checkout-kit / rules

---
description: Swift development workflow and language server workarounds
globs: ["**/*.swift"]
alwaysApply: true
---

# SWIFT DEVELOPMENT WORKFLOW

## ⚠️ IMPORTANT: Language Server Issues

**IGNORE ALL LANGUAGE SERVER ERRORS IN SWIFT FILES**
- The language server reports errors erroneously while code compiles fine
- Do NOT trust red squiggles or inline error messages
- Always verify issues using the commands below instead

## Verification Commands

### Check your work systematically:
1. **Lint & Format** → `dev swift lint` (or `dev swift style`) - Checks for linting and stylistic errors
2. **Build Issues** → `dev swift build` - Checks for compilation issues
3. **Test Issues** → `dev swift test` - Checks for failing tests

### Available dev commands:
**See `dev.yml` in project root for complete list of commands and descriptions.**

Key commands for verification:
- `dev swift lint` (alias: `dev swift style`) - Check format & lint issues
- `dev swift format` - Auto-format and apply safe lint autocorrections
- `dev swift build packages` - Build Swift package targets
- `dev swift test` - Run all tests

## Concurrency Best Practices

### DO: Use actors for thread-safe shared state
```swift
actor QueryCache {
    private var cache: [String: Any] = [:]
    private var inflightRequests: [String: Any] = [:]
    
    func loadCached<T>(...) async throws -> T {
        // Safe concurrent access to shared state
    }
}
```

## Workflow Best Practices

### When you see errors:
❌ DON'T: Trust language server errors in Xcode/editor
✅ DO: Run the appropriate dev command to verify

### After making changes:
- ALWAYS run `dev swift format && dev swift lint` to check your code is formatted and written in our style.

## Example Workflow

```bash
# Make your Swift changes...

# Fix any auto-fixable issues
dev swift format

# Check for any remaining lint issues
dev swift lint

# Verify it compiles
dev swift build

# Run tests if needed
dev swift test
```