Day 25 of 30 · First contribution
Capture the regression first
- Time
- About 150 minutes: 20 reading, 100 lab, 20 testing, 10 notes.
- Prerequisites
- Day 24: Locate the smallest responsible code path
Toolchain: current-main build
Use build/bin/clang++ and build/bin/llvm-lit from your llvm-main checkout, not whichever clang++ is first on PATH. Reproduce upstream behavior on current main and record the commit SHA. Setup guide
Learn
- A meaningful failing test or a demonstrable documentation defect.
Read Reading
- Your llvm-project checkout
Nearby test conventions · 20 min - R10 · LLVM testing guide
Review only as needed
Reading budgets cover selected sections, not whole chapters. Link to the book; this site does not reproduce it.
Build Build or investigate
- Add a minimal regression test to the appropriate Clang directory.
- Show it fails against the unchanged compiler for the intended reason.
- Include a valid nearby case when useful.
- For a test-coverage-only contribution, explain the missing coverage instead of claiming a fail-before result.
Done when
A baseline failure log for a behavior fix, or a precise coverage/documentation justification.
Recall question
Would this test catch the original defect if the implementation were reverted?
Completion checks
Progress tracking needs JavaScript. The lesson above is complete without it.
Notes
Saved only in this browser. Keep it short enough to finish in ten minutes; none of the prompts are required. All notes, export and import