                                         HasServer ty) => HasServer (ty :> sub) context
 
 instance {-# OVERLAPPABLE #-} TypeError (NoInstanceFor (HasServer api context)) => HasServer api context
 

servant-server/src/Servant/Server/Internal/Router.hs

@@ -28,9 +28,12 @@ import           Servant.Server.Internal.ServerError
 
 type Router env = Router' env RoutingApplication
 
+-- | Holds information about pieces of url that are captured as variables.
 data CaptureHint = CaptureHint
   { captureName :: Text
+  -- ^ Holds the name of the captured variable
   , captureType :: TypeRep
+  -- ^ Holds the type of the captured variable
   }
   deriving (Show, Eq)
 
@@ -54,10 +57,21 @@ data Router' env a =
       --   for the empty path, to be tried in order
   | CaptureRouter [CaptureHint] (Router' (Text, env) a)
       -- ^ first path component is passed to the child router in its
-      --   environment and removed afterwards
+      --   environment and removed afterwards.
+      --   The first argument is a list of hints for all variables that can be
+      --   captured by the router. The fact that it is a list is counter-intuitive,
+      --   because the 'Capture' combinator only allows to capture a single varible,
+      --   with a single name and a single type. However, the 'choice' smart
+      --   constructor may merge two 'Capture' combinators with different hints, thus
+      --   forcing the type to be '[CaptureHint]'.
+      --   Because 'CaptureRouter' is built from a 'Capture' combinator, the list of
+      --   hints should always be non-empty.
   | CaptureAllRouter [CaptureHint] (Router' ([Text], env) a)
       -- ^ all path components are passed to the child router in its
       --   environment and are removed afterwards
+      --   The first argument is a hint for the list of variables that can be
+      --   captured by the router. Note that the 'captureType' field of the hint
+      --   should always be '[a]' for some 'a'.
   | RawRouter     (env -> a)
       -- ^ to be used for routes we do not know anything about
   | Choice        (Router' env a) (Router' env a)
@@ -101,6 +115,10 @@ choice router1 router2 = Choice router1 router2
 data RouterStructure =
     StaticRouterStructure  (Map Text RouterStructure) Int
   | CaptureRouterStructure [CaptureHint] RouterStructure
+  -- ^ The first argument holds information about variables
+  -- that are captured by the router. There may be several hints
+  -- if several routers have been aggregated by the 'choice'
+  -- smart constructor.
   | RawRouterStructure
   | ChoiceStructure        RouterStructure RouterStructure
   deriving (Eq, Show)

servant-server/test/Servant/ServerSpec.hs

@@ -21,6 +21,8 @@ import           Control.Monad.Error.Class
                  (MonadError (..))
 import           Data.Aeson
                  (FromJSON, ToJSON, decode', encode)
+import           Data.Acquire
+                 (Acquire, mkAcquire)
 import qualified Data.ByteString                   as BS
 import qualified Data.ByteString.Base64            as Base64
 import           Data.Char
@@ -81,8 +83,11 @@ import           Servant.Server.Internal.Context
 -- This declaration simply checks that all instances are in place.
 _ = serveWithContext comprehensiveAPI comprehensiveApiContext
 
-comprehensiveApiContext :: Context '[NamedContext "foo" '[]]
-comprehensiveApiContext = NamedContext EmptyContext :. EmptyContext
+comprehensiveApiContext :: Context '[NamedContext "foo" '[], Acquire Int]
+comprehensiveApiContext =
+  NamedContext EmptyContext :.
+  mkAcquire (pure 10) (\_ -> pure ()) :.
+  EmptyContext
 
