Use configured gson instance for toString

This is important when users have registered custom type adapters

Fixes eclipse-lsp4j#768

CHANGELOG.md

@@ -6,6 +6,9 @@ Fixed issues: <https://github.com/eclipse-lsp4j/lsp4j/milestone/29?closed=1>
 
 Breaking API changes:
 
+  * The Message class now has a new transient field, `jsonHandler` to enable the `toString` implementation to properly format messages when custom type adapters are in used.
+    * For consumers that have their own custom serializers they may need to be updated to ensure that transient fields are skipped, for example by using [`Modifier.isTransient`](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/reflect/Modifier.html#isTransient(int))
+    * See [#768](https://github.com/eclipse-lsp4j/lsp4j/issues/768) for detailed discussion.
   * The name field in WorkspaceFolder is no longer optional according to the specification.
     * See [#741](https://github.com/eclipse-lsp4j/lsp4j/issues/741) for detailed discussion.
 

org.eclipse.lsp4j.jsonrpc.debug/src/main/java/org/eclipse/lsp4j/jsonrpc/debug/DebugLauncher.java

@@ -218,6 +218,7 @@ protected RemoteEndpoint createRemoteEndpoint(MessageJsonHandler jsonHandler) {
 			else
 				remoteEndpoint = new DebugRemoteEndpoint(outgoingMessageStream, localEndpoint, exceptionHandler);
 			jsonHandler.setMethodProvider(remoteEndpoint);
+			remoteEndpoint.setJsonHandler(jsonHandler);
 			return remoteEndpoint;
 		}
 

org.eclipse.lsp4j.jsonrpc.debug/src/main/java/org/eclipse/lsp4j/jsonrpc/debug/DebugRemoteEndpoint.java

@@ -38,6 +38,7 @@ public DebugRemoteEndpoint(MessageConsumer out, Endpoint localEndpoint,
 	@Override
 	protected DebugRequestMessage createRequestMessage(String method, Object parameter) {
 		DebugRequestMessage requestMessage = new DebugRequestMessage();
+		requestMessage.setJsonHandler(getJsonHandler());
 		requestMessage.setId(nextSeqId.incrementAndGet());
 		requestMessage.setMethod(method);
 		requestMessage.setParams(parameter);
@@ -47,6 +48,7 @@ protected DebugRequestMessage createRequestMessage(String method, Object paramet
 	@Override
 	protected DebugResponseMessage createResponseMessage(RequestMessage requestMessage) {
 		DebugResponseMessage responseMessage = new DebugResponseMessage();
+		responseMessage.setJsonHandler(getJsonHandler());
 		responseMessage.setResponseId(nextSeqId.incrementAndGet());
 		responseMessage.setRawId(requestMessage.getRawId());
 		responseMessage.setMethod(requestMessage.getMethod());
@@ -56,6 +58,7 @@ protected DebugResponseMessage createResponseMessage(RequestMessage requestMessa
 	@Override
 	protected DebugNotificationMessage createNotificationMessage(String method, Object parameter) {
 		DebugNotificationMessage notificationMessage = new DebugNotificationMessage();
+		notificationMessage.setJsonHandler(getJsonHandler());
 		notificationMessage.setId(nextSeqId.incrementAndGet());
 		notificationMessage.setMethod(method);
 		notificationMessage.setParams(parameter);

org.eclipse.lsp4j.jsonrpc.debug/src/main/java/org/eclipse/lsp4j/jsonrpc/debug/adapters/DebugMessageTypeAdapter.java

@@ -343,20 +343,23 @@ private Message createMessage(String messageType, int seq, int request_seq, Stri
 		switch (messageType) {
 		case "request": {
 			DebugRequestMessage message = new DebugRequestMessage();
+			message.setJsonHandler(handler);
 			message.setId(seq);
 			message.setMethod(method);
 			message.setParams(params);
 			return message;
 		}
 		case "event": {
 			DebugNotificationMessage message = new DebugNotificationMessage();
+			message.setJsonHandler(handler);
 			message.setId(seq);
 			message.setMethod(method);
 			message.setParams(body);
 			return message;
 		}
 		case "response": {
 			DebugResponseMessage message = new DebugResponseMessage();
+			message.setJsonHandler(handler);
 			message.setId(request_seq);
 			message.setResponseId(seq);
 			message.setMethod(method);

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/Launcher.java

@@ -317,6 +317,9 @@ public Launcher<T> create() {
 
 			// Create the JSON handler, remote endpoint and remote proxy
 			MessageJsonHandler jsonHandler = createJsonHandler();
+			if (messageTracer != null) {
+				messageTracer.setJsonHandler(jsonHandler);
+			}
 			RemoteEndpoint remoteEndpoint = createRemoteEndpoint(jsonHandler);
 			T remoteProxy = createProxy(remoteEndpoint);
 
