[Bug]: Accept-Language from setExtraHTTPHeaders ignored in redirects with new headless mode

[mathbruyen]

Bug expectation

After setting Accept-Language header with setExtraHTTPHeaders, I expected the header to overridden set on all requests.

The header is sent on initial request but on redirects the header takes its default value (en-US,en;q=0.9).

Reproducer in docker: reproducer.zip

Bug behavior

• [ ] Flaky
• [ ] PDF

Minimal, reproducible example

const http = require('node:http');
const puppeteer = require('puppeteer');

(async function () {
  const server = http.createServer((req, res) => {
    console.log(req.url, ' => ', req.headers['accept-language']);
    if (req.url === '/') {
      res.writeHead(302, {
        'location': '/redirected',
      });
    }
    res.end();
  });
  try {
    server.listen(8000);

    const oldHeadless = await puppeteer.launch({
      headless: 'old',
      args: [
        '--no-sandbox',
      ],
    });
    try {
      const oldHeadlessContext = await oldHeadless.createIncognitoBrowserContext();
      const oldPage = await oldHeadlessContext.newPage();
      await oldPage.setExtraHTTPHeaders({'Accept-Language': 'fr'});
      console.log('old mode');
      await oldPage.goto(`http://localhost:8000/`);
    } finally {
      await oldHeadless.close();
    }

    const newHeadless = await puppeteer.launch({
      headless: 'new',
      args: [
        '--no-sandbox',
      ],
    });
    try {
      const newHeadlessContext = await newHeadless.createIncognitoBrowserContext();
      const newPage = await newHeadlessContext.newPage();
      await newPage.setExtraHTTPHeaders({'Accept-Language': 'fr'});
      console.log('new mode');
      await newPage.goto(`http://localhost:8000/`);
    } finally {
      await newHeadless.close();
    }
  } finally {
    server.close();
  }
})();

Error string

Print "/redirected => fr" for both old/new headless mode

Puppeteer configuration

No response

Puppeteer version

20.3.0

Node version

20.2.0

Package manager

npm

Package manager version

9.6.6

Operating system

Linux

[github-actions[bot]]

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.

---

Analyzer run

[OrKoN]

The new headless behaviour matches the headful behaviour so the issue is not headless mode specific.

[OrKoN]

Upstream https://crbug.com/1448205