Break down ghcide functionality in HLS plugins (#1257)

* Clean up no longer needed handlers

* Move some log lines to debug verbosity

* Extract type signature code lenses to an HLS plugin

This was worth doing to clean up the messy command handlers

* Extract the block command handler to an HLS plugin

Previously defined together with the type lenses command handler

* fix command capability check

* Extract completions into an HLS plugin

We might want to break them down into multiple HLS plugins
later on (local, non local, and module header).

* Extract code actions into an HLS plugin

* Group ghcide plugins

Author: pepeiborra

exe/Plugins.hs

@@ -2,14 +2,14 @@
 {-# LANGUAGE OverloadedStrings #-}
 module Plugins where
 
-import           Ide.Types                 (IdePlugins)
+import Ide.Types (IdePlugins)
 import           Ide.PluginUtils           (pluginDescToIdePlugins)
 
 -- fixed plugins
 import           Ide.Plugin.Example        as Example
 import           Ide.Plugin.Example2       as Example2
 import           Development.IDE           (IdeState)
-import           Development.IDE.Plugin.HLS.GhcIde as GhcIde
+import Development.IDE.Plugin.HLS.GhcIde as GhcIde
 
 -- haskell-language-server optional plugins
 
@@ -89,53 +89,53 @@ idePlugins includeExamples = pluginDescToIdePlugins allPlugins
                    then basePlugins ++ examplePlugins
                    else basePlugins
     basePlugins =
-      [ GhcIde.descriptor  "ghcide"
+      GhcIde.descriptors ++
 #if pragmas
-      , Pragmas.descriptor  "pragmas"
+      Pragmas.descriptor  "pragmas" :
 #endif
 #if floskell
-      , Floskell.descriptor "floskell"
+      Floskell.descriptor "floskell" :
 #endif
 #if fourmolu
-      , Fourmolu.descriptor "fourmolu"
+      Fourmolu.descriptor "fourmolu" :
 #endif
 #if tactic
-      , Tactic.descriptor "tactic"
+      Tactic.descriptor "tactic" :
 #endif
 #if ormolu
-      , Ormolu.descriptor   "ormolu"
+      Ormolu.descriptor   "ormolu" :
 #endif
 #if stylishHaskell
-      , StylishHaskell.descriptor "stylish-haskell"
+      StylishHaskell.descriptor "stylish-haskell" :
 #endif
 #if retrie
-      , Retrie.descriptor "retrie"
+      Retrie.descriptor "retrie" :
 #endif
 #if AGPL && brittany
-      , Brittany.descriptor "brittany"
+      Brittany.descriptor "brittany" :
 #endif
 #if class
-      , Class.descriptor "class"
+      Class.descriptor "class" :
 #endif
 #if haddockComments
-      , HaddockComments.descriptor "haddockComments"
+      HaddockComments.descriptor "haddockComments" :
 #endif
 #if eval
-      , Eval.descriptor "eval"
+      Eval.descriptor "eval" :
 #endif
 #if importLens
-      , ExplicitImports.descriptor "importLens"
+      ExplicitImports.descriptor "importLens" :
 #endif
 #if moduleName
-      , ModuleName.descriptor "moduleName"
+      ModuleName.descriptor "moduleName" :
 #endif
 #if hlint
-      , Hlint.descriptor "hlint"
+      Hlint.descriptor "hlint" :
 #endif
 #if splice
-      , Splice.descriptor "splice"
+      Splice.descriptor "splice" :
 #endif
-      ]
+      []
     examplePlugins =
       [Example.descriptor  "eg"
       ,Example2.descriptor "eg2"

ghcide/exe/Main.hs

@@ -87,7 +87,9 @@ main = do
 
     dir <- IO.getCurrentDirectory
 
-    let hlsPlugins = pluginDescToIdePlugins [GhcIde.descriptor "ghcide"]
+    let hlsPlugins = pluginDescToIdePlugins $
+            GhcIde.descriptors ++
+            [ Test.blockCommandDescriptor "block-command" | argsTesting]
 
     pid <- T.pack . show <$> getProcessID
     let hlsPlugin = asGhcIdePlugin hlsPlugins

ghcide/ghcide.cabal

@@ -173,6 +173,7 @@ library
         Development.IDE.Plugin.HLS
         Development.IDE.Plugin.HLS.GhcIde
         Development.IDE.Plugin.Test
+        Development.IDE.Plugin.TypeLenses
 
