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www.octo.com - www.usievents.com 1@mdomenjoud #NCrafts #CultureCode@mdomenjoud #NCrafts #CultureCode
HOW TO FAIL AT CODE REVIEW
IN FIVE LESSONS
Michel DOMENJOUD

www.octo.com - www.usievents.com 2@mdomenjoud #NCrafts #CultureCode
Développeur, in love with code since 2003.
Tech Lead – Coach Craft @OctoTechnology
@mdomenjoud #CultureCode
MICHEL DOMENJOUD

Code review?
Of course we all know about it!

An effective team practice to provide feedback about
code quality

Software Craftsmanship : essential practices
+ Continuous integration, Coding standards, Refactoring,
Design, etc.
Feedback
Clean Code Automated
Testing
Test Driven
Development
Code Review

Proven effective for many years

http://sail.cs.queensu.ca/publications/pubs/msr2014-mcintosh.pdf
http://www.reviewtechnik.de/NationalSoftwareQualityExperiment.pdf
Objective : detect defects early
Up to 65% of detected defects
ROI of 4 to 1
1h of review → 4h of debug saved

Other substantial benefits
Shared coding standards
Reinforce collective code
ownership
Facilitate learning
Improve communication about
code

Peer Review
Pair programming
Collective Review

Fail #1 : We still have bugs everywhere !

Go as fast as you
can !
Do not prepare
anything !
Do not ask how to
do it !
- Take your time, at a sustainable pace
- Ask for code review as soon as possible
- Prepare the review beforehand
- Share coding standards and checklists
- Train together
To miss defects And to detect them ?

Fail #2 My team does not progress

Do not speak to
each other !
Correct the defects
in place of the
author !
Do not write you
coding standards
- Talk with your teammates during reviews
- The author fixes the defects, using pair
programming if necessary
- Write your coding standards down
- Reevaluate them over time
Not to progress And to progress ?

Fail #3 : Reviews look like a wrestling match

Criticize people first
Always start a
debate or language
/ framework war !
To be sure to
have a fight
- Criticize the code, not the developer
- Rely on Egoless Programming principles
- This is not the time
- Find compromises
- Pick a standard and write it down
And for a peaceful review ?

Three complementary formats
Peer review
Pair
programming
Start a User Story,
Complex code,
Legacy code, debug,
Learning
Define coding standards
Critical code
New technologies
All the time
On a
regular basis
On demand
For every code change
Collective
review

5 lessons to be learned for successful reviews
1 – Take your time
Prepare the review beforehand
Sustainable pace (max 1h30 &
300 LoC at a time)
2 – Progress together
Talk with your teammates during
reviews
The author fixes the defects,
using pair programming if
necessary
3 – Use coding standards
Share standards and checklists
Reevaluate them over time
4 – Criticize the code, not the
developer
Egoless Programming principles
5 – Find the format(s) which fit
your team and adapt them.

Culture Code
Software Craftsmanship : Better Places with Better Code
A collective book about Software
Craftsmanship’ culture and practices
(in French)
Freely available for download
http://blog.octo.com/tag/software-craftsmanship
http://www.octo.com/fr/publications/20-culture-code

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How to fail at code reviews in 5 lessons

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