1.
How And When To Code Review
Paul Gower
@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
Good for Mission Critical Software

7.
Code
Review
History

8.
Over-the-shoulder

9.
Email pass-around

10.
Email pass-around
Please don’t do this!

11.
Pair Programming

12.
Tool-Assisted Code Review

13.
Tool-Assisted Code Review

14.
Tool-Assisted Code Review

15.
Tool-Assisted Code Review

16.
Tool-Assisted Code Review

17.
Tool-Assisted Code Review

18.
Tool-Assisted Code Review

19.
Tool-Assisted Code Review

20.
Tool-Assisted Code Review

21.
How and When
2

22.
How NOT to Code Review

23.
Don’t
Be This
Guy

24.
Reviewer: Focus on the code

25.
Reviewer: Focus on the code
Don’t say: “You didn’t name these variables well!”

26.
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?”

27.
Reviewer: Be respectful

28.
Reviewer: Find a positive point

29.
Developer: Be humble

30.
Developer: Prepare Before

31.
Tips and Tricks

32.
Less Than 200 Lines Of Code

33.
Less Than 60 Minutes

34.
Less Than 60 Minutes
http://www.news.illinois.edu/news/11/0208focus_AlejandroLleras.html

35.
Daily Code Review

36.
Daily Code Review
http://blog.fogcreek.com/effective-code-reviews-9-tips-from-a-converted-skeptic/

37.
Always Use A Checklist

38.
Always Use A Checklist
http://www.codeproject.com/Articles/593751/Code-Review-Checklist-and-Guidelines-for-Csharp-De

39.
Don’t Review What Can Be
Automated

40.
Static Code Analysis Tools

41.
Static Code Analysis Tools

42.
Static Code Analysis Tools

43.
Static Code Analysis Tools

44.
Static Code Analysis Tools

45.
Static Code Analysis Tools

46.
3
Why Code Review

47.
“
“…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

48.
Before
After 2%
55%
Code Review Case Studies

49.
Code Review Case Studies
Without
With 0.82 errors / 100 loc
4.5 errors / 100 loc

50.
Before Code Reviews

51.
After Code Reviews

52.
Reasons to Code Review

53.
Save Money

54.
Easier To Find
Other’s Mistakes

55.
Use Peer Pressure
To Your Advantage

56.
Alternative
Implementations

57.
Knowledge
Sharing

58.
“
“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

59.
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

60.
THANK YOU!
@paulmgower
http://bit.ly/cs2016-cr