Remove IsHiFileStable rule

Author: wz1000

Diff for: ghcide/src/Development/IDE.hs

@@ -17,8 +17,7 @@ import           Development.IDE.Core.IdeConfiguration as X (IdeConfiguration (.
                                                              isWorkspaceFile)
 import           Development.IDE.Core.OfInterest       as X (getFilesOfInterestUntracked)
 import           Development.IDE.Core.RuleTypes        as X
-import           Development.IDE.Core.Rules            as X (IsHiFileStable (..),
-                                                             getClientConfigAction,
+import           Development.IDE.Core.Rules            as X (getClientConfigAction,
                                                              getParsedModule)
 import           Development.IDE.Core.Service          as X (runAction)
 import           Development.IDE.Core.Shake            as X (FastResult (..),

Diff for: ghcide/src/Development/IDE/Core/Rules.hs

@@ -30,7 +30,6 @@ module Development.IDE.Core.Rules(
     usePropertyAction,
     -- * Rules
     CompiledLinkables(..),
-    IsHiFileStable(..),
     getParsedModuleRule,
     getParsedModuleWithCommentsRule,
     getLocatedImportsRule,
@@ -42,7 +41,6 @@ module Development.IDE.Core.Rules(
     getModIfaceFromDiskRule,
     getModIfaceRule,
     getModSummaryRule,
-    isHiFileStableRule,
     getModuleGraphRule,
     knownFilesRule,
     getClientSettingsRule,
@@ -150,6 +148,7 @@ import Control.Concurrent.STM.Stats (atomically)
 import Language.LSP.Server (LspT)
 import System.Info.Extra (isWindows)
 import HIE.Bios.Ghc.Gap (hostIsDynamic)
+import qualified Development.IDE.Types.Shake as Shake
 
 templateHaskellInstructions :: T.Text
 templateHaskellInstructions = "https://haskell-language-server.readthedocs.io/en/latest/troubleshooting.html#static-binaries"
@@ -743,14 +742,18 @@ ghcSessionDepsDefinition fullModSummary GhcSessionDepsConfig{..} env file = do
 -- | Load a iface from disk, or generate it if there isn't one or it is out of date
 -- This rule also ensures that the `.hie` and `.o` (if needed) files are written out.
 getModIfaceFromDiskRule :: Rules ()
-getModIfaceFromDiskRule = defineEarlyCutoff $ Rule $ \GetModIfaceFromDisk f -> do
+getModIfaceFromDiskRule = defineEarlyCutoff $ RuleWithOldValue $ \GetModIfaceFromDisk f old -> do
   ms <- msrModSummary <$> use_ GetModSummary f
   mb_session <- use GhcSessionDeps f
   case mb_session of
     Nothing -> return (Nothing, ([], Nothing))
     Just session -> do
-      sourceModified <- use_ IsHiFileStable f
       linkableType <- getLinkableType f
+      ver <- use_ GetModificationTime f
+      let sourceModified = case old of
+            Shake.Succeeded (Just old_version) _ | old_version == ver -> SourceUnmodified
+            Shake.Stale _   (Just old_version) _ | old_version == ver -> SourceUnmodified
+            _ -> SourceModified
       r <- loadInterface (hscEnv session) ms sourceModified linkableType (regenerateHiFile session f ms)
       case r of
         (diags, Nothing) -> return (Nothing, (diags, Nothing))
@@ -802,31 +805,6 @@ getModIfaceFromDiskAndIndexRule =
 
   return (Just x)
 
-isHiFileStableRule :: Rules ()
-isHiFileStableRule = defineEarlyCutoff $ RuleNoDiagnostics $ \IsHiFileStable f -> do
-    ms <- msrModSummary <$> use_ GetModSummaryWithoutTimestamps f
-    let hiFile = toNormalizedFilePath'
-                $ Compat.ml_hi_file $ ms_location ms
-    mbHiVersion <- use  GetModificationTime_{missingFileDiagnostics=False} hiFile
-    modVersion  <- use_ GetModificationTime f
-    sourceModified <- case mbHiVersion of
-        Nothing -> pure SourceModified
-        Just x ->
-            if modificationTime x < modificationTime modVersion
-                then pure SourceModified
-                else do
-                    fileImports <- use_ GetLocatedImports f
-                    let imports = fmap artifactFilePath . snd <$> fileImports
-                    deps <- uses_ IsHiFileStable (catMaybes imports)
-                    pure $ if all (== SourceUnmodifiedAndStable) deps
-                           then SourceUnmodifiedAndStable
-                           else SourceUnmodified
-    return (Just (summarize sourceModified), Just sourceModified)
-  where
-      summarize SourceModified            = BS.singleton 1
-      summarize SourceUnmodified          = BS.singleton 2
-      summarize SourceUnmodifiedAndStable = BS.singleton 3
-
 displayTHWarning :: LspT c IO ()
 displayTHWarning
   | not isWindows && not hostIsDynamic = do
@@ -1122,7 +1100,6 @@ mainRule RulesConfig{..} = do
     getModIfaceFromDiskAndIndexRule
     getModIfaceRule
     getModSummaryRule
-    isHiFileStableRule
     getModuleGraphRule
     knownFilesRule
     getClientSettingsRule
@@ -1144,13 +1121,3 @@ mainRule RulesConfig{..} = do
     persistentHieFileRule
     persistentDocMapRule
     persistentImportMapRule
-
--- | Given the path to a module src file, this rule returns True if the
--- corresponding `.hi` file is stable, that is, if it is newer
---   than the src file, and all its dependencies are stable too.
-data IsHiFileStable = IsHiFileStable
-    deriving (Eq, Show, Typeable, Generic)
-instance Hashable IsHiFileStable
-instance NFData   IsHiFileStable
-
-type instance RuleResult IsHiFileStable = SourceModified