Contribution Overview:

• Rubinius started ruby/spec in 2006 and was the main contributor until 2014. Then development slowed and spec contributions decreased.
• TruffleRuby started in 2014 and became the main contributor since, contributing more than half of commits.
• CRuby has consistently contributed around 20% each year, implementing new methods first.
• JRuby contributed significantly until 2012 but has made few since.
• Natalie started in 2019 and made significant contributions since 2022, thanks to @herwinw.
• External contributors have always been important, with a huge spike in 2009 due to @runpaint.

Methodology:

• Individual author contributions available on GitHub.
• Data computed by a script and chart generated by another script.
• GitHub API only provides stats for top 100 contributors.
• Authors classified by Ruby implementation based on top 100 contributors.
• Commits are not a perfect measure but the best available.

More Charts:

• Redid chart with 100 commits minimum to classify authors. Result similar with more external contributors.
• Chart with absolute commit numbers instead of relative to per year. 2025 commits are fewer as it's only May.

Conclusion:

• ruby/spec is key for correct and efficient Ruby implementation.
• It provides more precise coverage than documentation and relies on external contributions.
• CRuby test suite alone is not enough to implement Ruby correctly.
• ruby/spec's spec structure encourages more comprehensive testing compared to CRuby's unit tests.
• Intends to pick 10 random methods to compare specs and tests in a future blog post.