Skill: Octane bug hunter

Use this to find, reproduce, minimize, and fix a suspected Octane bug.

Read first

• AGENTS.md
• Owning source and nearby tests
• docs/differences-from-react.md before assuming React mismatch is a bug

Workflow

1. State the suspected behavior

   • Expected behavior, actual behavior, package, environment, and reproduction path.
   • Decide whether the issue concerns runtime, compiler, SSR/hydration, Vite plugin, or an ecosystem binding.

2. Reproduce before fixing

   • Add or locate the smallest failing test/fixture.
   • For compiler/runtime behavior, prefer packages/octane/tests/_fixtures/*.tsrx plus a focused *.test.ts.
   • For React parity, cite source React tests and use conformance/differential conventions.
   • For ecosystem packages, use that package's tests/ harness.

3. Minimize

   • Remove unrelated props, effects, timing, and DOM.
   • Keep .tsrx fixtures tiny.
   • Confirm the test fails for the intended reason, not setup/aliasing/jsdom.

4. Localize

   • Runtime: inspect packages/octane/src/runtime.ts comments and closest tests.
   • Compiler: inspect packages/octane/src/compiler/compile.js and emitted output if needed.
   • SSR: inspect runtime.server.ts, server/index.ts, hydration tests.
   • Bindings: compare existing package patterns and upstream React binding behavior.

5. Patch carefully

   • Preserve documented intentional divergences.
   • Prefer fixing owning source over weakening tests.
   • Add regression coverage that would fail on the old behavior.
   • Keep changes minimal and idiomatic.

6. Validate

   • Run the new failing test until it passes.
   • Run nearby affected tests.
   • If runtime/compiler changed, consider wider packages/octane/tests or pnpm test depending on scope.
   • Run pnpm typecheck when TS/API surfaces changed.

7. Report

   • Root cause.
   • Files changed.
   • Tests added/updated and commands run.
   • Any remaining risks or intentional divergences.

Common traps

• React synthetic onChange, StrictMode double invoke, and class components are not bugs by default. Controlled value/checked is supported, but text editing uses native onInput; OCTANE_NATIVE_TEXT_ONCHANGE warns about likely React-style host wiring without changing native behavior. Deliberate commit-on-blur uses suppressNativeChangeWarning.
• Differential innerHTML cannot catch render counts, effect timing, refs, focus, or node move sets.
• jsdom layout/focus limitations can masquerade as library bugs.