fix(repo): repair the vm runner and config subpath after 11.0.0

.changeset/dry-run-failure-names-tests.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-js': patch
+---
+
+A failed dry run now says which tests broke and why. The refusal names every failing test with its failure message in the error output and in the log at the default level, instead of reporting only how many failed.

.changeset/restore-config-authoring-helpers.md

@@ -0,0 +1,10 @@
+---
+'@systemfsoftware/stryker-js': major
+---
+
+Restore `defineConfig` and `mergeConfig` on `@systemfsoftware/stryker-js/config`. `defineConfig` accepts an options object, a promise of one, or a `(env: ConfigEnv) => …` factory, as in 10.1.1, and `mergeConfig(defaults, overrides)` composes presets again. `StrykerConfig` is again the partial-options type, so `const config: StrykerConfig = defineConfig({ … })` typechecks. Config files written against the 10.1.1 `./config` surface load and typecheck without edits.
+
+This removes the 11.0.0 `StrykerConfig` class value. If you adopted it:
+
+- Replace `StrykerConfig.define(…)` with `defineConfig(…)` and `StrykerConfig.merge(…)` with `mergeConfig(…)`, imported from `@systemfsoftware/stryker-js/config`.
+- Replace `StrykerConfig.createDefaultOptions()` and `StrykerConfig.defaultOptions` with `Configuration.createDefaultOptions()` and `Configuration.defaultOptions` from the package entry point.

.changeset/stryker-js-effect-required-peer.md

@@ -0,0 +1,5 @@
+---
+"@systemfsoftware/stryker-js": patch
+---
+
+Installing `@systemfsoftware/stryker-js` on its own now works. `effect` was declared an optional peer even though Stryker imports it at runtime. Package managers never install optional peers, so a project without `effect` failed with `Failed to read config` before the run started. `effect` is now a required peer: pnpm and npm install it automatically, and a project that already uses Effect shares its own copy with Stryker.

.changeset/test-contribution-property-input-schema.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-test-contribution': none
+---
+
+Tests only, no release: the `judgeTestContribution` laws now generate their commands from a purpose-built schema of the fields the judgement reads instead of deriving them from the command's whole mutation-test report schema, which keeps every property inside its CI run budget.

.changeset/vm-harness-pass-with-no-tests.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-vm-harness': patch
+---
+
+The vm runner now honours Vitest's `passWithNoTests`. A test file that registers no tests no longer fails the dry run when its Vitest project sets `passWithNoTests: true`, and still fails with `No test suite found in file <path>` when the option is false or unset. The option applies per project, as in Vitest: a root-level `test.passWithNoTests` covers every project, and one project in `test.projects` can opt in while another does not.

.changeset/vm-harness-resolves-itself.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-vm-harness': patch
+---
+
+Projects that install `@systemfsoftware/stryker-js` and `vitest`, but not the vm runner package directly, now complete a `testRunner: 'vm'` dry run under pnpm's default isolated `node_modules` layout, instead of failing with a `Cannot find module` error for the vm runner's own package. The project's own `vitest` is still the one that runs your tests.

.changeset/vm-runner-marker-text-preserved.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-vm-harness': patch
+---
+
+The vm runner no longer rewrites `import.meta.vitest` text that is not an expression. A string, template literal, comment or regex literal that mentions `import.meta.vitest` now reaches your code unchanged, so suites whose fixtures contain it, such as lint-rule tests, pass on the vm runner as they do under Vitest. In-source `if (import.meta.vitest)` tests still register and run, and `import.meta.vitest` inside a template `${…}` substitution still evaluates to the Vitest API.

.changeset/vm-runner-serves-vitest-outside-root.md

@@ -0,0 +1,5 @@
+---
+'@systemfsoftware/stryker-vm-harness': patch
+---
+
+The vm runner now gives the Vitest API to every module a suite loads that imports `vitest`, not only to files inside the project directory. A Vitest `setupFiles` entry, helper module or workspace package outside the project used to receive a runner-less `vitest` and stop the whole run with "Vitest failed to find the runner"; its `beforeEach` and `it` calls now register against the current test file, as they do under Vitest. Dependencies under `node_modules` stay shared across test files, and `@effect/vitest` and `@systemfsoftware/effect-gherkin-spec` behave as before.

