Support .buildinfo files in stack ghci.

src/Stack/Ghci.hs

@@ -18,12 +18,12 @@ module Stack.Ghci
 
 import           Control.Applicative
 import           Control.Exception.Enclosed (tryAny)
-import           Control.Monad
+import           Control.Monad hiding (forM)
 import           Control.Monad.Catch
 import           Control.Monad.IO.Class
 import           Control.Monad.Logger
-import           Control.Monad.RWS.Strict
-import           Control.Monad.State.Strict
+import           Control.Monad.State.Strict (State, execState, get, modify)
+import           Control.Monad.Reader (MonadReader, asks)
 import           Control.Monad.Trans.Unlift (MonadBaseUnlift)
 import qualified Data.ByteString.Char8 as S8
 import           Data.Either
@@ -35,12 +35,15 @@ import           Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
 import           Data.Maybe
 import           Data.Maybe.Extra (forMaybeM)
+import           Data.Monoid
 import           Data.Set (Set)
 import qualified Data.Set as S
+import           Data.Traversable (forM)
 import           Data.Text (Text)
 import qualified Data.Text as T
 import           Data.Typeable (Typeable)
 import           Distribution.ModuleName (ModuleName)
+import           Distribution.PackageDescription (updatePackageDescription)
 import           Distribution.Text (display)
 import           Network.HTTP.Client.Conduit
 import           Path
@@ -379,7 +382,21 @@ makeGhciPkgInfo boptsCli sourceMap installedMap locals addPkgs name cabalfp targ
             , packageConfigCompilerVersion = envConfigCompilerVersion econfig
             , packageConfigPlatform = configPlatform (getConfig bconfig)
             }
-    (warnings,pkg) <- readPackage config cabalfp
+    (warnings,gpkgdesc) <- readPackageUnresolved cabalfp
+
+    -- Source the package's *.buildinfo file created by configure if any. See
+    -- https://www.haskell.org/cabal/users-guide/developing-packages.html#system-dependent-parameters
+    buildinfofp <- parseRelFile (T.unpack (packageNameText name) ++ ".buildinfo")
+    hasDotBuildinfo <- doesFileExist (parent cabalfp </> buildinfofp)
+    let mbuildinfofp
+          | hasDotBuildinfo = Just (parent cabalfp </> buildinfofp)
+          | otherwise = Nothing
+    mbuildinfo <- forM mbuildinfofp readDotBuildinfo
+    let pkg =
+            packageFromPackageDescription config gpkgdesc $
+            maybe id (updatePackageDescription) mbuildinfo $
+            resolvePackageDescription config gpkgdesc
+
     mapM_ (printCabalFileWarning cabalfp) warnings
     (mods,files,opts) <- getPackageOpts (packageOpts pkg) sourceMap installedMap locals addPkgs cabalfp
     let filteredOpts = filterWanted opts

src/Stack/Package.hs

@@ -18,9 +18,11 @@ module Stack.Package
   (readPackage
   ,readPackageBS
   ,readPackageDescriptionDir
+  ,readDotBuildinfo
   ,readPackageUnresolved
   ,readPackageUnresolvedBS
   ,resolvePackage
+  ,packageFromPackageDescription
   ,findOrGenerateCabalFile
   ,hpack
   ,Package(..)
@@ -146,6 +148,17 @@ readPackageDescriptionDir config pkgDir = do
     gdesc   <- liftM snd (readPackageUnresolved cabalfp)
     return (gdesc, resolvePackageDescription config gdesc)
 
+-- | Read @<package>.buildinfo@ ancillary files produced by some Setup.hs hooks.
+-- The file includes Cabal file syntax to be merged into the package description
+-- derived from the package's .cabal file.
+--
+-- NOTE: not to be confused with BuildInfo, an Stack-internal datatype.
+readDotBuildinfo :: MonadIO m
+                 => Path Abs File
+                 -> m HookedBuildInfo
+readDotBuildinfo buildinfofp =
+    liftIO $ readHookedBuildInfo D.silent (toFilePath buildinfofp)
+
 -- | Print cabal file warnings.
 printCabalFileWarning
     :: (MonadLogger m)
@@ -179,6 +192,16 @@ resolvePackage :: PackageConfig
                -> GenericPackageDescription
                -> Package
 resolvePackage packageConfig gpkg =
+    packageFromPackageDescription
+        packageConfig
+        gpkg
+        (resolvePackageDescription packageConfig gpkg)
+
+packageFromPackageDescription :: PackageConfig
+                              -> GenericPackageDescription
+                              -> PackageDescription
+                              -> Package
+packageFromPackageDescription packageConfig gpkg pkg =
     Package
     { packageName = name
     , packageVersion = fromCabalVersion (pkgVersion pkgId)
@@ -210,7 +233,7 @@ resolvePackage packageConfig gpkg =
           False
           (not . null . exposedModules)
           (library pkg)
-    , packageSimpleType = buildType (packageDescription gpkg) == Just Simple
+    , packageSimpleType = buildType pkg == Just Simple
     }
   where
     pkgFiles = GetPackageFiles $
@@ -236,9 +259,8 @@ resolvePackage packageConfig gpkg =
                     hpackExists <- doesFileExist hpackPath
                     return $ if hpackExists then S.singleton hpackPath else S.empty
                 return (componentModules, componentFiles, buildFiles <> dataFiles', warnings)
-    pkgId = package (packageDescription gpkg)
+    pkgId = package pkg
     name = fromCabalPackageName (pkgName pkgId)
-    pkg = resolvePackageDescription packageConfig gpkg
     deps = M.filterWithKey (const . (/= name)) (packageDependencies pkg)
 
 -- | Generate GHC options for the package's components, and a list of