 -- * Specs
 

servant-swagger/servant-swagger.cabal

@@ -106,11 +106,11 @@ test-suite spec
   type:             exitcode-stdio-1.0
   hs-source-dirs:   test
   main-is:          Spec.hs
-  build-tool-depends: hspec-discover:hspec-discover >=2.6.0 && <2.10
+  build-tool-depends: hspec-discover:hspec-discover >=2.6.0 && <2.11
   build-depends:    base
                   , base-compat
                   , aeson >=1.4.2.0 && <3
-                  , hspec >=2.6.0 && <2.10
+                  , hspec >=2.6.0 && <2.11
                   , QuickCheck
                   , lens
                   , lens-aeson >=1.0.2    && <1.3

servant-swagger/src/Servant/Swagger.hs

@@ -55,6 +55,7 @@ import           Servant.Swagger.Internal.Orphans ()
 -- >>> import Data.Typeable
 -- >>> import GHC.Generics
 -- >>> import Servant.API
+-- >>> import System.Environment
 -- >>> import Test.Hspec
 -- >>> import Test.QuickCheck
 -- >>> import qualified Data.ByteString.Lazy.Char8 as BSL8
@@ -64,6 +65,7 @@ import           Servant.Swagger.Internal.Orphans ()
 -- >>> :set -XGeneralizedNewtypeDeriving
 -- >>> :set -XOverloadedStrings
 -- >>> :set -XTypeOperators
+-- >>> setEnv "HSPEC_COLOR" "no"
 -- >>> data User = User { name :: String, age :: Int } deriving (Show, Generic, Typeable)
 -- >>> newtype UserId = UserId Integer deriving (Show, Generic, Typeable, ToJSON)
 -- >>> instance ToJSON User

servant-swagger/src/Servant/Swagger/Internal.hs

@@ -3,11 +3,13 @@
 {-# LANGUAGE DataKinds            #-}
 {-# LANGUAGE FlexibleContexts     #-}
 {-# LANGUAGE FlexibleInstances    #-}
+{-# LANGUAGE OverloadedLists      #-}
 {-# LANGUAGE OverloadedStrings    #-}
 {-# LANGUAGE PolyKinds            #-}
 {-# LANGUAGE RankNTypes           #-}
 {-# LANGUAGE ScopedTypeVariables  #-}
 {-# LANGUAGE TypeOperators        #-}
+{-# LANGUAGE TypeFamilies         #-}
 #if __GLASGOW_HASKELL__ >= 806
 {-# LANGUAGE UndecidableInstances #-}
 #endif
@@ -30,11 +32,13 @@ import qualified Data.Swagger                           as Swagger
 import           Data.Swagger.Declare
 import           Data.Text                              (Text)
 import qualified Data.Text                              as Text
+import           GHC.Generics                           (D1, Meta(..), Rep)
 import           GHC.TypeLits
 import           Network.HTTP.Media                     (MediaType)
 import           Servant.API
 import           Servant.API.Description                (FoldDescription,
                                                          reflectDescription)
+import           Servant.API.Generic                    (ToServantApi, AsApi)
 import           Servant.API.Modifiers                  (FoldRequired)
 
 import           Servant.Swagger.Internal.TypeLevel.API
@@ -149,6 +153,10 @@ mkEndpointNoContentVerb path _ = mempty
 addParam :: Param -> Swagger -> Swagger
 addParam param = allOperations.parameters %~ (Inline param :)
 
+-- | Add a tag to every operation in the spec.
+addTag :: Text -> Swagger -> Swagger
+addTag tag = allOperations.tags %~ ([tag] <>)
+
 -- | Add accepted content types to every operation in the spec.
 addConsumes :: [MediaType] -> Swagger -> Swagger
 addConsumes cs = allOperations.consumes %~ (<> Just (MimeList cs))
@@ -296,6 +304,10 @@ instance (HasSwagger sub) => HasSwagger (HttpVersion :> sub) where
 instance (HasSwagger sub) => HasSwagger (WithNamedContext x c sub) where
   toSwagger _ = toSwagger (Proxy :: Proxy sub)
 
+-- | @'WithResource'@ combinator does not change our specification at all.
+instance (HasSwagger sub) => HasSwagger (WithResource res :> sub) where
+  toSwagger _ = toSwagger (Proxy :: Proxy sub)
+
 instance (KnownSymbol sym, HasSwagger sub) => HasSwagger (sym :> sub) where
   toSwagger _ = prependPath piece (toSwagger (Proxy :: Proxy sub))
     where
@@ -439,6 +451,9 @@ instance (ToSchema a, Accept ct, HasSwagger sub, KnownSymbol (FoldDescription mo
         & required  ?~ True
         & schema    .~ ParamBody ref
 
