fix(core): run macrotasks and next ticks after polling dynamic imports (#17173)

This commit fixes handling of rejected promises in dynamic imports
evaluation.

Previously we were running callbacks for next ticks and macrotasks
_before_ polling
dynamic imports and checked for unhandled rejections immediately after.
This is wrong,
as `unhandledrejection` event is dispatched and its callbacks are run as
macrotasks.

This commit changes order of actions performed by the event loop to
following:
- poll async ops
- poll dynamic imports
- run next tick callbacks
- run macrotask callbacks
- check for unhandled promise rejections

cli/tests/run_tests.rs

@@ -2945,6 +2945,19 @@ mod run {
     output: "run/unhandled_rejection_sync_error.ts.out",
   });
 
+  // Regression test for https://github.com/denoland/deno/issues/15661
+  itest!(unhandled_rejection_dynamic_import {
+    args: "run --allow-read run/unhandled_rejection_dynamic_import/main.ts",
+    output: "run/unhandled_rejection_dynamic_import/main.ts.out",
+    exit_code: 1,
+  });
+
+  // Regression test for https://github.com/denoland/deno/issues/16909
+  itest!(unhandled_rejection_dynamic_import2 {
+    args: "run --allow-read run/unhandled_rejection_dynamic_import2/main.ts",
+    output: "run/unhandled_rejection_dynamic_import2/main.ts.out",
+  });
+
   itest!(nested_error {
     args: "run run/nested_error.ts",
     output: "run/nested_error.ts.out",

cli/tests/testdata/run/unhandled_rejection_dynamic_import/import.ts

@@ -0,0 +1,5 @@
+globalThis.addEventListener("unhandledrejection", () => {
+  console.log("hey");
+});
+console.log("---");
+Promise.reject();

cli/tests/testdata/run/unhandled_rejection_dynamic_import/main.ts

@@ -0,0 +1 @@
+await import("./import.ts");

cli/tests/testdata/run/unhandled_rejection_dynamic_import/main.ts.out

@@ -0,0 +1,3 @@
+---
+hey
+error: Uncaught (in promise) undefined

cli/tests/testdata/run/unhandled_rejection_dynamic_import2/import.ts

@@ -0,0 +1,3 @@
+export default {
+  a: "a",
+};

cli/tests/testdata/run/unhandled_rejection_dynamic_import2/main.ts

@@ -0,0 +1,21 @@
+globalThis.addEventListener("unhandledrejection", (e) => {
+  console.log("unhandled rejection", e.reason);
+  e.preventDefault();
+});
+
+const dummyImport = (await import("./import.ts")).default;
+
+let a = new Promise((resolve, reject) => {
+  throw "errA";
+});
+
+let i = 0;
+while (true) {
+  await new Promise((resolve) => setTimeout(resolve, 100));
+  i++;
+  console.log("running...");
+
+  if (i > 3) {
+    break;
+  }
+}

cli/tests/testdata/run/unhandled_rejection_dynamic_import2/main.ts.out

@@ -0,0 +1,5 @@
+unhandled rejection errA
+running...
+running...
+running...
+running...

core/runtime.rs

@@ -1127,12 +1127,7 @@ impl JsRuntime {
     self.pump_v8_message_loop()?;
 
     // Ops
-    {
     self.resolve_async_ops(cx)?;
-      self.drain_nexttick()?;
-      self.drain_macrotasks()?;
-      self.check_promise_exceptions()?;
-    }
     // Dynamic module loading - ie. modules loaded using "import()"
     {
       // Run in a loop so that dynamic imports that only depend on another
@@ -1157,9 +1152,13 @@ impl JsRuntime {
           break;
         }
       }
-
-      self.check_promise_exceptions()?;
     }
+    // Run all next tick callbacks and macrotasks callbacks and only then
+    // check for any promise exceptions (`unhandledrejection` handlers are
+    // run in macrotasks callbacks so we need to let them run first).
+    self.drain_nexttick()?;
+    self.drain_macrotasks()?;
+    self.check_promise_exceptions()?;
 
     // Event loop middlewares
     let mut maybe_scheduling = false;