We share our lessons learned on how to regain control of a legacy codebase written in Java (https://github.com/xpepper/fifty-shades-of-legacy-goose-game/tree/master/goose-game-two). This codebase shows some classic design problems but more than that, badly expresses the domain of the problem we want to solve. During the session we will tackle the code the XP way: it will be a live refactoring in pair programming; we will show how the quality and expressiveness of the code can be progressively improved if we apply some good development practices with the help of some effective tools.

1. Surviving to a legacy codebase
Paolo D’Incau & Pietro Di Bello
Berlin | November 20 - 21, 2018

2. Surviving to a legacy codebase
How we take back control of legacy
codebases

3. Pietro Di Bello
@pierodibello
Paolo D’Incau
@pdincau

4. What is legacy code? 🤔

5. “Code without tests.” 🤠
Michael Feathers

6. “Valuable code that we feel afraid
to change.” 💰
J.B. Rainsberger

7. Welcome to Board Games GmbH…

9. Surviving principle #1: understand
the context of your software 🔦

10. Go talk with the business

11. The business of Board Games GmbH
knows that…

12. Users complain about a bug and we
are losing customers and
reputation! 💸

13. In a few weeks one of our
key gaming policies will change…

14. Let’s open the project and start
gaining confidence

15. Surviving principle #2: maximize
safety ⛑

16. Move carefully and take tiny steps

17. Remember to keep the focus on
what matters 👁

18. Remember to be a good scout

19. Reduce the information overload 🤯

20. Slowly expand your sphere of
control on the codebase

21. To summarise…

22. “The journey of a thousand miles
begins with one step.”
Lao Tzu

23. Refactoring should be driven by real
and emergent needs

24. www.xpeppers.com
/xpepperssrl@xpeppers

25. Have fun with the Goose Game:
https://github.com/xpepper/fifty-shades-
of-legacy-goose-game/

26. https://goo.gl/gvu1ZK
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