     -- Unfortunately, we cannot use loadSession with ghc-lib since hie-bios uses
     -- the real GHC library and the types are incompatible. Furthermore, when

ghcide/src/Development/IDE/LSP/HoverDefinition.hs

@@ -4,8 +4,7 @@
 
 -- | Display information on hover.
 module Development.IDE.LSP.HoverDefinition
-    ( setHandlersHover
-    , setHandlersDefinition
+    ( setHandlersDefinition
     , setHandlersTypeDefinition
     , setHandlersDocHighlight
     -- * For haskell-language-server
@@ -38,13 +37,11 @@ foundHover :: (Maybe Range, [T.Text]) -> Maybe Hover
 foundHover (mbRange, contents) =
   Just $ Hover (HoverContents $ MarkupContent MkMarkdown $ T.intercalate sectionSeparator contents) mbRange
 
-setHandlersDefinition, setHandlersHover, setHandlersTypeDefinition, setHandlersDocHighlight :: PartialHandlers c
+setHandlersDefinition, setHandlersTypeDefinition, setHandlersDocHighlight :: PartialHandlers c
 setHandlersDefinition = PartialHandlers $ \WithMessage{..} x ->
   return x{LSP.definitionHandler = withResponse RspDefinition $ const gotoDefinition}
 setHandlersTypeDefinition = PartialHandlers $ \WithMessage{..} x ->
-  return x{LSP.typeDefinitionHandler = withResponse RspDefinition $ const gotoTypeDefinition}
-setHandlersHover      = PartialHandlers $ \WithMessage{..} x ->
-  return x{LSP.hoverHandler      = withResponse RspHover      $ const hover}
+  return x {LSP.typeDefinitionHandler = withResponse RspDefinition $ const gotoTypeDefinition}
 setHandlersDocHighlight = PartialHandlers $ \WithMessage{..} x ->
   return x{LSP.documentHighlightHandler = withResponse RspDocumentHighlights $ const documentHighlight}
 

ghcide/src/Development/IDE/LSP/LanguageServer.hs

@@ -108,7 +108,7 @@ runLanguageServer options userHandlers onInitialConfig onConfigChange getIdeStat
     let PartialHandlers parts =
             initializeRequestHandler <>
             setHandlersIgnore <> -- least important
-            setHandlersDefinition <> setHandlersHover <> setHandlersTypeDefinition <>
+            setHandlersDefinition <> setHandlersTypeDefinition <>
             setHandlersDocHighlight <>
             setHandlersOutline <>
             userHandlers <>

ghcide/src/Development/IDE/Plugin.hs

@@ -1,19 +1,10 @@
 module Development.IDE.Plugin
   ( Plugin(..)
-  , codeActionPlugin
-  , codeActionPluginWithRules
-  , makeLspCommandId
   ) where
 
 import Data.Default
-import qualified Data.Text as T
 import Development.Shake
 import Development.IDE.LSP.Server
-import Development.IDE.Core.Rules
-import Ide.PluginUtils
-import           Language.Haskell.LSP.Types
-import qualified Language.Haskell.LSP.Core as LSP
-import Language.Haskell.LSP.Messages
 
 
 data Plugin c = Plugin
@@ -29,29 +20,3 @@ instance Semigroup (Plugin c) where
 
 instance Monoid (Plugin c) where
     mempty = def
-
-
-codeActionPlugin :: (LSP.LspFuncs c -> IdeState -> TextDocumentIdentifier -> Range -> CodeActionContext -> IO (Either ResponseError [CAResult])) -> Plugin c
-codeActionPlugin = codeActionPluginWithRules mempty
-
-codeActionPluginWithRules :: Rules () -> (LSP.LspFuncs c -> IdeState -> TextDocumentIdentifier -> Range -> CodeActionContext -> IO (Either ResponseError [CAResult])) -> Plugin c
-codeActionPluginWithRules rr f = Plugin rr $ PartialHandlers $ \WithMessage{..} x -> return x{
-    LSP.codeActionHandler = withResponse RspCodeAction g
-    }
-    where
-      g lsp state (CodeActionParams a b c _) = fmap List <$> f lsp state a b c
-
--- | Prefix to uniquely identify commands sent to the client.  This
--- has two parts
---
--- - A representation of the process id to make sure that a client has
---   unique commands if it is running multiple servers, since some
---   clients have a global command table and get confused otherwise.
---
--- - A string to identify ghcide, to ease integration into
---   haskell-language-server, which routes commands to plugins based
---   on that.
-makeLspCommandId :: T.Text -> IO T.Text
-makeLspCommandId command = do
-    pid <- getProcessID
-    return $ T.pack (show pid) <> ":ghcide:" <> command

ghcide/src/Development/IDE/Plugin/CodeAction.hs

@@ -7,46 +7,33 @@
 
 -- | Go to the definition of a variable.
 module Development.IDE.Plugin.CodeAction
-    (
-      plugin
-
-    -- * For haskell-language-server
-    , codeAction
-    , codeLens
-    , rulePackageExports
-    , commandHandler
+    ( descriptor
 
