'stack ghci' is now spawned fixes commercialhaskell#1306

src/Stack/Exec.hs

@@ -14,16 +14,16 @@ import           Control.Monad.Catch hiding (try)
 import           Control.Monad.Trans.Control (MonadBaseControl)
 import           Stack.Types
 import           System.Process.Log
-import           System.Process.Read (EnvOverride)
 
-#ifdef WINDOWS
 import           Control.Exception.Lifted
 import           Data.Streaming.Process (ProcessExitedUnsuccessfully(..))
 import           System.Exit
 import           System.Process.Run (callProcess, Cmd(..))
+#ifdef WINDOWS
+import           System.Process.Read (EnvOverride)
 #else
-import           System.Process.Read (envHelper, preProcess)
 import           System.Posix.Process (executeFile)
+import           System.Process.Read (EnvOverride, envHelper, preProcess)
 #endif
 
 -- | Default @EnvSettings@ which includes locals and GHC_PACKAGE_PATH
@@ -47,14 +47,21 @@ plainEnvSettings = EnvSettings
 -- | Execute a process within the Stack configured environment.
 exec :: (MonadIO m, MonadLogger m, MonadThrow m, MonadBaseControl IO m)
      => EnvOverride -> String -> [String] -> m b
+#ifdef WINDOWS
+exec = execSpawn
+#else
 exec menv cmd0 args = do
     $logProcessRun cmd0 args
-#ifdef WINDOWS
+    cmd <- preProcess Nothing menv cmd0
+    liftIO $ executeFile cmd True args (envHelper menv)
+#endif
+
+-- | Execute a spawned process within the Stack configured environment.
+execSpawn :: (MonadIO m, MonadLogger m, MonadThrow m, MonadBaseControl IO m)
+     => EnvOverride -> String -> [String] -> m b
+execSpawn menv cmd0 args = do
+    $logProcessRun cmd0 args
     e <- try (callProcess (Cmd Nothing cmd0 menv args))
     liftIO $ case e of
         Left (ProcessExitedUnsuccessfully _ ec) -> exitWith ec
         Right () -> exitSuccess
-#else
-    cmd <- preProcess Nothing menv cmd0
-    liftIO $ executeFile cmd True args (envHelper menv)
-#endif

src/Stack/Ghci.hs

@@ -145,7 +145,7 @@ ghci opts@GhciOpts{..} = do
          T.intercalate ", " (map (packageNameText . ghciPkgName) pkgs))
     let execGhci extras = do
             menv <- liftIO $ configEnvOverride config defaultEnvSettings
-            exec menv
+            execSpawn menv
                  (fromMaybe (compilerExeName wc) ghciGhcCommand)
                  ("--interactive" :
                  -- This initial "-i" resets the include directories to not