@@ -352,6 +355,7 @@ protected RemoteEndpoint createRemoteEndpoint(MessageJsonHandler jsonHandler) {
 			else
 				remoteEndpoint = new RemoteEndpoint(outgoingMessageStream, localEndpoint, exceptionHandler);
 			jsonHandler.setMethodProvider(remoteEndpoint);
+			remoteEndpoint.setJsonHandler(jsonHandler);
 			return remoteEndpoint;
 		}
 

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/MessageTracer.java

@@ -11,15 +11,16 @@
  ******************************************************************************/
 package org.eclipse.lsp4j.jsonrpc;
 
-import org.eclipse.lsp4j.jsonrpc.TracingMessageConsumer.RequestMetadata;
-
 import java.io.PrintWriter;
 import java.time.Clock;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Function;
 
+import org.eclipse.lsp4j.jsonrpc.TracingMessageConsumer.RequestMetadata;
+import org.eclipse.lsp4j.jsonrpc.json.MessageJsonHandler;
+
 /**
  * Wraps a {@link MessageConsumer} with one that logs in a way that the LSP Inspector can parse. *
  * https://microsoft.github.io/language-server-protocol/inspector/
@@ -28,14 +29,21 @@ public class MessageTracer implements Function<MessageConsumer, MessageConsumer>
 	private final PrintWriter printWriter;
 	private final Map<String, RequestMetadata> sentRequests = new HashMap<>();
 	private final Map<String, RequestMetadata> receivedRequests = new HashMap<>();
+	private MessageJsonHandler jsonHandler;
 
 	MessageTracer(PrintWriter printWriter) {
 		this.printWriter = Objects.requireNonNull(printWriter);
 	}
 
+	public void setJsonHandler(MessageJsonHandler jsonHandler) {
+		this.jsonHandler = jsonHandler;
+	}
+
 	@Override
 	public MessageConsumer apply(MessageConsumer messageConsumer) {
-		return new TracingMessageConsumer(
+		TracingMessageConsumer tracingMessageConsumer = new TracingMessageConsumer(
 				messageConsumer, sentRequests, receivedRequests, printWriter, Clock.systemDefaultZone());
+		tracingMessageConsumer.setJsonHandler(jsonHandler);
+		return tracingMessageConsumer;
 	}
 }

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/RemoteEndpoint.java

@@ -74,6 +74,7 @@ private static ResponseError fallbackResponseError(String header, Throwable thro
 	private final MessageConsumer out;
 	private final Endpoint localEndpoint;
 	private final Function<Throwable, ResponseError> exceptionHandler;
+	private MessageJsonHandler jsonHandler;
 
 	private final AtomicInteger nextRequestId = new AtomicInteger();
 	private final Map<String, PendingRequestInfo> sentRequestMap = new LinkedHashMap<>();
@@ -116,6 +117,14 @@ public RemoteEndpoint(MessageConsumer out, Endpoint localEndpoint) {
 		this(out, localEndpoint, DEFAULT_EXCEPTION_HANDLER);
 	}
 
+	public void setJsonHandler(MessageJsonHandler jsonHandler) {
+		this.jsonHandler = jsonHandler;
+	}
+
+	public MessageJsonHandler getJsonHandler() {
+		return jsonHandler;
+	}
+
 	/**
 	 * Send a notification to the remote endpoint.
 	 */
@@ -132,6 +141,7 @@ public void notify(String method, Object parameter) {
 
 	protected NotificationMessage createNotificationMessage(String method, Object parameter) {
 		NotificationMessage notificationMessage = new NotificationMessage();
+		notificationMessage.setJsonHandler(getJsonHandler());
 		notificationMessage.setJsonrpc(MessageConstants.JSONRPC_VERSION);
 		notificationMessage.setMethod(method);
 		notificationMessage.setParams(parameter);
@@ -168,6 +178,7 @@ public boolean cancel(boolean mayInterruptIfRunning) {
 
 	protected RequestMessage createRequestMessage(String method, Object parameter) {
 		RequestMessage requestMessage = new RequestMessage();
+		requestMessage.setJsonHandler(getJsonHandler());
 		requestMessage.setId(String.valueOf(nextRequestId.incrementAndGet()));
 		requestMessage.setMethod(method);
 		requestMessage.setParams(parameter);
@@ -361,6 +372,7 @@ protected void handleResponseIssues(ResponseMessage responseMessage, List<Messag
 
 	protected ResponseMessage createResponseMessage(RequestMessage requestMessage) {
 		ResponseMessage responseMessage = new ResponseMessage();
+		responseMessage.setJsonHandler(getJsonHandler());
 		responseMessage.setRawId(requestMessage.getRawId());
 		responseMessage.setJsonrpc(MessageConstants.JSONRPC_VERSION);
 		return responseMessage;

