0005-use-google-python-style-guide.md

Use Google Python style guide with minimal refinements

Technical Story: #1128

Context and Problem Statement

The Secure Systems Lab code style guide, which has been used for most of the code base, has become outdated. Through the upcoming rewrite, we have the chance to ignore consistency considerations with existing code style and can choose a more standard and up-to-date style guide.

Decision Drivers

• Flaws in original Secure Systems Lab style guide
• Curating a complete custom style guide is time consuming
• Well-established style rules lower contribution barrier
• Custom style is not supported by default in common tooling (i.e. editors and linters)

Considered Options

• Use custom style guide
• Use Google style guide with refinements

Decision Outcome

Chosen option: "Use Google style guide with refinements", because the Google style guide is a comprehensive, well-established style guide that is mostly based on PEP-8 and was accepted by everyone on the TUF team. There is no need to replicate these recommendations. However, we do provide a very slim document with additional refinements, in order to emphasize items the we consider especially important, want to be handled differently, or in one specific way, where the Google guide would allow multiple.

Course of Action:

• Follow existing style when working on existing code (files)
• Follow new style in any new code (files)
• Consider providing linter and formatter configuration (e.g. pylint, flake8, black, yapf) to enforce and facilitate new style

Links

• New Slim Secure Systems Lab style guide
• Google Python style guide
• PEP 8
• Issues in original Secure Systems Lab style guide