Koichi Sasada
Ruby Engineer at STORES
Chiyoda, Japan
Summary
🤩
Rockstar🎓
Top SchoolKoichi Sasada is a seasoned Ruby interpreter engineer with 22 years of experience, holding a Ph.D. in Information Science and Technology from the University of Tokyo and a background as an assistant professor who led systems software research. He has spent over a decade improving CRuby/MRI across academia, Heroku, Cookpad, and STORES, focusing on interpreter quality, debugging, and test-suite robustness. An active open-source maintainer, Koichi has fixed concurrency deadlocks in RubyGems, rewritten parts of the ruby/debug tooling (adding features like reloaded breakpoints and whereami), and hardened ruby/spec for diverse environments. As a director of the Ruby Association, he combines deep language internals expertise with practical production experience that few interpreter programmers maintain.
22 years of coding experience
11 years of employment as a software developer
University of TokyoMaster of Engineering (M.Eng.), Computer Science, Master of Engineering (M.Eng.), Computer Science at Tokyo University of Agriculture and Technology
Japanese, English
Stackoverflow
269reputation
867reached
0answers
2questions
Github Skills (20)
debugging10
testing10
ruby10
mspec10
rubyspec10
test-suite10
concurrency10
test-automation10
back-end-development9
package-manager-tool9
package-manager9
cli8
command-line-interface8
command-line8
git8
Programming languages (14)
Github contributions (5)
ruby/debug
Jul 2008 - Dec 2022
Debugging functionality for Ruby
Role in this project:
Back-end Developer
Back-end DeveloperContributions:15 releases, 237 reviews, 514 commits in 14 years 8 months
Contributions summary:Koichi primarily worked on the `debug` gem, a debugging functionality for Ruby. Their contributions included fixing issues related to the use of `RubyVM`, adding features such as reloaded breakpoints, and enhancing the command line interface (CLI) and debugging capabilities. They also implemented several improvements to the backtrace and introduced the `whereami` command. The changes involve a complete rewrite of parts of the debugging functionality, and extension of the API.
debuggingrubydebuggerdebugging-tooldebug
ruby/spec
Mar 2015 - Dec 2022
The Ruby Spec Suite aka ruby/spec
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:34 commits, 5 PRs, 14 comments in 7 years 10 months
Contributions summary:Koichi primarily contributed to the Ruby spec suite by addressing style issues, fixing bugs, and adding test skips. Their contributions included correcting code style, adapting tests for different environments such as Vboxfs, and skipping tests on unsupported platforms or configurations. They focused on ensuring the test suite's functionality and robustness across various Ruby versions and environments.
rubylanguage-specsmspecrubyspec
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