Skills

Debug False Positive

Diagnose and fix a Fallow false positive or false negative through extraction...

Install

npx skills add fallow-rs/fallow --skill debug-false-positive -g -a claude-code -y
Repository
fallow-rs/fallow5.3k
Category
Engineering
Updated
3d ago
License
MIT
Context cost
Lightabout 321 tokens
Runs scripts
No, instructions only

What it does

Diagnose and fix a Fallow false positive or false negative through extraction, resolution, graph, analysis, reporting, and real-consumer verification.

Debug a false result

  1. Reproduce on current main with --format json --quiet. Save one command that shows the wrong result. Change no code before this command exists. After a restart or an update, clear the .fallow/ cache first.
  2. Reduce to a minimal fixture without losing the behavior.
  3. Write 3 to 5 ranked hypotheses. Each one predicts a result that one probe can disprove. Test one hypothesis per probe.
  4. Trace the finding through extract, resolve, graph, reachability, analysis, suppression, filters, and report assembly.
  5. Fix the earliest incorrect layer. Fix the pattern, not the instance (see test evidence in docs/development/quality-gates.md). After 3 failed fixes, stop and write down the premise that they share. Question that premise before a fourth fix.
  6. Add a regression test that fails without the fix.
  7. Run the fixed binary on a real consumer project with a cleared .fallow/ cache and compare old versus new output. A debug build (cargo build -p fallow-cli) is enough for this comparison. A release build adds a slow LTO link and gives the same findings.
  8. Run review with the affected surface reviewers.

Do not tune expected output around one fixture when the semantic model requires a broader correction.

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