### Install ruff-ecosystem with uv

Source: https://github.com/astral-sh/ruff/blob/main/python/ruff-ecosystem/README.md

Install the ruff-ecosystem tool from the Ruff project root using uv.

```shell
uv tool install -e ./python/ruff-ecosystem
```

--------------------------------

### Install Ruff with standalone installer (Windows)

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Download and execute the standalone installer script for Ruff on Windows using PowerShell.

```powershell
$ # On Windows.
$ powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
```

--------------------------------

### Install Ruff with pip

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install Ruff using pip.

```shell
pip install ruff

```

--------------------------------

### Install Hyperfine for Benchmarking

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Install the `hyperfine` tool, which is used for benchmarking Rust projects.

```shell
cargo install hyperfine
```

--------------------------------

### String Slicing Examples

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/subscript/string.md

Illustrates various string slicing techniques, including start, stop, and step parameters, negative indices, and omitting bounds. Also shows type checking for slices.

```python
def _(m: int, n: int, s2: str):
    s = "abcde"

    reveal_type(s[0:0])  # revealed: Literal[""]
    reveal_type(s[0:1])  # revealed: Literal["a"]
    reveal_type(s[0:2])  # revealed: Literal["ab"]
    reveal_type(s[0:5])  # revealed: Literal["abcde"]
    reveal_type(s[0:6])  # revealed: Literal["abcde"]
    reveal_type(s[1:3])  # revealed: Literal["bc"]

    reveal_type(s[-3:5])  # revealed: Literal["cde"]
    reveal_type(s[-4:-2])  # revealed: Literal["bc"]
    reveal_type(s[-10:10])  # revealed: Literal["abcde"]

    reveal_type(s[0:])  # revealed: Literal["abcde"]
    reveal_type(s[2:])  # revealed: Literal["cde"]
    reveal_type(s[5:])  # revealed: Literal[""]
    reveal_type(s[:2])  # revealed: Literal["ab"]
    reveal_type(s[:0])  # revealed: Literal[""]
    reveal_type(s[:2])  # revealed: Literal["ab"]
    reveal_type(s[:10])  # revealed: Literal["abcde"]
    reveal_type(s[:])  # revealed: Literal["abcde"]

    reveal_type(s[::-1])  # revealed: Literal["edcba"]
    reveal_type(s[::2])  # revealed: Literal["ace"]
    reveal_type(s[-2:-5:-1])  # revealed: Literal["dcb"]
    reveal_type(s[::-2])  # revealed: Literal["eca"]
    reveal_type(s[-1::-3])  # revealed: Literal["eb"]

    reveal_type(s[None:2:None])  # revealed: Literal["ab"]
    reveal_type(s[1:None:1])  # revealed: Literal["bcde"]
    reveal_type(s[None:None:None])  # revealed: Literal["abcde"]

    start = 1
    stop = None
    step = 2
    reveal_type(s[start:stop:step])  # revealed: Literal["bd"]

    reveal_type(s[False:True])  # revealed: Literal["a"]
    reveal_type(s[True:3])  # revealed: Literal["bc"]

    s[0:4:0]  # error: [zero-stepsize-in-slice]
    s[:4:0]  # error: [zero-stepsize-in-slice]
    s[0::0]  # error: [zero-stepsize-in-slice]
    s[::0]  # error: [zero-stepsize-in-slice]

    substring1 = s[m:n]
    reveal_type(substring1)  # revealed: LiteralString

    substring2 = s2[0:5]
    reveal_type(substring2)  # revealed: str
```

--------------------------------

### Install Ruff with standalone installers (Windows)

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install Ruff using the standalone installer script for Windows.

```shell
# On Windows.
powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"

```

--------------------------------

### Install Ruff with pkgx

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff using the pkgx package manager.

```console
$ pkgx install ruff
```

--------------------------------

### Install pre-commit hooks

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty/CONTRIBUTING.md

Installs the prek tool and sets up hooks for automatic validation checks.

```shell
uv tool install prek
prek install
```

