Pull Request, code review and the GitHub Flow

Pull Requests are one of most essential workflow pieces of modern application development. If used effectively with proper code review and your existing workflow, they can not only help ensure high quality of written code, but do so without sacrificing the speed of development.
We'll start out by looking at what makes a great pull request, and what barriers people have with sending and receiving them. Next, we'll remove some of those barriers by discussing some code review best practices to ensure the code we're writing is well written and well tested. Lastly, we'll see how and why these pieces are a crucial part of a proper workflow, and what advantages the GitHub Flow has.

Transcript

1. the best way to build and ship software Pull Requests, code review, and the GitHub Flow What are these things, why are they important, and how can they make everyone’s lives better
2. the best way to build and ship software 2 ! ! " BRENT BEER SALES ENGINEER San Francisco, CA Who am I? GitHub
3. the best way to build and ship software What we’re about to talk about 3 # $ $ WHAT’S OUR GOAL HERE? HOW ARE WE GETTING THERE? Talk about Pull Requests and understand how to use them effectively. How can we maintain quality of code without requiring our developers to have meetings that ruin productivity. What is the GitHub Flow? Why should you care? How does all this tie together? Better understanding of what Pull Requests, code review, and the GitHub Flow.
4. the best way to build and ship software What we’re about to talk about 4 # $ $ WHAT’S OUR GOAL HERE? HOW ARE WE GETTING THERE? Talk about Pull Requests and understand how to use them effectively. How can we maintain quality of code without requiring our developers to have meetings that ruin productivity. What is the GitHub Flow? Why should you care? How does all this tie together? Better understanding of what Pull Requests, code review, and the GitHub Flow.
5. the best way to build and ship software Traditional software development 5 % issues, bugs, features backlog sprint planning & ! % ' ( continuous integration code review sprint review ) ' * ' + no go go no go go no go go
6. the best way to build and ship software What you’d like to have 6 , issues, bugs, features backlog collaboration + , ' ! - continuous deploy merge (master) deploy to production . ) / 0 close merge ) & & &
7. the best way to build and ship software GitHub’s software development 7 1 issues, bugs, features backlog collaboration + , ' ! - continuous deploy merge (master) deploy to production . ) / 0 close merge ) & & &
8. the best way to build and ship software GitHub’s software development 8 1 issues, bugs, features backlog collaboration + , ' ! - continuous deploy merge (master) deploy to production . ) / 0 close merge ) & & &
9. the best way to build and ship software Guides 9 2
10. the best way to build and ship software Guides 10 2
11. the best way to build and ship software Guides 11 2
12. the best way to build and ship software GitHub Engineering 12 )
13. the best way to build and ship software Pull Requests 13 , , WHAT ARE PULL REQUESTS? Pull requests are proposed changes from one branch to another. They are more than just changes, they are the start of a discussion.
14. the best way to build and ship software Pull Requests 14 , , WHAT ARE PULL REQUESTS? Pull requests are proposed changes from one branch to another. They are more than just changes, they are the start of a discussion.
15. the best way to build and ship software Pull Requests 15 , , HOW DO YOU USE THEM? When you create a new branch and make some changes, you can propose those changes to be merged into master.
16. the best way to build and ship software Basic Pull Request 16 ,
17. the best way to build and ship software What makes a good pull request? 17 , , HOW DO YOU USE THEM WELL?
