RBS Sync

Synchronize RBS type signatures with Ruby code changes to keep types up-to-date.

Instructions

1. Detect Changes

Identify what changed in Ruby source:

Method changes:

• New methods added
• Methods removed
• Parameter changes (added/removed/reordered)
• Return type changes

Class structure changes:

• New classes/modules
• Inheritance changes
• Module inclusions
• Constant additions/removals

Attribute changes:

• New attr_* declarations
• Instance variable additions

2. Compare Source and Signatures

For each Ruby file with changes:

1. Parse the Ruby file to extract:

   • Class/module hierarchy
   • Method definitions with parameters
   • Attribute accessors
   • Constants

2. Parse corresponding RBS file to get current signatures

3. Generate diff:

   • Methods in Ruby but not in RBS (additions needed)
   • Methods in RBS but not in Ruby (removals needed)
   • Parameter mismatches (updates needed)

3. Update Strategy

For new methods:

• Infer types from implementation
• Add signature to appropriate location in RBS
• Maintain alphabetical or logical ordering

For removed methods:

• Remove from RBS file
• Check for references in other signatures

For parameter changes:

• Update parameter types
• Preserve existing type annotations where valid
• Re-infer types for new parameters

For renamed methods:

• Remove old signature
• Add new signature with inferred types

4. Sync Commands

# Generate RBS prototype from Ruby
rbs prototype rb lib/my_class.rb > sig/lib/my_class.rbs

# Update from runtime (if typeprof available)
typeprof lib/my_class.rb -o sig/lib/my_class.rbs

5. Preserve Manual Annotations

When syncing, preserve:

• Manually refined types (more specific than auto-generated)
• Documentation comments
• Complex generic types
• Custom type aliases

6. Sync Report Format

## RBS Sync Report

### Files Analyzed
- `lib/user.rb` -> `sig/lib/user.rbs`

### Additions
```rbs
def validate_email: (String email) -> bool

Removals

def legacy_process: () -> void

Updates

# Parameter added
- def create: (String name) -> User
+ def create: (String name, ?String email) -> User

### 7. Handling Edge Cases

**Metaprogramming:**
- `define_method` - add comment noting dynamic definition
- `method_missing` - use `...` for catch-all

**DSLs:**
- Rails associations - generate relationship types
- Callbacks - document but may not need signatures

## Sync Workflow

1. **Identify changed Ruby files:**
```bash
git diff --name-only HEAD~1 -- '*.rb'

2. For each changed file, compare with RBS:

   • Read Ruby source
   • Read existing RBS
   • Compute differences

3. Generate updates:

   • Create new signatures for additions
   • Mark removals
   • Update changed signatures

4. Apply changes:

   • Edit RBS files
   • Validate syntax
   • Run type checker