When the option --cov is specified, multiprocessing.Process.join causes a deadlock occationally in a pytest session.
mkdir .venv
pipenv --python $HOME/miniconda/envs/py39/bin/python
pipenv installPython 3.8 & 3.9 on Linux. On Mac, the problem does not occur.
$ ./.venv/bin/pip list
Package Version
---------- -------
attrs 21.2.0
coverage 5.5
iniconfig 1.1.1
packaging 21.0
pip 21.0.1
pluggy 1.0.0
py 1.10.0
pyparsing 2.4.7
pytest 6.2.5
pytest-cov 2.12.1
setuptools 52.0.0
toml 0.10.2
wheel 0.36.2$ ./.venv/bin/python --version
Python 3.9.6$ ./.venv/bin/pytest --version
pytest 6.2.5$ pipenv run pytest
============================= test session starts =============================
platform linux -- Python 3.9.6, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /mnt/das02/michitaro/work/pytest-cov-bug
plugins: cov-2.12.1
collected 1 item
test_test.py . [100%]
============================== 1 passed in 1.40s ==============================
$ pipenv run pytest --cov
============================= test session starts =============================
platform linux -- Python 3.9.6, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /mnt/das02/michitaro/work/pytest-cov-bug
plugins: cov-2.12.1
collected 1 item
test_test.py F [100%]
================================== FAILURES ===================================
__________________________________ test_main __________________________________
def test_main():
for i in range(200):
run_thread()
if len(errors) > 0:
> raise RuntimeError(f'join timeout occured in trial {i}')
E RuntimeError: join timeout occured in trial 11
test_test.py:33: RuntimeError
----------- coverage: platform linux, python 3.9.6-final-0 -----------
Name Stmts Miss Cover
------------------------------------------------------------------------------------------------
.venv/lib/python3.9/site-packages/_pytest/_argcomplete.py 37 36 3%
.venv/lib/python3.9/site-packages/_pytest/_code/code.py 699 489 30%
.venv/lib/python3.9/site-packages/_pytest/_code/source.py 142 91 36%
.venv/lib/python3.9/site-packages/_pytest/_io/terminalwriter.py 113 65 42%
.venv/lib/python3.9/site-packages/_pytest/_io/wcwidth.py 25 16 36%
.venv/lib/python3.9/site-packages/_pytest/assertion/__init__.py 84 73 13%
.venv/lib/python3.9/site-packages/_pytest/assertion/rewrite.py 626 504 19%
.venv/lib/python3.9/site-packages/_pytest/cacheprovider.py 314 266 15%
.venv/lib/python3.9/site-packages/_pytest/capture.py 560 481 14%
.venv/lib/python3.9/site-packages/_pytest/compat.py 162 129 20%
.venv/lib/python3.9/site-packages/_pytest/config/__init__.py 806 692 14%
.venv/lib/python3.9/site-packages/_pytest/config/argparsing.py 253 208 18%
.venv/lib/python3.9/site-packages/_pytest/debugging.py 228 219 4%
.venv/lib/python3.9/site-packages/_pytest/deprecated.py 16 15 6%
.venv/lib/python3.9/site-packages/_pytest/doctest.py 351 341 3%
.venv/lib/python3.9/site-packages/_pytest/faulthandler.py 64 46 28%
.venv/lib/python3.9/site-packages/_pytest/fixtures.py 833 709 15%
.venv/lib/python3.9/site-packages/_pytest/helpconfig.py 133 123 8%
.venv/lib/python3.9/site-packages/_pytest/junitxml.py 373 371 1%
.venv/lib/python3.9/site-packages/_pytest/logging.py 402 294 27%
.venv/lib/python3.9/site-packages/_pytest/main.py 461 287 38%
.venv/lib/python3.9/site-packages/_pytest/mark/__init__.py 141 126 11%
.venv/lib/python3.9/site-packages/_pytest/mark/structures.py 244 227 7%
.venv/lib/python3.9/site-packages/_pytest/monkeypatch.py 171 158 8%
.venv/lib/python3.9/site-packages/_pytest/nodes.py 271 173 36%
.venv/lib/python3.9/site-packages/_pytest/nose.py 22 11 50%
.venv/lib/python3.9/site-packages/_pytest/pastebin.py 70 69 1%
.venv/lib/python3.9/site-packages/_pytest/pathlib.py 338 279 17%
.venv/lib/python3.9/site-packages/_pytest/python.py 851 677 20%
.venv/lib/python3.9/site-packages/_pytest/reports.py 279 244 13%
.venv/lib/python3.9/site-packages/_pytest/runner.py 299 161 46%
.venv/lib/python3.9/site-packages/_pytest/setuponly.py 56 54 4%
.venv/lib/python3.9/site-packages/_pytest/setupplan.py 24 22 8%
.venv/lib/python3.9/site-packages/_pytest/skipping.py 178 146 18%
