[Bug]: sessionattached events no longer emitted on parent session

[adamraine]

Minimal, reproducible example

import puppeteer from 'puppeteer';

const browser = await puppeteer.launch({
  headless: false,
  defaultViewport: null,
  ignoreDefaultArgs: ['--enable-automation'],
});
const page = await browser.newPage();
const session = await page.target().createCDPSession();
await session.send('Target.setAutoAttach', {
  autoAttach: true,
  waitForDebuggerOnStart: true,
  flatten: true,
});
session.on('sessionattached', () => {
  console.log('EMITTED');
});

await page.goto('http://localhost:10200/oopif-scripts.html', {
  waitUntil: ['networkidle0'],
});

await page.close();
await browser.close();

Error string

N/A

Bug behavior

• Flaky
• PDF

Background

Lighthouse looks for these events to get sessions for child targets:
https://github.com/GoogleChrome/lighthouse/blob/main/core/gather/driver/target-manager.js#L149

Expectation

sessionattached events are emitted and console logs "EMITTED"

Reality

sessionattached events are not emitted and console does not log

Puppeteer configuration file (if used)

No response

Puppeteer version

21.3.0

Node version

18.17.0

Package manager

yarn

Package manager version

1.22.19

Operating system

macOS

[github-actions]

This issue was not reproducible. Please check that your example runs locally and the following:

• Ensure the script does not rely on dependencies outside of puppeteer and puppeteer-core.
• Ensure the error string is just the error message.

  • Bad:

    Error: something went wrong
      at Object.<anonymous> (/Users/username/repository/script.js:2:1)
      at Module._compile (node:internal/modules/cjs/loader:1159:14)
      at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)
      at Module.load (node:internal/modules/cjs/loader:1037:32)
      at Module._load (node:internal/modules/cjs/loader:878:12)
      at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
      at node:internal/main/run_main_module:23:47

  • Good: Error: something went wrong.

• Ensure your configuration file (if applicable) is valid.
• If the issue is flaky (does not reproduce all the time), make sure 'Flaky' is checked.
• If the issue is not expected to error, make sure to write 'no error'.

Once the above checks are satisfied, please edit your issue with the changes and we will
try to reproduce the bug again.

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