Code Reviews vs. Pull Requests
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The document discusses the history and methodology of code reviews and pull requests at Atlassian, particularly focusing on tools like Crucible and Gerrit. It contrasts post-commit and pre-commit reviews, detailing how feedback is addressed by authors and given by reviewers. Additionally, it covers different merge strategies and the implications of each in maintaining a clean commit history.
![PRE-COMMIT REVIEW
From: Tim Pettersen <tim@atlassian.com>
Date: Mon, 12 Sep 2016 10:24:10 +1000
Subject: [PATCH] Calculate federal transport tax correctly
--- a/com/atlassian/airfare/AirfareCalculator.java
+++ b/com/atlassian/airfare/AirfareCalculator.java
@@ -10,7 +10,7 @@
public float calculateAirfare(float baseFare) {
float fare = baseFare;
fare += immigrationFee + customsFee;
- fare *= federalTransportTax;
+ fare *= (1 + federalTransportTax);
return fare;
}
git format-patch HEAD~1 --stdout$](https://image.slidesharecdn.com/04-build-pettersen-170504103948/85/Code-Reviews-vs-Pull-Requests-8-320.jpg)
![public float calculateAirfare(float baseFare) {
float fare = baseFare;
fare += immigrationFee + customsFee;
- fare *= federalTransportTax;
+ fare *= (1 + federalTransportTax);
return fare;
}
Subject: [PATCH] Calculate federal transport tax
PRE-COMMIT REVIEW](https://image.slidesharecdn.com/04-build-pettersen-170504103948/85/Code-Reviews-vs-Pull-Requests-9-320.jpg)
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The braces are unnecessary.
public float calculateAirfare(float baseFare) {
float fare = baseFare;
fare += immigrationFee + customsFee;
- fare *= federalTransportTax;
+ fare *= (1 + federalTransportTax);
return fare;
}
Subject: Re: [PATCH] Calculate federal transport tax
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PRE-COMMIT REVIEW](https://image.slidesharecdn.com/04-build-pettersen-170504103948/85/Code-Reviews-vs-Pull-Requests-10-320.jpg)
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Technically true, but I think they add clarity.
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The braces are unnecessary.
public float calculateAirfare(float baseFare) {
float fare = baseFare;
fare += immigrationFee + customsFee;
- fare *= federalTransportTax;
+ fare *= (1 + federalTransportTax);
return fare;
}
Subject: Re: Re: [PATCH] Calculate federal transport tax
PRE-COMMIT REVIEW](https://image.slidesharecdn.com/04-build-pettersen-170504103948/85/Code-Reviews-vs-Pull-Requests-11-320.jpg)
![$ git push origin HEAD:refs/for/master
# typey type type
$ git commit -am “Review feedback”
Counting objects: 2108776, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (59/59), done.
Writing objects: 100% (86/86), 893.21 KiB, done.
Total 86 (delta 0), reused 0 (delta 0)
! [remote rejected] HEAD -> refs/for/master (squash commits first)
error: failed to push some refs to ‘ssh://...'
“SQUASH COMMITS FIRST”](https://image.slidesharecdn.com/04-build-pettersen-170504103948/85/Code-Reviews-vs-Pull-Requests-27-320.jpg)
Code Reviews vs. Pull Requests
- 1. Code reviews vs Pull requests TIM PETTERSEN | SENIOR DEVELOPER | ATLASSIAN | @KANNONBOY
- 2. 2006 2007 Atlassian acquires Cenqua, starts using Crucible CODE REVIEW AT ATLASSIAN
- 4. Creation How is a review composed? History How does a review impact your repository? Criteria Iteration How does an author address feedback? Collaboration How do reviewers leave feedback?
