Set cabal_macros.h work directory in stack ghci to something non-temporary

ChangeLog.md

@@ -19,6 +19,10 @@ Other enhancements:
 
 Bug fixes:
 
+* `stack ghci` now does not invalidate `.o` files on repeated runs,
+  meaning any modules compiled with `-fobject-code` will be cached
+  between ghci runs. See
+  [#4038](https://github.com/commercialhaskell/stack/pull/4038).
 * `~/.stack/config.yaml` and `stack.yaml` terminating by newline
 * The previous released caused a regression where some `stderr` from the
   `ghc-pkg` command showed up in the terminal. This output is now silenced.

src/Stack/Constants/Config.hs

@@ -15,6 +15,7 @@ module Stack.Constants.Config
   , hpcRelativeDir
   , hpcDirFromDir
   , objectInterfaceDirL
+  , ghciDirL
   , templatesDir
   ) where
 
@@ -32,11 +33,18 @@ objectInterfaceDirL = to $ \env -> -- FIXME is this idomatic lens code?
       root = view projectRootL env
    in root </> workDir </> $(mkRelDir "odir/")
 
+-- | GHCi files directory.
+ghciDirL :: HasBuildConfig env => Getting r env (Path Abs Dir)
+ghciDirL = to $ \env -> -- FIXME is this idomatic lens code?
+  let workDir = view workDirL env
+      root = view projectRootL env
+   in root </> workDir </> $(mkRelDir "ghci/")
+
 -- | The directory containing the files used for dirtiness check of source files.
 buildCachesDir :: (MonadThrow m, MonadReader env m, HasEnvConfig env)
                => Path Abs Dir      -- ^ Package directory.
                -> m (Path Abs Dir)
-buildCachesDir dir = 
+buildCachesDir dir =
     liftM
         (</> $(mkRelDir "stack-build-caches"))
         (distDirFromDir dir)

src/Stack/Ghci.hs

@@ -398,8 +398,10 @@ runGhci GhciOpts{..} targets mainIsTargets pkgs extraFiles exposePackages = do
     tmpDirectory <-
         (</> $(mkRelDir "haskell-stack-ghci")) <$>
         (parseAbsDir =<< liftIO getCanonicalTemporaryDirectory)
+    ghciDir <- view ghciDirL
+    ensureDir ghciDir
     ensureDir tmpDirectory
-    macrosOptions <- writeMacrosFile tmpDirectory pkgs
+    macrosOptions <- writeMacrosFile ghciDir pkgs
     if ghciNoLoadModules
         then execGhci macrosOptions
         else do
@@ -411,7 +413,7 @@ runGhci GhciOpts{..} targets mainIsTargets pkgs extraFiles exposePackages = do
             execGhci (macrosOptions ++ scriptOptions)
 
 writeMacrosFile :: HasRunner env => Path Abs Dir -> [GhciPkgInfo] -> RIO env [String]
-writeMacrosFile tmpDirectory pkgs = do
+writeMacrosFile outputDirectory pkgs = do
     fps <- fmap (nubOrd . catMaybes . concat) $
         forM pkgs $ \pkg -> forM (ghciPkgOpts pkg) $ \(_, bio) -> do
             let cabalMacros = bioCabalMacros bio
@@ -423,22 +425,22 @@ writeMacrosFile tmpDirectory pkgs = do
                     return Nothing
     files <- liftIO $ mapM (S8.readFile . toFilePath) fps
     if null files then return [] else do
-        out <- liftIO $ writeHashedFile tmpDirectory $(mkRelFile "cabal_macros.h") $
+        out <- liftIO $ writeHashedFile outputDirectory $(mkRelFile "cabal_macros.h") $
             S8.concat $ map (<> "\n#undef CURRENT_PACKAGE_KEY\n#undef CURRENT_COMPONENT_ID\n") files
         return ["-optP-include", "-optP" <> toFilePath out]
 
 writeGhciScript :: (MonadIO m) => Path Abs Dir -> GhciScript -> m [String]
-writeGhciScript tmpDirectory script = do
-    scriptPath <- liftIO $ writeHashedFile tmpDirectory $(mkRelFile "ghci-script") $
+writeGhciScript outputDirectory script = do
+    scriptPath <- liftIO $ writeHashedFile outputDirectory $(mkRelFile "ghci-script") $
         LBS.toStrict $ scriptToLazyByteString script
     let scriptFilePath = toFilePath scriptPath
     setScriptPerms scriptFilePath
     return ["-ghci-script=" <> scriptFilePath]
 
 writeHashedFile :: Path Abs Dir -> Path Rel File -> ByteString -> IO (Path Abs File)
-writeHashedFile tmpDirectory relFile contents = do
+writeHashedFile outputDirectory relFile contents = do
     relSha <- shaPathForBytes contents
-    let outDir = tmpDirectory </> relSha
+    let outDir = outputDirectory </> relSha
         outFile = outDir </> relFile
     alreadyExists <- doesFileExist outFile
     unless alreadyExists $ do