.changeset/worker-options-law-domain.md

@@ -0,0 +1,5 @@
+---
+"@systemfsoftware/stryker-js-plugin-runtime": none
+---
+
+`WorkerOptionsWire` gained an internal declaration so its round-trip law suite draws option keys that the JSON parser reads back unchanged on V8 13.6 (Node 24 and 26). Decoding and encoding worker options are unchanged, and every exported name, type and runtime behaviour is identical, so no release is warranted.

README.md

@@ -32,15 +32,15 @@ A high mutation score guarantees test assertions catch regressions rather than j
 
 ## ⚡ Dual-Engine Workflow: In-Process `vm` vs Vitest Worker Sandbox
 
-Mutation testing feedback latency slows down local development when every mutant forks new child processes. Stryker JS Effect provides a dual execution architecture configured through `StrykerConfig.define`:
+Mutation testing feedback latency slows down local development when every mutant forks new child processes. Stryker JS Effect provides a dual execution architecture configured through `defineConfig`:
 
 1. **Local Developer Loop (`testRunner: 'vm'`)**: The default runner. Runs your Vitest suites in-process in a worker thread per test runner, loading each test file as native ESM through Node's module hooks. No child process and no bundler step; the matchers, mocks, and snapshots come from the `vitest` installed in your project.
 2. **CI Regression Gate (`testRunner: 'vitest'`)**: Executes integration suites in isolated Vitest worker threads with per-test coverage analysis.
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define(({ isCi }) => ({
+export default defineConfig(({ isCi }) => ({
   // In-process vm locally for instant feedback; isolated Vitest workers in CI
   testRunner: isCi ? 'vitest' : 'vm',
   checkers: ['typescript'],
@@ -81,9 +81,9 @@ pnpm add -D @systemfsoftware/stryker-js \
 Recommended for integration suites requiring full Vitest mocking APIs, DOM emulation, or browser runners:
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'vitest',
   checkers: ['typescript'],
   plugins: [
@@ -103,9 +103,9 @@ pnpm add -D @systemfsoftware/stryker-js @systemfsoftware/stryker-js-typescript-c
 ```
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'vm',
   checkers: ['typescript'],
   plugins: [
@@ -121,9 +121,9 @@ export default StrykerConfig.define({
 Execute any test framework (Jest, Mocha, Node test runner) via custom shell commands:
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'command',
   commandRunner: {
     command: 'pnpm test',
@@ -147,9 +147,9 @@ pnpm add -D @systemfsoftware/stryker-js-svelte # .svelte (Svelte 5 only)
 ```
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'vitest',
   plugins: ['@systemfsoftware/stryker-js-angular'],
   mutate: ['src/**/*.html', 'src/**/*.vue'],
@@ -186,9 +186,9 @@ pnpm add -D @systemfsoftware/stryker-js \
 ```
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define(({ isCi }) => ({
+export default defineConfig(({ isCi }) => ({
   testRunner: 'vitest',
   checkers: ['typescript'],
   plugins: [
@@ -218,12 +218,12 @@ export default StrykerConfig.define(({ isCi }) => ({
 
 ### Environment-Aware Configuration
 
-`StrykerConfig.define` accepts a callback instead of a static object. It receives a `ConfigEnv` of `{ command, isDryRun, mode, isCi }`, where `command` is `'run'` or `'merge-reports'` and `mode` is the resolved output mode:
+`defineConfig` accepts a callback instead of a static object. It receives a `ConfigEnv` of `{ command, isDryRun, mode, isCi }`, where `command` is `'run'` or `'merge-reports'` and `mode` is the resolved output mode:
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define(({ command, isCi, isDryRun }) => ({
+export default defineConfig(({ command, isCi, isDryRun }) => ({
   testRunner: 'vitest',
   plugins: ['@systemfsoftware/stryker-js-vitest-runner'],
   mutate: ['src/**/*.ts', '!src/**/*.test.ts'],
@@ -300,20 +300,20 @@ $ STRYKER_MODE=machine pnpm exec stryker run
 
 ## 📦 Workspace Packages
 
-| Package                                                                                                       | Purpose                                                                                                           |
-| ------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- |
-| [`@systemfsoftware/stryker-js`](packages/stryker-js)                                                          | Flagship CLI binary, run engine, and `./config` authoring surface (`StrykerConfig.define`, `StrykerConfig.merge`) |
-| [`@systemfsoftware/stryker-js-vitest-runner`](packages/stryker-js-vitest-runner)                              | Vitest test runner plugin with sandbox isolation and per-test coverage analysis                                   |
-| [`@systemfsoftware/stryker-js-typescript-checker`](packages/stryker-js-typescript-checker)                    | TypeScript type checker plugin rejecting uncompilable mutants before running tests                                |
-| [`@systemfsoftware/stryker-js-html-reporter`](packages/stryker-js-html-reporter)                              | Interactive HTML mutation report generator (`reports/mutation/index.html`)                                        |
-| [`@systemfsoftware/stryker-js-angular`](packages/frameworks/angular)                                          | Framework plugin instrumenting `.html`, `.htm`, and `.vue` script regions                                         |
