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# Superset Frontend Linting Architecture

## Overview
We use a hybrid linting approach combining OXC (fast, standard rules) with custom AST-based checks for Superset-specific patterns.

## Components

### 1. Primary Linter: OXC
- **What**: Oxidation Compiler's linter (oxlint)
- **Handles**: 95% of linting rules (standard ESLint rules, TypeScript, React, etc.)
- **Speed**: ~50-100x faster than ESLint
- **Config**: `oxlint.json`

### 2. Custom Rule Checker
- **What**: Node.js AST-based script
- **Handles**: Superset-specific rules:
  - No literal colors (use theme)
  - No FontAwesome icons (use Icons component)
  - No template vars in i18n
- **Speed**: Fast enough for pre-commit
- **Script**: `scripts/check-custom-rules.js`

## Developer Workflow

### Local Development
```bash
# Fast linting (OXC only)
npm run lint

# Full linting (OXC + custom rules)
npm run lint:full

# Auto-fix what's possible
npm run lint-fix
```

### Pre-commit
1. OXC runs first (via `scripts/oxlint.sh`)
2. Custom rules check runs second (lightweight, AST-based)
3. Both must pass for commit to succeed

### CI Pipeline
```yaml
- name: Lint with OXC
  run: npm run lint

- name: Check custom rules
  run: npm run check:custom-rules
```

## Why This Architecture?

### ✅ Pros
1. **No binary distribution issues** - ASF compatible
2. **Fast performance** - OXC for bulk, lightweight script for custom
3. **Maintainable** - Custom rules in JavaScript, not Rust
4. **Flexible** - Can evolve as OXC adds plugin support
5. **Cacheable** - Both OXC and Node.js are standard tools

### ❌ Cons  
1. **Two tools** - Slightly more complex than single linter
2. **Duplicate parsing** - Files parsed twice (once by each tool)

### 🔄 Migration Path
When OXC supports JavaScript plugins:
1. Convert `check-custom-rules.js` to OXC plugin format
2. Consolidate back to single tool
3. Keep same rules and developer experience

## Implementation Checklist

- [x] OXC for standard linting
- [x] Pre-commit integration  
- [ ] Custom rules script
- [ ] Combine in npm scripts
- [ ] Update CI pipeline
- [ ] Developer documentation

## Performance Targets

| Operation | Target Time | Current |
|-----------|------------|---------|
| Pre-commit (changed files) | <2s | ✅ 1.5s |
| Full lint (all files) | <10s | ✅ 8s |
| Custom rules check | <5s | 🔄 TBD |

## Caching Strategy

### Local Development
- OXC: Built-in incremental checking
- Custom rules: Use file hash cache (similar to pytest cache)

### CI
- Cache `node_modules` (includes oxlint binary)
- Cache custom rules results by commit hash
- Skip unchanged files using git diff

## Future Improvements

1. **When OXC adds plugin support**: Migrate custom rules to OXC plugins
2. **Consider Biome**: Another Rust-based linter with plugin support
3. **AST sharing**: Investigate sharing AST between tools to avoid double parsing