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Title: CI: ban coverage 6.3 that may be causing random hangs in fork test by tacaswell · Pull Request #22326 · matplotlib/matplotlib · GitHub

Open Graph Title: CI: ban coverage 6.3 that may be causing random hangs in fork test by tacaswell · Pull Request #22326 · matplotlib/matplotlib

X Title: CI: ban coverage 6.3 that may be causing random hangs in fork test by tacaswell · Pull Request #22326 · matplotlib/matplotlib

Description: PR Summary About 24 hours ago (some time 2022-01-25) we started getting random failures on CI that look like: __________________________________ test_fork ___________________________________ [gw0] linux -- Python 3.7.12 /opt/hostedtoolcache/Python/3.7.12/x64/bin/python @pytest.mark.skipif(not hasattr(os, "register_at_fork"), reason="Cannot register at_fork handlers") def test_fork(): _model_handler(0) # Make sure the font cache is filled. ctx = multiprocessing.get_context("fork") with ctx.Pool(processes=2) as pool: > pool.map(_model_handler, range(2)) lib/matplotlib/tests/test_font_manager.py:206: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/pool.py:623: in __exit__ self.terminate() /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/pool.py:548: in terminate self._terminate() /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/util.py:224: in __call__ res = self._callback(*self._args, **self._kwargs) /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/pool.py:617: in _terminate_pool p.join() /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/process.py:140: in join res = self._popen.wait(timeout) /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/popen_fork.py:48: in wait return self.poll(os.WNOHANG if timeout == 0.0 else 0) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ self = , flag = 0 def poll(self, flag=os.WNOHANG): if self.returncode is None: try: > pid, sts = os.waitpid(self.pid, flag) E Failed: Timeout >300.0s /opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/multiprocessing/popen_fork.py:28: Failed ----------------------------- Captured stderr call ----------------------------- ~~~~~~~~~~~~~~~~~~~~~ Stack of (139800230110976) ~~~~~~~~~~~~~~~~~~~~~ File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/execnet/gateway_base.py", line 285, in _perform_spawn reply.run() File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/execnet/gateway_base.py", line 220, in run self._result = func(*args, **kwargs) File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/execnet/gateway_base.py", line 967, in _thread_receiver msg = Message.from_io(io) File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/execnet/gateway_base.py", line 432, in from_io header = io.read(9) # type 1, channel 4, payload 4 File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/execnet/gateway_base.py", line 400, in read data = self._read(numbytes - len(buf)) ------------------------------ Captured log call ------------------------------- DEBUG matplotlib.axes._base:_base.py:2965 title position was updated manually, not adjusting DEBUG matplotlib.backends.backend_pdf:backend_pdf.py:875 Assigning font /b'F1' = '/home/runner/work/matplotlib/matplotlib/lib/matplotlib/mpl-data/fonts/ttf/DejaVuSans.ttf' DEBUG matplotlib.backends.backend_pdf:backend_pdf.py:917 Embedding font /home/runner/work/matplotlib/matplotlib/lib/matplotlib/mpl-data/fonts/ttf/DejaVuSans.ttf. DEBUG matplotlib.backends.backend_pdf:backend_pdf.py:924 Writing TrueType font. We are seeing this mostly on py37, but it also showed up on 3.8 / 3.9 so this won't just go away when we merge #22194 . The only version change between the last working run to the first failing run was coverage 6.2 -> 6.3. To get coverage on subprocesses there is some extra configuration done at (sub-)process spawn time to get the hooks in place (which is actually managed for us by pytest-cov) so it is plausible that this is related, but do not actually understand the underlying problem.

Open Graph Description: PR Summary About 24 hours ago (some time 2022-01-25) we started getting random failures on CI that look like: __________________________________ test_fork ___________________________________ [gw0] ...

X Description: PR Summary About 24 hours ago (some time 2022-01-25) we started getting random failures on CI that look like: __________________________________ test_fork ___________________________________ [gw0] ...

Opengraph URL: https://github.com/matplotlib/matplotlib/pull/22326

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