Ruff check for other file formats especially config file formats

[inoa-jboliveira]

I know ruff is a Python only tool and almost all checks are related to python files (.py and .pyi), but there is an exception which is RUF200 that checks if a toml file is valid within the python spec.

Having said that, I believe other file types that belong to the python ecosystem could also have linter checks at least to know if they have valid syntax or not. Specially with file types meant for configuration or tests.

Which of you never accidentally added a trailing comma to a JSON file? A check that is basically says if JSON is valid or not would be extremely helpful.

Proposal: Provide checks for standardized file formats that would not require Ruff to write parsers, so no maintenance burden

• FMT001 - Check if JSON file is valid
• FMT002 - Check if JSONL file is valid
• FMT010 - Check if YAML file is valid
  • I believe rust have only libs with rev 1.2 of the standard, and the most common python binding is pyyaml which uses rev 1.1
  • That could be just a disclaimer and the check will still be very helpful
• FMT020 - Check if INI file is valid
• FMT021 - Check if TOML file is valid
• FMT022 - Failed to parse pyproject.toml
  • deprecate RUF200 and move it here
• FMT030 - Check if requirements TXT file is valid
• FMT031 - Check if requirements IN file is valid
  • Both relate to the UV project that already have the parsers

All this gives ruff the opportunity to have more checks related to these files and possibly extend the formatter from python only.

Example -- not saying this is a good check to have, just illustrating:

• FMT011 - Check all yaml keys are strings (the standard allows non strings, but for JSON compatibility it should not happen)