+instance (HasSwagger (ToServantApi routes), KnownSymbol datatypeName, Rep (routes AsApi) ~ D1 ('MetaData datatypeName moduleName packageName isNewtype) f) => HasSwagger (NamedRoutes routes) where
+  toSwagger _ = addTag (Text.pack $ symbolVal (Proxy :: Proxy datatypeName)) (toSwagger (Proxy :: Proxy (ToServantApi routes)))
+
 -- =======================================================================
 -- Below are the definitions that should be in Servant.API.ContentTypes
 -- =======================================================================

servant-swagger/src/Servant/Swagger/Internal/Test.hs

@@ -29,10 +29,12 @@ import           Servant.Swagger.Internal.TypeLevel
 -- >>> import Control.Applicative
 -- >>> import GHC.Generics
 -- >>> import Test.QuickCheck
+-- >>> import System.Environment (setEnv)
 -- >>> :set -XDeriveGeneric
 -- >>> :set -XGeneralizedNewtypeDeriving
 -- >>> :set -XDataKinds
 -- >>> :set -XTypeOperators
+-- >>> setEnv "HSPEC_COLOR" "no"
 
 -- | Verify that every type used with @'JSON'@ content type in a servant API
 -- has compatible @'ToJSON'@ and @'ToSchema'@ instances using @'validateToJSON'@.

servant/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 Package versions follow the [Package Versioning Policy](https://pvp.haskell.org/): in A.B.C, bumps to either A or B represent major versions.
 
+0.19.1
+------
+
+Compatibility with GHC 9.4, see [PR #1592](https://github.com/haskell-servant/servant/pull/1592).
+
 0.19
 ----
 

servant/servant.cabal

@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                servant
-version:             0.19
+version:             0.19.1
 
 synopsis:            A family of combinators for defining webservices APIs
 category:            Servant, Web
@@ -62,6 +62,7 @@ library
     Servant.API.Vault
     Servant.API.Verbs
     Servant.API.WithNamedContext
+    Servant.API.WithResource
 
   -- Types
   exposed-modules:
@@ -80,19 +81,19 @@ library
   --
   -- note: mtl lower bound is so low because of GHC-7.8
   build-depends:
-      base                   >= 4.9      && < 4.17
+      base                   >= 4.9      && < 4.18
     , bytestring             >= 0.10.8.1 && < 0.12
     , constraints            >= 0.2
-    , mtl                    >= 2.2.2    && < 2.3
+    , mtl                    ^>= 2.2.2   || ^>= 2.3.1
     , sop-core               >= 0.4.0.0  && < 0.6
-    , transformers           >= 0.5.2.0  && < 0.6
+    , transformers           >= 0.5.2.0  && < 0.7
     , text                   >= 1.2.3.0  && < 2.1
 
 
   -- We depend (heavily) on the API of these packages:
   -- i.e. re-export, or allow using without direct dependency
   build-depends:
-      http-api-data          >= 0.4.1    && < 0.4.4
+      http-api-data          >= 0.4.1    && < 0.5.1
     , singleton-bool         >= 0.1.4    && < 0.1.7
 
   -- Other dependencies: Lower bound around what is in the latest Stackage LTS.

servant/src/Servant/API.hs

@@ -31,6 +31,8 @@ module Servant.API (
   -- | Access the location for arbitrary data to be shared by applications and middleware
   module Servant.API.WithNamedContext,
   -- | Access context entries in combinators in servant-server
+  module Servant.API.WithResource,
+  -- | Access a managed resource scoped to a single request
 
