ruff-lsp

0.0.62 · deprecated · verified Thu Apr 16

ruff-lsp is a Language Server Protocol (LSP) implementation for Ruff, an extremely fast Python linter and code formatter. It enables Ruff to be integrated with any editor that supports the LSP, providing features like surfacing diagnostics and offering code actions to fix them. The library is currently at version 0.0.62, with releases often coinciding with updates to the underlying Ruff tool. However, ruff-lsp is officially deprecated in favor of Ruff's native Rust-based language server, `ruff server`.

Common errors

```
[lspconfig] Cannot access configuration for ruff. Ensure this server is listed in `server_configurations.md` or added as a custom server.
```
cause Your LSP client (e.g., nvim-lspconfig) cannot find or properly interpret the configuration for `ruff-lsp` or the native `ruff` language server. This can happen if the client is outdated or the configuration path is incorrect.

fix Update your LSP client plugin (e.g., `nvim-lspconfig`). Ensure your editor's LSP configuration for `ruff` (or `ruff-lsp` if still using it) matches the recommended setup in Ruff's official editor integration documentation. Verify that `ruff` is installed and accessible in your environment.
```
ruff-lsp doesn't start because of errors / Source actions not appearing in VS Code integration
```
cause General misconfiguration, missing dependencies (like Ruff itself), or conflicts with other extensions/LSP servers preventing `ruff-lsp` from initializing or providing features correctly.

fix Check your editor's LSP logs for detailed error messages. Ensure `ruff` and `ruff-lsp` are installed and accessible in the Python environment used by your editor. Disable other potentially conflicting Python linting/formatting extensions or LSP servers to isolate the issue. Confirm your editor's `ruff-lsp` settings (or Ruff extension settings for VS Code) are correct.

Warnings

breaking ruff-lsp is officially deprecated and is being replaced by Ruff's native Rust-based language server (`ruff server`). It is recommended to migrate to `ruff server` for improved performance and ongoing support. ruff-lsp is expected to be archived with the release of Ruff 0.11.
Fix: Migrate your editor's LSP configuration to use `ruff server`. Refer to Ruff's official documentation for migration guides and setup instructions for your specific editor. This often involves ensuring you have a recent version of Ruff installed (`pip install --upgrade ruff`) and configuring your editor's LSP client to use the `ruff server` command.
gotcha Configuration settings for ruff-lsp are not fully compatible with the native `ruff server`. Many settings have been renamed or replaced.
Fix: Consult the Ruff migration guide from `ruff-lsp` to `ruff server` to update your configuration files (e.g., `pyproject.toml` or editor-specific settings). Unsupported settings should be removed, and new granular settings should be adopted.
gotcha When integrating ruff-lsp (or `ruff server`) into an editor, it may conflict with other installed Python Language Servers (e.g., Pyright, Pylsp) if not configured to defer specific capabilities.
Fix: Configure your editor's LSP client to explicitly specify which LSP handles which capabilities (e.g., `textDocument/hover`, `textDocument/completion`). For instance, you might defer auto-completion and navigation to another LSP while letting Ruff handle linting and formatting.

Install

pip install ruff-lsp Install ruff-lsp

Quickstart

ruff-lsp functions as a Language Server, meant to be launched and managed by an editor or IDE supporting the Language Server Protocol. It is not designed for direct programmatic import and use within Python scripts. The command above starts the LSP server process, which editors connect to.

# ruff-lsp is typically launched by an LSP-capable editor.
# To run it manually (e.g., for testing or debugging):
ruff-lsp

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