moai-workflow-ddd

To refactor legacy code while preserving behavior, you must first establish a safety net using characterization tests and behavior snapshots. Then, apply incremental structural improvements with continuous validation to guarantee functional equivalence throughout the process.

AST-grep enables safe code refactoring by analyzing structural code patterns and domain boundaries at the syntax tree level. This allows you to apply incremental transformations while continuously validating that the changes preserve the original behavior.

The best way to migrate legacy APIs without regressions is to use behavior-preserving code transformation. This involves creating characterization tests to capture existing behavior, followed by incremental AST-based modifications to ensure functional equivalence.

Yes, ast-grep supports analyzing domain boundaries and coupling metrics to identify structural code patterns. This analysis helps target technical debt reduction safely by guiding incremental refactoring steps while preserving functional equivalence.

To create characterization tests before improving code structure, you capture behavior snapshots of the current system. These tests act as a safety net, ensuring that any incremental structural changes or API migrations maintain strict functional equivalence.

You should avoid incremental refactoring for legacy systems when you cannot establish characterization tests or behavior snapshots. Without this safety net, guaranteeing functional equivalence during structural improvements and technical debt reduction is not possible.