   -- * Actual endpoints, distinguished by HTTP method
   module Servant.API.Verbs,
@@ -101,17 +103,19 @@ import           Servant.API.Experimental.Auth
                  (AuthProtect)
 import           Servant.API.Fragment
                  (Fragment)
+import           Servant.API.Generic
+                 (AsApi, GServantProduct, GenericMode ((:-)), GenericServant,
+                 ToServant, ToServantApi, fromServant, genericApi, toServant)
 import           Servant.API.Header
                  (Header, Header')
-import           Servant.API.Generic
-                 (GenericMode ((:-)), AsApi, ToServant, ToServantApi, GServantProduct,
-                 GenericServant, fromServant, toServant, genericApi)
 import           Servant.API.HttpVersion
                  (HttpVersion (..))
 import           Servant.API.IsSecure
                  (IsSecure (..))
 import           Servant.API.Modifiers
                  (Lenient, Optional, Required, Strict)
+import           Servant.API.NamedRoutes
+                 (NamedRoutes)
 import           Servant.API.QueryParam
                  (QueryFlag, QueryParam, QueryParam', QueryParams)
 import           Servant.API.Raw
@@ -137,8 +141,6 @@ import           Servant.API.UVerb
                  Unique, WithStatus (..), inject, statusOf)
 import           Servant.API.Vault
                  (Vault)
-import           Servant.API.NamedRoutes
-                 (NamedRoutes)
 import           Servant.API.Verbs
                  (Delete, DeleteAccepted, DeleteNoContent,
                  DeleteNonAuthoritative, Get, GetAccepted, GetNoContent,
@@ -150,6 +152,8 @@ import           Servant.API.Verbs
                  ReflectMethod (reflectMethod), StdMethod (..), Verb)
 import           Servant.API.WithNamedContext
                  (WithNamedContext)
+import           Servant.API.WithResource
+                 (WithResource)
 import           Servant.Links
                  (HasLink (..), IsElem, IsElem', Link, URI (..), safeLink)
 import           Web.HttpApiData

servant/src/Servant/API/ContentTypes.hs

@@ -295,7 +295,7 @@ instance {-# OVERLAPPABLE #-}
 -- then this would be taken care of. However there is no more specific instance
 -- between that and 'MimeRender JSON a', so we do this instead
 instance {-# OVERLAPPING #-} ( Accept ctyp ) => AllMimeRender '[ctyp] NoContent where
-    allMimeRender _ _ = map (, "") $ NE.toList $ contentTypes pctyp
+    allMimeRender _ NoContent = map (, "") $ NE.toList $ contentTypes pctyp
       where
         pctyp = Proxy :: Proxy ctyp
 

servant/src/Servant/API/TypeLevel.hs

@@ -110,7 +110,7 @@ type family IsElem' a s :: Constraint
 --
 -- >>> ok (Proxy :: Proxy (IsElem ("bye" :> Get '[JSON] Int) SampleAPI))
 -- ...
--- ... Could not deduce...
+-- ... Could not ...
 -- ...
 --
 -- An endpoint is considered within an api even if it is missing combinators
@@ -151,7 +151,7 @@ type family IsElem endpoint api :: Constraint where
 --
 -- >>> ok (Proxy :: Proxy (IsSubAPI (SampleAPI :<|> Get '[JSON] Int) SampleAPI))
 -- ...
--- ... Could not deduce...
+-- ... Could not ...
 -- ...
 --
 -- This uses @IsElem@ for checking; thus the note there applies here.
@@ -174,7 +174,7 @@ type family AllIsElem xs api :: Constraint where
 --
 -- >>> ok (Proxy :: Proxy (IsIn (Get '[JSON] Int) (Header "h" Bool :> Get '[JSON] Int)))
 -- ...
--- ... Could not deduce...
+-- ... Could not ...
 -- ...
 type family IsIn (endpoint :: *) (api :: *) :: Constraint where
   IsIn e (sa :<|> sb)                = Or (IsIn e sa) (IsIn e sb)

servant/src/Servant/API/UVerb.hs

@@ -38,6 +38,7 @@ import GHC.TypeLits (Nat)
 import Network.HTTP.Types (Status, StdMethod)
 import Servant.API.ContentTypes (JSON, PlainText, FormUrlEncoded, OctetStream, NoContent, MimeRender(mimeRender), MimeUnrender(mimeUnrender))
 import Servant.API.Status (KnownStatus, statusVal)
+import Servant.API.ResponseHeaders (Headers)
 import Servant.API.UVerb.Union
 
 class KnownStatus (StatusOf a) => HasStatus (a :: *) where
@@ -52,6 +53,9 @@ statusOf = const (statusVal (Proxy :: Proxy (StatusOf a)))
 instance HasStatus NoContent where
   type StatusOf NoContent = 204
 
