Code Review is an Architectural Necessity - Github Universe 2016

Code Review is not a new concept, but a specific term for an older concept -- Peer Review -- that focuses the review process on the code under examination instead of the person who submitted it. While Code Review is common in open source projects, organizations developing in private often employ inefficient, frustrating, or virtually non-existent review processes. This talk looks at Code Review from an architect's viewpoint, arguing that Code Review is an essential component in a product's architectural plan because of the quality attributes it may provide. It also covers tips and sets expectations for what Code Review can and cannot solve.

Transcript

1. #githubuniverse #codereview Code review is an architectural necessity Colin Dean @colindean 1
2. #githubuniverse #codereview @ColinDean Software Engineer Organizer, Abstractions.io Wearer of many hats 2
3. #githubuniverse #codereview My words are my own and not my employer’s, past or present. Please save questions until the end of the presentation. 3
4. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 4
5. #githubuniverse #codereview 5
6. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems do code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 6
7. #githubuniverse #codereview What is code review? 7
8. #githubuniverse #codereview Code review is the process by which those who maintain a software codebase evaluate a proposed change to that codebase, regardless of the source of the proposed change. 8
9. #githubuniverse #codereview Code review is systematic examination of computer source code. Code Review, Wikipedia 9
10. #githubuniverse #codereview Peer Review 10
11. #githubuniverse #codereview Code Review 11
12. #githubuniverse #codereview Code Review Vocabulary • Change - an individual unit of work altering what exists • Submission - a collection of changes • Submitter - the person proposing the submission • Reviewer - the people evaluating the submission • Annotation - remarks or ratings bestowed upon the submission 12
13. #githubuniverse #codereview The submitter proposes changes in a submission, which is evaluated by a reviewer, who annotates or accepts it. 13
14. #githubuniverse #codereview Inspection Team review Walkthrough Pair programming Peer deskcheck, passaround Ad-hoc review Wiegers’ peer review formality spectrum Least formal Most formal 14
15. #githubuniverse #codereview Most formal Least formal Inspection Team review Walkthrough Pair programming Peer deskcheck, passaround Ad-hoc review Wiegers’ peer review formality spectrum 15
17. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 17
18. #githubuniverse #codereview Code review solves two major problems. Aside from the primary goal of reducing defects, 18
19. #githubuniverse #codereview Mental model synchronization Code review solves 19
20. #githubuniverse #codereview 20
21. #githubuniverse #codereview 21
22. #githubuniverse #codereview Close enough Need guidance On target 22
23. #githubuniverse #codereview Alternative solutions New idea Open to new idea 23
24. #githubuniverse #codereview Tribal knowledge development 24 Code review solves
25. #githubuniverse #codereview Michael Keeling
 Creating an Architecture Oral History, SATURN 2012 “Architecture oral history requires that the team is both willing and able to retell the stories and keep the oral history alive.” 25
26. #githubuniverse #codereview Application code Code review audits 26
27. #githubuniverse #codereview Application infrastructure Code review audits 27
28. #githubuniverse #codereview Application architecture 28 Code review audits
29. #githubuniverse #codereview Write it down. Make it searchable. Code review forces us to 29
30. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 30
31. #githubuniverse #codereview Maintainability Code review ensures 31
32. #githubuniverse #codereview Maintainability • Learnability • Understandability • Serviceability Code review drives 32
33. #githubuniverse #codereview Learnability • Developing Code • Patterns & Conventions • Risks & Goals • Developing People • Common Vocabulary • Teaching Moments Understandability Serviceability Code review drives 33 Maintainability Learnability
34. #githubuniverse #codereview Learner Expert Coding Reviewing Coding Reviewing Synchronous Pairing & Teaching Exemplary Reading Constructively Critical Evaluation Serendipitous Evaluation of Example Understandability Serviceability 34 Maintainability Learnability
35. #githubuniverse #codereview Understandability • Establishes common yet evolving mental model • Builds confidence in direction and design decisions • Builds tribal knowledge • Bonus: Enables elevator pitch Serviceability Code review drives 35 Maintainability Learnability Understandability
36. #githubuniverse #codereview Serviceability • Exposes addressable “gotchas” • Exposes end-user interaction points • Establishes consensus on supported workflows Maintainability Learnability Understandability Serviceability Code review drives 36
37. #githubuniverse #codereview Linus’s Law “Given enough eyes, all bugs are shallow.” 37
38. #githubuniverse #codereview Maintainability ✓Learnability ✓Understandability ✓Serviceability Code review drives 38
39. #githubuniverse #codereview First programming job out of school - B2B imprinting company if($customer == “spacely_sprockets”) { do_something(); }
 else { cry(); } • Version control! • No code review tooling or process • Minimal pairing • Continuous integration easily circumvented 39
40. #githubuniverse #codereview Lack of code review Lost Opportunities 40
41. #githubuniverse #codereview Lack of code review Lost Opportunities Lost Revenue 41
42. #githubuniverse #codereview Lack of code review Lost Opportunities Lost Revenue Lost Job 42
43. #githubuniverse #codereview Compliance 43 Code review ensures
