Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Confident refactors

Avatar for Mehdi Lahmam B. Mehdi Lahmam B.
June 19, 2017
Technology
150
1

Confident refactors

Avatar for Mehdi Lahmam B.

Mehdi Lahmam B.

June 19, 2017

More Decks by Mehdi Lahmam B.

See All by Mehdi Lahmam B.
Beyond code: Becoming a Product Engineer
Avatar for Mehdi Lahmam B. mehlah
0
47
Possible to measure developer productivity?
Avatar for Mehdi Lahmam B. mehlah
0
56
PG FDW FTW
Avatar for Mehdi Lahmam B. mehlah
0
190
Product culture
Avatar for Mehdi Lahmam B. mehlah
0
91
OpenAPI and AsyncAPI specifications as contracts
Avatar for Mehdi Lahmam B. mehlah
0
680
Technical Debt
Avatar for Mehdi Lahmam B. mehlah
1
300
Data informed growth
Avatar for Mehdi Lahmam B. mehlah
0
260
Serverless Ruby and AWS Lambda
Avatar for Mehdi Lahmam B. mehlah
0
190
Middleware all the things
Avatar for Mehdi Lahmam B. mehlah
2
880

Other Decks in Technology

See All in Technology
推し活エージェント
Avatar for ゆんたん yuntan_t
1
900
CC Workflow Studio
Avatar for breaking-brake seiyakobayashi
0
240
Webアクセシビリティは“もしも”に備える設計
Avatar for tomokusaba tomokusaba
0
180
【Findy FDE登壇_2026_04_14】— 現場課題を本気で解いてたら、FDEになってた話
Avatar for Koji Miyata miyatakoji
0
850
AI時代に新卒採用、はじめました/junior-engineer-never-die
Avatar for dmnlk dmnlk
0
230
Autonomous Database - Dedicated 技術詳細 / adb-d_technical_detail_jp
Avatar for oracle4engineer oracle4engineer
PRO
5
13k
Oracle AI Database@Google Cloud：サービス概要のご紹介
Avatar for oracle4engineer oracle4engineer
PRO
6
1.3k
すごいぞManaged Kubernetes
Avatar for Haruka Sakihara harukasakihara
1
380
AIがコードを書く時代の ジェネレーティブプログラミング
Avatar for polidog polidog
PRO
3
660
【PHPカンファレンス小田原2026】Webアプリケーションエンジニアにも知ってほしい オブザーバビリティ の本質
Avatar for Futoshi Endo fendo181
0
530
ASTのGitHub CopilotとCopilot CLIの現在地をお話しします/How AST Operates GitHub Copilot and Copilot CLI
Avatar for AEON aeonpeople
1
210
Oracle Cloud Infrastructure(OCI)：Onboarding Session(はじめてのOCI/Oracle Supportご利⽤ガイド)
Avatar for oracle4engineer oracle4engineer
PRO
2
17k

Featured

See All Featured
Practical Orchestrator
Avatar for Shlomi Noach shlominoach
191
11k
Public Speaking Without Barfing On Your Shoes - THAT 2023
Avatar for David Neal reverentgeek
1
370
Principles of Awesome APIs and How to Build Them.
Avatar for Keavy McMinn keavy
128
17k
DBのスキルで生き残る技術 - AI時代におけるテーブル設計の勘所
Avatar for soudai sone soudai
PRO
64
53k
For a Future-Friendly Web
Avatar for Brad Frost brad_frost
183
10k
Mind Mapping
Avatar for Hélio Medeiros helmedeiros
PRO
1
150
The Straight Up "How To Draw Better" Workshop
Avatar for Dennis Kardys denniskardys
239
140k
The Language of Interfaces
Avatar for Des Traynor destraynor
162
26k
SEO for Brand Visibility & Recognition
Avatar for Aleyda Solis aleyda
0
4.4k
A Modern Web Designer's Workflow
Avatar for Chris Coyier chriscoyier
698
190k
End of SEO as We Know It (SMX Advanced Version)
Avatar for Michael King ipullrank
3
4.1k
Redefining SEO in the New Era of Traffic Generation
Avatar for Szymon Słowik szymonslowik
1
270

Transcript

  1. Confident Refactors

  2. Mehdi Lahmam @mehlah

  3. 25kV Rails app, started in Feb 2009 Never rewritten 23k+

    commits from 52 contributors

  4. Ruby is a massively successful language!

  5. Early success Making it easy to make new things

  6. Later success Making it easy to maintain old things

  7. Today, let’s refactor some legacy code

  8. Today, let’s refactor some legacy code

  9. Refactor - verb To change the design of code without

    changing its observable behavior.

  10. Refactor - verb To change in advance of a new

    feature or bug fix, making the job easier.

  11. Today, let’s refactor some legacy code

  12. Legacy - noun Old code.

  13. Legacy - noun Code without tests.

  14. Legacy - noun Code that we don’t like.

  15. Legacy - noun Code we don’t understand well enough
 to

    change confidently.

  16. Today, let’s refactor some legacy code

  17. Refactoring is hard

  18. Refactoring legacy code is very hard

  19. Easy to accidentally break functionality

  20. Legacy refactors feels unsafe

  21. Legacy refactors are hard to sell

  22. Business priority Cost / risks

  23. Business priority Cost / risks New features

  24. Business priority Cost / risks New features Bugs fixes

  25. Business priority Cost / risks New features Bugs fixes Testing

  26. Business priority Cost / risks New features Bug fixes Testing

    Refactoring

  27. Business priority Cost / risks New features Bug fixes Testing

    Refactoring no selling needed easy to sell can often sell very hard to sell

  28. Selling refactoring is hard ⏲ ⛔

  29. Business priority Cost / risks Refactoring

  30. Too much pressure ⏳ ⚒

  31. Refactors are scary

  32. What techniques we have? PDD - Pray Driven Development Fowler’s

    refactoring book Characterization testing A/B testing, experiments

  33. Refactors as surgeries

  34. Refactors as surgeries Requires careful planning Follow a clear process

    Multiple observations Flexible tools Things can get bloody

  35. 1. Plan 2. Cut 3. Record 4. Validate 5. Refactor

    6. Verify 7. Compare 8. Fallback 9. Delete Clear process
  36. None
  37. None
  38. None

  39. Cut

  40. Record

  41. Validate ✅

  42. Refactor <Insert magic here />

  43. Verify

  44. Compare ⚖

  45. Fallback

  46. Delete ✂

  47. We dit it

  48. We dit it Time to celebrate hard