Flutter PR Review Skill

Expert code review assistance for Flutter pull requests, focusing on code quality, architecture patterns, performance, and Flutter/Dart best practices.

When to Use This Skill

• Reviewing pull requests in Flutter projects
• Performing code audits on Flutter/Dart code
• Checking adherence to project coding standards
• Identifying potential bugs, performance issues, or security concerns
• Ensuring consistent code style and architecture

Review Process

1. Initial Assessment

Before diving into details, understand the scope:

• What feature/fix does this PR implement?
• How many files are changed?
• What areas of the codebase are affected?

2. Review Checklist

Code Quality

• Code follows Dart style guide and project conventions
• No unused imports, variables, or dead code
• Meaningful variable and function names
• Appropriate use of const constructors
• Proper null safety handling (no unnecessary ! operators)
• No hardcoded strings (use LocaleKeys for user-facing text)

Architecture & Design

• Follows clean architecture (data/domain/presentation separation)
• Business logic separated from UI code
• Proper dependency injection patterns
• Single responsibility principle followed
• No circular dependencies

Flutter Specifics

• Widgets are properly composed (not too large)
• StatelessWidget used where possible (StatefulWidget only when needed)
• Proper widget keys used for lists and animations
• No unnecessary widget rebuilds
• Responsive design considerations

State Management

• State management follows project patterns (Riverpod/BLoC)
• State is properly scoped (not too global, not too local)
• Side effects handled appropriately
• Loading/error states handled

Performance

• ListView.builder used for long lists
• Images optimized and cached
• No expensive operations in build methods
• Async operations properly handled
• Memory leaks avoided (dispose called, subscriptions cancelled)

Security

• Sensitive data stored securely (flutter_secure_storage)
• No hardcoded API keys or secrets
• User input validated and sanitized
• No SQL injection or XSS vulnerabilities

Data Handling

• Freezed used for data models
• Dio used for HTTP requests (not http package)
• Hive used for caching (non-sensitive data)
• flutter_secure_storage for sensitive data
• Proper error handling for network calls

Testing

• Unit tests for business logic
• Widget tests for UI components
• Edge cases covered
• Mocks used appropriately

3. Review Commands

# Get list of changed files
git diff --name-only origin/main...HEAD

# Get detailed diff
git diff origin/main...HEAD

# Check for lint issues
flutter analyze

# Run tests
flutter test

# Check test coverage
flutter test --coverage

Review Response Format

When providing review feedback, use this structure:

Summary

Brief overview of the PR and overall assessment.

Critical Issues

Issues that must be fixed before merging:

• [CRITICAL] Description of blocking issue
  • File: path/to/file.dart:line
  • Suggestion: How to fix

Improvements

Suggested changes that would improve code quality:

• [SUGGESTION] Description
  • File: path/to/file.dart:line
  • Why: Explanation
  • Suggestion: How to improve

Nitpicks

Minor style or preference issues:

• [NIT] Description
  • File: path/to/file.dart:line

Positive Feedback

Highlight good practices observed:

• Good use of const constructors in WidgetName
• Clean separation of concerns in feature module

Common Flutter Anti-Patterns to Watch For

1. God Widgets

// Bad: One widget doing everything
class HomePage extends StatefulWidget {
  // 500+ lines of code
}

// Good: Composed smaller widgets
class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        const HomeHeader(),
        const HomeContent(),
        const HomeFooter(),
      ],
    );
  }
}

2. Business Logic in Widgets

// Bad: Logic in widget
class UserProfile extends StatelessWidget {
  String formatName(String first, String last) => '$first $last';

  @override
  Widget build(BuildContext context) {
    final name = formatName(user.firstName, user.lastName);
    // ...
  }
}

// Good: Logic in separate class/extension
extension UserExtension on User {
  String get fullName => '$firstName $lastName';
}

3. Missing Error Handling

// Bad: No error handling
Future<void> fetchData() async {
  final response = await dio.get('/api/data');
  setState(() => data = response.data);
}

// Good: Proper error handling
Future<void> fetchData() async {
  try {
    final response = await dio.get('/api/data');
    if (mounted) {
      setState(() => data = response.data);
    }
  } on DioException catch (e) {
    // Handle error appropriately
  }
}

4. Hardcoded Strings

// Bad: Hardcoded strings
Text('Welcome to our app')

// Good: Use LocaleKeys
Text(LocaleKeys.home_welcome.tr())

5. Improper Async in initState

// Bad: Direct async in initState
@override
void initState() {
  super.initState();
  await fetchData(); // Error: can't await in initState
}

// Good: Separate async method
@override
void initState() {
  super.initState();
  _loadData();
}

Future<void> _loadData() async {
  await fetchData();
}

6. Not Using const

// Bad: Missing const
return Container(
  padding: EdgeInsets.all(16),
  child: Text('Hello'),
);

// Good: Using const where possible
return Container(
  padding: const EdgeInsets.all(16),
  child: const Text('Hello'),
);

Security Review Points

Authentication & Authorization

• Check token storage (must use flutter_secure_storage)
• Verify token refresh logic
• Check permission handling

Data Protection

• Sensitive data encrypted at rest
• Secure communication (HTTPS only)
• No logging of sensitive information

Input Validation

• Form inputs validated
• API responses validated
• File uploads checked

Performance Review Points

Widget Optimization

• Const constructors used
• RepaintBoundary for heavy custom painters
• AutomaticKeepAliveClientMixin for tab content

List Performance

• ListView.builder for dynamic lists
• Proper itemExtent for fixed-height items
• Pagination for large datasets

Image Optimization

• Cached network images
• Proper image sizing
• WebP format when possible

Memory Management

• Dispose controllers and subscriptions
• Avoid holding references in closures
• Use weak references where appropriate

Review Etiquette

1. Be Constructive: Frame feedback as suggestions, not criticisms
2. Explain Why: Don't just say what to change, explain the reasoning
3. Prioritize: Distinguish between blocking issues and nice-to-haves
4. Acknowledge Good Work: Highlight positive aspects
5. Be Specific: Reference exact file and line numbers
6. Suggest Solutions: Provide code examples when helpful

Notes

This skill focuses on Flutter-specific review concerns. For state management specifics (Riverpod/BLoC), refer to the dedicated state management skills for deeper review of those patterns.