1. Code Review
How And When
@paulmgower

2. I’m Paul Gower.
Principal Consultant at Lunamark
@paulmgower

3. AGENDA
What Is Code Review1
2
3
How and When
Why Code Review

4. What Is Code Review
1

5. Father of Code Review
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5388086&filter%3DAND%28p_IS_Number%3A5388084%29
aka Fagan Inspections

6. Fagan Inspections
https://en.wikipedia.org/wiki/Fagan_inspection

7. Code
Review
History

9. Why Use Fagan Inspections?

10. Why Use Fagan Inspections?
Good for Mission Critical Software

11. Lightweight Code Reviews
https://en.wikipedia.org/wiki/Code_review

12. Over-the-shoulder

13. Email pass-around

14. Email pass-around
Please don’t do this!

15. Pair Programming

16. Code Review Tools

27. Code Review Tool Resources
• github reviews - https://github.com/universe-2016#reviews
• video demo - https://www.youtube.com/watch?v=HW0RPaJqm4g
• reviewable - https://reviewable.io/
• demo - https://reviewable.io/reviews/Reviewable/demo/1
• gerrit code review - https://www.gerritcodereview.com
• tutorial - http://www.vogella.com/tutorials/Gerrit/article.html
• VSTS Code Review (TFVC) - https://www.visualstudio.com/en-us/docs/
tfvc/get-code-reviewed-vs
• walk through - https://www.visualstudio.com/en-us/docs/tfvc/day-life-
alm-developer-suspend-work-fix-bug-conduct-code-review

28. • Review Assistant - https://www.devart.com/review-assistant/
• comparison - https://www.devart.com/review-assistant/learnmore/
visual-studio-vs-review-assistant.html
• Crucible - https://www.atlassian.com/software/crucible
• video demo - https://www.youtube.com/watch?v=UFNPgfQFJHk
• Collaborator - https://smartbear.com/product/collaborator/overview/
• video demo - https://www.youtube.com/watch?v=1MBb21DgRYg
• FogBugz Dev Hub - http://www.fogcreek.com/fogbugz/devhub
• demo - http://www.joelonsoftware.com/items/2011/02/03.html
Code Review Tool Resources

29. How and When
2

31. Reviewer: Focus on the code

32. Reviewer: Focus on the code
Don’t say: “You didn’t name these variables well!”

33. Reviewer: Focus on the code
Don’t say: “You didn’t name these variables well!”
Instead: “I don’t understand these variable
names, can you help me understand them?”

34. Reviewer: Be respectful

35. Reviewer: Find a positive point

36. How NOT to Code Review

37. Author: Be humble

38. Author: Prepare Before

39. “
“The objective is for everyone to find
defects, including the author, not to
prove the work product has no defects.
People exchange work products to
review, with the expectation that as
authors, they will produce errors, and as
reviewers, they will find errors.
Everyone ends up learning from their
own mistakes and other people’s
mistakes.”
– Jerry Weinberg, “The Psychology of
Computer Programming”, 1971

40. Tips and Tricks

41. Less Than 200 Lines Of Code

43. Less Than 60 Minutes

44. Less Than 60 Minutes
http://www.news.illinois.edu/news/11/0208focus_AlejandroLleras.html

45. Daily Code Review

46. Daily Code Review
http://blog.fogcreek.com/effective-code-reviews-9-tips-from-a-converted-skeptic/

47. Always Use A Checklist
http://www.codeproject.com/Articles/593751/Code-Review-Checklist-and-Guidelines-for-Csharp-De

48. Developer Checklist
• Does my code compile without errors and run without exceptions in
“happy path” conditions?
• Have I checked this code to see if it triggers compiler or static analysis
warnings?
• Have I covered this code with appropriate tests, and are those test
currently green?
• Have I run our performance/load/smoke tests to make sure nothing I’ve
introduced is a performance killer?
http://blog.smartbear.com/code-review/creating-your-code-review-checklist/

49. Reviewer Checklist
• Does this code read like prose?
• Do the methods do what the name of the method claims that they’ll do?
Same for classes?
• Can I get an understanding of the desired behavior just by doing quick
scans through unit and acceptance tests?
• Is anything here a re-implementation of existing functionality the developer
may not be aware of?
http://blog.smartbear.com/code-review/creating-your-code-review-checklist/

50. Don’t
Be This
Guy

51. Don’t Review What Can Be
Automated

52. Static Code Analysis Tools

55. https://www.npmjs.com/package/eslint-watch

59. Static Code Analysis Resources
• JSLint - http://www.jslint.com
• video demo - https://www.youtube.com/watch?v=QWjMZBoSBtQ
• JSHint - http://jshint.com
• video demo - https://www.youtube.com/watch?v=MvV6fljX538
• ESLint - http://eslint.org
• video demo - https://www.youtube.com/watch?v=L6vMey4FtQ0
• StyleCop - https://stylecop.codeplex.com
• video demo - https://www.youtube.com/watch?v=6v8_PdePM7M
• Visual Studio Code Analysis - https://msdn.microsoft.com/en-us/library/
3z0aeatx.aspx
• walkthrough - https://msdn.microsoft.com/en-us/library/ms182066.aspx
• ReSharper - https://www.jetbrains.com/resharper/
• demo - https://www.youtube.com/watch?v=jq1JDlIiRmg

60. 3
Why Code Review

61. “
“…the average defect detection rate
is only 25 percent for unit testing,
35 percent for function testing, and
45 percent for integration testing.
In contrast, the average
effectiveness of design and code
inspections are 55 and 60 percent.”
- Steve McConnell, Code
Complete, 2004

63. Before 55%
Code Review Case Studies

64. Before
After 2%
55%
Code Review Case Studies

65. Before Code Reviews

66. After Code Reviews

67. Reasons to Code Review

69. Save Money

70. Easier To Find
Other’s Mistakes

71. Alternative
Implementations

72. Knowledge
Sharing

74. “
“The aim is to catch
what mistakes you can
and to get better – not
to attempt perfection.”
- Erik Dietrich,
“Creating Your Code
Review Checklist”, 2015

75. Review
• No more than 60 mins
• No more than 200 lines of code
• Use Static Code Analysis
• Use Check Lists
• Use A Code Review Tool

76. THANK YOU!
@paulmgower
bit.ly/lrtf2016-cr
lunamark.com