Working With Legacy Rails Apps

Transcript

1. Working With Legacy Rails Apps @this_ahmed
2. Working With Legacy Rails Apps @this_ahmed
3. legacy code • untested code (Michael C. Feathers) • code someone else wrote (old gems, outsourcing, maintainers left) • difficult to work with • risky to change • but serves a useful function
4. googling legacy code …
5. every project has legacy code?
7. • learning & experimenting • ambitious applications • big project, developer churn, hiring outside help • bad code … even with the best of intentions • “Technical debt”
9. –Robert C. Martin “Even the most disciplined development team, knowing the best principles, using the best patterns, and following the best practices will create messes from time to time.”
10. in the face of legacy code you can …
12. or…
14. Useful techniques
15. Rebuild Refactor
16. –Robert C. Martin “…taking a tangled, opaque, convoluted system and slowly, gradually, piece by piece, step by step, turning it into a simple, nicely structured, well-designed system.”
17. Boy Scout Rule Clean up around you work area. Small fixes; small refractors.
18. cover and modify • add unit test • test passes • modify code • test passes
19. use mock objects to break dependencies
21. mock dependencies
22. break complicated dependencies with seams
24. seam => put in method + stub
25. first step to later refactor
26. i don’t understand this code…
27. Ask someone
28. code archeology
29. code archeology git blame / Github
30. code archeology search code for context git blame / Github
31. code archeology project management ticket git blame / Github search code for context
32. code archeology git blame / Github project management ticket commit message search code for context
33. review • boy scout rule • cover and modify • break dependencies with mocks and seams • understand code with archeology
34. some parting thoughts
35. unit test
38. • code review • small git branches • add lots of context in pull request / commit message