--------------------------------

### Install Ruff with pipx

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install Ruff using pipx.

```shell
pipx install ruff

```

--------------------------------

### Python Code Example After Formatting

Source: https://github.com/astral-sh/ruff/blob/main/docs/formatter.md

Shows the same Python function as above, but with the docstring code example reformatted according to the configuration.

```python
def f(x):
    """
    Something about `f`. And an example:

    .. code-block:: python

        (
            foo,
            bar,
            quux,
        ) = this_is_a_long_line(
            lion,
            hippo,
            lemur,
            bear,
        )
    """
    pass
```

--------------------------------

### Install Pyright

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/README.md

Install Pyright using npm, ignoring scripts to speed up the process.

```shell
npm ci --ignore-scripts
```

--------------------------------

### Start the ty language server

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty/docs/cli.md

Use this command to start the 'ty' language server. No specific options are detailed for this basic usage.

```bash
ty server
```

--------------------------------

### Python Code Example Before Formatting

Source: https://github.com/astral-sh/ruff/blob/main/docs/formatter.md

Illustrates a Python function with a docstring containing a code example that will be reformatted.

```python
def f(x):
    '''
    Something about `f`. And an example:

    .. code-block:: python

        foo, bar, quux = this_is_a_long_line(lion, hippo, lemur, bear)
    '''
    pass
```

--------------------------------

### Install Ruff with standalone installers (macOS/Linux)

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install Ruff using the standalone installer script for macOS and Linux.

```shell
# On macOS and Linux.
curl -LsSf https://astral.sh/ruff/install.sh | sh

```

--------------------------------

### Install uv

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Installs the `uv` package manager. This is a prerequisite for several development and release tasks.

```shell
curl -LsSf https://astral.sh/uv/install.sh | sh
```

--------------------------------

### Install Ruff with uv

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install Ruff globally or add it to your project's development dependencies using uv.

```shell
# With uv.
uv tool install ruff@latest

```

```shell
# Or add Ruff to your project.
uv add --dev ruff

```

--------------------------------

### Install Pre-commit Hooks

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Installs pre-commit hooks using uv to automate validation checks before committing.

```shell
uv tool install prek
prek install
```

--------------------------------

### Install Ruff Globally with uv

Source: https://github.com/astral-sh/ruff/blob/main/docs/faq.md

Install Ruff globally using the uv package manager. This is a recommended method for managing Ruff installations.

```console
$ uv tool install ruff@latest
```

--------------------------------

### Install specific Ruff version with standalone installer (Windows)

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Download and execute the standalone installer script for a specific Ruff version on Windows using PowerShell.

```powershell
$ powershell -c "irm https://astral.sh/ruff/0.5.0/install.ps1 | iex"
```

--------------------------------

### Install Ruff on Alpine Linux

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff from the community repositories on Alpine Linux using apk.

```console
$ apk add ruff
```

--------------------------------

### Install Ruff on Arch Linux

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff from the official repositories on Arch Linux using pacman.

```console
$ pacman -S ruff
```

--------------------------------

### Install Ruff on openSUSE Tumbleweed

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff from the distribution repository on openSUSE Tumbleweed using zypper.

```console
$ sudo zypper install python3-ruff
```

--------------------------------

### Install Insta for snapshot testing

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty/CONTRIBUTING.md

Installs the cargo-insta tool required for updating snapshot tests.

```shell
cargo install cargo-insta
```

--------------------------------

### Install Ruff with pip

Source: https://github.com/astral-sh/ruff/blob/main/docs/faq.md

Install Ruff using the standard pip package manager. This is a common alternative if uv is not being used.

```console
$ pip install ruff
```

--------------------------------

### Install Nextest for Running Tests

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Installs Nextest, a recommended tool for running Ruff's test suite, though not strictly necessary.

```shell
cargo install cargo-nextest --locked
```

--------------------------------

### Install Insta for Snapshot Tests

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Installs the Insta tool, which is required for updating snapshot tests in the Ruff project.

```shell
cargo install cargo-insta
```

