v24.0 StepLogger may be started twice which results in errors.

[jremmet]

We use pytester to test our hooks together with labgrid.
Since v24.0 we run into errors because StepLogger.start is called again by pytester via pytest_configure hook.

minimal example:
test_mini.py

import pytest

pytest_plugins = ["pytester"]

DUMMY_TEST = """
import pytest

def test_success():
    pass
"""

def test_pytester(pytester):
    """Test pytester."""
    pytester.makepyfile(DUMMY_TEST)
    result = pytester.runpytest()
    assert result.ret == pytest.ExitCode.OK

==================================================================== test session starts ====================================================================
platform linux -- Python 3.10.12, pytest-8.3.2, pluggy-1.5.0
rootdir: /tmp/labgtid
plugins: labgrid-24.0
collected 1 item                                                                                                                                            

test_mini.py F                                                                                                                                        [100%]

========================================================================= FAILURES ==========================================================================
_______________________________________________________________________ test_pytester _______________________________________________________________________

pytester = <Pytester PosixPath('/tmp/pytest-of-jremmet/pytest-0/test_pytester0')>

    def test_pytester(pytester):
        """Test pytester."""
        pytester.makepyfile(DUMMY_TEST)
        result = pytester.runpytest()
>       assert result.ret == pytest.ExitCode.OK
E       AssertionError: assert <ExitCode.INTERNAL_ERROR: 3> == <ExitCode.OK: 0>
E        +  where <ExitCode.INTERNAL_ERROR: 3> = <RunResult ret=ExitCode.INTERNAL_ERROR len(stdout.lines)=19 len(stderr.lines)=0 duration=0.02s>.ret
E        +  and   <ExitCode.OK: 0> = <enum 'ExitCode'>.OK
E        +    where <enum 'ExitCode'> = pytest.ExitCode

/tmp/labgtid/test_mini.py:16: AssertionError
------------------------------------------------------------------- Captured stdout call --------------------------------------------------------------------
INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/_pytest/main.py", line 279, in wrap_session
INTERNALERROR>     config._do_configure()
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/_pytest/config/__init__.py", line 1118, in _do_configure
INTERNALERROR>     self.hook.pytest_configure.call_historic(kwargs=dict(config=self))
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/pluggy/_hooks.py", line 535, in call_historic
INTERNALERROR>     res = self._hookexec(self.name, self._hookimpls.copy(), kwargs, False)
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/pluggy/_manager.py", line 120, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/pluggy/_callers.py", line 139, in _multicall
INTERNALERROR>     raise exception.with_traceback(exception.__traceback__)
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/pluggy/_callers.py", line 103, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/labgrid/pytestplugin/hooks.py", line 65, in pytest_configure
INTERNALERROR>     StepLogger.start()
INTERNALERROR>   File "/tmp/labgtid/venv/lib/python3.10/site-packages/labgrid/logging.py", line 147, in start
INTERNALERROR>     assert not cls._started
INTERNALERROR> AssertionError: assert not True
INTERNALERROR>  +  where True = <class 'labgrid.logging.StepLogger'>._started
================================================================== short test summary info ==================================================================
FAILED test_mini.py::test_pytester - AssertionError: assert <ExitCode.INTERNAL_ERROR: 3> == <ExitCode.OK: 0>
===================================================================== 1 failed in 0.05s =====================================================================

Is it possible to replace the asserion by a if clause here:

labgrid/labgrid/logging.py

Line 147 in 7f2c8fc

assert not cls._started

Or add a "is-already-running" check here:

labgrid/labgrid/pytestplugin/hooks.py

Line 65 in 7f2c8fc

StepLogger.start()

?

[Emantor]

Thats unfortunate. I guess allowing multiple starts for the StepLogger should not be too bad, so I think we should handle that in the the Steplogger class, if @jluebbe and @Bastian-Krause agree.

[jremmet]

Thats unfortunate. I guess allowing multiple starts for the StepLogger should not be too bad, so I think we should handle that in the the Steplogger class, if @jluebbe and @Bastian-Krause agree.

I added a PR which handle it in the pytest hook. If we just ignore multiple calls, we will run stop to early.
Alternatively we need to count the starts and stops, which seams fragile if called directly.

[Bastian-Krause]

Thats unfortunate. I guess allowing multiple starts for the StepLogger should not be too bad, so I think we should handle that in the the Steplogger class, if @jluebbe and @Bastian-Krause agree.

I don't know the implications of that. As long as you say it's safe, I have no objections.