General Refactoring Patterns
Pattern: Nested Ifs → Guard Clauses
Before:
python
def process_user(user):
if user is not None:
if user.is_active:
if user.has_permission('write'):
return user.update_profile()
else:
return None
else:
return None
else:
return None
After:
python
def process_user(user):
if user is None:
return None
if not user.is_active:
return None
if not user.has_permission('write'):
return None
return user.update_profile()
Pattern: Long Function → Extract Method
Before:
python
def generate_report(data):
# Validation
if not data:
raise ValueError("No data")
# Calculation
total = sum(item['value'] for item in data)
average = total / len(data)
# Formatting
return f"Total: {total}, Average: {average:.2f}"
After:
python
def generate_report(data):
_validate_data(data)
stats = _calculate_statistics(data)
return _format_report(stats)
def _validate_data(data):
if not data:
raise ValueError("No data")
def _calculate_statistics(data):
values = [item['value'] for item in data]
return {'total': sum(values), 'average': sum(values) / len(values)}
def _format_report(stats):
return f"Total: {stats['total']}, Average: {stats['average']:.2f}"
Migration Principles
Semantic Correctness
- •CRITICAL: Migrated code must produce identical outputs for all inputs
- •Preserve error handling behavior
- •Maintain side effects (file I/O, DB calls)
Test Coverage
- •Project 1: Aim for 100% line coverage (maximizes 30% scoring weight)
- •Project 3: All RAW SQL must be covered by tests (30% scoring weight)
- •Generate edge case tests (zero, null, boundary values)
Comment Handling
- •Preserve meaningful comments explaining "why"
- •Update comments if code structure changes
- •When migrating languages, translate comments to target language
Formatting Standards
- •Python: PEP 8 (4 spaces, snake_case)
- •Go: gofmt (tabs, CamelCase)
- •TypeScript: Prettier (2 spaces, camelCase)