Open
Description
Bug summary
We've previously not been installing Qt wrappers such as PyQt6 or PySide. #27723 adds those back, but we have discovered that test_other_signal_before_sigint fails on CI. The subprocess appears to segfault somewhere in the Qt event loop.
I had tried to debug it with c1afbac, but then it stopped failing. Reverting that change then failed again, though one time it passed. So this seems to be fairly flaky.
I went through all CI runs, and found that this is not particularly limited to any parametrization:
4 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtcairo-QT_API=PyQt6-BACKEND_DEPS=PyQt6,cairocffi] _
3 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtcairo-QT_API=PySide6-BACKEND_DEPS=PySide6,cairocffi] _
3 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtcairo-QT_API=PyQt5-BACKEND_DEPS=PyQt5,cairocffi] _
3 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtagg-QT_API=PyQt6-BACKEND_DEPS=PyQt6] _
2 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtcairo-QT_API=PySide2-BACKEND_DEPS=PySide2,cairocffi] _
2 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtagg-QT_API=PySide6-BACKEND_DEPS=PySide6] _
1 _ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtagg-QT_API=PySide2-BACKEND_DEPS=PySide2] _
Unfortunately, I don't think @tacaswell was able to reproduce the crash, and @ksunden was only able to reproduce once, but only as part of a full test suite, and never again later in a smaller run.
So as part of #27723, I've marked these as xfail, but if we can figure out a way to reproduce, we should be able to fix this.
Code for reproduction
pytest -k test_other_signal_before_sigint lib/matplotlib/tests/test_backends_interactive.pyActual outcome
_ test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtagg-QT_API=PySide6-BACKEND_DEPS=PySide6] _
[gw1] darwin -- Python 3.12.2 /Library/Frameworks/Python.framework/Versions/3.12/bin/python
env = {'BACKEND_DEPS': 'PySide6', 'MPLBACKEND': 'qtagg', 'QT_API': 'PySide6'}
target = 'show', kwargs = {'block': True}
request = <FixtureRequest for <Function test_other_signal_before_sigint[show-kwargs0-MPLBACKEND=qtagg-QT_API=PySide6-BACKEND_DEPS=PySide6]>>
@pytest.mark.skipif(sys.platform == 'win32',
reason='No other signal available to send on Windows')
@pytest.mark.parametrize("env", _get_testable_interactive_backends())
@pytest.mark.parametrize("target, kwargs", [
('show', {'block': True}),
('pause', {'interval': 10})
])
def test_other_signal_before_sigint(env, target, kwargs, request):
backend = env.get("MPLBACKEND")
if not backend.startswith(("qt", "macosx")):
pytest.skip("SIGINT currently only tested on qt and macosx")
if backend == "macosx":
request.node.add_marker(pytest.mark.xfail(reason="macosx backend is buggy"))
proc = _WaitForStringPopen(
[sys.executable, "-c",
inspect.getsource(_test_other_signal_before_sigint_impl) +
"\n_test_other_signal_before_sigint_impl("
f"{backend!r}, {target!r}, {kwargs!r})"])
try:
proc.wait_for('DRAW')
os.kill(proc.pid, signal.SIGUSR1)
proc.wait_for('SIGUSR1')
os.kill(proc.pid, signal.SIGINT)
stdout, _ = proc.communicate(timeout=_test_timeout)
except Exception:
proc.kill()
stdout, _ = proc.communicate()
raise
print(stdout)
> assert 'SUCCESS' in stdout
E AssertionError
/Users/runner/work/matplotlib/matplotlib/lib/matplotlib/tests/test_backends_interactive.py:790: AssertionError
----------------------------- Captured stdout call -----------------------------
----------------------------- Captured stderr call -----------------------------
Fatal Python error: Segmentation fault
Current thread 0x00000001d88a9c40 (most recent call first):
File "/Users/runner/work/matplotlib/matplotlib/lib/matplotlib/backends/qt_compat.py", line 159 in _exec
File "/Users/runner/work/matplotlib/matplotlib/lib/matplotlib/backends/backend_qt.py", line 633 in start_main_loop
File "/Users/runner/work/matplotlib/matplotlib/lib/matplotlib/backend_bases.py", line 3536 in show
File "/Users/runner/work/matplotlib/matplotlib/lib/matplotlib/pyplot.py", line 590 in show
File "<string>", line 21 in _test_other_signal_before_sigint_impl
File "<string>", line 25 in <module>
Extension modules: numpy.core._multiarray_umath, numpy.core._multiarray_tests, numpy.linalg._umath_linalg, numpy.fft._pocketfft_internal, numpy.random._common, numpy.random.bit_generator, numpy.random._bounded_integers, numpy.random._mt19937, numpy.random.mtrand, numpy.random._philox, numpy.random._pcg64, numpy.random._sfc64, numpy.random._generator, PIL._imaging, kiwisolver._cext, PyQt6.QtCore, PyQt6.QtGui, PyQt6.QtWidgets (total: 18)
Expected outcome
Tests pass
Additional information
No response
Operating system
macOS
Matplotlib Version
main
Matplotlib Backend
QtAgg
Python version
3.10 or 3.12
Jupyter version
No response
Installation
git checkout