--------------------------------

### Install Ruff Standalone (Windows)

Source: https://github.com/astral-sh/ruff/blob/main/docs/faq.md

Install Ruff using the standalone PowerShell script for Windows. This method does not require a Rust toolchain.

```console
$ powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
```

--------------------------------

### Ignore specific rules for Jupyter Notebooks

Source: https://github.com/astral-sh/ruff/blob/main/docs/configuration.md

Use the `per-file-ignores` setting to apply specific rule exclusions to Jupyter Notebook files. This example ignores all rules starting with `T20` for `.ipynb` files.

```toml
[tool.ruff.lint.per-file-ignores]
"*.ipynb" = ["T20"]

```

```toml
[lint.per-file-ignores]
"*.ipynb" = ["T20"]

```

--------------------------------

### Initialize Project with uv

Source: https://github.com/astral-sh/ruff/blob/main/docs/tutorial.md

Initializes a new Python project with a specified library using uv. Creates a basic project structure.

```console
$ uv init --lib numbers
```

--------------------------------

### Run MkDocs Development Server

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Start the MkDocs development server to view the documentation locally. This command uses `uvx` to manage the execution environment.

```shell
uvx --with-requirements docs/requirements.txt -- mkdocs serve -f mkdocs.yml
```

--------------------------------

### Monorepo environment configuration for editable installs

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/import/workspaces.md

Configures a virtual environment to include editable source directories for multiple projects. This setup allows Ruff to resolve imports across separate project boundaries.

```toml
[environment]
# Setup a venv with editables for aproj/src/ and bproj/src/
python = "/.venv"
```

```pth
aproj/src/
```

```pth
bproj/src/
```

--------------------------------

### Develop WASM and Local Server for Ruff Playground (Shell)

Source: https://github.com/astral-sh/ruff/blob/main/crates/ruff_python_formatter/CONTRIBUTING.md

Set up and run the development environment for the Ruff playground. This involves installing Node.js dependencies, building the WebAssembly component, and starting the local development server.

```shell
cd playground && npm ci --ignore-scripts && npm run dev:wasm && npm run dev
```

--------------------------------

### Mock Environment with Site-Packages Path

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_test/README.md

Demonstrates writing a Python file to the mock environment's site-packages directory, adapting to platform differences.

```toml
[environment]
python = ".venv"
python-version = "3.13"

```

--------------------------------

### Install npm

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Installs Node Package Manager (`npm`), which may be required for certain development tasks. Use your system's package manager (e.g., Homebrew) if preferred.

```shell
brew install npm
```

--------------------------------

### Configure ruff-action with Custom Parameters

Source: https://github.com/astral-sh/ruff/blob/main/docs/integrations.md

This example shows how to configure `ruff-action` with specific parameters, such as Ruff version, command-line arguments, and source paths, to customize the linting process.

```yaml
- uses: astral-sh/ruff-action@v3
  with:
    version: 0.8.0
    args: check --select B
    src: "./src"
```

--------------------------------

### Initialize AWS MediaTailor Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaTailor client. Provide the region name and any necessary authentication or configuration details.

```python
(service_name: Literal['mediatailor'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Project Structure

Source: https://github.com/astral-sh/ruff/blob/main/docs/tutorial.md

Displays the default file structure created by `uv init`.

```text
numbers
  	├── README.md
  	├── pyproject.toml
  	└── src
      	└── numbers
          	├── __init__.py
          	└── py.typed
```

--------------------------------

### Install specific Ruff version with standalone installers

Source: https://github.com/astral-sh/ruff/blob/main/README.md

Install a specific version of Ruff using the standalone installer script.

```shell
# For a specific version.
curl -LsSf https://astral.sh/ruff/0.15.18/install.sh | sh

```

```shell
powershell -c "irm https://astral.sh/ruff/0.15.18/install.ps1 | iex"

```

--------------------------------

### Initialize AWS MediaPackage v2 Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaPackage v2 client. Provide the region name and any necessary authentication or configuration details.

