Bug 255873 – REGRESSION: iOS layout tests intermittently failing with TypeError: 'NoneType' object is not subscriptable in _test_passes_fuzzy_matching

• Status: RESOLVED
• Resolution: FIXED
• Component: Tools / Tests

[Ryan Haddad]

iOS layout tests on EWS appear to be intermittently failing with the following exception:

Traceback (most recent call last):
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py", line 92, in main
    run_details = run(port, options, args, stderr)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py", line 522, in run
    run_details = manager.run(args)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py", line 413, in run
    temp_initial_results, temp_retry_results, temp_enabled_pixel_tests_in_retry = self._run_test_subset(test_inputs, device_type=device_type)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py", line 487, in _run_test_subset
    initial_results = self._run_tests(test_inputs, self._options.repeat_each, self._options.iterations, int(self._options.child_processes), retrying=False, device_type=device_type)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py", line 570, in _run_tests
    return self._runner.run_tests(self._expectations[device_type], new_test_inputs, num_workers, retrying, device_type)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 180, in run_tests
    pool.wait()
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/libraries/webkitcorepy/webkitcorepy/task_pool.py", line 432, in wait
    self.queue.receive()(self)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/libraries/webkitcorepy/webkitcorepy/task_pool.py", line 134, in __call__
    reraise(*self.exc_info)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/libraries/autoinstalled/python-3-arm64/six.py", line 702, in reraise
    raise value.with_traceback(tb)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/libraries/webkitcorepy/webkitcorepy/task_pool.py", line 303, in main
    queue.send(_Result(value=task(None), id=task.id))
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/libraries/webkitcorepy/webkitcorepy/task_pool.py", line 56, in __call__
    return self.function(*self.args, **self.kwargs)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 77, in run_shard
    return Worker.instance.run_tests(shard)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 319, in run_tests
    Worker.instance.run_test(input, shard.name)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 347, in run_test
    result = self._run_test_with_or_without_timeout(test_input, test_timeout_sec, stop_when_done)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 404, in _run_test_with_or_without_timeout
    return self._run_test_in_this_thread(test_input, stop_when_done)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 490, in _run_test_in_this_thread
    return self._run_single_test(self._driver, test_input, stop_when_done)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 493, in _run_single_test
    return single_test_runner.run_single_test(
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 48, in run_single_test
    return runner.run()
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 123, in run
    return self._run_reftest()
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 370, in _run_reftest
    test_result = self._compare_output_with_reference(reference_output, test_output, reference_filename, expectation == '!=')
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 476, in _compare_output_with_reference
    diff_result.passed = self._test_passes_fuzzy_matching(fuzzy_tolerance, diff_result.fuzzy_data)
  File "/Volumes/Data/worker/iOS-16-Simulator-WPT-WK2-Tests-EWS/build/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 431, in _test_passes_fuzzy_matching
    actualMaxDifference = fuzzy_result['max_difference']
TypeError: 'NoneType' object is not subscriptable (from worker/0)

https://ews-build.webkit.org/#/builders/39/builds/1913/steps/17/logs/stdio

[Ryan Haddad]

I think this is a new issue that may have started when we updated to iOS 16.4 and/or moved to new macOS hardware.

[Radar WebKit Bug Importer]

<rdar://problem/108455505>

[Ryan Haddad]

https://ews-build.webkit.org/#/builders/15/builds/4729 happened here on all three layout test attempts.

[Aakash Jain]

Pull request: https://github.com/WebKit/WebKit/pull/13412

[EWS]

Committed 263649@main (2e9ec190c7f6): <https://commits.webkit.org/263649@main>

Reviewed commits have been landed. Closing PR #13412 and removing active labels.

[Ryan Haddad]

Re-opening for pull request https://github.com/apple/WebKit/pull/593

[EWS]

Committed 259548.750@safari-7615-branch (47c1f159af10): <https://commits.webkit.org/259548.750@safari-7615-branch>

Reviewed commits have been landed. Closing PR #593 and removing active labels.