[Fixed] Ruff does not autofix line-too-long violation – Ruff

The Problem:

Given a Python project, the latest version of ruff is configured for linting and formatting with specific settings in pyproject.toml. When using the ruff check command with the autofix feature (--fix), ruff identifies lines that exceed the specified line length (E501 errors) but does not automatically format the code to wrap to the next line. The goal is to enable ruff to fix this issue or determine if it is not currently possible.

The Solutions:

Solution 1: Ruff doesn’t autofix line-too-long violation

Ruff’s current version, v0.0.280, does not have the ability to autofix line-length violations (E501). However, Ruff has released a Python formatter in alpha state as part of v0.0.289. This new feature allows for autofixing line-length violations.

As a workaround, you can use a combination of Black and Ruff, tailoring them to meet your specific project requirements.

Solution 2: Autofix Disabled For `E501` Lint Rule

As of today’s Ruff autoformatter, not every lint rule can be autofixed, and `E501` is one of them. Ruff does not enforce autofixing rules that overlap with the use of a formatter, as `E501` inherently does. Here’s what you can do:

• Use Ruff’s formatter (or Black) to autoformat E501 issues according to the line-length setting, where possible.
• Ignore the E501 lint rule in your configuration to allow the formatter to do the work. For example:

[tool.ruff]
line-length = 99

[tool.ruff.lint]
select = ["E", "F", "W", "Q", "I"]
ignore = ["E203", "E501"]

Note that fixable = ["ALL"] is the default in Ruff, and should be used to specify a subset of selected rules that you want to autofix, if available and not unsafe.