[systemfsoftware-maker]

Summary

The ignorer family's protocol is now two fields over a path that carries its ancestors as data, and the workspace types and walks ASTs in oxc's own vocabulary. A consumer installs one types-only package; no ignorer, and no part of the instrumenter behind them, declares a node shape by hand any more.

What changed

Outcome	Before → after
Entry contract	A module had to declare a Standard Schema beside shouldIgnore. It now exports strykerIgnorers: { name, shouldIgnore(path: NodePath): string | undefined }[], and the engine checks exactly that: a non-string name or non-callable shouldIgnore fails the load with PluginLoadFailedError naming the module. Native strykerPlugins modules load unchanged.
Ignorer path	NodePath was a parentPath chain with five is*() methods, and each ignorer shipped its own AstNode.ts and AncestorWalk.ts. It is now { node: unknown, ancestors: readonly unknown[] } — plain data, nearest ancestor first, no methods — and both packages' node shapes and walkers are deleted, their guards inlined into the decision file over the ancestor array.
AST vocabulary	The interface hand-rolled partial node shapes. It now re-exports the node types from @oxc-project/types — the parser's own view of the same objects — inlined into its emitted declarations, so consumers gain no dependency. The instrumenter went further: its thirty-odd local node declarations are gone, replaced by 139 aliases over the same types, derived through type-fest.
Instrumenter traversal	The hand-rolled descent loop and its estree-walker runtime load are gone; the mutation traversal and the Svelte walk both resolve oxc-walker. stop() aborts through a Schema.TaggedError, because the walker exposes only skip/remove/replace and no abort primitive; comment records stay excluded by key.
Out-of-repo ignorer	stryker-ignorer-workflow-make-boundary is deleted. It encodes the systemfsoftware DMMF stack's Workflow.make convention, which this repo does not own. Its entry left the engine's base preset, the plugin-manifest specifier list, and the changeset set.
API surface	Every publishable package now carries API Extractor: a root api-extractor.json, plus api-extractor.<entry>.json and tsconfig.api-<entry>.json per extra subpath. Sixteen reports live under <package>/etc/, covering engine's five entries, vitest-runner's two, and one per single-entry package.
Cache correctness	test and lint did not declare the shared toolchain presets they import. Editing packages/toolchain/vitest-config/lib/** or .../oxlint-ignorer-config/lib/** left the consuming tasks at an unchanged hash and status HIT — a stale green. Both are inputs now.

Two gates stayed out of this PR by design: the CI workflow, and the root check:ci / gate:tasks / gate:dist scripts. Wiring api:check into them is the owner's edit.

Verification

• pnpm check:ci green at the tip of the branch (format, task gate, dist gate).
• turbo lint typecheck test --force green.
• Ignorer decisions unmoved: 48 effect-schema cases, 15 in-source cases — the added case proves the decision reads ancestors with no parentPath in the input.
• Instrumenter: 13 tests across 6 suites, including the new angular-ignorer.integration.test.ts, which drives the published instrument surface with the published angularIgnorer as configuration data and pins both Angular status reasons; the Svelte suite now reaches its mutants through oxc-walker.
• Interface stays types-only and self-contained: dist/index.mjs is export {}, dist/index.d.ts contains no import, and the API report carries no ae-forgotten-export.
• estree-walker appears nowhere under packages/** source or manifests.
• turbo api:check --force: 23/23, all sixteen reports current.
• attw --pack clean for every subpath export, under node10 / node16-cjs / node16-esm / bundler.
• pnpm peers check: no unmet peers. Removing the unused vite-tsconfig-paths devDependency dropped tsconfck, which wanted TypeScript ^5 against this catalog's ^7.
• Preset-input fix probed by mutation: touching a toolchain preset now moves exactly the one task that consumes it, and nothing else.
• Reports are pinned byte-exact (**/etc/*.api.md -text). API Extractor writes CRLF, and the repo's * text=auto eol=lf was normalising the reports to LF in git, which made api:check fail on a fresh checkout while the working tree stayed green.

Review accounting

Structured review raised two P0s against .github/workflows/ci.yml — the graded change scoped the gate it is graded by. That change is reverted; the scoping idea belongs to the gate's owner. Review drove the contract cut: the descriptor no longer demands a schema member and the engine no longer re-declares one. Follow-ups recorded, not defects: an engine scenario loading a published dist entry, a native-only loader scenario, duplicate-name warnings for plain entries, and five turbo graph proposals that would deviate from the house pattern (the largest: api:check's script re-runs the tsdown its own turbo dependency already ran).

The walker swap was driven by a challenge worth recording: Built<T> cannot be Simplifyd inside itself (tsc reports TS2615/TS2589 on the recursive AST), and oxc-walker's walk is not generic, so the aliases at that seam admit parsed nodes alongside synthesized ones rather than casting.

Docs

• Corrected plan: docs/plans/2026-09-14-0520-refactor-ignorer-plain-entry-plan.md (supersedes the deleted 0150 plan).
• Learning: docs/solutions/tooling-decisions/plain-entry-contract-without-a-declared-schema.md.