inspector: report when main context is destroyed

PR-URL: nodejs#12814
Reimplements: nodejs#7756
Fixes: nodejs#7742
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>

src/inspector_agent.cc

@@ -271,11 +271,6 @@ class NodeInspectorClient : public v8_inspector::V8InspectorClient {
                                                 terminated_(false),
                                                 running_nested_loop_(false) {
     inspector_ = V8Inspector::create(env->isolate(), this);
-    const uint8_t CONTEXT_NAME[] = "Node.js Main Context";
-    StringView context_name(CONTEXT_NAME, sizeof(CONTEXT_NAME) - 1);
-    v8_inspector::V8ContextInfo info(env->context(), CONTEXT_GROUP_ID,
-                                     context_name);
-    inspector_->contextCreated(info);
   }
 
   void runMessageLoopOnPause(int context_group_id) override {
@@ -296,6 +291,17 @@ class NodeInspectorClient : public v8_inspector::V8InspectorClient {
     return uv_hrtime() * 1.0 / NANOS_PER_MSEC;
   }
 
+  void contextCreated(Local<Context> context, const std::string& name) {
+    std::unique_ptr<StringBuffer> name_buffer = Utf8ToStringView(name);
+    v8_inspector::V8ContextInfo info(context, CONTEXT_GROUP_ID,
+                                     name_buffer->string());
+    inspector_->contextCreated(info);
+  }
+
+  void contextDestroyed(Local<Context> context) {
+    inspector_->contextDestroyed(context);
+  }
+
   void quitMessageLoopOnPause() override {
     terminated_ = true;
   }
@@ -379,6 +385,7 @@ bool Agent::Start(v8::Platform* platform, const char* path,
   inspector_ =
       std::unique_ptr<NodeInspectorClient>(
           new NodeInspectorClient(parent_env_, platform));
+  inspector_->contextCreated(parent_env_->context(), "Node.js Main Context");
   platform_ = platform;
   if (options.inspector_enabled()) {
     return StartIoThread();
@@ -451,6 +458,8 @@ bool Agent::IsStarted() {
 }
 
 void Agent::WaitForDisconnect() {
+  CHECK_NE(inspector_, nullptr);
+  inspector_->contextDestroyed(parent_env_->context());
   if (io_ != nullptr) {
     io_->WaitForDisconnect();
   }

test/inspector/test-inspector.js

@@ -87,6 +87,13 @@ function setupExpectValue(value) {
   };
 }
 
+function setupExpectContextDestroyed(id) {
+  return function(message) {
+    if ('Runtime.executionContextDestroyed' === message['method'])
+      return message['params']['executionContextId'] === id;
+  };
+}
+
 function testBreakpointOnStart(session) {
   console.log('[test]',
               'Verifying debugger stops on start (--inspect-brk option)');
@@ -203,6 +210,7 @@ function testI18NCharacters(session) {
 function testWaitsForFrontendDisconnect(session, harness) {
   console.log('[test]', 'Verify node waits for the frontend to disconnect');
   session.sendInspectorCommands({ 'method': 'Debugger.resume'})
+    .expectMessages(setupExpectContextDestroyed(1))
     .expectStderrOutput('Waiting for the debugger to disconnect...')
     .disconnect(true);
 }