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

1 files changed, 7 insertions, 8 deletions

diff --git a/core/runtime.rs b/core/runtime.rs
index 2e417bb9d..f735f5575 100644
--- a/core/runtime.rs
+++ b/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()?;
-    }
+    self.resolve_async_ops(cx)?;
     // 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;