- 7. PRE-COMMIT REVIEW // flat fees and taxes final float customsFee = 5.5f; final float immigrationFee = 7f; final float federalTransportTax = .025f; public float calculateAirfare(float baseFare) { float fare = baseFare; fare += immigrationFee + customsFee; fare *= return fare; } (1 + )federalTransportTax;
- 8. PRE-COMMIT REVIEW From: Tim Pettersen <tim@atlassian.com> Date: Mon, 12 Sep 2016 10:24:10 +1000 Subject: [PATCH] Calculate federal transport tax correctly --- a/com/atlassian/airfare/AirfareCalculator.java +++ b/com/atlassian/airfare/AirfareCalculator.java @@ -10,7 +10,7 @@ public float calculateAirfare(float baseFare) { float fare = baseFare; fare += immigrationFee + customsFee; - fare *= federalTransportTax; + fare *= (1 + federalTransportTax); return fare; } git format-patch HEAD~1 --stdout$
- 9. public float calculateAirfare(float baseFare) { float fare = baseFare; fare += immigrationFee + customsFee; - fare *= federalTransportTax; + fare *= (1 + federalTransportTax); return fare; } Subject: [PATCH] Calculate federal transport tax PRE-COMMIT REVIEW
- 10. > > > > > The braces are unnecessary. public float calculateAirfare(float baseFare) { float fare = baseFare; fare += immigrationFee + customsFee; - fare *= federalTransportTax; + fare *= (1 + federalTransportTax); return fare; } Subject: Re: [PATCH] Calculate federal transport tax > > PRE-COMMIT REVIEW
- 11. > > > > > > > > > > Technically true, but I think they add clarity. > > > > > > > The braces are unnecessary. public float calculateAirfare(float baseFare) { float fare = baseFare; fare += immigrationFee + customsFee; - fare *= federalTransportTax; + fare *= (1 + federalTransportTax); return fare; } Subject: Re: Re: [PATCH] Calculate federal transport tax PRE-COMMIT REVIEW
- 12. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Subject: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: PRE-COMMIT REVIEW
- 15. Pull requests Post-commit review Pre-commit review master for/master Gerrit Version control agnostic Simple and decentralized Easy to keep ‘000s of people in the loop Plain text diffs One contributor per patch Difficult to iterate Have to manually merge work PRE-COMMIT REVIEW
- 19. master master patches & untracked files commits branches specific filesmultiple repos FLEXIBLE STRUCTURE
- 20. ITERATIVE REVIEW IN CRUCIBLE
- 21. SCM host (e.g. Bitbucket) Review host (e.g. Crucible) Dev team push & pull code review slurp slurp slurp slurp NOT AN SCM HOST
- 22. Pull requests Post-commit review Pre-commit review master for/master Gerrit Supports popular CVCS and DVCS Flexible review content Easy to iterate Have to manually merge work Need a separate SCM host Hard to enforce process POST-COMMIT REVIEW
- 23. Gerrit and DIFFY the Kung Foo Review Cuckoo
- 24. $ git config -f ~/gerrit/etc/gerrit.config gerrit.canonicalWebUrl http://localhost:8080/ GERRIT IS VERY “GIT”
- 25. for/master master reviewers approved? verified (build passing)? fetch push GERRIT FLOW Dev team
- 26. From: Gerrit Code Review - A Quick Introduction +2 +1 0 -1 -2
- 27. $ git push origin HEAD:refs/for/master # typey type type $ git commit -am “Review feedback” Counting objects: 2108776, done. Delta compression using up to 8 threads. Compressing objects: 100% (59/59), done. Writing objects: 100% (86/86), 893.21 KiB, done. Total 86 (delta 0), reused 0 (delta 0) ! [remote rejected] HEAD -> refs/for/master (squash commits first) error: failed to push some refs to ‘ssh://...' “SQUASH COMMITS FIRST”
- 28. for/master push push --force push --force “SQUASH COMMITS FIRST”
- 29. From: Gerrit Code Review - A Quick Introduction
- 30. Pull requests Post-commit review Pre-commit review master for/master Staging area Sophisticated policy enforcement FOSS project built in Java, on JGit Clean commit history Steep learning curve to use & administer Iteration is a little awkward Git only One contributor per patch GERRIT
- 31. master master patches & untracked files commits branches specific filesmultiple repos BRANCHES ONLY
- 33. ITERATIVE REVIEW IN BITBUCKET
- 34. review before merging Passing build Reviewer sign-off Ready for deployment PULL REQUESTS > CODE REVIEW
- 35. IN REVIEW DONEIN PROGRESSOPEN Branch created! Pull request created! Pull request merged! PULL REQUEST == ISSUE
- 36. Two developers about to press the “Merge” button
- 37. master Pull requestsPULL REQUESTS MAILING LIST / GERRIT
- 38. Merge Strategies
- 40. git merge --ffm aster feature/JIR A -123 “Fast forward if you can, otherwise create a merge commit.”
- 41. git merge --no-ffm aster feature/JIR A -123 “Always create a merge commit.”
- 42. git merge --ff-only m aster feature/JIR A -123 “Only allow fast forwards.”
- 43. git merge --squash “Combine commits on branch into a new commit on master.” m aster feature/JIR A -123
- 44. git merge --squash “Combine commits on branch into a new commit on master. Fail if master has any commits that branch doesn’t.” m aster --ff-only
- 45. Merge Commit Fast forward Squash Concise history Lose context of how features evolved Which should I use? “Ugly” history Full traceability Hard to screw up mostly some --no-ff --ff-only --squash No merge commits Verbose history Requires rebasing
- 46. Sophisticated policy enforcement Choice of merge strategies Multiple team members can author code under review Git & Mercurial Less flexible review content PULL REQUESTS
- 47. Pull requestsTRADITIONAL CODE REVIEW PULL REQUESTS Need to review multiple repos at once Not on Git Heavily iterative workflow Literally everyone else Dendrophobia
- 48. Thanks! TIM PETTERSEN | SENIOR DEVELOPER | ATLASSIAN | @KANNONBOY Questions?