```python
(service_name: Literal['mediapackagev2'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Ruff Configuration in ruff.toml

Source: https://github.com/astral-sh/ruff/blob/main/docs/configuration.md

This example shows the equivalent configuration in `ruff.toml`, demonstrating the omission of the `[tool.ruff]` header and `tool.ruff` prefix.

```toml
[lint]
# 1. Enable flake8-bugbear (`B`) rules, in addition to the defaults.
select = ["E4", "E7", "E9", "F", "B"]

# 2. Avoid enforcing line-length violations (`E501`)
ignore = ["E501"]

# 3. Avoid trying to fix flake8-bugbear (`B`) violations.
unfixable = ["B"]

# 4. Ignore `E402` (import violations) in all `__init__.py` files, and in selected subdirectories.
[lint.per-file-ignores]
"__init__.py" = ["E402"]
"**/{tests,docs,tools}/*" = ["E402"]

[format]
# 5. Use single quotes in `ruff format`.
quote-style = "single"
```

--------------------------------

### Install specific Ruff version with standalone installer (macOS/Linux)

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Download and execute the standalone installer script for a specific Ruff version on macOS and Linux.

```shell
$ # For a specific version.
$ curl -LsSf https://astral.sh/ruff/0.5.0/install.sh | sh
```

--------------------------------

### `__new__` and `__init__` with Incompatible Signatures (Example 2)

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/call/constructor.md

Continues the analysis of incompatible `__new__` and `__init__` signatures. This example shows a class where `__new__` requires an argument, but `__init__` does not, leading to specific type errors.

```python
class Foo2:
    def __new__(cls, x) -> "Foo2":
        return object.__new__(cls)

    def __init__(self):
        pass

# error: [missing-argument] "No argument provided for required parameter `x` of constructor `Foo2.__new__`"
reveal_type(Foo2())  # revealed: Foo2

# error: [too-many-positional-arguments] "Too many positional arguments to `Foo2.__init__`: expected 1, got 2"
reveal_type(Foo2(42))  # revealed: Foo2
```

--------------------------------

### Writing to Mock Site-Packages

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_test/README.md

Example of writing a Python file to the mock environment's site-packages directory using a magic path.

```py
X = 1

```

--------------------------------

### Initialize AWS MediaStore Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaStore client. Ensure the region name is correctly specified for your AWS environment.

```python
(service_name: Literal['mediastore'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Install Specific Ruff Version Standalone (macOS/Linux)

Source: https://github.com/astral-sh/ruff/blob/main/docs/faq.md

Install a specific version of Ruff using the standalone installer script for macOS and Linux. Replace '0.5.0' with the desired version.

```console
$ curl -LsSf https://astral.sh/ruff/0.5.0/install.sh | sh
```

--------------------------------

### Navigate to benchmark directory

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/README.md

Change the current directory to the 'ty' benchmark directory.

```shell
cd scripts/ty_benchmark
```

--------------------------------

### Run Ruff from command line

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Execute Ruff commands for linting and formatting after installation.

```console
$ ruff check   # Lint all files in the current directory.
$ ruff format  # Format all files in the current directory.
```

--------------------------------

### Install Ruff with Conda

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff from the conda-forge channel using the Conda package manager.

```console
$ conda install -c conda-forge ruff
```

--------------------------------

### Install Ruff with Homebrew

Source: https://github.com/astral-sh/ruff/blob/main/docs/installation.md

Install Ruff using the Homebrew package manager on macOS and Linux.

```console
$ brew install ruff
```

--------------------------------

### Configure Project Root Directories

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty/docs/configuration.md

Specify multiple directories for finding first-party modules. Paths are searched in priority order. If unspecified, Ty attempts to detect common project layouts.

