Generate Bug Fix

Bug Fix Generator

Templates and patterns for generating minimal, safe bug fixes.

Fix Generation Principles

1. Minimal Change

• Fix only what's broken
• No refactoring
• No "improvements"
• No formatting changes

2. Safe Change

• Preserve existing behavior
• Maintain API contracts
• Keep backward compatibility
• Add, don't remove

3. Tested Change

• Reproduction test first
• Fix makes test pass
• Existing tests still pass

Fix Templates by Category

Quick Reference

Null Pointer → Guard Clause

$entity = $this->repository->find($id);
if ($entity === null) {
    throw new EntityNotFoundException($id);
}

Logic Error → Condition Fix

// Wrong: if ($a > $b)
// Fixed: if ($a >= $b)

Boundary → Empty Check

if ($items === []) {
    throw new EmptyCollectionException();
}

Race Condition → Locking

$this->em->beginTransaction();
try {
    $entity = $this->repository->findWithLock($id);
    // ... modify ...
    $this->em->commit();
} catch (\Throwable $e) {
    $this->em->rollback();
    throw $e;
}

Resource Leak → Try-Finally

$resource = acquire();
try {
    return process($resource);
} finally {
    release($resource);
}

Fix Composition Rules

Order of Operations

1. Add validation/guards at the top
2. Make the minimal code change
3. Keep existing code paths intact
4. Add new exception types if needed

What NOT to Change

• Method signatures (unless required)
• Return types (unless fixing wrong type)
• Visibility modifiers
• Class structure
• Unrelated code

Commit Message Format

fix(<scope>): <short description>

<detailed description of what was wrong and how it's fixed>

Fixes #<issue-number>