Code Review
How And When
@paulmgower

DevSpace would like to thank our sponsors!

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

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

What Is Code Review
1

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

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

Code
Review
History

Why Use Fagan Inspections?

Why Use Fagan Inspections?
Good for Mission Critical Software

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

Over-the-shoulder

Email pass-around

Email pass-around
Please don’t do this!

Pair Programming

Code Review Tools

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

• 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

How and When
2

Reviewer: Focus on the code

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

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?”

Reviewer: Be respectful

Reviewer: Find a positive point

How NOT to Code Review

Author: Be humble

Author: Prepare Before

“
“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

Tips and Tricks

Less Than 200 Lines Of Code

Less Than 60 Minutes

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

Daily Code Review

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

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

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/

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/

Don’t
Be This
Guy

Don’t Review What Can Be
Automated

Static Code Analysis Tools

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

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

3
Why Code Review

“
“…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

Before 55%
Code Review Case Studies

Before
After 2%
55%
Code Review Case Studies

Before Code Reviews

After Code Reviews

Reasons to Code Review

Save Money

Easier To Find
Other’s Mistakes

Alternative
Implementations

Knowledge
Sharing

“
“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

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

THANK YOU!
@paulmgower
http://bit.ly/ds2016-cr
lunamark.com