-| [`@systemfsoftware/stryker-js-svelte`](packages/frameworks/svelte)                                            | Framework plugin instrumenting Svelte 5 `.svelte` scripts and template expressions                                |
-| [`@systemfsoftware/stryker-framework-interface`](packages/frameworks/interface)                               | Types-only `Framework` contract a framework plugin implements                                                     |
-| [`@systemfsoftware/stryker-ignorer-kit`](packages/ignorers/kit)                                               | Authoring kit (`defineIgnorer`) and test harness (`testIgnorer`) for custom ignorers                              |
-| [`@systemfsoftware/stryker-ignorer-interface`](packages/ignorers/interface)                                   | AST node types and `Ignorer` contract                                                                             |
-| [`@systemfsoftware/stryker-ignorer-effect-schema-declarations`](packages/ignorers/effect-schema-declarations) | Ignorer filtering equivalent mutants on Effect Schema and Brand declarations                                      |
-| [`@systemfsoftware/stryker-ignorer-in-source-vitest-block`](packages/ignorers/in-source-vitest-block)         | Ignorer removing unreachable mutants inside `if (import.meta.vitest)` blocks                                      |
-| [`@systemfsoftware/stryker-test-contribution`](packages/stryker-test-contribution)                            | Test suite hygiene plugin enforcing unique mutant kills per test file                                             |
+| Package                                                                                                       | Purpose                                                                                           |
+| ------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
+| [`@systemfsoftware/stryker-js`](packages/stryker-js)                                                          | Flagship CLI binary, run engine, and `./config` authoring surface (`defineConfig`, `mergeConfig`) |
+| [`@systemfsoftware/stryker-js-vitest-runner`](packages/stryker-js-vitest-runner)                              | Vitest test runner plugin with sandbox isolation and per-test coverage analysis                   |
+| [`@systemfsoftware/stryker-js-typescript-checker`](packages/stryker-js-typescript-checker)                    | TypeScript type checker plugin rejecting uncompilable mutants before running tests                |
+| [`@systemfsoftware/stryker-js-html-reporter`](packages/stryker-js-html-reporter)                              | Interactive HTML mutation report generator (`reports/mutation/index.html`)                        |
+| [`@systemfsoftware/stryker-js-angular`](packages/frameworks/angular)                                          | Framework plugin instrumenting `.html`, `.htm`, and `.vue` script regions                         |
+| [`@systemfsoftware/stryker-js-svelte`](packages/frameworks/svelte)                                            | Framework plugin instrumenting Svelte 5 `.svelte` scripts and template expressions                |
+| [`@systemfsoftware/stryker-framework-interface`](packages/frameworks/interface)                               | Types-only `Framework` contract a framework plugin implements                                     |
+| [`@systemfsoftware/stryker-ignorer-kit`](packages/ignorers/kit)                                               | Authoring kit (`defineIgnorer`) and test harness (`testIgnorer`) for custom ignorers              |
+| [`@systemfsoftware/stryker-ignorer-interface`](packages/ignorers/interface)                                   | AST node types and `Ignorer` contract                                                             |
+| [`@systemfsoftware/stryker-ignorer-effect-schema-declarations`](packages/ignorers/effect-schema-declarations) | Ignorer filtering equivalent mutants on Effect Schema and Brand declarations                      |
+| [`@systemfsoftware/stryker-ignorer-in-source-vitest-block`](packages/ignorers/in-source-vitest-block)         | Ignorer removing unreachable mutants inside `if (import.meta.vitest)` blocks                      |
+| [`@systemfsoftware/stryker-test-contribution`](packages/stryker-test-contribution)                            | Test suite hygiene plugin enforcing unique mutant kills per test file                             |
 
 ---
 

docs/solutions/tooling-decisions/agent-plugin-packaging-dual-engine-mutation-testing.md

@@ -32,9 +32,9 @@ $$\text{Runner}(E) = \begin{cases} \text{In-Process Worker-Thread `vm`}, & E \ne
 - **CI (`testRunner: 'vitest'`)**: Executes within isolated worker processes, capturing comprehensive per-test coverage analysis and supporting complete mock/DOM environments.
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define(({ isCi }) => ({
+export default defineConfig(({ isCi }) => ({
   testRunner: isCi ? 'vitest' : 'vm',
   checkers: ['typescript'],
   plugins: [
@@ -52,7 +52,7 @@ export default StrykerConfig.define(({ isCi }) => ({
 Installed packages take the bare name, resolved from the project under test. A `file://` URL to a local build stays accepted:
 