     -- * For testing
-    , blockCommandId
-    , typeSignatureCommandId
     , matchRegExMultipleImports
     ) where
 
 import Control.Monad (join, guard)
-import Development.IDE.Plugin
 import Development.IDE.GHC.Compat
 import Development.IDE.Core.Rules
 import Development.IDE.Core.RuleTypes
 import Development.IDE.Core.Service
 import Development.IDE.Core.Shake
 import Development.IDE.GHC.Error
 import Development.IDE.GHC.ExactPrint
-import Development.IDE.LSP.Server
 import Development.IDE.Plugin.CodeAction.ExactPrint
 import Development.IDE.Plugin.CodeAction.PositionIndexed
 import Development.IDE.Plugin.CodeAction.RuleTypes
 import Development.IDE.Plugin.CodeAction.Rules
+import Development.IDE.Plugin.TypeLenses (suggestSignature)
 import Development.IDE.Types.Exports
 import Development.IDE.Types.Location
 import Development.IDE.Types.Options
-import Development.Shake (Rules)
 import qualified Data.HashMap.Strict as Map
 import qualified Language.Haskell.LSP.Core as LSP
 import Language.Haskell.LSP.VFS
-import Language.Haskell.LSP.Messages
 import Language.Haskell.LSP.Types
 import qualified Data.Rope.UTF16 as Rope
-import Data.Aeson.Types (toJSON, fromJSON, Value(..), Result(..))
 import Data.Char
 import Data.Maybe
 import Data.List.Extra
@@ -62,33 +49,28 @@ import Control.Applicative ((<|>))
 import Safe (atMay)
 import Bag (isEmptyBag)
 import qualified Data.HashSet as Set
-import Control.Concurrent.Extra (threadDelay, readVar)
+import Control.Concurrent.Extra (readVar)
 import Development.IDE.GHC.Util (printRdrName)
 import Ide.PluginUtils (subRange)
+import Ide.Types
 
-plugin :: Plugin c
-plugin = codeActionPluginWithRules rules codeAction <> Plugin mempty setHandlersCodeLens
-
-rules :: Rules ()
-rules = do
-  rulePackageExports
-
--- | a command that blocks forever. Used for testing
-blockCommandId :: T.Text
-blockCommandId = "ghcide.command.block"
-
-typeSignatureCommandId :: T.Text
-typeSignatureCommandId = "typesignature.add"
+descriptor :: PluginId -> PluginDescriptor IdeState
+descriptor plId =
+  (defaultPluginDescriptor plId)
+    { pluginRules = rulePackageExports,
+      pluginCodeActionProvider = Just codeAction
+    }
 
 -- | Generate code actions.
 codeAction
     :: LSP.LspFuncs c
     -> IdeState
+    -> PluginId
     -> TextDocumentIdentifier
     -> Range
     -> CodeActionContext
-    -> IO (Either ResponseError [CAResult])
-codeAction lsp state (TextDocumentIdentifier uri) _range CodeActionContext{_diagnostics=List xs} = do
+    -> IO (Either ResponseError (List CAResult))
+codeAction lsp state _ (TextDocumentIdentifier uri) _range CodeActionContext{_diagnostics=List xs} = do
     contents <- LSP.getVirtualFileFunc lsp $ toNormalizedUri uri
     let text = Rope.toText . (_text :: VirtualFile -> Rope.Rope) <$> contents
         mbFile = toNormalizedFilePath' <$> uriToFilePath uri
@@ -122,58 +104,12 @@ codeAction lsp state (TextDocumentIdentifier uri) _range CodeActionContext{_diag
                <> actions
                <> actions'
                <> caRemoveInvalidExports parsedModule text diag xs uri
-    pure $ Right actions''
+    pure $ Right $ List actions''
 
 mkCA :: T.Text -> [Diagnostic] -> WorkspaceEdit -> CAResult
 mkCA title diags edit =
   CACodeAction $ CodeAction title (Just CodeActionQuickFix) (Just $ List diags) (Just edit) Nothing
 