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/TracingMessageConsumer.java

@@ -42,6 +42,7 @@ public class TracingMessageConsumer implements MessageConsumer {
 	private final PrintWriter printWriter;
 	private final Clock clock;
 	private final DateTimeFormatter dateTimeFormatter;
+	private MessageJsonHandler jsonHandler;
 
 	/**
 	 * @param messageConsumer The {@link MessageConsumer} to wrap.
@@ -86,6 +87,10 @@ public TracingMessageConsumer(
 		}
 	}
 
+	public void setJsonHandler(MessageJsonHandler jsonHandler) {
+		this.jsonHandler = jsonHandler;
+	}
+
 	/**
 	 * Constructs a log string for a given {@link Message}. The type of the {@link MessageConsumer}
 	 * determines if we're sending or receiving a message. The type of the @{link Message} determines
@@ -122,33 +127,33 @@ private String consumeMessageSending(Message message, Instant now, String date)
 			RequestMetadata requestMetadata = new RequestMetadata(method, now);
 			sentRequests.put(id, requestMetadata);
 			Object params = requestMessage.getParams();
-			String paramsJson = MessageJsonHandler.toString(params);
+			String paramsJson = toString(params);
 			String format = "[Trace - %s] Sending request '%s - (%s)'\nParams: %s\n\n\n";
 			return String.format(format, date, method, id, paramsJson);
 		} else if (message instanceof ResponseMessage) {
 			ResponseMessage responseMessage = (ResponseMessage) message;
 			String id = responseMessage.getId();
 			RequestMetadata requestMetadata = receivedRequests.remove(id);
 			if (requestMetadata == null) {
-				LOG.log(WARNING, String.format("Unmatched response message: %s", message));
+				LOG.log(WARNING, String.format("Unmatched response message: %s", toString(message)));
 				return null;
 			}
 			String method = requestMetadata.method;
 			long latencyMillis = now.toEpochMilli() - requestMetadata.start.toEpochMilli();
 			Object result = responseMessage.getResult();
-			String resultJson = MessageJsonHandler.toString(result);
+			String resultJson = toString(result);
 			String format =
 					"[Trace - %s] Sending response '%s - (%s)'. Processing request took %sms\nResult: %s\n\n\n";
 			return String.format(format, date, method, id, latencyMillis, resultJson);
 		} else if (message instanceof NotificationMessage) {
 			NotificationMessage notificationMessage = (NotificationMessage) message;
 			String method = notificationMessage.getMethod();
 			Object params = notificationMessage.getParams();
-			String paramsJson = MessageJsonHandler.toString(params);
+			String paramsJson = toString(params);
 			String format = "[Trace - %s] Sending notification '%s'\nParams: %s\n\n\n";
 			return String.format(format, date, method, paramsJson);
 		} else {
-			LOG.log(WARNING, String.format("Unknown message type: %s", message));
+			LOG.log(WARNING, String.format("Unknown message type: %s", toString(message)));
 			return null;
 		}
 	}
@@ -161,38 +166,42 @@ private String consumeMessageReceiving(Message message, Instant now, String date
 			RequestMetadata requestMetadata = new RequestMetadata(method, now);
 			receivedRequests.put(id, requestMetadata);
 			Object params = requestMessage.getParams();
-			String paramsJson = MessageJsonHandler.toString(params);
+			String paramsJson = toString(params);
 			String format = "[Trace - %s] Received request '%s - (%s)'\nParams: %s\n\n\n";
 			return String.format(format, date, method, id, paramsJson);
 		} else if (message instanceof ResponseMessage) {
 			ResponseMessage responseMessage = (ResponseMessage) message;
 			String id = responseMessage.getId();
 			RequestMetadata requestMetadata = sentRequests.remove(id);
 			if (requestMetadata == null) {
-				LOG.log(WARNING, String.format("Unmatched response message: %s", message));
+				LOG.log(WARNING, String.format("Unmatched response message: %s", toString(message)));
 				return null;
 			}
 			String method = requestMetadata.method;
 			long latencyMillis = now.toEpochMilli() - requestMetadata.start.toEpochMilli();
 			Object result = responseMessage.getResult();
-			String resultJson = MessageJsonHandler.toString(result);
+			String resultJson = toString(result);
 			Object error = responseMessage.getError();
-			String errorJson = MessageJsonHandler.toString(error);
+			String errorJson = toString(error);
 			String format = "[Trace - %s] Received response '%s - (%s)' in %sms\nResult: %s\nError: %s\n\n\n";
 			return String.format(format, date, method, id, latencyMillis, resultJson, errorJson);
 		} else if (message instanceof NotificationMessage) {
 			NotificationMessage notificationMessage = (NotificationMessage) message;
 			String method = notificationMessage.getMethod();
 			Object params = notificationMessage.getParams();
-			String paramsJson = MessageJsonHandler.toString(params);
+			String paramsJson = toString(params);
 			String format = "[Trace - %s] Received notification '%s'\nParams: %s\n\n\n";
 			return String.format(format, date, method, paramsJson);
 		} else {
-			LOG.log(WARNING, String.format("Unknown message type: %s", message));
+			LOG.log(WARNING, String.format("Unknown message type: %s", toString(message)));
 			return null;
 		}
 	}
 
