From Simple to PubGrub: The Evolution of Cargo's Resolver

Cargo’s 10 year journey from basic dependency handling to its upcoming PubGrub-based resolver, reflects the growing complexity of the Rust ecosystem. We’ll start with fundamental concepts of dependency resolution, explore a minimal implementation, and see how performance requirements drive complexity, and how complexity resist development. From this history we will understand why logical consistency becomes crucial for maintainability, ultimately leading to Cargo’s effort to adopt PubGrub’s algorithm.