Use cabal-helper for stack

Language/Haskell/GhcMod/CabalHelper.hs

@@ -169,9 +169,7 @@ withCabal action = do
 
            Nothing -> return False
 
-    cusPkgStack <- maybe [] ((PackageDb "clear"):) <$> getCustomPkgDbStack
-
-    --TODO: also invalidate when sandboxConfig file changed
+    projType <- cradleProjectType <$> cradle
 
     when (isSetupConfigOutOfDate mCabalFile mCabalConfig) $
       gmLog GmDebug "" $ strDoc $ "setup configuration is out of date, reconfiguring Cabal project."
@@ -185,7 +183,21 @@ withCabal action = do
     when ( isSetupConfigOutOfDate mCabalFile mCabalConfig
         || pkgDbStackOutOfSync
         || isSetupConfigOutOfDate mCabalSandboxConfig mCabalConfig) $
+          case projType of
+            CabalProject ->
+                cabalReconfigure readProc opts crdl projdir distdir
+            StackProject ->
+                -- https://github.com/commercialhaskell/stack/issues/820
+                gmLog GmWarning "" $ strDoc $ "Stack project configuration is out of date, please reconfigure manually using 'stack build'"
+            _ ->
+                error $ "withCabal: unsupported project type: " ++ show projType
+
+    action
+
+ where
+   cabalReconfigure readProc opts crdl projdir distdir = do
      withDirectory_ (cradleRootDir crdl) $ do
+        cusPkgStack <- maybe [] ((PackageDb "clear"):) <$> getCustomPkgDbStack
         let progOpts =
                 [ "--with-ghc=" ++ T.ghcProgram opts ]
                 -- Only pass ghc-pkg if it was actually set otherwise we
@@ -197,7 +209,7 @@ withCabal action = do
         liftIO $ void $ readProc (T.cabalProgram opts) ("configure":progOpts) ""
         gmLog GmDebug "" $ strDoc $ "writing Cabal autogen files"
         liftIO $ writeAutogenFiles readProc projdir distdir
-    action
+
 
 pkgDbArg :: GhcPkgDb -> String
 pkgDbArg GlobalDb      = "--package-db=global"

Language/Haskell/GhcMod/Target.hs

@@ -149,7 +149,7 @@ targetGhcOptions crdl sefnmn = do
 
     case cradleProjectType crdl of
       CabalProject -> cabalOpts crdl
-      StackProject -> stackOpts crdl
+      StackProject -> cabalOpts crdl
       _ -> sandboxOpts crdl
  where
    zipMap f l = l `zip` (f `map` l)
@@ -266,17 +266,9 @@ packageGhcOptions = do
     crdl <- cradle
     case cradleProjectType crdl of
       CabalProject -> getGhcMergedPkgOptions
-      StackProject -> stackOpts crdl
+      StackProject -> getGhcMergedPkgOptions
       _ -> sandboxOpts crdl
 
-stackOpts :: MonadIO m => Cradle -> m [String]
-stackOpts crdl = do
-    pkgDbStack <- liftIO getStackPackageDbStack
-    let pkgOpts = ghcDbStackOpts pkgDbStack
-    return $ ["-i" ++ d | d <- [wdir,rdir]] ++ pkgOpts ++ ["-Wall"]
-  where
-    (wdir, rdir) = (cradleCurrentDir crdl, cradleRootDir crdl)
-
 -- also works for plain projects!
 sandboxOpts :: MonadIO m => Cradle -> m [String]
 sandboxOpts crdl = do