18. “ ” the best way to build and ship software 18 3 NATURALLY, THE SIZE OF THE PULL REQUEST MATTERS: THE SHORTER IT IS THE FASTER IT WILL BE REVIEWED. OTHER ACTIONABLE STRONG PREDICTORS ARE THE DELAY TO THE FIRST HUMAN RESPONSE AND THE AVAILABILITY OF THE CI PIPELINE. IMPROVING ON BOTH MAY HASTEN THE REVIEW PROCESS. - WAIT FOR IT: DETERMINANTS OF PULL REQUEST EVALUATION LATENCY ON GITHUB Research
19. “ ” the best way to build and ship software 19 3 NATURALLY, THE SIZE OF THE PULL REQUEST MATTERS: THE SHORTER IT IS THE FASTER IT WILL BE REVIEWED. OTHER ACTIONABLE STRONG PREDICTORS ARE THE DELAY TO THE FIRST HUMAN RESPONSE AND THE AVAILABILITY OF THE CI PIPELINE. IMPROVING ON BOTH MAY HASTEN THE REVIEW PROCESS. - WAIT FOR IT: DETERMINANTS OF PULL REQUEST EVALUATION LATENCY ON GITHUB Research
20. “ ” the best way to build and ship software 20 3 NATURALLY, THE SIZE OF THE PULL REQUEST MATTERS: THE SHORTER IT IS THE FASTER IT WILL BE REVIEWED. OTHER ACTIONABLE STRONG PREDICTORS ARE THE DELAY TO THE FIRST HUMAN RESPONSE AND THE AVAILABILITY OF THE CI PIPELINE. IMPROVING ON BOTH MAY HASTEN THE REVIEW PROCESS. - WAIT FOR IT: DETERMINANTS OF PULL REQUEST EVALUATION LATENCY ON GITHUB Research
21. “ ” the best way to build and ship software 21 3 NATURALLY, THE SIZE OF THE PULL REQUEST MATTERS: THE SHORTER IT IS THE FASTER IT WILL BE REVIEWED. OTHER ACTIONABLE STRONG PREDICTORS ARE THE DELAY TO THE FIRST HUMAN RESPONSE AND THE AVAILABILITY OF THE CI PIPELINE. IMPROVING ON BOTH MAY HASTEN THE REVIEW PROCESS. - WAIT FOR IT: DETERMINANTS OF PULL REQUEST EVALUATION LATENCY ON GITHUB Research
22. “ ” the best way to build and ship software 22 3 NATURALLY, THE SIZE OF THE PULL REQUEST MATTERS: THE SHORTER IT IS THE FASTER IT WILL BE REVIEWED. OTHER ACTIONABLE STRONG PREDICTORS ARE THE DELAY TO THE FIRST HUMAN RESPONSE AND THE AVAILABILITY OF THE CI PIPELINE. IMPROVING ON BOTH MAY HASTEN THE REVIEW PROCESS. - WAIT FOR IT: DETERMINANTS OF PULL REQUEST EVALUATION LATENCY ON GITHUB Research
23. the best way to build and ship software Pull Requests with CI 23 4
24. the best way to build and ship software Pull Requests 24 , , SUMMARY - Use Pull Request. - Create your pull request early. - Use CI to ensure your pull request is merged with confidence.
25. the best way to build and ship software Code review 25 5 5 WHAT IS CODE REVIEW Types of code review may vary. It can range from telling your collaborators that you looked that the pull request, to having a meeting.
26. the best way to build and ship software Code review 26 5 5 WHAT IS CODE REVIEW Types of code review may vary. It can range from telling your collaborators that you looked that the pull request, to having a meeting.
27. “ ” the best way to build and ship software 27 5 “PEER CODE REVIEWS ARE THE SINGLE BIGGEST THING YOU CAN DO TO IMPROVE YOUR CODE.” - JEFF ATWOOD Code review
28. “ ” the best way to build and ship software 28 3 “PEER CODE REVIEWS ARE THE SINGLE BIGGEST THING YOU CAN DO TO IMPROVE YOUR CODE.” - JEFF ATWOOD Code review
29. the best way to build and ship software Code review 29 5 5 HOW DO YOU CODE REVIEW There are many ways to start reviewing code. Start small and grow from there.
30. the best way to build and ship software Code review 30 5
31. the best way to build and ship software Code review 31 5 5 STRONGER CODE REVIEW What if we want to ensure some things happen before we can even merge? CI needs to pass, someone needs to sign off!
