Remove Maybe from cabalConfigDependencies and fromInstalledPackageId

Language/Haskell/GhcMod/CabalApi.hs

@@ -20,7 +20,7 @@ import Control.Applicative ((<$>))
 import Control.Exception (throwIO,catch,SomeException)
 import Control.Monad (filterM)
 import CoreMonad (liftIO)
-import Data.Maybe (maybeToList, mapMaybe)
+import Data.Maybe (maybeToList)
 import Data.Set (fromList, toList)
 import Data.List (find,tails,isPrefixOf)
 import Distribution.ModuleName (ModuleName,toFilePath)
@@ -53,7 +53,7 @@ getCompilerOptions :: [GHCOption]
                    -> IO CompilerOptions
 getCompilerOptions ghcopts cradle pkgDesc = do
     gopts <- getGHCOptions ghcopts cradle rdir $ head buildInfos
-    Just depPkgs <- cabalConfigDependencies <$> cabalGetConfig cradle
+    depPkgs <- cabalConfigDependencies <$> cabalGetConfig cradle
     return $ CompilerOptions gopts idirs depPkgs
   where
     wdir       = cradleCurrentDir cradle
@@ -225,12 +225,17 @@ cabalGetConfig cradle =
 cabalConfigPath :: FilePath
 cabalConfigPath = localBuildInfoFile defaultDistPref
 
-cabalConfigDependencies :: CabalConfig -> Maybe [Package]
+cabalConfigDependencies :: CabalConfig -> [Package]
 cabalConfigDependencies config =
-    cfgDepends >>= return . mapMaybe (fromInstalledPackageId . snd)
+    (fromInstalledPackageId . snd) <$> cfgDepends
  where
-    cfgDepends :: Maybe [(PackageName, InstalledPackageId)]
+    cfgDepends :: [(PackageName, InstalledPackageId)]
-    cfgDepends =  extractCabalSetupConfig "configDependencies" config
+    cfgDepends =
+      case extractCabalSetupConfig "configDependencies" config of
+        Just x -> x
+        Nothing -> error $
+          "cabalConfigDependencies: Extracting field `configDependencies' from"
+          ++ " setup-config failed"
 
 
 -- | Extract part of cabal's @setup-config@, this is done with a mix of manual

Language/Haskell/GhcMod/GhcPkg.hs

@@ -7,6 +7,7 @@ module Language.Haskell.GhcMod.GhcPkg (
   , ghcDbStackOpts
   , ghcDbOpt
   , fromInstalledPackageId
+  , fromInstalledPackageId'
   , getSandboxDb
   , getPackageDbStack
   ) where
@@ -84,13 +85,20 @@ packageLine l =
       Just ((Hidden,p),_) -> Just p
       _ -> Nothing
 
-fromInstalledPackageId :: InstalledPackageId -> Maybe Package
+fromInstalledPackageId' :: InstalledPackageId -> Maybe Package
-fromInstalledPackageId pid = let
+fromInstalledPackageId' pid = let
     InstalledPackageId pkg = pid
     in case reverse $ splitOn "-" pkg of
       i:v:rest -> Just (intercalate "-" (reverse rest), v, i)
       _ -> Nothing
 
+fromInstalledPackageId :: InstalledPackageId -> Package
+fromInstalledPackageId pid =
+    case fromInstalledPackageId' pid of
+      Just p -> p
+      Nothing -> error $
+        "fromInstalledPackageId: `"++show pid++"' is not a valid package-id"
+
 data PackageState = Normal | Hidden | Broken deriving (Eq,Show)
 
 packageLineP :: ReadP (PackageState, Package)