+instance HasStatus a => HasStatus (Headers hs a) where
+  type StatusOf (Headers hs a) = StatusOf a
+
 class HasStatuses (as :: [*]) where
   type Statuses (as :: [*]) :: [Nat]
   statuses :: Proxy as -> [Status]

servant/src/Servant/API/UVerb/Union.hs

@@ -128,9 +128,9 @@ type DuplicateElementError (rs :: [k]) =
     ':$$: 'Text "    " ':<>: 'ShowType rs
 
 type family Elem (x :: k) (xs :: [k]) :: Bool where
+  Elem x (x ': _) = 'True
+  Elem x (_ ': xs) = Elem x xs
   Elem _ '[] = 'False
-  Elem x (x' ': xs) =
-    If (x == x') 'True (Elem x xs)
 
 type family Unique xs :: Constraint where
   Unique xs = If (Nubbed xs == 'True) (() :: Constraint) (TypeError (DuplicateElementError xs))

servant/src/Servant/API/WithResource.hs

@@ -0,0 +1,3 @@
+module Servant.API.WithResource (WithResource) where
+
+data WithResource res

servant/src/Servant/Links.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE AllowAmbiguousTypes    #-}
 {-# LANGUAGE ConstraintKinds        #-}
+{-# LANGUAGE CPP                    #-}
 {-# LANGUAGE DataKinds              #-}
 {-# LANGUAGE FlexibleContexts       #-}
 {-# LANGUAGE FlexibleInstances      #-}
@@ -91,7 +92,7 @@
 -- >>> let bad_link = Proxy :: Proxy ("hello" :> Delete '[JSON] NoContent)
 -- >>> safeLink api bad_link
 -- ...
--- ...Could not deduce...
+-- ...Could not ...
 -- ...
 --
 --  This error is essentially saying that the type family couldn't find
@@ -192,7 +193,11 @@ import           Servant.API.Verbs
                  (Verb, NoContentVerb)
 import           Servant.API.WithNamedContext
                  (WithNamedContext)
+import           Servant.API.WithResource
+                 (WithResource)
 import           Web.HttpApiData
+import           Data.Kind
+                 (Type)
 
 -- | A safe link datatype.
 -- The only way of constructing a 'Link' is using 'safeLink', which means any
@@ -555,6 +560,10 @@ instance HasLink sub => HasLink (WithNamedContext name context sub) where
     type MkLink (WithNamedContext name context sub) a = MkLink sub a
     toLink toA _ = toLink toA (Proxy :: Proxy sub)
 
+instance HasLink sub => HasLink (WithResource res :> sub) where
+    type MkLink (WithResource res :> sub) a = MkLink sub a
+    toLink toA _ = toLink toA (Proxy :: Proxy sub)
+
 instance HasLink sub => HasLink (RemoteHost :> sub) where
     type MkLink (RemoteHost :> sub) a = MkLink sub a
     toLink = simpleToLink (Proxy :: Proxy sub)
@@ -647,12 +656,20 @@ simpleToLink _ toA _ = toLink toA (Proxy :: Proxy sub)
 -- >>> import Data.Text (Text)
 
 -- Erroring instance for 'HasLink' when a combinator is not fully applied
-instance TypeError (PartialApplication HasLink arr) => HasLink ((arr :: a -> b) :> sub)
+instance TypeError (PartialApplication 
+#if __GLASGOW_HASKELL__ >= 904
+                    @(Type -> Constraint) 
+#endif
+                    HasLink arr) => HasLink ((arr :: a -> b) :> sub)
   where
     type MkLink (arr :> sub) _ = TypeError (PartialApplication (HasLink :: * -> Constraint) arr)
     toLink = error "unreachable"
 
