Invert the dependency between ghcide and hls-plugin-api

This PR includes changes both to ghcide and HLS to implement the reorg described in https://github.com/haskell/ghcide/issues/936#issuecomment-751437853

To summarise:

- `hls-plugin-api` no longer depends on ghcide.
- `ghcide` now depends on `hls-plugin-api` and exposes:
  - The ghcide HLS plugin
  - The `asGhcIdePlugin` adaptor

The goals are:
- to be able to break the `ghcide` HLS plugin down
- to rewrite exe:ghcide on top of the HLS plugin model.

The ghcide side is reviewed in haskell/ghcide#963

If this change is accepted there are two further considerations:
- This would be a good moment to merge the 2 repos, so that there is no history loss.
- `hls-plugin-api` will need to be released to Hackage prior to merging haskell/ghcide#963

Author: pepeiborra

exe/Plugins.hs

@@ -3,12 +3,13 @@
 module Plugins where
 
 import           Ide.Types                 (IdePlugins)
-import           Ide.Plugin                (pluginDescToIdePlugins)
+import           Ide.PluginUtils           (pluginDescToIdePlugins)
 
 -- fixed plugins
 import           Ide.Plugin.Example        as Example
 import           Ide.Plugin.Example2       as Example2
-import           Ide.Plugin.GhcIde         as GhcIde
+import           Development.IDE           (IdeState)
+import           Development.IDE.Plugin.GhcIde as GhcIde
 
 -- haskell-language-server optional plugins
 
@@ -73,7 +74,7 @@ import           Ide.Plugin.Brittany       as Brittany
 -- These can be freely added or removed to tailor the available
 -- features of the server.
 
-idePlugins :: Bool -> IdePlugins
+idePlugins :: Bool -> IdePlugins IdeState
 idePlugins includeExamples = pluginDescToIdePlugins allPlugins
   where
     allPlugins = if includeExamples

ghcide/ghcide.cabal

@@ -56,6 +56,8 @@ library
         haskell-lsp-types == 0.22.*,
         haskell-lsp == 0.22.*,
         hie-compat,
+        hls-plugin-api,
+        lens,
         mtl,
         network-uri,
         parallel,
@@ -127,7 +129,6 @@ library
         include
     exposed-modules:
         Development.IDE
-        Development.IDE.Compat
         Development.IDE.Core.Debouncer
         Development.IDE.Core.FileStore
         Development.IDE.Core.IdeConfiguration
@@ -163,6 +164,9 @@ library
         Development.IDE.Plugin
         Development.IDE.Plugin.Completions
         Development.IDE.Plugin.CodeAction
+        Development.IDE.Plugin.Formatter
+        Development.IDE.Plugin.GhcIde
+        Development.IDE.Plugin.HLS
         Development.IDE.Plugin.Test
 
     -- Unfortunately, we cannot use loadSession with ghc-lib since hie-bios uses

ghcide/src/Development/IDE.hs

@@ -9,6 +9,7 @@ module Development.IDE
 import Development.IDE.Core.RuleTypes as X
 import Development.IDE.Core.Rules as X
   (getAtPoint
+  ,getClientConfigAction
   ,getDefinition
   ,getParsedModule
   ,getTypeDefinition

ghcide/src/Development/IDE/Compat.hs

@@ -88,4 +88,4 @@ isWorkspaceFile file =
           workspaceFolders
 
 getClientSettings :: Action (Maybe Value)
-getClientSettings = unhashed . clientSettings <$> getIdeConfiguration
+getClientSettings = unhashed . clientSettings <$> getIdeConfiguration

