add option using dynamically loaded plugin class - unrecognized arguments

description

I try to run pytest with dynamically loaded plugin class with pytest_addoption hook.
The cmd options in the plugin hook do not added to the parser. So pytest exists with error 'unrecognized arguments':

(issue_with_pytest_add_option) $ pytest --feature test
ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
pytest: error: unrecognized arguments: --feature
  inifile: None
  rootdir: /home/alsoroki/src/issue_with_pytest_add_option

output of pip list from the virtual environment you are using

(issue_with_pytest_add_option)  $ pip list
Package            Version
------------------ -------
attrs              19.3.0 
importlib-metadata 1.3.0  
more-itertools     8.0.2  
packaging          19.2   
pip                19.3.1 
pkg-resources      0.0.0  
pluggy             0.13.1 
py                 1.8.1  
pyparsing          2.4.6  
pytest             5.3.2  
setuptools         42.0.2 
six                1.13.0 
wcwidth            0.1.7  
wheel              0.33.6 
zipp               0.6.0  

pytest and operating system versions

(issue_with_pytest_add_option)  $ issue_with_pytest_add_option pytest --version
This is pytest version 5.3.2, imported from /home/user/.virtualenvs/issue_with_pytest_add_option/lib/python3.6/site-packages/pytest/__init__.py
$ uname -a
Linux pcname 4.15.0-33-generic #36~16.04.1-Ubuntu SMP Wed Aug 15 17:21:05 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Minimal example (aka steps to reproduce)

1. Extract minimal_example.zip to a separate folder and cd there
2. Create and activate virtual env: $ mkvirtualenv --python=python3.6 issue_with_pytest_add_option
3. Run tests: (issue_with_pytest_add_option) $ pytest --feature test
4. Note the error py.test: error: unrecognized arguments: --feature

Start by extracting minimal_example.zip and running pytest --feature test in the Python 3.6 environment described. Trace how the dynamically loaded plugin's pytest_addoption hook is handled and why --feature is rejected as unrecognized. Done means the reproduced command accepts the plugin-defined option without the reported parser error.