Accept a list of defaults

README.md

@@ -52,7 +52,7 @@ meetup: http://typeful.net/talks/hpack
 | `executable` | `executable <package-name>` | | Shortcut for `executables: { package-name: ... }` | | `0.18.0` |
 | `tests` | `test-suite <name>` | | Map from test name to test (see [Test fields](#test-fields)) | | |
 | `benchmarks` | `benchmark <name>` | | Map from benchmark name to benchmark (see [Benchmark fields](#benchmark-fields)) | | |
-| `defaults` | | | See [Defaults](#defaults) | | |
+| `defaults` | | | See [Defaults](#defaults), may be a list | | |
 
 **Note:** Hpack does not require you to specify a `cabal-version` manually.  When
 generating a `.cabal` file, Hpack sets the `cabal-version` automatically based

src/Hpack/Config.hs

@@ -10,6 +10,7 @@
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE ViewPatterns #-}
 {-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE FlexibleContexts #-}
 module Hpack.Config (
   packageConfig
 , readPackageConfig
@@ -452,7 +453,7 @@ data PackageConfig capture cSources jsSources = PackageConfig {
 , packageConfigExecutables :: Maybe (Map String (SectionConfig capture cSources jsSources ExecutableSection))
 , packageConfigTests :: Maybe (Map String (SectionConfig capture cSources jsSources ExecutableSection))
 , packageConfigBenchmarks :: Maybe (Map String (SectionConfig capture cSources jsSources ExecutableSection))
-, packageConfigDefaults :: Maybe (capture Defaults)
+, packageConfigDefaults :: Maybe (List (capture Defaults))
 } deriving Generic
 
 traversePackageConfig :: Traversal PackageConfig
@@ -465,7 +466,7 @@ traversePackageConfig t@Traverse{..} p@PackageConfig{..} = do
   executables <- traverseNamedConfigs t packageConfigExecutables
   tests <- traverseNamedConfigs t packageConfigTests
   benchmarks <- traverseNamedConfigs t packageConfigBenchmarks
-  defaults <- traverse traverseCapture packageConfigDefaults
+  defaults <- traverse (traverse traverseCapture) packageConfigDefaults
   return p {
       packageConfigFlags = flags
     , packageConfigCustomSetup = customSetup
@@ -652,11 +653,12 @@ getDefaults
   :: FilePath
   -> PackageConfig Identity cSources jsSources
   -> Warnings (Errors IO) (CommonOptions Identity ParseCSources ParseJsSources Empty)
-getDefaults userDataDir PackageConfig{..} = case packageConfigDefaults of
-  Nothing -> return mempty
-  Just (runIdentity -> defaults) -> do
-    file <- lift $ ExceptT (ensure userDataDir defaults)
-    decodeYaml file >>= warnUnknownFieldsInDefaults file
+getDefaults userDataDir PackageConfig{..} = do
+  mconcat <$> mapM go (fromMaybeList packageConfigDefaults)
+  where
+    go (runIdentity -> defaults) = do
+      file <- lift $ ExceptT (ensure userDataDir defaults)
+      decodeYaml file >>= warnUnknownFieldsInDefaults file
 
 toExecutableMap :: Monad m => String -> Maybe (Map String a) -> Maybe a -> Warnings m (Maybe (Map String a))
 toExecutableMap name executables mExecutable = do
@@ -808,7 +810,7 @@ warnUnknownFieldsInConfig = warnGlobal >=> bitraverse return warnSections
       executables <- warnNamedSection "executable" packageConfigExecutables
       tests <- warnNamedSection "test" packageConfigTests
       benchmarks <- warnNamedSection "benchmark" packageConfigBenchmarks
-      defaults <- warnUnknownFields In "defaults section" (traverse (traverseCapture t) packageConfigDefaults)
+      defaults <- warnUnknownFields In "defaults section" (traverse (traverse $ traverseCapture t) packageConfigDefaults)
       return p {
           packageConfigFlags = flags
         , packageConfigCustomSetup = customSetup

test/EndToEndSpec.hs

@@ -46,6 +46,20 @@ spec = around_ (inTempDirectoryNamed "foo") $ do
         default-extensions: RecordWildCards DeriveFunctor
         |]
 
+      it "accepts a list of defaults" $ do
+        writeFile "defaults/foo/bar/v1/.hpack/defaults.yaml" "default-extensions: RecordWildCards"
+        writeFile "defaults/foo/bar/v2/.hpack/defaults.yaml" "default-extensions: DeriveFunctor"
+        [i|
+        defaults:
+          - foo/bar@v1
+          - foo/bar@v2
+        library: {}
+        |] `shouldRenderTo` library [i|
+        other-modules:
+            Paths_foo
+        default-extensions: RecordWildCards DeriveFunctor
+        |]
+
       it "fails if defaults don't exist" $ do
         pending
         [i|