From 0f72ef0584b3974d052e08f5738bcec5cf5b5924 Mon Sep 17 00:00:00 2001
From: Dmitry Gozman <dgozman@gmail.com>
Date: Mon, 25 Sep 2023 10:59:14 -0700
Subject: [PATCH] fix(streams): avoid leaking event listeners (#27291)

Fixes #26998.
---
 .../src/server/dispatchers/streamDispatcher.ts   | 16 ++++++++++------
 tests/library/chromium/tracing.spec.ts           | 10 +++++++++-
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/packages/playwright-core/src/server/dispatchers/streamDispatcher.ts b/packages/playwright-core/src/server/dispatchers/streamDispatcher.ts
index 53f14fbfdd..4a45468389 100644
--- a/packages/playwright-core/src/server/dispatchers/streamDispatcher.ts
+++ b/packages/playwright-core/src/server/dispatchers/streamDispatcher.ts
@@ -17,7 +17,7 @@
 import type * as channels from '@protocol/channels';
 import { Dispatcher } from './dispatcher';
 import type * as stream from 'stream';
-import { createGuid } from '../../utils';
+import { ManualPromise, createGuid } from '../../utils';
 import type { ArtifactDispatcher } from './artifactDispatcher';
 
 export class StreamDispatcher extends Dispatcher<{ guid: string, stream: stream.Readable }, channels.StreamChannel, ArtifactDispatcher> implements channels.StreamChannel {
@@ -36,11 +36,15 @@ export class StreamDispatcher extends Dispatcher<{ guid: string, stream: stream.
     if (this._ended)
       return { binary: Buffer.from('') };
     if (!stream.readableLength) {
-      await new Promise((fulfill, reject) => {
-        stream.once('readable', fulfill);
-        stream.once('end', fulfill);
-        stream.once('error', reject);
-      });
+      const readyPromise = new ManualPromise<void>();
+      const done = () => readyPromise.resolve();
+      stream.on('readable', done);
+      stream.on('end', done);
+      stream.on('error', done);
+      await readyPromise;
+      stream.off('readable', done);
+      stream.off('end', done);
+      stream.off('error', done);
     }
     const buffer = stream.read(Math.min(stream.readableLength, params.size || stream.readableLength));
     return { binary: buffer || Buffer.from('') };
diff --git a/tests/library/chromium/tracing.spec.ts b/tests/library/chromium/tracing.spec.ts
index 07bfdec534..a39f21ba27 100644
--- a/tests/library/chromium/tracing.spec.ts
+++ b/tests/library/chromium/tracing.spec.ts
@@ -19,13 +19,21 @@ import fs from 'fs';
 import path from 'path';
 
 it('should output a trace', async ({ browser, server }, testInfo) => {
+  let warning = null;
+  const warningHandler = w => warning = w;
+  process.on('warning', warningHandler);
+
   const page = await browser.newPage();
   const outputTraceFile = testInfo.outputPath(path.join(`trace.json`));
   await browser.startTracing(page, { screenshots: true, path: outputTraceFile });
-  await page.goto(server.PREFIX + '/grid.html');
+  for (let i = 0; i < 20; i++)
+    await page.goto(server.PREFIX + '/grid.html');
   await browser.stopTracing();
   expect(fs.existsSync(outputTraceFile)).toBe(true);
   await page.close();
+
+  process.off('warning', warningHandler);
+  expect(warning).toBe(null);
 });
 
 it('should create directories as needed', async ({ browser, server }, testInfo) => {