-p no:pluginname on pytest 2.9.x ignored on xdist slave node

[fizyk]

For pytest-dbfxitures plugin we run tests both with pytest-xdist and without to make sure we cover all the possibilities on travis. However, when running on xdist on pytest 2.9.x I get
argparse.ArgumentError: argument --dbfixtures-config: conflicting option string: --dbfixtures-config

to get the full coverage we run tests without the plugin (-p no:bfixtures) and import all pytest's plugins triggers in main conftest. It worked perfectly till the 2.9.x version, where it seems under xdist, the plugin is being loaded even thouth the options states it not to load.

alabaster (0.7.7)
apipkg (1.4)
Babel (2.2.0)
backports.shutil-get-terminal-size (1.0.0)
bumpversion (0.5.3)
coverage (4.1)
coveralls (1.1)
decorator (4.0.10)
docopt (0.6.2)
docutils (0.12)
execnet (1.4.1)
fancycompleter (0.4)
ipython (4.2.0)
ipython-genutils (0.1.0)
Jinja2 (2.8)
MarkupSafe (0.23)
mccabe (0.5.0)
mirakuru (0.7.0)
mock (2.0.0)
mysqlclient (1.3.7)
ordereddict (1.1)
pamqp (1.6.1)
path.py (8.2.1)
pbr (1.8.1)
pdbpp (0.8.3)
pep257 (0.7.0)
pep8 (1.7.0)
pexpect (4.1.0)
pickleshare (0.7.2)
pip (7.1.2)
port-for (0.3.1)
psycopg2 (2.6.1)
ptyprocess (0.5.1)
py (1.4.31)
pyaml (15.8.2)
pyflakes (1.2.3)
Pygments (2.1)
pylama (7.0.9)
pymlconf (0.4.0)
pymongo (3.2.2)
pytest (2.9.2)
pytest-cov (2.2.1)
pytest-dbfixtures (0.13.1)
pytest-xdist (1.14)
pytz (2015.7)
PyYAML (3.11)
rabbitpy (0.27.1)
redis (2.10.5)
requests (2.9.1)
setuptools (23.0.0)
simplegeneric (0.8.1)
six (1.10.0)
snowballstemmer (1.2.1)
Sphinx (1.3.5)
sphinx-rtd-theme (0.1.9)
traitlets (4.2.1)
wheel (0.24.0)
wmctrl (0.3)

py.test 2.9.2 and os is anything travis runs its tests on, and ubuntu 16.4
example https://github.com/ClearcodeHQ/pytest-dbfixtures and pull request I;m trying to upgreade the py.test on without sacrificing coverage.

[nicoddemus]

Thanks for the report!

I would guess the problem is that the option is not being interpreted correctly by the workers, but this needs more investigation.

[RonnyPfannschmidt]

we finished the investigation, your conftest imports the plugin addoption function

so pytest sees an addoption hook in 2 different plugins, thus runs it twice and ends with an conflict

[RonnyPfannschmidt]

after re-reading the message, there is probably more to it :)

[RonnyPfannschmidt]

a quick run down of the conditions

• have a installed python plugin
• disable it with -p no:my_entry_point
• reenable it via the conftest, that happens after pytest-cov
• watch xdist ignore the -p no:my_entry_point

[RonnyPfannschmidt]

after finishing investigation the issue is enforced by plugin blockers in xdist only being interpreted after initial loading of setuptools plugins,

thus the plugin in dbfixtures gets loaded, then unloaded, but the effects of the addoption stay
the solution will be to fix the behavior of the utility method that is invoked on the remote

[RonnyPfannschmidt]

0e55a87 was part of it

[RonnyPfannschmidt]

9c54958 introduced it

[nicoddemus]

@RonnyPfannschmidt how's the status on this issue?

[nicoddemus]

Oh #1673 attempts to solve this.

[nicoddemus]

I believe this has already been fixed with the config changes in pytest-xdist; if not we can reopen this later.