Protecting Your Source: Using Code Review To Improve Your Application Quality (Droidcon Boston 2018)

This is my talk on using code review to improve your application quality from Droidcon Boston.

Useful links:

Yelp's Code Review Guidelines: https://engineeringblog.yelp.com/2017/11/code-review-guidelines.html
How Square Writes Commit Messages: https://medium.com/square-corner-blog/how-square-writes-commit-messages-8e92fcbf77c9
How to Use Code Review To Execute Someone's Soul: https://www.daedtech.com/how-to-use-a-code-review-to-execute-someones-soul/
Creating a Strong Code Review Culture: https://www.youtube.com/watch?v=PJjmw9TRB7s
Honesty, Kindness, Inspiration: Pick Three: https://www.youtube.com/watch?v=hP_2XKYia9I
bettercode.reviews: http://www.bettercode.reviews/
Giving and Getting Technical Help: https://www.youtube.com/watch?v=hY14Er6JX2s
Crucial Conversations: https://www.amazon.com/Crucial-Conversations-Talking-Stakes-Second/dp/0071771328/ref=sr_1_3?ie=UTF8&qid=1521932464&sr=8-3&keywords=crucial+conversations
Pre-commit: https://pre-commit.com/

Transcript

1. Jonathan Maltz maltz@yelp.com/@maltzj Protect Your Source Using Code Review to Improve Your Application Quality
2. Yelp’s Mission Connecting people with great local businesses.
7. • Why do Code Review • Basic Code Review Outline • How to give code review feedback • How to find the right code to review What Will We Talk About?
8. Why do Code Review?
9. Make Sure Code is Correct
10. Make Sure Code is Well-Designed
11. Share Knowledge
12. Basic Code Review Outline
13. 1. Build Context
14. • You understand the goal of the change • You understand what is out of scope • You understand any high-level decisions What’s Success?
15. • Jumping into a code review right away • Not calling for backup as necessary ◦ Especially important at boundaries Failure Modes?
16. Authors are just as important here
17. How to do it?
18. Protip: pre-filled templates
19. 2. Evaluate Closer
20. • High-level design feedback • Bug-finding + edge case coverage • Test coverage • Sharing new patterns What’s Success?
21. • Commenting on anything a tool can catch ◦ PMD ◦ Checkstyle ◦ Findbugs ◦ Pre-commit hooks ◦ Google Java format • Can’t catch things with a tool but always disagree on them? Come to a consensus and move on What’s Failure?
22. 3. Step Back
23. Could this be done easier/better/faster?
24. Turnaround-time matters
25. Lisa Sam
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33. Lisa Sam
34. • Be conscious of burying teammates in code reviews • Try to get prioritize shipping 1 or 2 reviews before submitting more. • If your teammates are being slow to turnaround code reviews, don’t submit more How to avoid?
35. How to Give Feedback
37. • Discussion + collaboration • Individual ownership • People actively wanting to receive peer feedback What do you want to encourage?
39. Feedback that makes people feel worse
40. • “Your style here is inconsistent. Align your braces with our code style” • “This has a bug when running on Lollipop which will cause a crash. Fix it” • “Why did you do this refactor? The code was better in its previous form” What to avoid?
42. “This code is good. Let’s make it even better.”
44. 1. Start With Facts
45. The style guidelines say you should put braces on the same line, and this code puts braces on a new line. Align your braces with our styleguide.
47. Opinion == Facts
48. Static methods cannot be mocked in normal JUnit tests.
49. ✅ Static methods cannot be mocked in normal JUnit tests.
50. Static methods are bad. They cannot be mocked in normal JUnit tests.
51. Link to External Resources
52. 2. Invite a Discussion
53. The style guidelines say you should put braces on the same line, and this code puts braces on a new line. Can you align your braces with our styleguide?
54. 3. Replace “You” with “We” or “Us”
55. The style guidelines say we should put braces on the same line, and this code puts braces on a new line. Can we align our braces with our styleguide?
56. The style guidelines say we should put braces on the same line, and this code puts braces on a new line. Let’s align our braces with our styleguide.
59. Rule of Three
60. On a scale of 1-10, I care about this at a 5. What about you? What are your major concerns?
61. • Different concerns? Find a third way • Large Difference? Principle of the person who cares the most in the code review. ◦ Protip: This shouldn’t always be you • Both high? Maybe need to make a larger decision What to do with this?
62. Celebrate Good Stuff
63. Finding “The Right” Code to Review
65. Feedback Types
66. Blocking Feedback
67. • Things that need to be fixed before shipping ◦ Bugs, major code smells, lacking test coverage • E.g: Kitkat doesn’t support elevation, which means this will crash on older devices. Can we use ViewCompat instead? What’s it look like?
68. Non-Blocking Feedback
69. • Suggestions, ideas, or opportunities that may have been missed ◦ Alternate design, renaming, opportunistic refactoring • E.g: Not sure if this is a good idea, but what if we changed this code to use a builder pattern instead of some static factories? What’s it look like?
71. Get all code reviews forwarded to you
73. Risk 0 ∞
74. Opportunity 0 ∞
75. Opportunity 0 ∞ Risk 0 ∞ Don’t do them unless assigned
76. Opportunity 0 ∞ Risk 0 ∞ Don’t do them unless assigned Review for blocking feedback
77. Opportunity 0 ∞ Risk 0 ∞ Don’t do them unless assigned Review for blocking feedback Do you have a plan?
78. Opportunity 0 ∞ Risk 0 ∞ Don’t do them unless assigned Review for blocking feedback Add non- blocking feedback Do you have a plan?
79. Non-Blocking: This class has always felt a little clunky to me. Now that we’re in here, what if we clean it up a bit?
81. ∞ 0 Perceived authority Tech lead New hire
82. • Argue both sides of the case • Call-out a problem without suggesting a solution • Invite them to pair with you How to deal with this?
84. • Make sure to not overwhelm your teammates with code reviews • Phrase your feedback as a question • Don’t always be the person who cares the most Three Big Takeaways
85. • Yelp’s Code Review Guidelines • Writing Commit Messages • How to use code review to execute someone’s soul • Creating a strong code review culture • Honesty, Kindness, Inspiration: Pick Three • bettercode.reviews • Giving and getting technical help • Crucial Conversations • Pre-commit External Links
86. www.yelp.com/careers/ We're Hiring!
87. Questions
88. @YelpEngineering fb.com/YelpEngineers engineeringblog.yelp.com github.com/yelp