```toml
[tool.ty.environment]
# Multiple directories (priority order)
root = ["./src", "./lib", "./vendor"]
```

```toml
[environment]
# Multiple directories (priority order)
root = ["./src", "./lib", "./vendor"]
```

--------------------------------

### Initialize AWS MediaPackage Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaPackage client. Ensure the region name is correctly specified for your AWS environment.

```python
(service_name: Literal['mediapackage'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Initialize AWS Metering Marketplace Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the Metering Marketplace client. Provide the region name and any necessary authentication or configuration details.

```python
(service_name: Literal['meteringmarketplace'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Configure Ruff with conform.nvim

Source: https://github.com/astral-sh/ruff/blob/main/docs/editors/setup.md

Set up Ruff formatters (fix, format, organize_imports) for Python files using the conform.nvim plugin.

```lua
require("conform").setup({
    formatters_by_ft = {
        python = {
          -- To fix auto-fixable lint errors.
          "ruff_fix",
          -- To run the Ruff formatter.
          "ruff_format",
          -- To organize the imports.
          "ruff_organize_imports",
        },
    },
})
```

--------------------------------

### Install nextest for test execution

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty/CONTRIBUTING.md

Installs the nextest test runner for improved test suite execution.

```shell
cargo install cargo-nextest --locked
```

--------------------------------

### Non-Simplifiable Union Example

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/type_properties/constraints.md

Provides an example of a union that does not simplify due to comparability issues with intermediate types.

```python
def _[T]() -> None:
    # (Sub ≤ T@_ ≤ Super) ∨ (SubSub ≤ T@_ ≤ Base)
    ConstraintSet.range(SubSub, T, Base) | ConstraintSet.range(Sub, T, Super)
```

--------------------------------

### Fluent Layout for Method Chains (Preview Style)

Source: https://github.com/astral-sh/ruff/blob/main/docs/formatter.md

Demonstrates Ruff's preview style for formatting long method chains, breaking lines before the first attribute preceding a call.

```python
x = (
    df
    .filter(cond)
    .agg(func)
    .merge(other)
)
```

--------------------------------

### Initialize AWS MediaStore Data Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaStore Data client. Specify the region name and other optional parameters.

```python
(service_name: Literal['mediastore-data'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Build ty

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/README.md

Build the 'ty' binary in release mode.

```shell
cargo build --bin ty --release
```

--------------------------------

### Configure Custom Markdown Extensions (ruff.toml)

Source: https://github.com/astral-sh/ruff/blob/main/docs/formatter.md

Example TOML configuration for `ruff.toml` to treat `.mdx` and `.qmd` files as Markdown.

```toml
# Treat `.mdx` and `.qmd` files as Markdown
extension = {mdx="markdown", qmd="markdown"}
```

--------------------------------

### get Method with Closed TypedDicts

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/typed_dict.md

Demonstrates how the `get` method behaves with closed TypedDicts, accounting for declared items.

```Python
from typing_extensions import TypedDict

class Closed(TypedDict, closed=True):
    name: str
    year: int

FunctionalClosed = TypedDict(
    "FunctionalClosed",
    {"name": str, "year": int},
    closed=True,
)

class EmptyClosed(TypedDict, closed=True): ...

def _(closed: Closed, functional: FunctionalClosed, empty: EmptyClosed, key: str) -> None:
    reveal_type(closed.get(key))  # revealed: str | int | None
    reveal_type(functional.get(key))  # revealed: str | int | None
    reveal_type(empty.get(key))  # revealed: None
```

--------------------------------

### Neovim 0.11+ Ruff LSP Configuration (No Dependencies)

Source: https://github.com/astral-sh/ruff/blob/main/docs/editors/setup.md

Store this configuration in nvim/lsp/ruff.lua or nvim/after/lsp/ruff.lua for Neovim 0.11+ without external dependencies.

```lua
---@type vim.lsp.Config  
return {
  cmd = { 'ruff', 'server' },
  filetypes = { 'python' },
  root_markers = { 'pyproject.toml', 'ruff.toml', '.ruff.toml', '.git' },
  init_options = {
    settings = {
      -- Ruff language server settings go here
    }
  }
}
```

