Strategies for Managing and Refactoring Legacy Code

In a talk recorded at Code BEAM America 2024, Dmytro Lytovchenko describes the complexities and strategies associated with working with legacy code. The presentation begins by defining legacy code as often being large, complex, and undocumented code that no one currently feels responsible for. Lytovchenko proposes a step-by-step framework for approaching such codebases: understanding existing dependencies, reviewing documentation, leveraging tests, and planning incremental refactoring steps. He emphasizes the importance of scratch refactoring, where developers intentionally break parts of the code to understand it better by observing what fails and where errors occur. Using examples from his career, Lytovchenko outlines methods including replay testing, regression testing, and code coupling analysis to gradually transform legacy systems into maintainable software.