44. #githubuniverse #codereview Compliance • Accessibility • Auditability • Idiomaticity Code review drives 44
45. #githubuniverse #codereview Second job out of school - Consulting • Lone wolf working alongside other lone wolves • No version control in proprietary software with custom “IDE” a.k.a. textarea. • Last modified and modifier only • No process of our own 45
46. #githubuniverse #codereview First professional code review experience was group review • Subcontractor on government project, 2010-2012 • Lone SME on platform • Borland StarTeam + in house review system • My tools for version control integration • Weekly merge window • Round robin inspection 46
48. #githubuniverse #codereview Not a pleasant experience • Three to four hour weekly round robin inspection • Cutthroat mixture of competing contractors, subcontractors, and employees • Embarrassment galore ‛ Not a learning environment • Immediate defensive posture • “Merge next week” = you failed, possibly delayed project 48
49. #githubuniverse #codereview $1,450 per hour 49
50. #githubuniverse #codereview $1,450 per hour $5,800 per weekly meeting 50
51. #githubuniverse #codereview $1,450 per hour $5,800 per weekly meeting $290,000 per year 51
52. #githubuniverse #codereview Effects? • Waste • “Get this over with.” • Obstructionism • Plenty of bugs • “I’ll fix that mistake later.” 52
53. #githubuniverse #codereview Missed opportunities • Accessibility expert was most vocal • Project manager was vocal on contractual and HF matters ➡Both could have reviewed asynchronously • Project was behind ➡Too many people could say No 53
54. #githubuniverse #codereview Security 54 Code review ensures
55. #githubuniverse #codereview Security • Spot vulnerabilities • Teach best practices • Filter unnecessary code • YAGNI Code review drives 55
56. #githubuniverse #codereview Reviewers are like your lawyer Screening and recommending actions to minimize risk, avoid preventable mistakes 56
57. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 57
58. #githubuniverse #codereview When should you integrate code review? 58
59. #githubuniverse #codereview Context • Project • Technical 59
60. #githubuniverse #codereview Keep reviews informal and short. 60
61. #githubuniverse #codereview Tips for thorough code review • Devote time • Accept debt • Identify churn • Minimize pedantry • Make progress 61
62. #githubuniverse #codereview Major things we look for • Algorithmic complexity • Exception & error handling • Exception, class, & variable naming • Logging sufficiency & level • Style conformation (automate!) • Long lines & methods • Readability • Single purpose per commit 62
63. #githubuniverse #codereview Most importantly Does it work? Is it tested? 63
64. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 64
65. #githubuniverse #codereview Analyze dynamic structures 65 Code review cannot
66. #githubuniverse #codereview Go on endlessly 66 Code review cannot
67. #githubuniverse #codereview Solve political problems 67 Code review cannot
68. #githubuniverse #codereview Agenda • Quick anecdote • What is code review? • What problems do code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations 68
69. #githubuniverse #codereview 69
70. #githubuniverse #codereview Code Review is systemic examination of proposed changes to a codebase. solves mental model synchronization and tribal knowledge development. ensures maintainability, compliance, & security. must be short, thorough, and automated where possible. will not solve all human problems, but some is better than none. 70
71. #githubuniverse #codereview www.codeandsupply.co the folks behind @codeandsupply 71
72. #githubuniverse #codereview @ColinDean github.com/
 colindean/talks speakerdeck.com/colindean 72
73. #githubuniverse #codereview –Johnny Appleseed FIN 73
74. #githubuniverse #codereview Attributions • Westminster College picture: https://www.flickr.com/photos/westminstercollege/15759678054/in/album-72157649340620016/ • RMU picture: http://cfbarchitects.com/higher-education/selected-projects/academic-buildings-libraries-learning-commons/robert- morris-university/ • Pittsburgh picture: probably Dave DiCello • “Their first code review” http://classicprogrammerpaintings.tumblr.com/post/142702963264/their-first-code-review-william-frederick • Bass, Len; Paul Clements, and Rick Kazman. Software Architecture in Practice. Addison Wesley, 2013. • Wiegers, Karl E. Peer Reviews in Software. Addison Wesley, 2012. • Cohen, Jason, Steven Teleki, and Eric Brown. Best Kept Secrets of Peer Code Review. Smart Bear Software, 2006. • Wilhelm, Alex and Alexia Tsotsis. Julie Ann Horvath Describes Sexism and Intimidation behind Her Github Exit. TechCruch, 2014 March 15. Retrieved 2016 April 26. http://techcrunch.com/2014/03/15/julie-ann-horvath-describes-sexism-and-intimidation-behind- her-github-exit/ • Baccehlli, Alberto and Christian Bird. Expectations, Outcomes, and Challenges Of Modern Code Review. Proceedings of the International Conference on Software Engineering, Proceedings of the International Conference on Software Engineering, May 2013. • and others mentioned in the slides 74
75. #githubuniverse #codereview No, really. Fin. Srsly. 75
76. #githubuniverse #codereview Third out of school and current job - Engineering • Highly disciplined team using Java, Scala, and Groovy • Git + Gerrit • Constructively critical feedback • No criticism without alternative solution and reasoning • Wide experience range: 1-2 yrs to 25+ yrs • Team split in late 2014, I was asked to be tech lead 76
77. #githubuniverse #codereview Github Enterprise in 2016 • All new projects • Same workflow as public Github 77
78. #githubuniverse #codereview Code Review Tools Used Haven’t Used Like Dislike ̣ Github ̣ Gerrit ̣ Gitlab • Gitbucket • BitBucket ̣ StarTeam •Phabricator • git-assess 78