 -- Erroring instances for 'HasLink' for unknown API combinators
-instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub HasLink ty) => HasLink (ty :> sub)
+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub 
+#if __GLASGOW_HASKELL__ >= 904
+                                         @(Type -> Constraint) 
+#endif
+                                         HasLink ty) => HasLink (ty :> sub)
 
 instance {-# OVERLAPPABLE #-} TypeError (NoInstanceFor (HasLink api)) => HasLink api

servant/src/Servant/Test/ComprehensiveAPI.hs

@@ -72,6 +72,7 @@ type ComprehensiveAPIWithoutStreamingOrRaw' endpoint =
     :<|> "description"      :> Description "foo" :> GET
     :<|> "alternative"      :> ("left" :> GET :<|> "right" :> GET)
     :<|> "fragment"         :> Fragment Int :> GET
+    :<|> "resource"         :> WithResource Int :> GET
     :<|> endpoint
 
 type ComprehensiveAPIWithoutStreamingOrRaw = ComprehensiveAPIWithoutStreamingOrRaw' EmptyEndpoint

servant/src/Servant/Types/SourceT.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                 #-}
 {-# LANGUAGE DeriveFunctor       #-}
 {-# LANGUAGE GADTs               #-}
 {-# LANGUAGE RankNTypes          #-}
@@ -154,8 +155,10 @@ instance (Applicative m, Show1 m, Show a) => Show (StepT m a) where
 -- | >>> lift [1,2,3] :: StepT [] Int
 -- Effect [Yield 1 Stop,Yield 2 Stop,Yield 3 Stop]
 --
+#if !MIN_VERSION_transformers(0,6,0)
 instance MonadTrans StepT where
     lift = Effect . fmap (`Yield` Stop)
+#endif
 
 instance MFunctor StepT where
     hoist f = go where

servant/test/Servant/API/ContentTypesSpec.hs

@@ -33,6 +33,8 @@ import           Data.String.Conversions
 import qualified Data.Text                                        as TextS
 import qualified Data.Text.Encoding                               as TextSE
 import qualified Data.Text.Lazy                                   as TextL
+import           Control.Exception
+                 (evaluate)
 import           GHC.Generics
 import           Test.Hspec
 import           Test.QuickCheck
@@ -78,6 +80,15 @@ spec = describe "Servant.API.ContentTypes" $ do
         it "has mimeUnrender reverse mimeRender for valid top-level json " $ do
             property $ \x -> mimeUnrender p (mimeRender p x) == Right (x::SomeData)
 
+    describe "The NoContent Content-Type type" $ do
+        let p = Proxy :: Proxy '[JSON]
+
+        it "does not render any content" $
+          allMimeRender p NoContent `shouldSatisfy` (all (BSL8.null . snd))
+
+        it "evaluates the NoContent value" $
+          evaluate (allMimeRender p (undefined :: NoContent)) `shouldThrow` anyErrorCall
+
     describe "The PlainText Content-Type type" $ do
         let p = Proxy :: Proxy PlainText
 

servant/test/Servant/API/ResponseHeadersSpec.hs

@@ -2,10 +2,14 @@
 {-# LANGUAGE OverloadedStrings #-}
 module Servant.API.ResponseHeadersSpec where
 
+import           Data.Proxy
+import           GHC.TypeLits
 import           Test.Hspec
 
+import           Servant.API.ContentTypes
 import           Servant.API.Header
 import           Servant.API.ResponseHeaders
+import           Servant.API.UVerb
 
 spec :: Spec
 spec = describe "Servant.API.ResponseHeaders" $ do
@@ -28,3 +32,10 @@ spec = describe "Servant.API.ResponseHeaders" $ do
     it "does not add a header" $ do
       let val = noHeader 5 :: Headers '[Header "test" Int] Int
       getHeaders val `shouldBe` []
+
+  describe "HasStatus Headers" $ do
+
+    it "gets the status from the underlying value" $ do
+      natVal (Proxy :: Proxy (StatusOf (Headers '[Header "first" Int] NoContent))) `shouldBe` 204
+      natVal (Proxy :: Proxy (StatusOf (Headers '[Header "first" Int] (WithStatus 503 ())))) `shouldBe` 503
+