incremental-implementation

To implement multi-file features without breaking the build, deliver incremental, testable vertical slices that keep the repository buildable at each step. Each code change must compile, pass tests, and be committed atomically.

A vertical slice in incremental software development is a complete, testable end-to-end increment spanning database, API, and UI. Delivering these slices ensures each increment ships working functionality rather than partial horizontal layers.

Feature flags for incomplete code changes keep the codebase compilable and safe by hiding unfinished work behind toggles. This supports safe defaults and rollback-friendly commits without exposing partial functionality.

The best way to refactor a codebase across multiple layers is applying incremental discipline with atomic, rollback-friendly commits. Surface high-risk assumptions early using a risk-first strategy and avoid touching unrelated files.

Test-driven development works with large cross-layer refactors by enforcing small, testable increments that pass the test suite at each step. This prevents hidden bugs and ensures each committed increment is reversible.

Large feature implementations cause painful rollbacks because single-pass multi-file changes hide bugs and break builds. Enforcing incremental, testable commits ensures each change is small, reversible, and keeps the repository buildable.