Series

Changing Existing Software

Find what the old system actually does, preserve the behavior that matters, and create a seam small enough to change without betting everything on the rewrite.

  1. A Directory Map Is Not a Redesign Plan
  2. A Characterization Suite Is Scoped to a Change
  3. A Characterization Test Is Not a Product Decision
  4. Parallel Implementations Are Not a Replacement Seam
  5. A Rewrite Needs a Behavior Ledger
  6. Technical Debt Is a Change Tax You Can Name
  7. A Small Change Limits the States a Reviewer Must Hold
  8. A Code Review Should Test the Decision, Not the Author
  9. Static Analysis Turns Assumptions into Questions
  10. Deprecation Is a Migration, Not a Warning
  11. The Strangler Pattern Still Needs an Exit Plan
  12. Stored Data Is a Caller You Cannot Find with Code Search