.venv/lib/python3.9/site-packages/_pytest/stepwise.py 68 67 1%
.venv/lib/python3.9/site-packages/_pytest/store.py 34 27 21%
.venv/lib/python3.9/site-packages/_pytest/terminal.py 897 682 24%
.venv/lib/python3.9/site-packages/_pytest/threadexception.py 44 29 34%
.venv/lib/python3.9/site-packages/_pytest/tmpdir.py 117 102 13%
.venv/lib/python3.9/site-packages/_pytest/unittest.py 243 234 4%
.venv/lib/python3.9/site-packages/_pytest/unraisableexception.py 44 29 34%
.venv/lib/python3.9/site-packages/_pytest/warnings.py 63 44 30%
.venv/lib/python3.9/site-packages/_virtualenv.py 81 80 1%
.venv/lib/python3.9/site-packages/pluggy/_callers.py 40 10 75%
.venv/lib/python3.9/site-packages/pluggy/_hooks.py 156 92 41%
.venv/lib/python3.9/site-packages/pluggy/_manager.py 190 148 22%
.venv/lib/python3.9/site-packages/pluggy/_result.py 30 22 27%
.venv/lib/python3.9/site-packages/pluggy/_tracing.py 41 31 24%
.venv/lib/python3.9/site-packages/py/_builtin.py 112 78 30%
.venv/lib/python3.9/site-packages/py/_code/__init__.py 0 0 100%
.venv/lib/python3.9/site-packages/py/_code/code.py 531 408 23%
.venv/lib/python3.9/site-packages/py/_error.py 52 47 10%
.venv/lib/python3.9/site-packages/py/_path/common.py 277 211 24%
.venv/lib/python3.9/site-packages/py/_path/local.py 694 616 11%
.venv/lib/python3.9/site-packages/py/_vendored_packages/apipkg/__init__.py 152 129 15%
.venv/lib/python3.9/site-packages/pytest/collect.py 21 19 10%
.venv/lib/python3.9/site-packages/pytest_cov/compat.py 21 17 19%
.venv/lib/python3.9/site-packages/pytest_cov/embed.py 80 73 9%
.venv/lib/python3.9/site-packages/pytest_cov/engine.py 238 217 9%
.venv/lib/python3.9/site-packages/pytest_cov/plugin.py 209 191 9%
test_test.py 23 0 100%
------------------------------------------------------------------------------------------------
TOTAL 14084 11405 19%
=========================== short test summary info ===========================
FAILED test_test.py::test_main - RuntimeError: join timeout occured in trial 11
============================== 1 failed in 3.58s ==============================
^CError in atexit._run_exitfuncs:
Traceback (most recent call last):
File "/home/michitaro/anaconda3/envs/py39/lib/python3.9/multiprocessing/popen_fork.py", line 27, in poll
pid, sts = os.waitpid(self.pid, flag)
KeyboardInterrupt
docker build -t pytest-cov-deadlock .
docker run pytest-cov-deadlock pytest # OK
docker run pytest-cov-deadlock pytest --cov # NG$ docker run pytest-cov-deadlock pytest
============================= test session starts ==============================
platform linux -- Python 3.9.7, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /work
plugins: cov-2.12.1
collected 1 item
test_test.py . [100%]
============================== 1 passed in 2.84s ===============================
$ docker run pytest-cov-deadlock pytest --cov
============================= test session starts ==============================
platform linux -- Python 3.9.7, pytest-6.2.5, py-1.10.0, pluggy-1.0.0
rootdir: /work
plugins: cov-2.12.1
collected 1 item
test_test.py F [100%]
=================================== FAILURES ===================================
__________________________________ test_main ___________________________________
def test_main():
for i in range(400):
errors.clear()
run_thread()
if len(errors) > 0:
> raise RuntimeError(f'join timeout occured in trial {i}')
E RuntimeError: join timeout occured in trial 37
test_test.py:33: RuntimeError
----------- coverage: platform linux, python 3.9.7-final-0 -----------
Name Stmts Miss Cover
----------------------------------
test_test.py 23 0 100%
----------------------------------
TOTAL 23 0 100%
=========================== short test summary info ============================
FAILED test_test.py::test_main - RuntimeError: join timeout occured in trial 37
============================== 1 failed in 2.69s ===============================
^CError in atexit._run_exitfuncs:
Traceback (most recent call last):
File "/usr/local/lib/python3.9/multiprocessing/popen_fork.py", line 27, in poll
pid, sts = os.waitpid(self.pid, flag)
KeyboardInterrupt