[CI] nightly job test-conda-python-emscripten intermittently times out loading PyArrow in Chrome

[tadeja]

Describe the bug, including details regarding any error messages, version, and platform.

Follow-up to #50424 / #50425.
Nightly job test-conda-python-emscripten now successfully installs Chrome, see success logs 2026-07-18 Docker Test conda-python-emscripten

But the same job can intermittently hang while loading PyArrow in browser driver.load_arrow()
selenium.common.exceptions.TimeoutException: Message: script timeout
See failure logs examples:
2026-07-19 Docker Test conda-python-emscripten
and
2026-07-20 Docker Test conda-python-emscripten

Details

-------------- Running emscripten tests in Chrome --------------------
+ python scripts/run_emscripten_tests.py dist/pyarrow-26.0.0.dev13-cp312-cp312-pyemscripten_2024_0_wasm32.whl --dist-dir=/pyodide --runtime=chrome
127.0.0.1 - - [20/Jul/2026 04:28:17] code 404, message File not found
HTTP 404 for /favicon.ico
Traceback (most recent call last):
  File "/build/python/scripts/run_emscripten_tests.py", line 345, in <module>
dist dir=/pyodide
    _load_pyarrow_in_runner(driver, Path(args.wheel).name)
  File "/build/python/scripts/run_emscripten_tests.py", line 281, in _load_pyarrow_in_runner
    driver.load_arrow()
  File "/build/python/scripts/run_emscripten_tests.py", line 212, in load_arrow
    self.execute_python(
  File "/build/python/scripts/run_emscripten_tests.py", line 219, in execute_python
    self.driver.execute_async_script(
  File "/opt/conda/envs/arrow/lib/python3.12/site-packages/selenium/webdriver/remote/webdriver.py", line 551, in execute_async_script
    return self.execute(command, {"script": script, "args": converted_args})["value"]
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/arrow/lib/python3.12/site-packages/selenium/webdriver/remote/webdriver.py", line 446, in execute
    self.error_handler.check_response(response)
  File "/opt/conda/envs/arrow/lib/python3.12/site-packages/selenium/webdriver/remote/errorhandler.py", line 232, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.TimeoutException: Message: script timeout
  (Session info: chrome=150.0.7871.128)
Stacktrace:
#0 0x5621b39b449a <unknown>
#1 0x5621b338c680 <unknown>
#2 0x5621b342bcde <unknown>
#3 0x5621b342a55d <unknown>
#4 0x5621b33d53ff <unknown>
#5 0x5621b33d6261 <unknown>
#6 0x5621b3979d17 <unknown>
#7 0x5621b39784f8 <unknown>
#8 0x5621b39631e6 <unknown>
#9 0x5621b39790ba <unknown>
#10 0x5621b394b070 <unknown>
#11 0x5621b399fbe8 <unknown>
#12 0x5621b399fd85 <unknown>
#13 0x5621b39b304e <unknown>
#14 0x7fd6c0710aa4 <unknown>
#15 0x7fd6c079da64 __clone

Starting server for /pyodide at: ('127.0.0.1', 43055)
Load pyodide in browser
Load pyarrow in browser

Error: `docker compose --file=/home/runner/work/crossbow/crossbow/arrow/compose.yaml run --rm -e SETUPTOOLS_SCM_PRETEND_VERSION=26.0.0.dev13 conda-python-emscripten` exited with a non-zero exit code 1, see the process log above.

Component(s)

Continuous Integration

[raulcd]

Issue resolved by pull request 50598
#50598