Add code action for incorrect field names

Author: dyniec

plugins/hls-cabal-plugin/hls-cabal-plugin.cabal

@@ -26,6 +26,7 @@ library
     Ide.Plugin.Cabal
     Ide.Plugin.Cabal.Diagnostics
     Ide.Plugin.Cabal.LicenseSuggest
+    Ide.Plugin.Cabal.FieldSuggest
     Ide.Plugin.Cabal.Parse
 
   build-depends:

plugins/hls-cabal-plugin/src/Ide/Plugin/Cabal.hs

@@ -26,6 +26,7 @@ import qualified Development.IDE.Core.Shake      as Shake
 import           GHC.Generics
 import qualified Ide.Plugin.Cabal.Diagnostics    as Diagnostics
 import qualified Ide.Plugin.Cabal.LicenseSuggest as LicenseSuggest
+import qualified Ide.Plugin.Cabal.FieldSuggest as FieldSuggest
 import qualified Ide.Plugin.Cabal.Parse          as Parse
 import           Ide.Plugin.Config               (Config)
 import           Ide.Types
@@ -74,6 +75,7 @@ descriptor recorder plId = (defaultCabalPluginDescriptor plId)
   { pluginRules = cabalRules recorder
   , pluginHandlers = mkPluginHandler STextDocumentCodeAction licenseSuggestCodeAction 
                       <> mkPluginHandler J.STextDocumentCompletion completion
+                      <> mkPluginHandler STextDocumentCodeAction fieldSuggestCodeAction
   , pluginNotificationHandlers = mconcat
   [ mkPluginNotificationHandler LSP.STextDocumentDidOpen $
       \ide vfs _ (DidOpenTextDocumentParams TextDocumentItem{_uri,_version}) -> liftIO $ do
@@ -363,4 +365,12 @@ buildCompletion :: T.Text -> J.CompletionItem
 buildCompletion label =
   J.CompletionItem label (Just J.CiKeyword) Nothing Nothing
     Nothing Nothing Nothing Nothing Nothing Nothing Nothing
-    Nothing Nothing Nothing Nothing Nothing Nothing
+    Nothing Nothing Nothing Nothing Nothing Nothing
+fieldSuggestCodeAction
+  :: IdeState
+  -> PluginId
+  -> CodeActionParams
+  -> LspM Config (Either ResponseError (ResponseResult 'TextDocumentCodeAction))
+
+fieldSuggestCodeAction _ _ (CodeActionParams _ _ (TextDocumentIdentifier uri) _range CodeActionContext{_diagnostics=List diags}) =
+  pure $ Right $ List $ diags >>=(fmap InR . FieldSuggest.fieldErrorAction uri) 

plugins/hls-cabal-plugin/src/Ide/Plugin/Cabal/FieldSuggest.hs

@@ -0,0 +1,69 @@
+{-# LANGUAGE AllowAmbiguousTypes #-}
+{-# LANGUAGE ExplicitNamespaces  #-}
+{-# LANGUAGE FlexibleContexts    #-}
+{-# LANGUAGE LambdaCase          #-}
+{-# LANGUAGE OverloadedStrings   #-}
+module Ide.Plugin.Cabal.FieldSuggest
+( fieldErrorSuggestion
+, fieldErrorAction
+  -- * Re-exports
+, T.Text
+, Diagnostic(..)
+)
+where
+
+import qualified Data.HashMap.Strict as Map
+import qualified Data.Text           as T
+import           Language.LSP.Types  (CodeAction (CodeAction),
+                                      CodeActionKind (CodeActionQuickFix),
+                                      Diagnostic (..), List (List),
+                                      Position (Position), Range (Range),
+                                      TextEdit (TextEdit), Uri,
+                                      WorkspaceEdit (WorkspaceEdit))
+import           Text.Regex.TDFA
+
+-- | Given a diagnostic returned by 'Ide.Plugin.Cabal.Diag.errorDiagnostic',
+--   if it represents an "Unknown field"-error along
+--   with a incorrect field, then return a 'CodeAction' for replacing the
+--   the incorrect field with the suggestion.
+--   It should be context sensitive, but for now it isn't
+fieldErrorAction
+  :: Uri
+  -- ^ File for which the diagnostic was generated
+  -> Diagnostic
+  -- ^ Output of 'Ide.Plugin.Cabal.Diag.errorDiagnostic'
+  ->  [CodeAction]
+fieldErrorAction uri diag =
+  mkCodeAction <$> fieldErrorSuggestion diag
+  where
+    mkCodeAction (original, suggestion) =
+      let
+        -- Range returned by cabal here represents fragment from start of 
+        -- offending identifier to end of line, we modify it to the end of identifier
+        adjustRange (Range rangeFrom@(Position line col) _) =
+          Range rangeFrom (Position line (col + fromIntegral (T.length original)))
+        title = "Replace with " <> suggestion
+        tedit = [TextEdit (adjustRange $ _range diag) suggestion]
+        edit  = WorkspaceEdit (Just $ Map.singleton uri $ List tedit) Nothing Nothing
+      in CodeAction title (Just CodeActionQuickFix) (Just $ List []) Nothing Nothing (Just edit) Nothing Nothing
+
+-- | Given a diagnostic returned by 'Ide.Plugin.Cabal.Diag.errorDiagnostic',
+--   if it represents an "Unknown field"- error with incorrect identifier
+--   then return the suggestion (for now placeholder "name")
+--   along with the incorrect identifier.
+--   
+fieldErrorSuggestion
+  :: Diagnostic
+  -- ^ Output of 'Ide.Plugin.Cabal.Diag.errorDiagnostic'
+  -> [(T.Text, T.Text)]
+  -- ^ (Original (incorrect) license identifier, suggested replacement)
+fieldErrorSuggestion diag =
+  mSuggestion (_message diag) >>= \case
+    [original] -> [(original, "name")]
+    _                      -> []
+  where
+    regex :: T.Text
+    regex = "Unknown field: \"(.*)\""
+    mSuggestion msg = getMatch <$> (msg :: T.Text) =~~ regex
+    getMatch :: (T.Text, T.Text, T.Text, [T.Text]) -> [T.Text]
+    getMatch (_, _, _, results) = results