Harry Potter and The Legacy Code Base (Ruby On Ales)

It's your first day at Hogwarts.com, and everything is wonderful and thrilling. You dig in to classes, and soon find a dusty book with a cryptic warning:

"Do NOT on any circumstances make ANY change to this magic incantation without talking to Doug first!!!"

Sound familiar? Approaching a legacy code base can feel like unraveling a mystery, not just about the code, but about the personalities who wrote it. What tools and techniques can help you solve the maze of twisty code? Let's explore how to get a handle on legacy code, how to negotiate joining an existing team of developers, and how we can get a summa cum laude at graduation.

Transcript

1. Harry Potter and The Legacy Code Base Saturday, March 8, 14
2. Harry Potter and The Legacy Code Base Saturday, March 8, 14
3. Saturday, March 8, 14
4. Saturday, March 8, 14
5. Saturday, March 8, 14
6. Saturday, March 8, 14
7. Saturday, March 8, 14
8. MINSWAN Saturday, March 8, 14
9. NIRD.us Saturday, March 8, 14
10. AdaDevelopersAcademy.org Saturday, March 8, 14
11. Saturday, March 8, 14
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13. WHY YOU’RE HERE • House New Hire -- You’re a new developer joining an established team • House Reorg -- Hogwarts-Online reorg assigned this to you • House Feddup -- You’ve decided you’ve had enough and volunteered Saturday, March 8, 14
14. Saturday, March 8, 14
15. LEGACY CODE ISN’T EVIL, IT’S JUST MISUNDERSTOOD Saturday, March 8, 14
16. IDEAL HABITAT • Software that has been superseded but is difficult to replace because everyone and everything relies on it • Code without tests • Code that you didn’t write • Code written before today Saturday, March 8, 14
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19. CODE ARCHEOLOGY 101 Saturday, March 8, 14
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22. CODE ARCHEOLOGY 101 • Achieve a better understanding of the overall architecture • Discover the root cause of a critical bug • Determine the best way to extend the functionality of a vestigial class • Investigate a previous approach to solving a current problem In this class you will learn how to... Saturday, March 8, 14
23. CODE ARCHEOLOGY 101 •Surveyance •Excavation •Analysis Each House will complete one of three tasks... Saturday, March 8, 14
24. BE BRAVE Saturday, March 8, 14
25. TO FALLEN COMRADES Saturday, March 8, 14
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28. Saturday, March 8, 14
29. SURVEYANCE Saturday, March 8, 14
30. TAKE INVENTORY Saturday, March 8, 14
31. ASK DUMB QUESTIONS Saturday, March 8, 14
32. FLAG MYTHS Saturday, March 8, 14
33. Tricks ↓ Techniques ↓ Process ↓ Methodology ↓ Dogma Saturday, March 8, 14
34. class Basilisk < ActiveRecord::Base def remove_poison update!(poison_quantity: 0) end end Saturday, March 8, 14
35. class PoisonBarrel < ActiveRecord::Base def self.first_free_barrel(liters_needed) free = DEFAULT_CAPACITY - liters_needed PoisonBarrel.where("liters < ?", free) end def self.with_free_space(liters_needed) if self.first_free_barrel(liters_needed) return barrels.first else return PoisonBarrel.create! end end end Saturday, March 8, 14
36. class Basilisk < ActiveRecord::Base def remove_poison barrel = PoisonBarrel. with_free_space(poison_quantity) barrel.liters += poison_quantity barrel.save! update!(poison_quantity: 0) end end Saturday, March 8, 14
37. EXCAVATION Saturday, March 8, 14
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40. "FIRST, DO NO HARM" Saturday, March 8, 14
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42. class Basilisk < ActiveRecord::Base def remove_poison warn "#remove_poison has been deprecated. “ + “Use #harvest_poison instead." harvest_poison end def harvest_poison store_poison_in(poison_container, poison_quantity) update!(poison_quantity: 0) end private def store_poison_in(container, poison_quantity) container.first_with_free_space(poison_quantity). update!(liters: poison_quantity) end end Saturday, March 8, 14
43. ANALYSIS / DOCUMENTATION Saturday, March 8, 14
44. DOCUMENT EVERYTHING Saturday, March 8, 14
45. MAKE A MAP Saturday, March 8, 14
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47. FINAL EXAMS Saturday, March 8, 14
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50. ★ glass artist ★ Vespa mechanic ★ lighting designer ★ author & teacher ★ player of games ★ software developer @kerrizor KERRI MILLER Saturday, March 8, 14
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