--------------------------------

### Configure Ruff Import Strategy

Source: https://github.com/astral-sh/ruff/blob/main/docs/editors/settings.md

Set the strategy for loading the Ruff executable. 'fromEnvironment' finds Ruff in the environment, falling back to the bundled version, while 'useBundled' exclusively uses the bundled version.

```json
{
    "ruff.importStrategy": "useBundled"
}
```

--------------------------------

### Example Full Diagnostic Output

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_test/README.md

Provides an example of the expected diagnostic output format for a given Python code snippet.

```output
mdtest_snippet.py, line 1, col 1: revealed type is 'Literal[1]'
```

--------------------------------

### TypedDict get() with Gradual Defaults

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/typed_dict.md

Explains the type inference for `get()` when a gradual default is provided, resulting in 'Unknown' type.

```python
from typing import Any, TypedDict

class GradualDefault(TypedDict, total=False):
    x: int

def _(td: GradualDefault, default: Any) -> None:
    reveal_type(td.get("x", default))  # revealed: Unknown
```

--------------------------------

### Run benchmarks

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/README.md

Execute the 'ty' benchmarks using 'uv run'. Requires hyperfine 1.20 or newer.

```shell
uv run benchmark
```

--------------------------------

### TypedDict get() with Known-Key Context

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/typed_dict.md

Demonstrates how `get()` utilizes known-key context for default arguments, especially with nested TypedDicts.

```python
from typing import TypedDict

class ResolvedData(TypedDict, total=False):
    x: int

class Payload(TypedDict, total=False):
    resolved: ResolvedData

class Payload2(TypedDict, total=False):
    resolved: ResolvedData

def takes_resolved(value: ResolvedData) -> None: ...
def _(payload: Payload) -> None:
    reveal_type(payload.get("resolved", {}))  # revealed: ResolvedData
    takes_resolved(payload.get("resolved", {}))

def _(payload: Payload | Payload2) -> None:
    reveal_type(payload.get("resolved", {}))  # revealed: ResolvedData
    takes_resolved(payload.get("resolved", {}))
```

--------------------------------

### Initialize AWS MediaPackage VOD Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaPackage VOD client. Specify the region name and other optional parameters.

```python
(service_name: Literal['mediapackage-vod'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Mac Profiling with Cargo Instruments

Source: https://github.com/astral-sh/ruff/blob/main/CONTRIBUTING.md

Profile Ruff benchmarks on macOS using `cargo-instruments`. Install the tool with `cargo install cargo-instruments`.

```shell
cargo install cargo-instruments
```

```shell
cargo instruments -t time --bench linter --profile profiling -p ruff_benchmark -- --profile-time=1
```

--------------------------------

### Multi-File Test Setup

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_test/README.md

Define multiple files for a single test by specifying file paths before the code block. Files are relative to the workspace root, which also serves as an import root.

```python
from b import C
reveal_type(C)  # revealed: Literal[C]
```

```python
class C: pass
```

--------------------------------

### Unsupported Operator Examples in Ruff

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/binary/custom.md

These examples show common unsupported operator errors detected by Ruff when using incompatible types.

```python
reveal_type(No() @ Yes())  # revealed: Unknown
```

```python
reveal_type(No() / Yes())  # revealed: Unknown
```

```python
reveal_type(No() % Yes())  # revealed: Unknown
```

```python
reveal_type(No() ** Yes())  # revealed: Unknown
```

```python
reveal_type(No() << Yes())  # revealed: Unknown
```

```python
reveal_type(No() >> Yes())  # revealed: Unknown
```

```python
reveal_type(No() | Yes())  # revealed: Unknown
```

```python
reveal_type(No() ^ Yes())  # revealed: Unknown
```

```python
reveal_type(No() & Yes())  # revealed: Unknown
```

```python
reveal_type(No() // Yes())  # revealed: Unknown
```

--------------------------------

### Overloaded Function Usage Example

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/annotations/callable.md

An example showcasing the usage of an overloaded function `foo` within a loop, processing a range of integers.