32. the best way to build and ship software Code review: protected branches 32 6 6 PROTECTED BRANCHES - Protect against force pushes and branch deletion - Require status checks to pass
33. the best way to build and ship software Code review: protected branches 33 6 6 PROTECTED BRANCHES - Protect against force pushes and branch deletion - Require status checks to pass
34. the best way to build and ship software Code review: protected branches 34 6
35. the best way to build and ship software Code review: protected branches 35 6 6 PROTECTED BRANCHES - Protect against force pushes and branch deletion - Require status checks to pass
36. the best way to build and ship software Code review: ReviewNinja 36 6
37. the best way to build and ship software Code review: protected branches 37 6
38. the best way to build and ship software Code review: protected branches 38 6
39. the best way to build and ship software Code review: protected branches 39 6
40. the best way to build and ship software Code review: protected branches 40 6
41. the best way to build and ship software Code review: protected branches 41 6
42. the best way to build and ship software Code review: protected branches 42 6
43. the best way to build and ship software Code review: protected branches 43 6 6 SUMMARY - If you need code review, decide what’s best for your team - Protected branches can help ensure status checks are green - If you want more code review, use the API or a service like ReviewNinja
44. the best way to build and ship software GitHub Flow 44 7 7 WHAT IS THE GITHUB FLOW At it's core, GitHub Flow is a lightweight, branch-based workflow that supports teams and projects where deployments are made regularly.
45. the best way to build and ship software GitHub Flow 45 7 7 WHAT IS THE GITHUB FLOW At it's core, GitHub Flow is a lightweight, branch-based workflow that supports teams and projects where deployments are made regularly.
46. the best way to build and ship software GitHub Flow 46 7 7 WHAT IS THE GITHUB FLOW At it's core, GitHub Flow is a lightweight, branch-based workflow that supports teams and projects where deployments are made regularly.
47. the best way to build and ship software GitHub Flow 47 7 B U I L D C O L L A B O R AT E D E P L O Y Time spent coding: Bugs are found: Code Reviews: Deployment: Target 75-90% At time of push (CI) Code reviewed at time of push Based on automation rules Current 10-25% During code review Once a week Ops and PMO decide 
 when to deploy Example Developer Calendar Example Developer Calendar
48. the best way to build and ship software GitHub Flow 48 7 B U I L D C O L L A B O R AT E D E P L O Y Time spent coding: Bugs are found: Code Reviews: Deployment: Target 75-90% At time of push (CI) Code reviewed at time of push Based on automation rules Current 10-25% During code review Once a week Ops and PMO decide 
 when to deploy Example Developer Calendar Example Developer Calendar
49. the best way to build and ship software GitHub Flow 49 7
50. the best way to build and ship software GitHub Flow 50 , 7 PULL REQUESTS Help your development happen faster and increase communication.
51. the best way to build and ship software GitHub Flow 51 5 7 CODE REVIEW Ensure the code you write is reviewed and good quality code.
52. the best way to build and ship software Guides 52 2
53. the best way to build and ship software Guides 53 2
54. the best way to build and ship software GitHub Flow 54 7 7 GITHUB FLOW Work with a light-weight flexible workflow that helps your developers ship code faster.
55. the best way to build and ship software
56. the best way to build and ship software References 56 2 2 MANY PEOPLE HAVE TALKED ON THESE SUBJECTS - Why code reviews matter (and actually save time!): https://www.atlassian.com/ agile/code-reviews - When to do code reviews when doing CI: http://programmers.stackexchange.com/ questions/121664/when-to-do-code-reviews-when-doing-continuous-integration - Fog Creek( Jeff Atwood quote) on when to do code review: http:// blog.fogcreek.com/effective-code-reviews-9-tips-from-a-converted-skeptic/ - Wait For It: Determinants of Pull Request Latency on GitHub: https:// bvasiles.github.io/papers/msr15.pdf - Why You Should Use Continuous Integration and Continuous Deployment: http:// blog.teamtreehouse.com/use-continuous-integration-continuous-deployment