fix(core): unhandled rejection in top-level scope (#15204)

Update "deno_core" to not forward rejection of top level module
if it was already handled by appropriate handlers.

Co-authored-by: Colin Ihrig cjihrig@gmail.com

core/bindings.rs

@@ -292,12 +292,20 @@ pub extern "C" fn promise_reject_callback(message: v8::PromiseRejectMessage) {
   // a) asynchronous, and b) always terminates.
   if let Some(js_promise_reject_cb) = state.js_promise_reject_cb.clone() {
     let js_uncaught_exception_cb = state.js_uncaught_exception_cb.clone();
-    drop(state); // Drop borrow, callbacks can call back into runtime.
 
     let tc_scope = &mut v8::TryCatch::new(scope);
     let undefined: v8::Local<v8::Value> = v8::undefined(tc_scope).into();
     let type_ = v8::Integer::new(tc_scope, message.get_event() as i32);
     let promise = message.get_promise();
+    if let Some(pending_mod_evaluate) = state.pending_mod_evaluate.as_mut() {
+      if !pending_mod_evaluate.has_evaluated {
+        let promise_global = v8::Global::new(tc_scope, promise);
+        pending_mod_evaluate
+          .handled_promise_rejections
+          .push(promise_global);
+      }
+    }
+    drop(state); // Drop borrow, callbacks can call back into runtime.
 
     let reason = match message.get_event() {
       PromiseRejectWithNoHandler

core/runtime.rs

@@ -98,7 +98,9 @@ pub(crate) struct DynImportModEvaluate {
 }
 
 pub(crate) struct ModEvaluate {
-  promise: v8::Global<v8::Promise>,
+  pub(crate) promise: Option<v8::Global<v8::Promise>>,
+  pub(crate) has_evaluated: bool,
+  pub(crate) handled_promise_rejections: Vec<v8::Global<v8::Promise>>,
   sender: oneshot::Sender<Result<(), Error>>,
 }
 
@@ -1288,7 +1290,26 @@ impl JsRuntime {
     // For more details see:
     // https://github.com/denoland/deno/issues/4908
     // https://v8.dev/features/top-level-await#module-execution-order
+    {
+      let mut state = state_rc.borrow_mut();
+      assert!(
+        state.pending_mod_evaluate.is_none(),
+        "There is already pending top level module evaluation"
+      );
+      state.pending_mod_evaluate = Some(ModEvaluate {
+        promise: None,
+        has_evaluated: false,
+        handled_promise_rejections: vec![],
+        sender,
+      });
+    }
+
     let maybe_value = module.evaluate(tc_scope);
+    {
+      let mut state = state_rc.borrow_mut();
+      let pending_mod_evaluate = state.pending_mod_evaluate.as_mut().unwrap();
+      pending_mod_evaluate.has_evaluated = true;
+    }
 
     // Update status after evaluating.
     status = module.get_status();
@@ -1297,7 +1318,12 @@ impl JsRuntime {
       state_rc.borrow_mut().explicit_terminate_exception.take();
     if let Some(exception) = explicit_terminate_exception {
       let exception = v8::Local::new(tc_scope, exception);
-      sender
+      let pending_mod_evaluate = {
+        let mut state = state_rc.borrow_mut();
+        state.pending_mod_evaluate.take().unwrap()
+      };
+      pending_mod_evaluate
+        .sender
         .send(exception_to_err_result(tc_scope, exception, false))
         .expect("Failed to send module evaluation error.");
     } else if let Some(value) = maybe_value {
@@ -1311,18 +1337,15 @@ impl JsRuntime {
       let mut state = state_rc.borrow_mut();
       state.pending_promise_exceptions.remove(&promise_global);
       let promise_global = v8::Global::new(tc_scope, promise);
-      assert!(
+      state.pending_mod_evaluate.as_mut().unwrap().promise =
-        state.pending_mod_evaluate.is_none(),
+        Some(promise_global);
-        "There is already pending top level module evaluation"
-      );
-
-      state.pending_mod_evaluate = Some(ModEvaluate {
-        promise: promise_global,
-        sender,
-      });
       tc_scope.perform_microtask_checkpoint();
     } else if tc_scope.has_terminated() || tc_scope.is_execution_terminating() {
-      sender.send(Err(
+      let pending_mod_evaluate = {
+        let mut state = state_rc.borrow_mut();
+        state.pending_mod_evaluate.take().unwrap()
+      };
+      pending_mod_evaluate.sender.send(Err(
         generic_error("Cannot evaluate module, because JavaScript execution has been terminated.")
       )).expect("Failed to send module evaluation error.");
     } else {
@@ -1530,10 +1553,11 @@ impl JsRuntime {
       return;
     }
 
