Compatibility Checker Analysis

Verify backward compatibility for public APIs, exported interfaces, and external contracts.

Analysis Checklist

Public API Compatibility

• Check function signatures for parameter changes (order, type, count)
• Verify return type consistency across versions
• Detect removed or renamed public methods and properties
• Validate default value changes that alter existing behavior

Interface Contracts

• Verify exported types and interfaces remain compatible
• Check protocol/trait implementations for missing methods
• Validate serialization format compatibility (JSON, protobuf, etc.)
• Ensure event schemas and message formats are backward compatible

Breaking Change Detection

• Identify semantic changes that alter behavior without API changes
• Detect configuration format changes requiring user updates
• Find removed feature flags or environment variables
• Check database schema changes affecting existing data

Migration Guide Requirements

• Define upgrade steps for each breaking change identified
• Provide deprecation warnings with recommended alternatives
• Plan compatibility shims for gradual consumer migration
• Document timeline for removing backward compatibility support

Version Strategy

• Recommend semantic versioning impact (major, minor, patch)
• Plan deprecation period length based on consumer count
• Define compatibility testing matrix across supported versions
• Identify opportunities to batch breaking changes together

Output Format

Report findings with impact ratings:

Impact	Description
Breaking	Incompatible change requiring all consumers to update
High	Behavioral change that may break consumers silently
Medium	Deprecation requiring consumer action within a timeline
Low	Compatible change with optional migration for improvement