Opinions

This is a Python library, designed to configure other Python projects with a set of tools to make development easier. Unlike tools like cookiecutter that are designed to start a project the right way, Opinions is designed to keep projects up to date with current tools and configurations as they change over time.

Originally, this tool came out of a frustration at how difficult it was to get Black, isort, pylint and pytest to work nicely together such that I could just run a single command and get told about all the ways I'd screwed up - I now prefer Ruff over the Black/isort/pylint trifecta - but there is still a bit of config that I hate copy-pasting between repos every time I start a new project. I wrote a hacky script that made this easier, which I then rewrote properly as Opinions.

Getting Started

• Install opinions as a development dependancy - eg, for Poetry:

poetry add --dev opinions

or with pip:

pip install opinions

• Apply the config

opinions apply

• Check if the configured tools have found places where things could be improved:

pytest

Goals

• Define a config for code formatting, linting and import sorting so everyone works to the same standard.
• Make it easier to write correct code by promoting the use of type hinting.
• Define a configuration for my editor to format code and sort imports automatically to minimize the amount of effort I need to spend meeting the code standard.
• Highlight formatting, linting and type checking issues by integrating these tools into the testing workflow and editor.
• Provide a "baseline" - the tool should not prevent projects from extending on top of the basic configuration.
• Accept that best practice changes over time, and provide a mechanism to bring old projects up to date.

The Configuration

• ruff, for linting, formatting and import sorting. Default config, except:
  • line-length set to 120 - 80 characters is too cramped
  • Linter rules:
    • E4, E7 and E9 (pycodestyle)
    • F (pyflakes)
    • UP (pyupgrade)
    • S (bandit)
    • A (flake8-builtins)
    • I (isort)
• pytest, configured to run:
  • ruff linter and format checks (using pytest-ruff)
  • mypy checks (using pytest-mypy)
  • opinions check to check if the opinions config is correctly applied
• VSCode configuration to:
  • Recommend the ruff integration extension be installed
  • Recommend the mypy integration extension be installed
  • Use ruff to format and organize imports on save
    • The ruff extension can also automatically fix some linter issues on save - this is explicitly not enabled as part of the configuration, but can be enabled if you want
• If the project is using Poetry
  • Explicitly configure the PyPI repository if no other default source is configured
  • Configure poetry-dynamic-versioning to set the project version
• Install poethepoet and configure it with a build task to build source and binary packages

Versioning and Compatibility

This project uses the following version scheme, based loosely off Semantic Versioning

• The "patch" number will be incremented if the release only includes a minor or patch level upgrade to a dependency (eg, "upgrade mypy from x.y.z to x.y+1.0" or "upgrade pytest from x.y.z to x.y.z+1"), or internal changes that don't impact an interface point (ie, the command line arguments)
• The "minor" number will be incremented (and the "patch" number reset to 0) if the release includes a major-level upgrade to a dependency (eg, "upgrade mypy from x.y.z to x+1.0.0"), if the release changes an interface point in a backwards-compatible way, or if the release adds a new feature
• The "major" number will be incremented (and the "minor" and "patch" numbers reset to 0) if the release changes The Configuration such that users will need to run opinions apply, if the release includes a backwards-incompatible change to an interface point, or if the minimum supported version of Python changes

Opinions supports Python 3.10 or newer.