Merged PRs: An Untapped Resource for Practice and Exploration
summary
Argues that studying merged PRs from the Rails codebase gives repeatable, low‑stakes debugging practice: clone the repo, checkout the merge parent, run bundle and rails new --dev to recreate the pre‑fix app, then reproduce the bug with puts, rdbg/pry, web console, git bisect, flame graphs or StackProf and tests. Cites studies that developers spend ~35–50% (up to 70%) of time debugging and that almost 50 cents of every dollar goes to fixes. Small fixes (e.g. net 11 lines) make ideal exercises; larger PRs (531 lines) are possible but often too big.
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chapters (11)
- 0:00Introduction
- 1:04Debugging theory
- 7:03Debugging competencies
- 11:44Becoming better debuggers
- 14:57Debugging with merged PRs
- 16:44Debugging practice setup
- 20:18Finding practice PRs
- 23:46Example debugging PRs
- 25:55Debugging tools overview
- 31:34Evaluating solutions
- 32:37Wrap-up








