Fixes #10170

src/bun.js/bindings/webcore/EventEmitter.cpp

@@ -183,8 +183,18 @@ void EventEmitter::fireEventListeners(const Identifier& eventType, const MarkedA
         return;
 
     auto* listenersVector = data->eventListenerMap.find(eventType);
-    if (UNLIKELY(!listenersVector))
+    if (UNLIKELY(!listenersVector)) {
+        if (eventType == scriptExecutionContext()->vm().propertyNames->error && arguments.size() > 0) {
+            Ref<EventEmitter> protectedThis(*this);
+            auto* thisObject = protectedThis->m_thisObject.get();
+            if (!thisObject)
+                return;
+
+            Bun__reportUnhandledError(thisObject->globalObject(), JSValue::encode(arguments.at(0)));
+            return;
+        }
         return;
+    }
 
     bool prevFiringEventListeners = data->isFiringEventListeners;
     data->isFiringEventListeners = true;
@@ -207,6 +217,11 @@ void EventEmitter::innerInvokeEventListeners(const Identifier& eventType, Simple
     auto* thisObject = protectedThis->m_thisObject.get();
     JSC::JSValue thisValue = thisObject ? JSC::JSValue(thisObject) : JSC::jsUndefined();
 
+    if (UNLIKELY(listeners.isEmpty() && eventType == vm.propertyNames->error) && arguments.size() > 0) {
+        Bun__reportUnhandledError(thisObject->globalObject(), JSValue::encode(arguments.at(0)));
+        return;
+    }
+
     for (auto& registeredListener : listeners) {
         if (UNLIKELY(registeredListener->wasRemoved()))
             continue;

src/js/node/child_process.ts

@@ -456,14 +456,11 @@ function exec(command, options, callback) {
   return execFile(opts.file, opts.options, opts.callback);
 }
 
+const kCustomPromisifySymbol = Symbol.for("nodejs.util.promisify.custom");
+
 const customPromiseExecFunction = orig => {
   return (...args) => {
-    let resolve;
-    let reject;
-    const promise = new Promise((res, rej) => {
-      resolve = res;
-      reject = rej;
-    });
+    const { resolve, reject, promise } = Promise.withResolvers();
 
     promise.child = orig(...args, (err, stdout, stderr) => {
       if (err !== null) {
@@ -479,12 +476,22 @@ const customPromiseExecFunction = orig => {
   };
 };
 
-Object.defineProperty(exec, Symbol.for("nodejs.util.promisify.custom"), {
+Object.defineProperty(exec, kCustomPromisifySymbol, {
   __proto__: null,
   configurable: true,
   value: customPromiseExecFunction(exec),
 });
 
+exec[kCustomPromisifySymbol][kCustomPromisifySymbol] = exec[kCustomPromisifySymbol];
+
+Object.defineProperty(execFile, kCustomPromisifySymbol, {
+  __proto__: null,
+  configurable: true,
+  value: customPromiseExecFunction(execFile),
+});
+
+execFile[kCustomPromisifySymbol][kCustomPromisifySymbol] = execFile[kCustomPromisifySymbol];
+
 /**
  * Spawns a new process synchronously using the given `file`.
  * @param {string} file

test/js/node/stream/node-stream.test.js

@@ -598,3 +598,19 @@ it("emits newListener event _before_ adding the listener", () => {
   stream.on("foo", () => {});
   expect(cb).toHaveBeenCalled();
 });
+
+it("reports error", () => {
+  expect(() => {
+    const dup = new Duplex({
+      read() {
+        this.push("Hello World!\n");
+        this.push(null);
+      },
+      write(chunk, encoding, callback) {
+        callback(new Error("test"));
+      },
+    });
+
+    dup.emit("error", new Error("test"));
+  }).toThrow("test");
+});

test/regression/issue/10170.test.ts

@@ -0,0 +1,11 @@
+import { test, expect } from "bun:test";
+import { bunExe } from "harness";
+import { execFile } from "node:child_process";
+import util from "node:util";
+
+test("issue 10170", async () => {
+  const execFileAsync = util.promisify(execFile);
+  const result = await execFileAsync(bunExe(), ["--version"]);
+  expect(result.stdout).toContain(Bun.version);
+  expect(result.stderr).toBe("");
+});