Taskcluster frequently failing trying to fetch Firefox profile

[gsnedders]

See the master branch https://github.com/web-platform-tests/wpt/runs/42387737071 or the tools/ integration tests https://github.com/web-platform-tests/wpt/pull/52455/checks?check_run_id=42357970828, both of which failed with:

Traceback (most recent call last):
  File "/home/test/web-platform-tests/./wpt", line 10, in <module>
    wpt.main()
  File "/home/test/web-platform-tests/tools/wpt/wpt.py", line 233, in main
    rv = script(*args, **kwargs)
  File "/home/test/web-platform-tests/tools/wpt/run.py", line 1007, in run
    setup_cls, wptrunner_kwargs = setup_wptrunner(venv, **kwargs)
  File "/home/test/web-platform-tests/tools/wpt/run.py", line 979, in setup_wptrunner
    setup_cls.setup(kwargs)
  File "/home/test/web-platform-tests/tools/wpt/run.py", line 246, in setup
    self.setup_kwargs(kwargs)
  File "/home/test/web-platform-tests/tools/wpt/run.py", line 318, in setup_kwargs
    prefs_root = self.browser.install_prefs(kwargs["binary"],
  File "/home/test/web-platform-tests/tools/wpt/browser.py", line 528, in install_prefs
    self.get_profile_github(version, channel, dest, rev)
  File "/home/test/web-platform-tests/tools/wpt/browser.py", line 484, in get_profile_github
    file_data[rel_path] = get_file_github("mozilla-firefox/firefox",
  File "/home/test/web-platform-tests/tools/wpt/browser.py", line 87, in get_file_github
    data: bytes = get(f"https://raw.githubusercontent.com/{repo}/{ref}/{path}").content  # type: ignore
  File "/home/test/web-platform-tests/tools/wpt/utils.py", line 109, in get
    resp.raise_for_status()
  File "/home/test/web-platform-tests/_venv3/lib/python3.10/site-packages/requests/models.py", line 1024, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 429 Client Error: Too Many Requests for url: https://raw.githubusercontent.com/mozilla-firefox/firefox/main/testing/profiles/base/user.js

[gsnedders]

We don't seem to do any rate-limited when fetching files from GitHub, which is quite possibly the problem.

[jonathan-j-lee]

This is causing wpt-firefox-nightly-* to fail regularly:

• https://github.com/web-platform-tests/wpt/pull/52650/checks?check_run_id=42512158059
• https://github.com/web-platform-tests/wpt/pull/52648/checks?check_run_id=42508394709
• https://github.com/web-platform-tests/wpt/runs/42389395235

@jgraham Would it be possible to vendor copies of profiles.json and user.js for WPT CI? Just guessing from the contents, but it doesn't look like they will change very frequently.

[gsnedders]

(Regression from 1af206e / #52391.)

[gsnedders]

https://github.com/web-platform-tests/wpt/pulls?q=is%3Apr++status%3Afailure+created%3A2025-05-13..2025-05-20 shows a lot of CI failures of the past week.