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

@@ -27,11 +27,14 @@ module Development.IDE.Core.Rules(
     highlightAtPoint,
     getDependencies,
     getParsedModule,
+    getClientConfigAction,
     ) where
 
 import Fingerprint
 
+import Data.Aeson (fromJSON, Result(Success), FromJSON)
 import Data.Binary hiding (get, put)
+import Data.Default
 import Data.Tuple.Extra
 import Control.Monad.Extra
 import Control.Monad.Trans.Class
@@ -890,6 +893,15 @@ getClientSettingsRule = defineEarlyCutOffNoFile $ \GetClientSettings -> do
   settings <- clientSettings <$> getIdeConfiguration
   return (BS.pack . show . hash $ settings, settings)
 
+-- | Returns the client configurarion stored in the IdeState.
+-- You can use this function to access it from shake Rules
+getClientConfigAction :: (Default a, FromJSON a) => Action a
+getClientConfigAction = do
+  mbVal <- unhashed <$> useNoFile_ GetClientSettings
+  case fromJSON <$> mbVal of
+    Just (Success c) -> return c
+    _ -> return def
+
 -- | For now we always use bytecode
 getLinkableType :: NormalizedFilePath -> Action (Maybe LinkableType)
 getLinkableType f = do

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

@@ -1,14 +1,17 @@
-
-module Development.IDE.Plugin(Plugin(..), codeActionPlugin, codeActionPluginWithRules,makeLspCommandId,getPid) where
+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           Language.Haskell.LSP.Types
-import Development.IDE.Compat
 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
 
@@ -50,11 +53,5 @@ codeActionPluginWithRules rr f = Plugin rr $ PartialHandlers $ \WithMessage{..}
 --   on that.
 makeLspCommandId :: T.Text -> IO T.Text
 makeLspCommandId command = do
-    pid <- getPid
-    return $ pid <> ":ghcide:" <> command
-
--- | Get the operating system process id for the running server
--- instance. This should be the same for the lifetime of the instance,
--- and different from that of any other currently running instance.
-getPid :: IO T.Text
-getPid = T.pack . show <$> getProcessID
+    pid <- getProcessID
+    return $ T.pack (show pid) <> ":ghcide:" <> command

ghcide/src/Development/IDE/Plugin.hs

@@ -4,20 +4,17 @@
 {-# LANGUAGE TypeApplications #-}
 {-# LANGUAGE ViewPatterns #-}
 
-module Ide.Plugin.Formatter
+module Development.IDE.Plugin.Formatter
   (
     formatting
   , rangeFormatting
-  , noneProvider
-  , responseError
-  , extractRange
-  , fullRange
   )
 where
 
 import qualified Data.Map  as Map
 import qualified Data.Text as T
 import           Development.IDE
+import           Ide.PluginUtils
 import           Ide.Types
 import           Ide.Plugin.Config
 import qualified Language.Haskell.LSP.Core as LSP
@@ -26,7 +23,7 @@ import           Text.Regex.TDFA.Text()
 
 -- ---------------------------------------------------------------------
 
-formatting :: Map.Map PluginId (FormattingProvider IO)
+formatting :: Map.Map PluginId (FormattingProvider IdeState IO)
            -> LSP.LspFuncs Config -> IdeState -> DocumentFormattingParams
            -> IO (Either ResponseError (List TextEdit))
 formatting providers lf ideState
@@ -35,7 +32,7 @@ formatting providers lf ideState
 
 -- ---------------------------------------------------------------------
 
-rangeFormatting :: Map.Map PluginId (FormattingProvider IO)
+rangeFormatting :: Map.Map PluginId (FormattingProvider IdeState IO)
                 -> LSP.LspFuncs Config -> IdeState -> DocumentRangeFormattingParams
                 -> IO (Either ResponseError (List TextEdit))
 rangeFormatting providers lf ideState
@@ -44,7 +41,7 @@ rangeFormatting providers lf ideState
 
 -- ---------------------------------------------------------------------
 
-doFormatting :: LSP.LspFuncs Config -> Map.Map PluginId (FormattingProvider IO)
+doFormatting :: LSP.LspFuncs Config -> Map.Map PluginId (FormattingProvider IdeState IO)
              -> IdeState -> FormattingType -> Uri -> FormattingOptions
              -> IO (Either ResponseError (List TextEdit))
 doFormatting lf providers ideState ft uri params = do
@@ -76,35 +73,3 @@ doFormatting lf providers ideState ft uri params = do
           else ""
         ]
 
