lock-less KnownTargets

Author: pepeiborra

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

@@ -78,7 +78,9 @@ import           Data.Void
 
 import           Control.Concurrent.STM               (atomically)
 import           Control.Concurrent.STM.TQueue
+import           Data.Foldable                        (for_)
 import qualified Data.HashSet                         as Set
+import           Data.Tuple                           (swap)
 import           Database.SQLite.Simple
 import           Development.IDE.Core.Tracing         (withTrace)
 import           HieDb.Create
@@ -265,12 +267,13 @@ loadSessionWithOptions SessionLoadingOptions{..} dir = do
                 found <- filterM (IO.doesFileExist . fromNormalizedFilePath) targetLocations
                 return (targetTarget, found)
           recordDirtyKeys extras GetKnownTargets  [emptyFilePath]
-          modifyVarIO' knownTargetsVar $ traverseHashed $ \known -> do
+          hasUpdate <- atomicModifyIORef' knownTargetsVar $ (swap .) $ traverseHashed $ \known -> do
             let known' = HM.unionWith (<>) known $ HM.fromList $ map (second Set.fromList) knownTargets
-            when (known /= known') $
+                hasUpdate = if known /= known' then Just known' else Nothing
+            (hasUpdate, known')
+          for_ hasUpdate $ \x ->
                 logDebug logger $ "Known files updated: " <>
-                    T.pack(show $ (HM.map . Set.map) fromNormalizedFilePath known')
-            pure known'
+                    T.pack(show $ (HM.map . Set.map) fromNormalizedFilePath x)
 
     -- Create a new HscEnv from a hieYaml root and a set of options
     -- If the hieYaml file already has an HscEnv, the new component is

ghcide/src/Development/IDE/Core/Shake.hs

@@ -212,7 +212,7 @@ data ShakeExtras = ShakeExtras
         -> IO ()
     ,ideNc :: IORef NameCache
     -- | A mapping of module name to known target (or candidate targets, if missing)
-    ,knownTargetsVar :: Var (Hashed KnownTargets)
+    ,knownTargetsVar :: IORef (Hashed KnownTargets)
     -- | A mapping of exported identifiers for local modules. Updated on kick
     ,exportsMap :: Var ExportsMap
     -- | A work queue for actions added via 'runInShakeSession'
@@ -470,7 +470,7 @@ getValues state key file = do
 knownTargets :: Action (Hashed KnownTargets)
 knownTargets = do
   ShakeExtras{knownTargetsVar} <- getShakeExtras
-  liftIO $ readVar knownTargetsVar
+  liftIO $ readIORef knownTargetsVar
 
 -- | Seq the result stored in the Shake value. This only
 -- evaluates the value to WHNF not NF. We take care of the latter
@@ -507,7 +507,7 @@ shakeOpen lspEnv defaultConfig logger debouncer
         hiddenDiagnostics <- STM.newIO
         publishedDiagnostics <- STM.newIO
         positionMapping <- STM.newIO
-        knownTargetsVar <- newVar $ hashed HMap.empty
+        knownTargetsVar <- newIORef $ hashed HMap.empty
         let restartShakeSession = shakeRestart ideState
         persistentKeys <- newVar HMap.empty
         indexPending <- newTVarIO HMap.empty

plugins/hls-retrie-plugin/src/Ide/Plugin/Retrie.hs

@@ -357,7 +357,7 @@ callRetrie ::
   Bool ->
   IO ([CallRetrieError], WorkspaceEdit)
 callRetrie state session rewrites origin restrictToOriginatingFile = do
-  knownFiles <- toKnownFiles . unhashed <$> readVar (knownTargetsVar $ shakeExtras state)
+  knownFiles <- toKnownFiles . unhashed <$> readIORef (knownTargetsVar $ shakeExtras state)
   let reuseParsedModule f = do
         pm <-
           useOrFail "GetParsedModule" NoParse GetParsedModule f