From 2542553018617a0ea40f766a1fda25edd4e6b44b Mon Sep 17 00:00:00 2001
From: Pepe Iborra <pepeiborra@gmail.com>
Date: Sun, 10 Oct 2021 11:09:18 +0100
Subject: [PATCH] ignore null WatchedFile events

---
 ghcide/src/Development/IDE/Core/FileExists.hs |  8 ++------
 ghcide/src/Development/IDE/Core/FileStore.hs  | 19 ++++++-------------
 .../src/Development/IDE/LSP/Notifications.hs  | 16 +++++++++-------
 3 files changed, 17 insertions(+), 26 deletions(-)

diff --git a/ghcide/src/Development/IDE/Core/FileExists.hs b/ghcide/src/Development/IDE/Core/FileExists.hs
index 80bdd84203..af9c402838 100644
--- a/ghcide/src/Development/IDE/Core/FileExists.hs
+++ b/ghcide/src/Development/IDE/Core/FileExists.hs
@@ -88,14 +88,10 @@ getFileExistsMapUntracked = do
   liftIO $ readVar v
 
 -- | Modify the global store of file exists.
-modifyFileExists :: IdeState -> [FileEvent] -> IO ()
+modifyFileExists :: IdeState -> [(NormalizedFilePath, FileChangeType)] -> IO ()
 modifyFileExists state changes = do
   FileExistsMapVar var <- getIdeGlobalState state
-  changesMap           <- evaluate $ HashMap.fromList $
-    [ (toNormalizedFilePath' f, change)
-    | FileEvent uri change <- changes
-    , Just f <- [uriToFilePath uri]
-    ]
+  changesMap           <- evaluate $ HashMap.fromList changes
   -- Masked to ensure that the previous values are flushed together with the map update
   mask $ \_ -> do
     -- update the map
diff --git a/ghcide/src/Development/IDE/Core/FileStore.hs b/ghcide/src/Development/IDE/Core/FileStore.hs
index cf7034de27..2cc9d1c7f1 100644
--- a/ghcide/src/Development/IDE/Core/FileStore.hs
+++ b/ghcide/src/Development/IDE/Core/FileStore.hs
@@ -32,14 +32,12 @@ import           Control.Monad.Extra
 import           Control.Monad.IO.Class
 import qualified Data.ByteString                              as BS
 import           Data.Either.Extra
-import qualified Data.HashMap.Strict                          as HM
 import qualified Data.Map.Strict                              as Map
 import           Data.Maybe
 import qualified Data.Rope.UTF16                              as Rope
 import qualified Data.Text                                    as T
 import           Data.Time
 import           Data.Time.Clock.POSIX
-import           Development.IDE.Core.OfInterest              (OfInterestVar (..))
 import           Development.IDE.Core.RuleTypes
 import           Development.IDE.Core.Shake
 import           Development.IDE.GHC.Orphans                  ()
@@ -74,12 +72,9 @@ import           Language.LSP.Server                          hiding
 import qualified Language.LSP.Server                          as LSP
 import           Language.LSP.Types                           (DidChangeWatchedFilesRegistrationOptions (DidChangeWatchedFilesRegistrationOptions),
                                                                FileChangeType (FcChanged),
-                                                               FileEvent (FileEvent),
                                                                FileSystemWatcher (..),
                                                                WatchKind (..),
-                                                               _watchers,
-                                                               toNormalizedFilePath,
-                                                               uriToFilePath)
+                                                               _watchers)
 import qualified Language.LSP.Types                           as LSP
 import qualified Language.LSP.Types.Capabilities              as LSP
 import           Language.LSP.VFS
@@ -170,18 +165,16 @@ resetInterfaceStore state f = do
     deleteValue state GetModificationTime f
 
 -- | Reset the GetModificationTime state of watched files
-resetFileStore :: IdeState -> [FileEvent] -> IO ()
+--   Assumes the list does not include any FOIs
+resetFileStore :: IdeState -> [(NormalizedFilePath, FileChangeType)] -> IO ()
 resetFileStore ideState changes = mask $ \_ -> do
     -- we record FOIs document versions in all the stored values
     -- so NEVER reset FOIs to avoid losing their versions
-    OfInterestVar foisVar <- getIdeGlobalExtras (shakeExtras ideState)
-    fois <- readVar foisVar
-    forM_ changes $ \(FileEvent uri c) -> do
+    -- FOI filtering is done by the caller (LSP Notification handler)
+    forM_ changes $ \(nfp, c) -> do
         case c of
             FcChanged
-              | Just f <- uriToFilePath uri
-              , nfp <- toNormalizedFilePath f
-              , not $ HM.member nfp fois
+            --  already checked elsewhere |  not $ HM.member nfp fois
               -> deleteValue (shakeExtras ideState) GetModificationTime nfp
             _ -> pure ()
 
diff --git a/ghcide/src/Development/IDE/LSP/Notifications.hs b/ghcide/src/Development/IDE/LSP/Notifications.hs
index 4fb1d4fac4..b2901bf32c 100644
--- a/ghcide/src/Development/IDE/LSP/Notifications.hs
+++ b/ghcide/src/Development/IDE/LSP/Notifications.hs
@@ -87,15 +87,17 @@ descriptor plId = (defaultPluginDescriptor plId) { pluginNotificationHandlers =
         -- filter also uris that do not map to filenames, since we cannot handle them
         filesOfInterest <- getFilesOfInterest ide
         let fileEvents' =
-                [ f | f@(FileEvent uri _) <- fileEvents
+                [ (nfp, event) | (FileEvent uri event) <- fileEvents
                 , Just fp <- [uriToFilePath uri]
-                , not $ HM.member (toNormalizedFilePath fp) filesOfInterest
+                , let nfp = toNormalizedFilePath fp
+                , not $ HM.member nfp filesOfInterest
                 ]
-        let msg = show fileEvents'
-        logDebug (ideLogger ide) $ "Watched file events: " <> Text.pack msg
-        modifyFileExists ide fileEvents'
-        resetFileStore ide fileEvents'
-        setSomethingModified ide [] msg
+        unless (null fileEvents') $ do
+            let msg = show fileEvents'
+            logDebug (ideLogger ide) $ "Watched file events: " <> Text.pack msg
+            modifyFileExists ide fileEvents'
+            resetFileStore ide fileEvents'
+            setSomethingModified ide [] msg
 
   , mkPluginNotificationHandler LSP.SWorkspaceDidChangeWorkspaceFolders $
       \ide _ (DidChangeWorkspaceFoldersParams events) -> liftIO $ do