Lets assume you start with python, pip, and python-venv installed.

python3 -m venv env will create a new directory named env and install a new virtual environment in it.

Activate the environment with. env/bin/activate.

Deactivate the environment when you're done with deactivate.

With your virtual environment activated, first upgrade pip to the latest version with

pip install --upgrade pip. Pip should be at least version 21.3.1.

Now install this repo as a package along with its development dependencies with pip install -e '.[dev]'. The -e option installs the package as "editable"--any changes you make in the source code will immediately be reflected in the environment without having to reinstall the package.

The package can be uninstalled with pip uninstall megh-pch if needed.

Simply run pytest and it should pickup on the tests to run.

Use pre-commit run --all-files to run linting on all files.

If you want to run your local changes, use pre-commit try-repo . --all-files.

If you want to run on only the files that have changed since <hash>, try:

pre-commit run --files $(git diff --diff-filter=ACMRT --name-only --no-ext-diff -z <hash> | xargs --null)

<hash> can be, for example, 961ac74, develop, 2022.1, or HEAD~1.

Adding new scripts, changing the directory structure, and adding requirements will require updating the packaging configuration. In order to run as a "language: python" pre-commit script, this project has to be installable with pip via pip install ..

A pyproject.toml was chosen over a setup.py file because it's going to be the new standard way. Also, this project is small and simple enough that pyproject.tomlis sufficient, regardless of how mature the support is. Flit's website is https://flit.pypa.io/en/latest/pyproject_toml.html.

Current popular build tools that can use a pyproject.toml are Setuptools (also the de facto standard for setup.py), Poetry, and Flit. Flit was chosen because it suppports the -e option for editable pip installs mentioned earlier.

Scripts are mapped under the [project.scripts] table. These deploy a shell script in the env that will invoke the given function.

Requirements are given in the project.dependencies list. These are installed along with the project with pip install .. Optional dependencies are installed with pip install '.[OPTION]'.

A wheel can be built with flit build after an initial pip install flit.