python-lsp-ruff is a plugin for python-lsp-server that adds linting, code action and formatting capabilities that are provided by ruff, an extremely fast Python linter written in Rust.

In the same virtualenv as python-lsp-server:

pip install python-lsp-ruff

There also exists an AUR package.

Ruff version 0.1.0 introduced API changes that are fixed in Python LSP Ruff v1.6.0. To continue with ruff<0.1.0 please use v1.5.3, e.g. using pip:

pip install "ruff<0.1.0" "python-lsp-ruff==1.5.3"

This plugin will disable pycodestyle, pyflakes, mccabe and pyls_isort by default, unless they are explicitly enabled in the client configuration. When enabled, all linting diagnostics will be provided by ruff. Sorting of the imports through ruff when formatting is enabled by default. The list of code fixes can be changed via the pylsp.plugins.ruff.format option.

Any codes given in the format option will only be marked as fixable for ruff during the formatting operation, the user has to make sure that these codes are also in the list of codes that ruff checks!

This example configuration for neovim shows how to always sort imports when running textDocument/formatting:

lspconfig.pylsp.setup {
	settings = {
		pylsp = {
			plugins = {
				ruff = {
					enabled = true,
					extendSelect = { "I" },
				},
			}
		}
	}
}

Configuration options can be passed to the python-language-server. If a pyproject.toml file is present in the project, python-lsp-ruff will use these configuration options. Note that any configuration options (except for extendIgnore and extendSelect, see this issue) passed to ruff via pylsp are ignored if the project has a pyproject.toml.

The plugin follows python-lsp-server's configuration. These are the valid configuration keys:

• pylsp.plugins.ruff.enabled: boolean to enable/disable the plugin. true by default.
• pylsp.plugins.ruff.config: Path to optional pyproject.toml file.
• pylsp.plugins.ruff.exclude: Exclude files from being checked by ruff.
• pylsp.plugins.ruff.executable: Path to the ruff executable. Uses os.executable -m "ruff" by default.
• pylsp.plugins.ruff.ignore: Error codes to ignore.
• pylsp.plugins.ruff.extendIgnore: Same as ignore, but append to existing ignores.
• pylsp.plugins.ruff.lineLength: Set the line-length for length checks.
• pylsp.plugins.ruff.perFileIgnores: File-specific error codes to be ignored.
• pylsp.plugins.ruff.select: List of error codes to enable.
• pylsp.plugins.ruff.extendSelect: Same as select, but append to existing error codes.
• pylsp.plugins.ruff.format: List of error codes to fix during formatting. The default is ["I"], any additional codes are appended to this list.
• pylsp.plugins.ruff.unsafeFixes: boolean that enables/disables fixes that are marked "unsafe" by ruff. false by default.
• pylsp.plugins.ruff.severities: Dictionary of custom severity levels for specific codes, see below.

For more information on the configuration visit Ruff's homepage.

By default, all diagnostics are marked as warning, except for "E999" and all error codes starting with "F", which are displayed as errors. This default can be changed through the pylsp.plugins.ruff.severities option, which takes the error code as a key and any of "E", "W", "I" and "H" to be displayed as errors, warnings, information and hints, respectively. For more information on the diagnostic severities please refer to the official LSP reference.

Note that python-lsp-ruff does not accept regex, and it will not check whether the error code exists. If the custom severity level is not displayed, please check first that the error code is correct and that the given value is one of the possible keys from above.