-    let module_evaluation = maybe_module_evaluation.unwrap();
+    let mut module_evaluation = maybe_module_evaluation.unwrap();
     let scope = &mut self.handle_scope();
 
-    let promise = module_evaluation.promise.open(scope);
+    let promise_global = module_evaluation.promise.clone().unwrap();
+    let promise = promise_global.open(scope);
     let promise_state = promise.state();
 
     match promise_state {
@@ -1546,14 +1570,24 @@ impl JsRuntime {
         scope.perform_microtask_checkpoint();
         // Receiver end might have been already dropped, ignore the result
         let _ = module_evaluation.sender.send(Ok(()));
+        module_evaluation.handled_promise_rejections.clear();
       }
       v8::PromiseState::Rejected => {
         let exception = promise.result(scope);
         scope.perform_microtask_checkpoint();
+
         // Receiver end might have been already dropped, ignore the result
-        let _ = module_evaluation
+        if module_evaluation
-          .sender
+          .handled_promise_rejections
-          .send(exception_to_err_result(scope, exception, false));
+          .contains(&promise_global)
+        {
+          let _ = module_evaluation.sender.send(Ok(()));
+          module_evaluation.handled_promise_rejections.clear();
+        } else {
+          let _ = module_evaluation
+            .sender
+            .send(exception_to_err_result(scope, exception, false));
+        }
       }
     }
   }
@@ -3254,6 +3288,95 @@ assertEquals(1, notify_return_value);
     assert_eq!(2, UNCAUGHT_EXCEPTION.load(Ordering::Relaxed));
   }
 
+  #[tokio::test]
+  async fn test_set_promise_reject_callback_top_level_await() {
+    static PROMISE_REJECT: AtomicUsize = AtomicUsize::new(0);
+    static UNCAUGHT_EXCEPTION: AtomicUsize = AtomicUsize::new(0);
+
+    #[op]
+    fn op_promise_reject() -> Result<(), AnyError> {
+      PROMISE_REJECT.fetch_add(1, Ordering::Relaxed);
+      Ok(())
+    }
+
+    #[op]
+    fn op_uncaught_exception() -> Result<(), AnyError> {
+      UNCAUGHT_EXCEPTION.fetch_add(1, Ordering::Relaxed);
+      Ok(())
+    }
+
+    let extension = Extension::builder()
+      .ops(vec![
+        op_promise_reject::decl(),
+        op_uncaught_exception::decl(),
+      ])
+      .build();
+
+    #[derive(Default)]
+    struct ModsLoader;
+
+    impl ModuleLoader for ModsLoader {
+      fn resolve(
+        &self,
+        specifier: &str,
+        referrer: &str,
+        _is_main: bool,
+      ) -> Result<ModuleSpecifier, Error> {
+        assert_eq!(specifier, "file:///main.js");
+        assert_eq!(referrer, ".");
+        let s = crate::resolve_import(specifier, referrer).unwrap();
+        Ok(s)
+      }
+
+      fn load(
+        &self,
+        _module_specifier: &ModuleSpecifier,
+        _maybe_referrer: Option<ModuleSpecifier>,
+        _is_dyn_import: bool,
+      ) -> Pin<Box<ModuleSourceFuture>> {
+        let source = r#"
+        Deno.core.opSync("op_set_promise_reject_callback", (type, promise, reason) => {
+          Deno.core.opSync("op_promise_reject");
+          throw reason;
+        });
+        
+        Deno.core.opSync("op_set_uncaught_exception_callback", (err) => {
+          Deno.core.opSync("op_uncaught_exception");
+        });
+        
+        throw new Error('top level throw');
+        "#;
+
+        async move {
+          Ok(ModuleSource {
+            code: source.as_bytes().to_vec().into_boxed_slice(),
+            module_url_specified: "file:///main.js".to_string(),
+            module_url_found: "file:///main.js".to_string(),
+            module_type: ModuleType::JavaScript,
+          })
+        }
+        .boxed_local()
+      }
+    }
+
+    let mut runtime = JsRuntime::new(RuntimeOptions {
+      extensions: vec![extension],
+      module_loader: Some(Rc::new(ModsLoader)),
+      ..Default::default()
+    });
+
+    let id = runtime
+      .load_main_module(&crate::resolve_url("file:///main.js").unwrap(), None)
+      .await
+      .unwrap();
+    let receiver = runtime.mod_evaluate(id);
+    runtime.run_event_loop(false).await.unwrap();
+    receiver.await.unwrap().unwrap();
+
+    assert_eq!(1, PROMISE_REJECT.load(Ordering::Relaxed));
+    assert_eq!(1, UNCAUGHT_EXCEPTION.load(Ordering::Relaxed));
+  }
+
   #[test]
   fn test_op_return_serde_v8_error() {
     #[op]