--- | Generate code lenses.
-codeLens
-    :: LSP.LspFuncs c
-    -> IdeState
-    -> CodeLensParams
-    -> IO (Either ResponseError (List CodeLens))
-codeLens _lsp ideState CodeLensParams{_textDocument=TextDocumentIdentifier uri} = do
-    commandId <- makeLspCommandId "typesignature.add"
-    fmap (Right . List) $ case uriToFilePath' uri of
-      Just (toNormalizedFilePath' -> filePath) -> do
-        _ <- runAction "codeLens" ideState (use TypeCheck filePath)
-        diag <- getDiagnostics ideState
-        hDiag <- getHiddenDiagnostics ideState
-        pure
-          [ CodeLens _range (Just (Command title commandId (Just $ List [toJSON edit]))) Nothing
-          | (dFile, _, dDiag@Diagnostic{_range=_range}) <- diag ++ hDiag
-          , dFile == filePath
-          , (title, tedit) <- suggestSignature False dDiag
-          , let edit = WorkspaceEdit (Just $ Map.singleton uri $ List tedit) Nothing
-          ]
-      Nothing -> pure []
-
--- | Execute the "typesignature.add" command.
-commandHandler
-    :: LSP.LspFuncs c
-    -> IdeState
-    -> ExecuteCommandParams
-    -> IO (Either ResponseError Value, Maybe (ServerMethod, ApplyWorkspaceEditParams))
-commandHandler lsp _ideState ExecuteCommandParams{..}
-    -- _command is prefixed with a process ID, because certain clients
-    -- have a global command registry, and all commands must be
-    -- unique. And there can be more than one ghcide instance running
-    -- at a time against the same client.
-    | T.isSuffixOf blockCommandId _command
-    = do
-        LSP.sendFunc lsp $ NotCustomServer $
-            NotificationMessage "2.0" (CustomServerMethod "ghcide/blocking/command") Null
-        threadDelay maxBound
-        return (Right Null, Nothing)
-    | T.isSuffixOf typeSignatureCommandId _command
-    , Just (List [edit]) <- _arguments
-    , Success wedit <- fromJSON edit
-    = return (Right Null, Just (WorkspaceApplyEdit, ApplyWorkspaceEditParams wedit))
-    | otherwise
-    = return (Right Null, Nothing)
-
 suggestExactAction ::
   ExportsMap ->
   DynFlags ->
@@ -783,31 +719,6 @@ suggestFixConstructorImport _ Diagnostic{_range=_range,..}
   = let fixedImport = typ <> "(" <> constructor <> ")"
     in [("Fix import of " <> fixedImport, [TextEdit _range fixedImport])]
   | otherwise = []
-
-suggestSignature :: Bool -> Diagnostic -> [(T.Text, [TextEdit])]
-suggestSignature isQuickFix Diagnostic{_range=_range@Range{..},..}
-    | _message =~
-      ("(Top-level binding|Polymorphic local binding|Pattern synonym) with no type signature" :: T.Text) = let
-      signature      = removeInitialForAll
-                     $ T.takeWhile (\x -> x/='*' && x/='•')
-                     $ T.strip $ unifySpaces $ last $ T.splitOn "type signature: " $ filterNewlines _message
-      startOfLine    = Position (_line _start) startCharacter
-      beforeLine     = Range startOfLine startOfLine
-      title          = if isQuickFix then "add signature: " <> signature else signature
-      action         = TextEdit beforeLine $ signature <> "\n" <> T.replicate startCharacter " "
-      in [(title, [action])]
-    where removeInitialForAll :: T.Text -> T.Text
-          removeInitialForAll (T.breakOnEnd " :: " -> (nm, ty))
-              | "forall" `T.isPrefixOf` ty = nm <> T.drop 2 (snd (T.breakOn "." ty))
-              | otherwise                  = nm <> ty
-          startCharacter
-            | "Polymorphic local binding" `T.isPrefixOf` _message
-            = _character _start
-            | otherwise
-            = 0
-
-suggestSignature _ _ = []
-
 -- | Suggests a constraint for a declaration for which a constraint is missing.
 suggestConstraint :: DynFlags -> ParsedSource -> Diagnostic -> [(T.Text, Rewrite)]
 suggestConstraint df parsedModule diag@Diagnostic {..}
@@ -1201,21 +1112,6 @@ matchRegex :: T.Text -> T.Text -> Maybe [T.Text]
 matchRegex message regex = case message =~~ regex of
     Just (_ :: T.Text, _ :: T.Text, _ :: T.Text, bindings) -> Just bindings
     Nothing -> Nothing
-
-setHandlersCodeLens :: PartialHandlers c
-setHandlersCodeLens = PartialHandlers $ \WithMessage{..} x -> return x{
-    LSP.codeLensHandler =
-        withResponse RspCodeLens codeLens,
-    LSP.executeCommandHandler =
-        withResponseAndRequest
-            RspExecuteCommand
-            ReqApplyWorkspaceEdit
-            commandHandler
-    }
-
-filterNewlines :: T.Text -> T.Text
-filterNewlines = T.concat  . T.lines
-
 unifySpaces :: T.Text -> T.Text
 unifySpaces    = T.unwords . T.words