watch: handled race conditions while relaying events from worker

Author: SudhansuBandha

lib/internal/worker.js

@@ -338,21 +338,28 @@ class Worker extends EventEmitter {
 
     this[kPublicPort] = publicPortToParent;
     ArrayPrototypeForEach(['message', 'messageerror'], (event) => {
-      this[kPublicPort].on(event, (message) => this.emit(event, message));
+      this[kPublicPort].on(event, (message) => {
+        // Extract watch messages first if needed and relay events from worker thread to watcher
+        if (
+          event === 'message' &&
+          process.env.WATCH_REPORT_DEPENDENCIES &&
+          process.send
+        ) {
+          const { isMainThread } = internalBinding('worker');
+          if (isMainThread) {
+            if (ArrayIsArray(message?.['watch:require'])) {
+              process.send({ 'watch:require': message['watch:require'] });
+            }
+            if (ArrayIsArray(message?.['watch:import'])) {
+              process.send({ 'watch:import': message['watch:import'] });
+            }
+          }
+        }
+        this.emit(event, message);
+      });
     });
     setupPortReferencing(this[kPublicPort], this, 'message');
 
-    // Relay events from worker thread to watcher
-    if (process.env.WATCH_REPORT_DEPENDENCIES && process.send) {
-      this[kPublicPort].on('message', (message) => {
-        if (ArrayIsArray(message?.['watch:require'])) {
-          process.send({ 'watch:require': message['watch:require'] });
-        }
-        if (ArrayIsArray(message?.['watch:import'])) {
-          process.send({ 'watch:import': message['watch:import'] });
-        }
-      });
-    }
     this[kPort].postMessage({
       argv,
       type: messageTypes.LOAD_SCRIPT,