Tempo Lints

Shared ast-grep lint rules for Tempo projects.

⚠️ This project is under active development ⚠️

Prerequisites

This package requires ast-grep (sg CLI) to run lints.

Installing ast-grep

macOS (Homebrew):

brew install ast-grep

Cargo (Rust):

cargo install ast-grep --locked

npm (global):

npm install -g @ast-grep/cli

Verify installation:

sg --version
# Should output: ast-grep 0.25.x or higher

Note: When using this package via npm/pnpm, the @ast-grep/cli dependency is included and installs the sg binary automatically via postinstall.

Installation

GitHub Action (Recommended for CI)

name: Lint
on: [push, pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: stripe/tempo-lints@v1
        with:
          language: rust  # or 'typescript' or 'all'

Action Inputs:

Input	Required	Default	Description
language	✅	—	rust, typescript, or all
path		.	Path to scan
fail-on-error		true	Fail if errors found
exclude-rules		—	Comma-separated rule IDs to skip
fix		false	Apply auto-fixes where available
post-comment		false	Post results as PR comment
github-token		—	Required if post-comment: true

npm / npx

# Run directly with npx
npx @stripe/tempo-lints rust ./src
npx @stripe/tempo-lints typescript
npx @stripe/tempo-lints all --json

# Or install globally
npm install -g @stripe/tempo-lints
tempo-lints rust ./src

Vendoring (for offline/locked environments)

# Using the CLI vendor command (recommended)
npx @stripe/tempo-lints vendor --lang rust --dest /path/to/your-project
npx @stripe/tempo-lints vendor --lang typescript --dest /path/to/your-project
npx @stripe/tempo-lints vendor --lang all --dest /path/to/your-project

This copies both language-specific rules and shared rules to .ast-grep/ and generates an sgconfig.yml.

After vendoring, run lints with:

ast-grep scan --config sgconfig.yml

CLI Usage

tempo-lints <language> [path] [options]

Arguments:
  language     Required: rust, typescript, or all
  path         Path to scan (default: current directory)

Options:
  --exclude <rules>   Comma-separated list of rules to exclude
  --json              Output results as JSON
  --fix               Apply auto-fixes where available
  --github-action     Output in GitHub Actions format with annotations
  --help, -h          Show help
  --version, -v       Show version

Examples:
  tempo-lints rust
  tempo-lints typescript ./src
  tempo-lints all --json
  tempo-lints rust --exclude no-dbg-macro,no-unwrap-in-lib
  tempo-lints typescript --fix
  tempo-lints rust --github-action   # For CI with annotations

Vendor Subcommand:
  tempo-lints vendor --lang <language> --dest <path>

  Copy lint rules to a destination project for offline/locked usage.

  Options:
    --lang <language>   Language rules to vendor (rust, typescript, or all)
    --dest <path>       Destination project path

  Examples:
    tempo-lints vendor --lang rust --dest ./my-project
    tempo-lints vendor --lang all --dest /path/to/project

Disabling Rules

Line-level disable

// ast-grep-ignore: no-emojis
let emoji = "🎉";

// ast-grep-ignore: no-console-log
console.log("debug");

Block-level disable

// ast-grep-ignore-start
let emoji1 = "🎉";
let emoji2 = "🚀";
// ast-grep-ignore-end

Adding New Rules

1. Create the rule YAML in the appropriate rules/ directory
2. Add test cases in rules/<language>/tests/<rule-id>-test.yml
3. Run npm test to generate snapshots

Development

# Install dependencies
npm install

# Test all rules
npm test

# Test specific language
npm run test:rust
npm run test:typescript
npm run test:shared-rules

# Update snapshots
npm run test:update-snapshots

# Typecheck
npm run typecheck

# Lint & format
npm run check

# Scan a directory manually
ast-grep scan --config rules/rust/sgconfig.yml /path/to/code

Contributing

1. Fork this repo
2. Add or modify rules
3. Run npm test to verify
4. Open a PR with description of the rule and rationale