'--workers 2' raise error when working with pytest5.x

[AndyFoolish]

Traceback (most recent call last):
File "run_case.py", line 37, in
ret = pytest.main()
File "/project/venv/lib/python3.6/site-packages/_pytest/config/init.py", line 74, in main
return config.hook.pytest_cmdline_main(config=config)
File "/project/venv/lib/python3.6/site-packages/pluggy/hooks.py", line 289, in call
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "/project/venv/lib/python3.6/site-packages/pluggy/manager.py", line 87, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "/project/venv/lib/python3.6/site-packages/pluggy/manager.py", line 81, in
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "/project/venv/lib/python3.6/site-packages/pluggy/callers.py", line 208, in _multicall
return outcome.get_result()
File "/project/venv/lib/python3.6/site-packages/pluggy/callers.py", line 80, in get_result
raise ex[1].with_traceback(ex[2])
File "/project/venv/lib/python3.6/site-packages/pluggy/callers.py", line 187, in _multicall
res = hook_impl.function(*args)
File "/project/venv/lib/python3.6/site-packages/_pytest/main.py", line 250, in pytest_cmdline_main
return wrap_session(config, _main)
File "/project/venv/lib/python3.6/site-packages/_pytest/main.py", line 243, in wrap_session
session=session, exitstatus=session.exitstatus
File "/project/venv/lib/python3.6/site-packages/pluggy/hooks.py", line 289, in call
return self._hookexec(self, self.get_hookimpls(), kwargs)
File "/project/venv/lib/python3.6/site-packages/pluggy/manager.py", line 87, in _hookexec
return self._inner_hookexec(hook, methods, kwargs)
File "/project/venv/lib/python3.6/site-packages/pluggy/manager.py", line 81, in
firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
File "/project/venv/lib/python3.6/site-packages/pluggy/callers.py", line 203, in _multicall
gen.send(outcome)
File "/project/venv/lib/python3.6/site-packages/_pytest/terminal.py", line 665, in pytest_sessionfinish
self.summary_stats()
File "/project/venv/lib/python3.6/site-packages/_pytest/terminal.py", line 863, in summary_stats
(line, color) = build_summary_stats_line(self.stats)
File "/project/venv/lib/python3.6/site-packages/_pytest/terminal.py", line 1014, in build_summary_stats_line
for found_type in stats:
File "", line 2, in __getitem__
File "/usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/multiprocessing/managers.py", line 772, in _callmethod
raise convert_to_error(kind, result)
KeyError: 0

[heibanke]

i got the same error.

[blueyed]

It works with 5.2.4.dev6+ge856638ba for me (master), but fails on the "features" branch:

  File "…/Vcs/pytest/src/_pytest/terminal.py", line 468, in pytest_runtest_logfinish
    main_color, _ = _get_main_color(self.stats)
  File "…/Vcs/pytest/src/_pytest/terminal.py", line 1102, in _get_main_color
    for found_type in stats:
  File "<string>", line 2, in __iter__
  File "/usr/lib/python3.7/multiprocessing/managers.py", line 825, in _callmethod
    proxytype = self._manager._registry[token.typeid][-1]
AttributeError: 'NoneType' object has no attribute '_registry'

The following patch for pytest fixes it:

diff --git i/src/_pytest/terminal.py w/src/_pytest/terminal.py
index 40e12e406..e88545eca 100644
--- i/src/_pytest/terminal.py
+++ w/src/_pytest/terminal.py
@@ -1099,7 +1099,7 @@ def _get_main_color(stats) -> Tuple[str, List[str]]:
         "failed passed skipped deselected xfailed xpassed warnings error".split()
     )
     unknown_type_seen = False
-    for found_type in stats:
+    for found_type in stats.keys():
         if found_type not in known_types:
             if found_type:  # setup/teardown reports have an empty key, ignore them
                 known_types.append(found_type)

I have some WIP in that area already, but pytest-parallel should handle iteration of stats probably, if it's easy.

Related code there: https://github.com/browsertron/pytest-parallel/blob/eb851777d354ba79d26d9b088bc1c22a8d44720b/pytest_parallel/__init__.py#L254-L269
(haven't looked at it really)

[blueyed]

JFI: the error I've posted happens when run in the subprocess, and starts to happen with pytest 5.3.0.

I am not sure why the original report is a problem / how it is triggered, since this should run in the main process.

pytest-dev/pytest#6261 however should fix both (at least the one from me).

[blueyed]

@AndyFoolish
Is this fixed with the latest release for you?

[HardNorth]

@azmeuk Please consider closing this out. It is seen by the discussion that the issue is related to pytest itself. And I also tested on my synthetic suite all major pytest versions starting from 5.2 till 7.1 without any issues. I would closed this until someone provide a reproducible example.