Crossplane YAML

Crossplane-aware YAML support for Zed.

This extension adds:

• Crossplane package diagnostics
• Crossplane YAML syntax highlighting
• Go-template highlighting inside Crossplane function-go-templating inline templates
• YAML highlighting inside generated YAML sections of those templates

The extension manages its language server automatically. No separate setup is needed for normal use.

Status

Crossplane YAML is waiting to be included in the Zed extension registry:

zed-industries/extensions#6157

If you want to show interest, add a thumbs-up reaction to that PR. Please avoid comment-only "+1" messages.

This only affects marketplace discovery and install through zed: extensions. The extension is usable today as a local dev extension.

Installation

Until the marketplace PR is merged, install it as a local dev extension.

Install Rust with rustup if you do not already have it. Zed's dev-extension workflow expects a rustup-managed Rust toolchain.

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

On macOS with Homebrew, install rustup with:

brew install rustup
$(brew --prefix rustup)/bin/rustup-init

Prefer rustup for this setup. Homebrew's rust formula installs a standalone Rust toolchain, while rustup installs and manages the Rust toolchains Zed expects for dev extensions.

Clone this repository:

git clone https://github.com/io41/crossplane-yaml.git

In Zed:

1. Open the command palette.
2. Run zed: install dev extension.
3. Select the cloned crossplane-yaml directory.
4. Restart Zed if the language does not appear immediately.

Usage

Open a file classified as Crossplane YAML.

The extension recognizes common Crossplane package filenames, including:

• crossplane.yaml
• crossplane.yml
• upbound.yaml
• upbound.yml
• composition.yaml
• composition.yml
• definition.yaml
• definition.yml

Many Crossplane repositories use project-specific filenames, such as xexample-composition.yaml, that Zed will otherwise open as regular YAML.

For a one-off file, use Zed's language selector in the status bar and choose Crossplane YAML.

For a repository naming pattern, open Zed settings with zed: open settings and add patterns under file_types:

{
  "file_types": {
    "Crossplane YAML": [
      "**/*-composition.yaml",
      "**/*-composition.yml",
      "**/*-definition.yaml",
      "**/*-definition.yml"
    ]
  }
}

Use patterns that only match Crossplane package files. For example, if all YAML files under your package api/ or apis/ directories are Crossplane resources, you can add directory-scoped patterns:

{
  "file_types": {
    "Crossplane YAML": [
      "**/api/**/*.yaml",
      "**/api/**/*.yml",
      "**/apis/**/*.yaml",
      "**/apis/**/*.yml"
    ]
  }
}

Reopen matching files after changing the setting.

If you want Zed extensions to be able to automatically select Crossplane YAML for Crossplane files without manual file_types settings, add a thumbs-up reaction to this Zed discussion:

zed-industries/zed#56434

Please avoid comment-only "+1" messages.

The extension keeps Zed's normal YAML support enabled for ordinary YAML files.

Template Highlighting

Crossplane function-go-templating templates often contain YAML inside Go-template blocks. Crossplane YAML highlights both the template expressions and the YAML they generate.

Some heavily templated YAML can still look imperfect when indentation, list items, or scalar values are split across template expressions.

Troubleshooting

If the language does not appear after installing as a dev extension, restart Zed and make sure you selected the repository root containing extension.toml.

If a Crossplane file opens as regular YAML, add a file_types mapping for that filename pattern.

For development, release, and maintainer notes, see DEVELOPMENT.md.

License

MIT. See LICENSE.