+	private String toString(Object object) {
+		return jsonHandler != null ? jsonHandler.format(object) : MessageJsonHandler.toString(object);
+	}
+
 	/** Data class for holding pending request metadata. */
 	public static class RequestMetadata {
 		final String method;

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/json/MessageJsonHandler.java

@@ -35,9 +35,11 @@
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonIOException;
+import com.google.gson.JsonNull;
 import com.google.gson.JsonParseException;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonToken;
+import com.google.gson.stream.JsonWriter;
 import com.google.gson.stream.MalformedJsonException;
 
 /**
@@ -48,7 +50,7 @@ public class MessageJsonHandler {
 	public static final JsonRpcMethod CANCEL_METHOD = JsonRpcMethod.notification("$/cancelRequest", CancelParams.class);
 
 	private final Gson gson;
-	
+
 	private final Map<String, JsonRpcMethod> supportedMethods;
 
 	private MethodProvider methodProvider;
@@ -119,6 +121,8 @@ public Message parseMessage(Reader input) throws JsonParseException {
 		Message message = gson.fromJson(jsonReader, Message.class);
 
 		if (message != null) {
+			message.setJsonHandler(this);
+
 			// Check whether the input has been fully consumed
 			try {
 				if (jsonReader.peek() != JsonToken.END_DOCUMENT) {
@@ -144,10 +148,32 @@ public String serialize(Message message) {
 	public void serialize(Message message, Writer output) throws JsonIOException {
 		gson.toJson(message, Message.class, output);
 	}
-
-
+
+	/**
+	 * Perform JSON serialization of the given object using the configuration of JSON-RPC messages
+	 * enhanced with the pretty printing option.
+	 */
+	public String format(Object object) {
+		StringWriter writer = new StringWriter();
+		JsonWriter jsonWriter = null;
+		try {
+			jsonWriter = gson.newJsonWriter(writer);
+			// Equivalent to set pretty printing on the gson builder
+			jsonWriter.setIndent("  ");
+		} catch (IOException e) {
+			throw new JsonIOException(e);
+		}
+		if (object != null) {
+			gson.toJson(object, object.getClass(), jsonWriter);
+		} else {
+			gson.toJson(JsonNull.INSTANCE, jsonWriter);
+		}
+		return writer.toString();
+	}
+
+
 	private static MessageJsonHandler toStringInstance;
-	
+
 	/**
 	 * Perform JSON serialization of the given object using the default configuration of JSON-RPC messages
 	 * enhanced with the pretty printing option.
@@ -160,5 +186,5 @@ public static String toString(Object object) {
 		}
 		return toStringInstance.gson.toJson(object);
 	}
-	
+
 }

org.eclipse.lsp4j.jsonrpc/src/main/java/org/eclipse/lsp4j/jsonrpc/json/adapters/MessageTypeAdapter.java

@@ -379,13 +379,15 @@ protected Message createMessage(String jsonrpc, Either<String, Number> id, Strin
 			Object responseResult, ResponseError responseError) throws JsonParseException {
 		if (id != null && method != null) {
 			RequestMessage message = new RequestMessage();
+			message.setJsonHandler(handler);
 			message.setJsonrpc(jsonrpc);
 			message.setRawId(id);
 			message.setMethod(method);
 			message.setParams(params);
 			return message;
 		} else if (id != null) {
 			ResponseMessage message = new ResponseMessage();
+			message.setJsonHandler(handler);
 			message.setJsonrpc(jsonrpc);
 			message.setRawId(id);
 			if (responseError != null)
@@ -395,6 +397,7 @@ protected Message createMessage(String jsonrpc, Either<String, Number> id, Strin
 			return message;
 		} else if (method != null) {
 			NotificationMessage message = new NotificationMessage();
+			message.setJsonHandler(handler);
 			message.setJsonrpc(jsonrpc);
 			message.setMethod(method);
 			message.setParams(params);