Allow using HsYAML instead of yaml

.hlint.yaml

@@ -17,7 +17,7 @@
   - name: [PackageImports]
   - name: [ConstraintKinds, RankNTypes, TypeFamilies]
   - name: [TemplateHaskell]
-  - {name: CPP, within: [HsColour]} # so it can be disabled to avoid GPL code
+  - {name: CPP, within: [HsColour, Config.Yaml, Test.Annotations]} # so it can be disabled to avoid GPL code
 
 - flags:
   - default: false

.weeder.yaml

@@ -4,4 +4,4 @@
 
 - message:
   - name: Redundant build-depends entry
-  - depends: [ghc-lib-parser, ghc, ghc-boot-th, ghc-boot] # Only some subset is required
+  - depends: [ghc-lib-parser, ghc, ghc-boot-th, ghc-boot, HsYAML, HsYAML-aeson, yaml] # Only some subset is required

hlint.cabal

@@ -48,6 +48,11 @@ flag ghc-lib
   manual: True
   description: Force dependency on ghc-lib-parser even if GHC API in the ghc package is supported
 
+flag hsyaml
+  default: False
+  manual: True
+  description: Use HsYAML instead of yaml
+
 library
     default-language:   Haskell2010
     build-depends:
@@ -59,7 +64,6 @@ library
         data-default >= 0.3,
         cpphs >= 1.20.1,
         cmdargs >= 0.10,
-        yaml >= 0.5.0,
         uniplate >= 1.5,
         ansi-terminal >= 0.6.2,
         extra >= 1.7.3,
@@ -83,6 +87,14 @@ library
     else
         cpp-options: -DGPL_SCARES_ME
 
+    if flag(hsyaml) && flag(gpl)
+        build-depends:
+          HsYAML >= 0.2,
+          HsYAML-aeson >= 0.2
+        cpp-options: -DHS_YAML
+    else
+        build-depends: yaml >= 0.5.0
+
     hs-source-dirs:     src
     exposed-modules:
         Language.Haskell.HLint

src/Config/Yaml.hs

@@ -1,5 +1,6 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE OverloadedStrings, ViewPatterns, RecordWildCards, GeneralizedNewtypeDeriving, TupleSections #-}
+{-# LANGUAGE CPP #-}
 
 module Config.Yaml(
     ConfigYaml,
@@ -8,13 +9,11 @@ module Config.Yaml(
     ) where
 
 import Config.Type
-import Data.Yaml
 import Data.Either
 import Data.Maybe
 import Data.List.Extra
 import Data.Tuple.Extra
 import Control.Monad.Extra
-import Control.Exception.Extra
 import qualified Data.Text as T
 import qualified Data.Vector as V
 import qualified Data.ByteString.Char8 as BS
@@ -42,6 +41,33 @@ import Language.Haskell.GhclibParserEx.GHC.Hs.ExtendInstances
 import Language.Haskell.GhclibParserEx.GHC.Types.Name.Reader
 import Data.Char
 
+#ifdef HS_YAML
+
+import Data.YAML (Pos)
+import Data.YAML.Aeson (encode1Strict, decode1Strict)
+import Data.Aeson hiding (encode)
+import Data.Aeson.Types (Parser)
+import qualified Data.ByteString as BSS
+
+decodeFileEither :: FilePath -> IO (Either (Pos, String) ConfigYaml)
+decodeFileEither path = decode1Strict <$> BSS.readFile path
+
+decodeEither' :: BSS.ByteString -> Either (Pos, String) ConfigYaml
+decodeEither' = decode1Strict
+
+displayException :: (Pos, String) -> String
+displayException = show
+
+encode :: Value -> BSS.ByteString
+encode = encode1Strict
+
+#else
+
+import Data.Yaml
+import Control.Exception.Extra
+
+#endif
+
 
 -- | Read a config file in YAML format. Takes a filename, and optionally the contents.
 --   Fails if the YAML doesn't parse or isn't valid HLint YAML

src/Test/Annotations.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE PatternGuards, RecordWildCards, ViewPatterns #-}
+{-# LANGUAGE CPP, PatternGuards, RecordWildCards, ViewPatterns #-}
 
 -- | Check the <TEST> annotations within source and hint files.
 module Test.Annotations(testAnnotations) where
@@ -13,7 +13,6 @@ import Data.Functor
 import Data.List.Extra
 import Data.Maybe
 import Data.Tuple.Extra
-import Data.Yaml
 import System.Exit
 import System.FilePath
 import System.IO.Extra
@@ -34,6 +33,21 @@ import GHC.Util
 import SrcLoc
 import Language.Haskell.GhclibParserEx.GHC.Utils.Outputable
 
+#ifdef HS_YAML
+
+import Data.YAML.Aeson (decode1Strict)
+import Data.YAML (Pos)
+import Data.ByteString (ByteString)
+
+decodeEither' :: ByteString -> Either (Pos, String) ConfigYaml
+decodeEither' = decode1Strict
+
+#else
+
+import Data.Yaml
+
+#endif
+
 -- Input, Output
 -- Output = Nothing, should not match
 -- Output = Just xs, should match xs