--- ---------------------------------------------------------------------
-
-noneProvider :: FormattingProvider IO
-noneProvider _ _ _ _ _ _ = return $ Right (List [])
-
--- ---------------------------------------------------------------------
-
-responseError :: T.Text -> ResponseError
-responseError txt = ResponseError InvalidParams txt Nothing
-
--- ---------------------------------------------------------------------
-
-extractRange :: Range -> T.Text -> T.Text
-extractRange (Range (Position sl _) (Position el _)) s = newS
-  where focusLines = take (el-sl+1) $ drop sl $ T.lines s
-        newS = T.unlines focusLines
-
--- | Gets the range that covers the entire text
-fullRange :: T.Text -> Range
-fullRange s = Range startPos endPos
-  where startPos = Position 0 0
-        endPos = Position lastLine 0
-        {-
-        In order to replace everything including newline characters,
-        the end range should extend below the last line. From the specification:
-        "If you want to specify a range that contains a line including
-        the line ending character(s) then use an end position denoting
-        the start of the next line"
-        -}
-        lastLine = length $ T.lines s
-
--- ---------------------------------------------------------------------

hls-plugin-api/src/Ide/Plugin/Formatter.hs renamed to ghcide/src/Development/IDE/Plugin/Formatter.hs

@@ -1,6 +1,6 @@
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE OverloadedStrings #-}
-module Ide.Plugin.GhcIde
+module Development.IDE.Plugin.GhcIde
   (
     descriptor
   ) where
@@ -11,14 +11,14 @@ import Development.IDE.Plugin.Completions
 import Development.IDE.Plugin.CodeAction
 import Development.IDE.LSP.HoverDefinition
 import Development.IDE.LSP.Outline
-import Ide.Plugin
+import Ide.PluginUtils
 import Ide.Types
 import Language.Haskell.LSP.Types
 import Text.Regex.TDFA.Text()
 
 -- ---------------------------------------------------------------------
 
-descriptor :: PluginId -> PluginDescriptor
+descriptor :: PluginId -> PluginDescriptor IdeState
 descriptor plId = (defaultPluginDescriptor plId)
   { pluginCommands = [PluginCommand (CommandId "typesignature.add") "adds a signature" commandAddSignature]
   , pluginCodeActionProvider = Just codeAction'
@@ -30,30 +30,30 @@ descriptor plId = (defaultPluginDescriptor plId)
 
 -- ---------------------------------------------------------------------
 
-hover' :: HoverProvider
+hover' :: HoverProvider IdeState
 hover' ideState params = do
     logInfo (ideLogger ideState) "GhcIde.hover entered (ideLogger)" -- AZ
     hover ideState params
 
 -- ---------------------------------------------------------------------
 
-commandAddSignature :: CommandFunction WorkspaceEdit
+commandAddSignature :: CommandFunction IdeState WorkspaceEdit
 commandAddSignature lf ide params
     = commandHandler lf ide (ExecuteCommandParams "typesignature.add" (Just (List [toJSON params])) Nothing)
 
 -- ---------------------------------------------------------------------
 
-codeAction' :: CodeActionProvider
+codeAction' :: CodeActionProvider IdeState
 codeAction' lf ide _ doc range context = fmap List <$> codeAction lf ide doc range context
 
 -- ---------------------------------------------------------------------
 
-codeLens' :: CodeLensProvider
+codeLens' :: CodeLensProvider IdeState
 codeLens' lf ide _ params = codeLens lf ide params
 
 -- ---------------------------------------------------------------------
 
-symbolsProvider :: SymbolsProvider
+symbolsProvider :: SymbolsProvider IdeState
 symbolsProvider ls ide params = do
     ds <- moduleOutline ls ide params
     case ds of