This presentation explains why and what for we should use: 1) Trunk Based Development 2) Pre-commit Code Review 3) Gerrit 4) How they can be used together This presentation was shared in one of Java User Groups in Astana, Kazakhstan

1. How Google Said
Ninja Code Review
created by Anuar Nurmakanov
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2. -35 ?
Welcome to Java
User Group!!! 2

3. About me
Kazakhstan, Karaganda
Lead Software
Engineer
XP/EngX Practices fan
Agile Believer
And I love Java!
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4. What does it mean to be brave developer?
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5. Intro
The world without you...
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6. When you start new project
It's new opportunity. You feel like a hero!
It's gonna be the best project!!
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7. Sometimes our projects become
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8. Code Smells
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9. And it is tough to make it better
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10. And only one thing you wanna
do
Run away!!!!!!
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11. Why?
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12. Feedback matters
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13. Lack of Code Review Lack of TDD Lack of Testing Pyramid
Lack of CI/CD/CD Lack of Release Strategy
and other engineering and agile practices
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14. A few words about Code
Review
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15. How much does it cost?
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16. When you fix it too late...
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17. Code Review Goals
Definition of Done Collective Code
Ownership
Code Quality
Knowledge Sharing Find compromise Education
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18. High-level overview
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19. Code Review
Is so huuuuuge topic
Why and when
Benefits
Goals
Approaches
Roles
Strategies
Tools
Best practices
etc
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20. Your code is not your
wife! You can share
it!
First rule of Code Review
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21. Pre-commit Code
Review
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22. Before or After
Changes aren't in a
branch.
Changes are in in a
branch.
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23. Make the right decision
To prevent anything like this
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24. Unstable build
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25. No one can make pushes
Jenkins is red
We cannot prepare build
Fix might break one of the test environments
It might take lots of time
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26. Who broke the build?
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27. Stable build
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28. What is Stable build?
Changes do not have any bugs
They do not fail existing tests
They have good test coverage
CI jobs are green
Unit/Integration/System/End-
To-End tests passed
Existing functionality works
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29. I wanna see everything in one
place
Feedback from teammates
Feedback from Team Lead
Feedback from Architect
Check that build is not broken
Check any type of tests
Feedback from Architect
New violations and errors
Any blocker issues
Any static analyse
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30. Trunk Based
Development
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31. Branching Strategies
Feature Branch Development
Git Flow
Mainline
Trunk Based Development
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32. 32

33. 33

34. 34

35. 35

36. Trunk Based Development
Everyone Develops in the trunk
Bug fixes too
No Code Freeze
No Merge Hell
Build never broken. It's always ready to
be released
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37. Don't mix them up
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38. Past Experience
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39. 39

40. Only with patches
Forget about CI integration
Forget about Static
Analyse Integration
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41. Pull/Merge Requests
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42. Pull requests are not pure
pre-commit review
You can integrate it with
CI. Some have CI out of the
box
Pull requests do not
show Static Code
Analyse comments
Pull/Merge Requests
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43. Gerrit Ninja
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44. Who is Ninja?
Always ready to hear feedback
from others and make changes
Fixes build before it breaks
main branches builds
Removes all SonarQube
violations
Knows how GIT works
Ready to share knowledge and
help
Checks
Unit/Integration/System/End-
To-End/UI tests
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45. What is Gerrit?
Created for Android
Development and now it's
in Google
And lots of other companies
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46. Gerrit Workflow
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47. Gerrit Review
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48. Diff and comments
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49. Access Control
A developer can
say that it's good
Architects and
Leads can approve
merge
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50. Gerrit Roles Model
Group Label Range
Registered Users Code-Review -1..+1
Team Leads Code-Review -2..+1
Architects Code-Review -2..+2
Non-interactive
users
Code-Review -1..+1
“ For example, only Architects
can allow to make a merge
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51. Patch Set
One code change, (be it a feature or
a bugfix, ) is one commit. Use
Ammend to update it.
git push gerrit
HEAD:refs/for/master
When it's
ready for
review
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52. Live Demo
Let's check it out.
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53. If you have a chance to try it
Do it! 53

54. Gerrit Users
Android –
LibreOffice –
Wikimedia –
Golang –
Tuleap –
Star Wars Galaxies Emulator –
https://android-review.googlesource.com/
https://gerrit.libreoffice.org/
https://gerrit.wikimedia.org/
https://go-review.googlesource.com/
https://gerrit.tuleap.net/
http://review.swgemu.com/
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55. Thanks
Feel free to ask any questions. =)
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56. Have a nice
weekend!
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