fix(inspector): send "isDefault" in aux data (#16836)

With trial and error I found that most debuggers expect "isDefault" to be sent
in "auxData" field of "executionContextCreated" notification. This stems from
the fact that Node.js sends this data and eg. VSCode requires it to close
connection to the debugger when the program finishes execution.

cli/tools/repl/session.rs

@@ -92,17 +92,19 @@ impl ReplSession {
     for notification in session.notifications() {
       let method = notification.get("method").unwrap().as_str().unwrap();
       let params = notification.get("params").unwrap();
-
       if method == "Runtime.executionContextCreated" {
-        context_id = params
-          .get("context")
+        let context = params.get("context").unwrap();
+        assert!(context
+          .get("auxData")
           .unwrap()
-          .get("id")
+          .get("isDefault")
           .unwrap()
-          .as_u64()
-          .unwrap();
+          .as_bool()
+          .unwrap());
+        context_id = context.get("id").unwrap().as_u64().unwrap();
       }
     }
+    assert_ne!(context_id, 0);
 
     let mut repl_session = ReplSession {
       worker,

core/inspector.rs

@@ -150,6 +150,7 @@ impl JsRuntimeInspector {
   pub fn new(
     isolate: &mut v8::OwnedIsolate,
     context: v8::Global<v8::Context>,
+    is_main: bool,
   ) -> Rc<RefCell<Self>> {
     let scope = &mut v8::HandleScope::new(isolate);
 
@@ -183,13 +184,26 @@ impl JsRuntimeInspector {
     // Tell the inspector about the global context.
     let context = v8::Local::new(scope, context);
     let context_name = v8::inspector::StringView::from(&b"global context"[..]);
-    let aux_data = v8::inspector::StringView::from(&b""[..]);
+    // NOTE(bartlomieju): this is what Node.js does and it turns out some
+    // debuggers (like VSCode) rely on this information to disconnect after
+    // program completes
+    let aux_data = if is_main {
+      r#"{"isDefault": true}"#
+    } else {
+      r#"{"isDefault": false}"#
+    };
+    let aux_data_view = v8::inspector::StringView::from(aux_data.as_bytes());
     self_
       .v8_inspector
       .borrow_mut()
       .as_mut()
       .unwrap()
-      .context_created(context, Self::CONTEXT_GROUP_ID, context_name, aux_data);
+      .context_created(
+        context,
+        Self::CONTEXT_GROUP_ID,
+        context_name,
+        aux_data_view,
+      );
 
     // Poll the session handler so we will get notified whenever there is
     // new incoming debugger activity.

core/runtime.rs

@@ -88,6 +88,8 @@ pub struct JsRuntime {
   allocations: IsolateAllocations,
   extensions: Vec<Extension>,
   event_loop_middlewares: Vec<Box<OpEventLoopFn>>,
+  // Marks if this is considered the top-level runtime. Used only be inspector.
+  is_main: bool,
 }
 
 pub(crate) struct DynImportModEvaluate {
@@ -274,7 +276,13 @@ pub struct RuntimeOptions {
   /// [CompiledWasmModuleStore]. If no [CompiledWasmModuleStore] is specified,
   /// `WebAssembly.Module` objects cannot be serialized.
   pub compiled_wasm_module_store: Option<CompiledWasmModuleStore>,
+
+  /// Start inspector instance to allow debuggers to connect.
   pub inspector: bool,
+
+  /// Describe if this is the main runtime instance, used by debuggers in some
+  /// situation - like disconnecting when program finishes running.
+  pub is_main: bool,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -498,6 +506,7 @@ impl JsRuntime {
       Some(JsRuntimeInspector::new(
         &mut isolate,
         global_context.clone(),
+        options.is_main,
       ))
     } else {
       None
@@ -532,6 +541,7 @@ impl JsRuntime {
       extensions: options.extensions,
       state: state_rc,
       module_map: Some(module_map_rc),
+      is_main: options.is_main,
     };
 
     // Init resources and ops before extensions to make sure they are
@@ -949,6 +959,7 @@ impl JsRuntime {
     state.inspector = Some(JsRuntimeInspector::new(
       self.v8_isolate.as_mut().unwrap(),
       state.global_realm.clone().unwrap().0,
+      self.is_main,
     ));
   }
 

runtime/worker.rs

@@ -240,6 +240,7 @@ impl MainWorker {
       compiled_wasm_module_store: options.compiled_wasm_module_store.clone(),
       extensions,
       inspector: options.maybe_inspector_server.is_some(),
+      is_main: true,
       ..Default::default()
     });