session-loader: remember which files caused old components to be loaded, and

also pass them on to hie-bios so it can in turn pass them to `cabal repl` when
loading newer components.

This allows us to create valid set of build flags encompassing both the old and
new components, and the closure of all components in between.

The observation is that if you want to load some components X, Y, Z and so on,
cabal repl X Y Z ... will be more likely to give you a valid multi component
build plan/flags than cabal repl all, or any way of combining the results of
cabal repl X, cabal repl Y ...

Author: wz1000

ghcide/session-loader/Development/IDE/Session.hs

@@ -437,6 +437,7 @@ loadSession recorder = loadSessionWithOptions recorder def
 
 loadSessionWithOptions :: Recorder (WithPriority Log) -> SessionLoadingOptions -> FilePath -> IO (Action IdeGhcSession)
 loadSessionWithOptions recorder SessionLoadingOptions{..} dir = do
+  cradle_files <- newIORef []
   -- Mapping from hie.yaml file to HscEnv, one per hie.yaml file
   hscEnvs <- newVar Map.empty :: IO (Var HieMap)
   -- Mapping from a Filepath to HscEnv
@@ -625,7 +626,8 @@ loadSessionWithOptions recorder SessionLoadingOptions{..} dir = do
            eopts <- mRunLspTCallback lspEnv (withIndefiniteProgress progMsg NotCancellable) $
               withTrace "Load cradle" $ \addTag -> do
                   addTag "file" lfp
-                  res <- cradleToOptsAndLibDir recorder cradle cfp
+                  old_files <- readIORef cradle_files
+                  res <- cradleToOptsAndLibDir recorder cradle cfp old_files
                   addTag "result" (show res)
                   return res
 
@@ -640,7 +642,8 @@ loadSessionWithOptions recorder SessionLoadingOptions{..} dir = do
                      error $ "GHC installation not found in libdir: " <> libdir
                  InstallationMismatch{..} ->
                      return (([renderPackageSetupException cfp GhcVersionMismatch{..}], Nothing),[])
-                 InstallationChecked _compileTime _ghcLibCheck ->
+                 InstallationChecked _compileTime _ghcLibCheck -> do
+                   atomicModifyIORef' cradle_files (\xs -> (cfp:xs,()))
                    session (hieYaml, toNormalizedFilePath' cfp, opts, libDir)
              -- Failure case, either a cradle error or the none cradle
              Left err -> do
@@ -698,15 +701,15 @@ loadSessionWithOptions recorder SessionLoadingOptions{..} dir = do
 -- | Run the specific cradle on a specific FilePath via hie-bios.
 -- This then builds dependencies or whatever based on the cradle, gets the
 -- GHC options/dynflags needed for the session and the GHC library directory
-cradleToOptsAndLibDir :: Recorder (WithPriority Log) -> Cradle Void -> FilePath
+cradleToOptsAndLibDir :: Recorder (WithPriority Log) -> Cradle Void -> FilePath -> [FilePath]
                       -> IO (Either [CradleError] (ComponentOptions, FilePath))
-cradleToOptsAndLibDir recorder cradle file = do
+cradleToOptsAndLibDir recorder cradle file old_files = do
     -- let noneCradleFoundMessage :: FilePath -> T.Text
     --     noneCradleFoundMessage f = T.pack $ "none cradle found for " <> f <> ", ignoring the file"
     -- Start off by getting the session options
     logWith recorder Debug $ LogCradle cradle
     let logger = toCologActionWithPrio $ cmapWithPrio LogHieBios recorder
-    cradleRes <- HieBios.getCompilerOptions logger file cradle
+    cradleRes <- HieBios.getCompilerOptions logger (file:old_files) cradle
     case cradleRes of
         CradleSuccess r -> do
             -- Now get the GHC lib dir