How to Break into Reading Open Source

There's a treasure trove of code that you could learn from hiding in plain sight: Open Source.

By reading other people's code you can pick up new tricks, names, and concepts — and apply them to your code. You can even be exposed to things you'd never think of.

My journey reading Open Source for the hell of it started back in 2013, when I set out to read all of Rails as a Google Summer of Code student.

Join this session to see how I've grown my skills through reading and have the process demystified so you can too. You'll walk away knowing how to start breaking into even the gnarliest codebases.

Transcript

1. How to Break into Reading Open Source
2. Hi, it's Kasper
3. We often talk about writing code
4. Today let's focus on reading
5. reading Open Source
6.  180.000 gems
7. be a sponge new Ruby syntax – Ruby methods – tricks – names – concepts –
8. Our meal plan reading ahead-of-time 1. reading just-in-time 2.
9. reading ahead-of-time AOT
10. reading just-in-time JIT
11. MINASWAN matz-is-nice-and-so-we-are-nice
12. WRAOTSTWCARJIT we-read-ahead-of-time- so-that-we-can-also-read-just-in-time
13. where I read
14. AOT happens on GitHub
15. JIT EDITOR=zed bundle open <gem> bundle open -h
16. cases we'll cover two AOTs from Rails and minitest a JIT from just last week
17. How this started
18. 2013 Google Summer of Code
20. Now as prep I thought…
21. "I'll just read all of Rails"
22. "what a truly dumb heroic endeavor"  Thomas Cannon
23. let's proceed, stupidly
24. a little more background
25. rails just bundles other gems
26. actionpack ↪ actioncontroller ↪ actionview actiondispatch actionmailer 2013 activerecord activesupport railties
27. what I did Demo Time
28. summary - went to https://github.com/rails/rails - clicked activesupport - read #blank? & #present?
29. then I gave up reading Rails
30. but I learned a ton
31. what stuck with me
32. it's not about getting it 100%
33. Open Source isn't a blackbox (literally)
34. read the parts you can come back and read more
35. reading principles 1. just click things 2. remain neutral 3. keep coming back
36. just click things
37. "Oh, that's an interesting name!"
38. "What does this method do? Is this a Ruby thing?"
39. "What the hell is this?"
40. remain neutral
41. Do you say things like…
42. "I should know this already" evens, odds = integers.partition(&:even?)
43. "I shouldn't need to do this, right?"
44. "I'm not smart enough to get this"
45. "there's too much magic"
46. judging yourself stops you
47. like listening to new music
48. with music, we'll just try listening
49. it's not smarts it's context
50. reading helps you build that context
51. set anger & frustration aside
52. try to have an open mind
53. keep coming back
54. with practice you'll be quicker
55. you'll be quicker - parsing brand new code - splitting it into chunks - picking up new names & concepts - spotting styles & patterns
56. it's a process, not a task
57. 1. just click things 2. remain neutral 3. keep coming back
58. it's much better just to look
59. before the next part
60. when you're learning something
61. follow a laid out path
62. WAY HARDER
63. part 2 a concept from minitest's source
64. minitest  Ruby's default test framework  1200 lines
65. Running 1 tests in a single process (parallelization threshold is 50) Run options: --seed 56269 # Running: . Finished in 0.018606s, 53.7461 runs/s, 53.7461 assertions/s. 1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
66. class Reporter < AbstractReporter def record result end end class SummaryReporter < Reporter; end # . class StatisticsReporter < Reporter; end # 1 assertions…
67. class CompositeReporter < AbstractReporter def << reporter end def record result end end
68. self.reporter = CompositeReporter.new self.reporter << SummaryReporter.new self.reporter << StatisticsReporter.new # in tests, minitest calls: self.reporter.record result
69. class CompositeReporter def record result self.reporters.each do |reporter| reporter.record result end end end
70. this is polymorphism
71. JIT from last week
72. audited + actiontext gem "audited" class Post < ApplicationRecord has_rich_text :content end ActionText::RichText.audited associated_with: :record
73. let's do a little ahead-of- time reading
74. YAML (not official docs, just looks nice) https://rubyapi.org/3.3/o/yaml
75. JIT Demo
76. summary we read a bit of YAML ahead-of-time – we used that knowledge to debug an issue – we looked at the source of audited and actiontext – we saw that ActionText::Content doesn't support YAML serialization –
77. wrap up
78. what the hell did we just do we learned about AOT and JIT reading – we nibbled some rails reading – we became experts at polymorphism from minitest – we used AOT to debug while also doing JIT –
79. reading principles 1. just click things 2. remain neutral 3. keep coming back
80. Work with me hey@kaspth.com
81. Special thanks Kim Burgestrand Sam Stephenson Thomas Cannon