Add shell completions by shtab

[Freed-Wu]

See #1992

pytest --print-completion bash | sudo tee /usr/share/bash-completion/completions/pytest
pytest --print-completion tcsh | sudo tee /etc/profile.d/pytest.completion.csh
pytest --print-completion zsh | sudo tee /usr/share/zsh/site-functions/_pytest

❯ pytest --<TAB>
option
--assert                          Control assertion debugging tools.
'plain' performs no assertion debugging.
'rewrite' (the default) rewrites assert statements in test modules on import to provide assert expression information.
--basetemp                        Base temporary directory for this test run. (Warning: this directory is removed if it exists.)
--cache-clear                     Remove all cache contents at start of test run
--cache-show                      Show cache contents, don't perform collection or tests. Optional argument: glob (default: '*').
--capture                         Per-test capturing method: one of fd|sys|no|tee-sys
...
❯ pytest --log-file <TAB>
log_file
AUTHORS             CHANGELOG.rst       CODE_OF_CONDUCT.md  extra/              pyproject.toml      scripts/            src/                tox.ini
bench/              CITATION            CONTRIBUTING.rst    LICENSE             README.rst          setup.cfg           testing/
changelog/          codecov.yml         doc/                OPENCOLLECTIVE.rst  RELEASING.rst       setup.py            TIDELIFT.rst

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[RonnyPfannschmidt]

as far as i recall we use argcomplete to also handle options added by pytest plugins after the fact or locally
i wonder how to enable something similar for this as pytest completion is optionally tricky

[RonnyPfannschmidt]

if we repeat that all over the place it might make sense to have a single module that exposes the api we need to have a optional dep

[Freed-Wu]

Your meaning is wrapping the code to expose an API, right?

[Freed-Wu]

handle options added by pytest plugins after the fact or locally

If any plugin add new option for pytest, I think regenerating the shell script can solve this problem.

[Freed-Wu]

How to fix coverage check failure?

[RonnyPfannschmidt]

i beleive the coverage diff issue can be ignored in this case

[RonnyPfannschmidt]

as far as i understand, this simply adds shtab generate support without touching the argcomplete dynamic support

i do wonder if we could add a better argparse wrapper to manage import costs there (but thats a followup)

it may be sensible/necessary to have better type values in the shims
but i would consider creating a better typesafe + shtab aware argpase wrapper a followup exercise)

thanks for getting this started ,i like the idea of a quick tab complete very much

[Freed-Wu]

i beleive the coverage diff issue can be ignored in this case

OK.

i like the idea of a quick tab complete very much

Me too.