Worked on the google/copybara repository to enhance repository initialization by adding SHA-256 support alongside existing SHA-1 handling in the GitRevision class. This update introduced hash length validation and label management to ensure correctness across both hash types, addressing a critical compatibility and security need for modern repositories. The approach included updating and extending unit tests to cover SHA-256 functionality, thereby increasing test coverage and preventing regressions. Delivered changes using Java and Git, focusing on robust software development practices. The work improved the security posture and future-proofed repository flows by broadening hash algorithm support without introducing regressions.