zed/crates/extension_api
Roman Cinis 7ccef1dd89
extension_api: Expose preferred_line_length in LanguageSettings (#52175)
Closes #21822

## Context

Exposes `preferred_line_length` from `AllLanguageSettings` to the
Extension
API's `LanguageSettings` struct. Currently only `tab_size` is available
to
extensions, which prevents language extensions (e.g. Dart) from reading
the
user's preferred line length and forwarding it to their language server
(e.g. as `dart.lineLength`).

Related: https://github.com/zed-extensions/dart/issues/2

## How to Review

Small change — follow how `tab_size` is plumbed through:
1. WIT definition (`language-settings` record)
2. `extension_api` Rust struct
3. Host-side bridge conversion

The new field follows the exact same pattern.

## Self-Review Checklist

<!-- Check before requesting review: -->
- [x] I've reviewed my own diff for quality, security, and reliability
- [ ] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
  - Compile-time verified via WIT bindings; no runtime behavior change
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A
2026-03-24 19:11:30 -04:00
..
src extension_api: Expose preferred_line_length in LanguageSettings (#52175) 2026-03-24 19:11:30 -04:00
wit extension_api: Expose preferred_line_length in LanguageSettings (#52175) 2026-03-24 19:11:30 -04:00
build.rs chore: Fix several style lints (#17488) 2024-09-06 11:58:39 +02:00
Cargo.toml zed_extension_api: Fork new version of extension API (#44025) 2025-12-02 22:26:40 +00:00
LICENSE-APACHE Add initial support for defining language server adapters in WebAssembly-based extensions (#8645) 2024-03-01 16:00:55 -08:00
PENDING_CHANGES.md zed_extension_api: Start a list of pending changes (#16305) 2024-08-15 13:10:46 -04:00
README.md zed_extension_api: Release v0.6.0 (#32945) 2025-06-18 14:05:29 +00:00

The Zed Rust Extension API

This crate lets you write extensions for Zed in Rust.

Extension Manifest

You'll need an extension.toml file at the root of your extension directory, with the following structure:

id = "my-extension"
name = "My Extension"
description = "..."
version = "0.0.1"
schema_version = 1
authors = ["Your Name <you@example.com>"]
repository = "https://github.com/your/extension-repository"

Cargo metadata

Zed extensions are packaged as WebAssembly files. In your Cargo.toml, you'll need to set your crate-type accordingly:

[dependencies]
zed_extension_api = "0.6.0"

[lib]
crate-type = ["cdylib"]

Implementing an Extension

To define your extension, create a type that implements the Extension trait, and register it.

use zed_extension_api as zed;

struct MyExtension {
    // ... state
}

impl zed::Extension for MyExtension {
    // ...
}

zed::register_extension!(MyExtension);

Testing your extension

To run your extension in Zed as you're developing it:

  • Make sure you have Rust installed
  • Have the wasm32-wasip2 target installed (rustup target add wasm32-wasip2)
  • Open the extensions view using the zed: extensions action in the command palette.
  • Click the Install Dev Extension button in the top right
  • Choose the path to your extension directory.

Compatible Zed versions

Extensions created using newer versions of the Zed extension API won't be compatible with older versions of Zed.

Here is the compatibility of the zed_extension_api with versions of Zed:

Zed version zed_extension_api version
0.192.x 0.0.1 - 0.6.0
0.186.x 0.0.1 - 0.5.0
0.184.x 0.0.1 - 0.4.0
0.178.x 0.0.1 - 0.3.0
0.162.x 0.0.1 - 0.2.0
0.149.x 0.0.1 - 0.1.0
0.131.x 0.0.1 - 0.0.6
0.130.x 0.0.1 - 0.0.5
0.129.x 0.0.1 - 0.0.4
0.128.x 0.0.1