Fix ambiguous Either type when parsing unresolved code action (#485)

Fixes #484

Signed-off-by: Vladimir Piskarev <[email protected]>

Author: pisv

org.eclipse.lsp4j/src/main/java/org/eclipse/lsp4j/adapters/CodeActionResponseAdapter.java

@@ -23,7 +23,6 @@
 
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
 import com.google.gson.JsonPrimitive;
 import com.google.gson.TypeAdapter;
 import com.google.gson.TypeAdapterFactory;
@@ -38,7 +37,7 @@ public class CodeActionResponseAdapter implements TypeAdapterFactory {
 	@Override
 	public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
 		Predicate<JsonElement> leftChecker = new PropertyChecker("command", JsonPrimitive.class);
-		Predicate<JsonElement> rightChecker = new PropertyChecker("edit").or(new PropertyChecker("command", JsonObject.class));
+		Predicate<JsonElement> rightChecker = new PropertyChecker("title");
 		TypeAdapter<Either<Command, CodeAction>> elementTypeAdapter = new EitherTypeAdapter<>(gson,
 				ELEMENT_TYPE, leftChecker, rightChecker);
 		return (TypeAdapter<T>) new CollectionTypeAdapter<>(gson, ELEMENT_TYPE.getType(), elementTypeAdapter, ArrayList::new);

org.eclipse.lsp4j/src/test/java/org/eclipse/lsp4j/test/services/JsonParseTest.xtend

@@ -488,6 +488,34 @@ class JsonParseTest {
 		])
 	}
 
+	@Test
+	def void testCodeActionResponse3() {
+		jsonHandler.methodProvider = [ id |
+			switch id {
+				case '12': MessageMethods.DOC_CODE_ACTION
+			}
+		]
+		'''
+			{
+				"jsonrpc": "2.0",
+				"id": "12",
+				"result": [
+					{
+						"title": "fixme"
+					}
+				]
+			}
+		'''.assertParse(new ResponseMessage => [
+			jsonrpc = "2.0"
+			id = "12"
+			result = newArrayList(Either.forRight(
+				new CodeAction => [
+					title = "fixme"
+				]
+			))
+		])
+	}
+
 	@Test
 	def void testPrepareRenameResponse1() {
 		jsonHandler.methodProvider = [ id |