```python
from typing import overload

@overload
def foo(x: int) -> str: ...
@overload
def foo(x: str) -> str: ...
def foo(x: int | str) -> str:
    return str(x)

def errors() -> None:
    for x in map(foo, range(1, 10)):
        print(x)
```

--------------------------------

### Enum with Custom Start Value

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/enums.md

Shows how to use the 'start' keyword argument to specify the initial value for Enum and Flag members.

```Python
from enum import Enum, Flag

Color = Enum("Color", "RED GREEN BLUE", start=0)

reveal_type(Color.RED.value)  # revealed: Literal[0]
reveal_type(Color.GREEN.value)  # revealed: Literal[1]
reveal_type(Color.BLUE.value)  # revealed: Literal[2]

Perm = Flag("Perm", "READ WRITE EXECUTE", start=3)

reveal_type(Perm.READ.value)  # revealed: Literal[3]
reveal_type(Perm.WRITE.value)  # revealed: Literal[4]
reveal_type(Perm.EXECUTE.value)  # revealed: Literal[8]
```

--------------------------------

### Initialize AWS MediaConvert Client

Source: https://github.com/astral-sh/ruff/blob/main/scripts/ty_benchmark/snapshots/homeassistant_Pyrefly.txt

Use this to initialize the MediaConvert client. Specify the region name and other optional parameters as needed.

```python
(service_name: Literal['mediaconvert'], region_name: str | None = ..., api_version: str | None = ..., use_ssl: bool | None = ..., verify: bool | str | None = ..., endpoint_url: str | None = ..., aws_access_key_id: str | None = ..., aws_secret_access_key: str | None = ..., aws_session_token: str | None = ..., config: Config | None = ..., aws_account_id: str | None = ...) -> Unknown
```

--------------------------------

### Migrate ruff-lsp Configuration to Native Server (JSON)

Source: https://github.com/astral-sh/ruff/blob/main/docs/editors/migration.md

This example shows how to migrate from using `ruff.lint.args` and `ruff.format.args` to specify a custom configuration file in `ruff-lsp` to using the `ruff.configuration` setting in the native Ruff server. This consolidates configuration for both linting and formatting.

```json
{
    "ruff.lint.args": "--config ~/.config/custom_ruff_config.toml",
    "ruff.format.args": "--config ~/.config/custom_ruff_config.toml"
}
```

```json
{
    "ruff.configuration": "~/.config/custom_ruff_config.toml"
}
```

--------------------------------

### Non-callable __init_subclass__ Example

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/lint_docs/non-callable-init-subclass.md

This example shows a class `Super` with `__init_subclass__` set to `None`. Attempting to subclass `Super` will result in a `TypeError` at runtime.

```python
class Super:
    __init_subclass__ = None


class Sub(Super): ...
```

--------------------------------

### Basic Dataclass Fields

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/dataclasses/fields.md

Demonstrates defining fields with default values and controlling initialization with `init=False`. Shows how to create instances and assign values to fields.

```Python
from dataclasses import dataclass, field

@dataclass
class Member:
    name: str
    role: str = field(default="user")
    tag: str | None = field(default=None, init=False)

# revealed: (self: Member, name: str, role: str = "user") -> None
reveal_type(Member.__init__)

alice = Member(name="Alice", role="admin")
reveal_type(alice.role)  # revealed: str
alice.role = "moderator"

# `tag` is marked as `init=False`, so this is an
# error: [unknown-argument] "Argument `tag` does not match any known parameter"
bob = Member(name="Bob", tag="VIP")
```

--------------------------------

### Multiline Interpolated String Suppression (Start Line)

Source: https://github.com/astral-sh/ruff/blob/main/crates/ty_python_semantic/resources/mdtest/suppressions/type_ignore.md

For multiline interpolated strings, the `type: ignore` comment can be placed on the line where the expression starts.

```python
# fmt:off
a = f"""
{
  10 /  # type: ignore
  0
}
"""
```