Enable console for vscode-js-debug

* Fix some bugs in case DAP process doesn't exist
* Buffer streams by default so they're not discarded when received
before console shows

org.eclipse.lsp4e.debug/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: Debug Adapter client for Eclipse IDE (Incubation)
 Bundle-SymbolicName: org.eclipse.lsp4e.debug;singleton:=true
-Bundle-Version: 0.15.4.qualifier
+Bundle-Version: 0.15.5.qualifier
 Bundle-Activator: org.eclipse.lsp4e.debug.DSPPlugin
 Require-Bundle: org.eclipse.ui,
  org.eclipse.core.runtime,

org.eclipse.lsp4e.debug/src/org/eclipse/lsp4e/debug/console/DSPProcess.java

@@ -36,7 +36,7 @@ public DSPProcess(DSPDebugTarget dspDebugTarget, ProcessEventArguments args) {
 		this.target = dspDebugTarget;
 		this.proxy = new DSPStreamsProxy(target.getDebugProtocolServer());
 		this.processArgs = args;
-		handle = ProcessHandle.of(args.getSystemProcessId());
+		handle = args != null && args.getSystemProcessId() != null ? ProcessHandle.of(args.getSystemProcessId()) : Optional.empty();
 	}
 
 	@Override

org.eclipse.lsp4e.debug/src/org/eclipse/lsp4e/debug/console/DSPStreamMonitor.java

@@ -17,7 +17,7 @@ public class DSPStreamMonitor implements IFlushableStreamMonitor {
 
 	private final ListenerList<IStreamListener> listeners = new ListenerList<>();
 	private final StringBuilder stream = new StringBuilder();
-	private boolean buffer;
+	private boolean buffer = true; // buffer by default as first output can happen before listeners are in place
 
 	@Override
 	public String getContents() {

org.eclipse.lsp4e.debug/src/org/eclipse/lsp4e/debug/debugmodel/DSPDebugTarget.java

@@ -556,7 +556,11 @@ public DSPThread[] getThreads() {
 			}
 		}
 		try {
-			CompletableFuture<ThreadsResponse> threads2 = getDebugProtocolServer().threads();
+			var server = getDebugProtocolServer();
+			if (server == null) {
+				return new DSPThread[0];
+			}
+			CompletableFuture<ThreadsResponse> threads2 = server.threads();
 			CompletableFuture<DSPThread[]> future = threads2.thenApplyAsync(threadsResponse -> {
 				synchronized (threads) {
 					final var lastThreads = new TreeMap<Integer, DSPThread>(threads);
@@ -628,18 +632,20 @@ public void thread(ThreadEventArguments args) {
 	@Override
 	public void output(OutputEventArguments args) {
 		boolean outputted = false;
-		if (process != null) {
-			DSPStreamsProxy dspStreamsProxy = process.getStreamsProxy();
-			String output = args.getOutput();
-			if (args.getCategory() == null || OutputEventArgumentsCategory.CONSOLE.equals(args.getCategory())
-					|| OutputEventArgumentsCategory.STDOUT.equals(args.getCategory())) {
-				// TODO put this data in a different region with a different colour
-				dspStreamsProxy.getOutputStreamMonitor().append(output);
-				outputted = true;
-			} else if (OutputEventArgumentsCategory.STDERR.equals(args.getCategory())) {
-				dspStreamsProxy.getErrorStreamMonitor().append(output);
-				outputted = true;
-			}
+		DSPStreamsProxy dspStreamsProxy;
+		if (process == null) {
+			process(null); // create dummy process to have a console
+		}
+		dspStreamsProxy = process.getStreamsProxy();
+		String output = args.getOutput();
+		if (args.getCategory() == null || OutputEventArgumentsCategory.CONSOLE.equals(args.getCategory())
+				|| OutputEventArgumentsCategory.STDOUT.equals(args.getCategory())) {
+			// TODO put this data in a different region with a different colour
+			dspStreamsProxy.getOutputStreamMonitor().append(output);
+			outputted = true;
+		} else if (OutputEventArgumentsCategory.STDERR.equals(args.getCategory())) {
+			dspStreamsProxy.getErrorStreamMonitor().append(output);
+			outputted = true;
 		}
 		if (!outputted && DSPPlugin.DEBUG) {
 			System.out.println("output: " + args);