Code Review is an Architectural Necessity - Code Daze Vol. 2; Sep 14, 2018

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 in addition to the knowledge sharing and culture it encourages. It also covers tips and sets expectations for what Code Review can and cannot solve.

This is the third iteration on this presentation. Previous iterations are also available on SpeakerDeck and at https://github.com/colindean/talks/tree/master/code_review.

Transcript

1. #codereview Code review is an architectural necessity Colin Dean @colindean
2. @ColinDean Software Engineer Organizer, Code & Supply Director, Abstractions.io Wearer of many hats
3. #codereview My words are my own and not my employer’s, past or present. Please save questions until the end of the presentation.
4. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
5. #codereview
6. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
7. #codereview What is code review?
8. #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.
9. #codereview Code review is systematic examination of computer source code. Code Review, Wikipedia
10. #codereview Peer Review
11. #codereview Code Review
12. #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
13. #codereview The submitter proposes changes in a submission, which is evaluated by a reviewer, who annotates or accepts it.
14. Inspection Team review Walkthrough Pair programming Peer deskcheck, passaround Ad-hoc review Wiegers’ peer review formality spectrum Least formal Most formal
15. Most formal Least formal Wiegers’ peer review formality spectrum Inspection Team review Walkthrough Pair programming Peer deskcheck, passaround Ad-hoc review
17. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
18. #codereview Code review solves two major problems. Aside from the primary goal of reducing defects,
19. #codereview Mental model synchronization Code review solves
22. Close enough Needs guidance On target
23. Alternative
 solutions New idea Open to
 new idea
24. #codereview Tribal knowledge development Code review solves
25. #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.”
26. #codereview Application code Code review audits
27. #codereview Application infrastructure Code review audits
28. #codereview Application architecture Code review audits
29. #codereview Write it down. Make it searchable. Code review forces us to
30. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
31. #codereview Maintainability Code review ensures
32. #codereview Maintainability • Learnability • Understandability • Serviceability Code review drives
33. #codereview Learnability • Developing Code • Patterns & Conventions • Risks & Goals • Developing People • Common Vocabulary • Teaching Moments Understandability Serviceability Code review drives Maintainability Learnability
34. Learner Expert Coding Reviewing Coding Reviewing Synchronous Pairing & Teaching Exemplary Reading Constructively Critical Evaluation Serendipitous Evaluation of Example Understandability Serviceability Maintainability Learnability
35. #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 Maintainability Learnability Understandability
36. #codereview Serviceability • Exposes addressable “gotchas” • Exposes end-user interaction points • Establishes consensus on supported workflows Maintainability Learnability Understandability Serviceability Code review drives
37. #codereview Linus’s Law “Given enough eyes, all bugs are shallow.”
38. #codereview Maintainability ✓Learnability ✓Understandability ✓Serviceability Code review drives
39. #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
40. #codereview Lack of code review Lost Opportunities
41. #codereview Lack of code review Lost Opportunities Lost Revenue
42. #codereview Lack of code review Lost Opportunities Lost Revenue Lost Job
43. #codereview Compliance Code review ensures
44. #codereview Compliance • Accessibility • Auditability • Idiomaticity Code review drives
45. #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
46. 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
48. #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
49. #codereview $1,450 per hour
50. #codereview $1,450 per hour $5,800 per weekly meeting
51. #codereview $1,450 per hour $5,800 per weekly meeting $290,000 per year
52. #codereview Effects? • Waste • “Get this over with.” • Obstructionism • Plenty of bugs • “I’ll fix that mistake later.”
53. #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
54. #codereview Security Code review ensures
55. #codereview Security • Spot vulnerabilities • Teach best practices • Filter unnecessary code • YAGNI Code review drives
56. #codereview Reviewers are like your lawyer Screening and recommending actions to minimize risk, avoid preventable mistakes
57. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
58. #codereview When should you integrate code review?
59. #codereview Context • Project • Technical
60. #codereview Keep reviews informal and short.
61. #codereview Tips for thorough code review • Devote time • Accept debt • Identify churn • Minimize pedantry • Make progress
62. #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
63. #codereview Most importantly Does it work? Is it tested?
64. #codereview Agenda • Quick anecdote • What is code review? • What problems does code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
65. #codereview Analyze dynamic structures Code review cannot
66. #codereview Go on endlessly Code review cannot
67. #codereview Solve political problems Code review cannot
68. #codereview Agenda • Quick anecdote • What is code review? • What problems do code review solve? • Quality attributes code review ensures • Tips for code reviews • Limitations
69. #codereview
70. #codereview Code Review is systematic 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.
71. #codereview codeandsupply.co the folks behind @codeandsupply codeandsupply.fund
72. @ColinDean github.com/
 colindean/talks speakerdeck.com/ colindean
73. #codereview –Johnny Appleseed FINITA (that’s Esperanto for “finished”)
74. #codereview Attributions • Westminster College picture: https://www.flickr.com/photos/westminstercollege/15759678054/in/ album-72157649340620016/ • “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. • Social media icons from FontAwesome • and others mentioned in the slides
75. #codereview No, really. Fin. Srsly. Ne, reale. Finita. Serioze.