 ```ts
-export default StrykerConfig.define({
+export default defineConfig({
   plugins: ['@systemfsoftware/stryker-js-vitest-runner'],
 })
 ```

packages/frameworks/angular/README.md

@@ -18,9 +18,9 @@ pnpm add -D @systemfsoftware/stryker-js-angular
 Add the package name to `plugins` in your StrykerJS config:
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'vitest',
   plugins: ['@systemfsoftware/stryker-js-angular'],
   mutate: [

packages/frameworks/svelte/README.md

@@ -17,9 +17,9 @@ pnpm add -D @systemfsoftware/stryker-js-svelte
 Add the package name to `plugins` in your StrykerJS config:
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: 'vitest',
   plugins: ['@systemfsoftware/stryker-js-svelte'],
   mutate: ['src/**/*.svelte'],

packages/ignorers/effect-schema-declarations/README.md

@@ -20,9 +20,9 @@ pnpm add -D @systemfsoftware/stryker-ignorer-effect-schema-declarations
 Add the package name to `ignorers`. Every ignorer the module exports is then active.
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: {
     plugin: '@systemfsoftware/stryker-js-vitest-runner',
   },

packages/ignorers/in-source-vitest-block/README.md

@@ -20,9 +20,9 @@ pnpm add -D @systemfsoftware/stryker-ignorer-in-source-vitest-block
 Add the package name to `ignorers`. Every ignorer the module exports is then active.
 
 ```ts
-import { StrykerConfig } from '@systemfsoftware/stryker-js/config'
+import { defineConfig } from '@systemfsoftware/stryker-js/config'
 
-export default StrykerConfig.define({
+export default defineConfig({
   testRunner: {
     plugin: '@systemfsoftware/stryker-js-vitest-runner',
   },

packages/stryker-js-instrumenter/tests/__fixtures__/effect-concurrency-files.ts

@@ -24,3 +24,19 @@ export const effectConcurrencyFixtureFiles = Effect.flatMap(
           })),
       )),
 )
+
+const CONCURRENCY_SELECTION_FIXTURE_NAMES: readonly string[] = [
+  'import-style-named.ts',
+  'import-style-aliased.ts',
+  'import-style-effect-namespace.ts',
+  'import-style-module-namespace.ts',
+  'import-style-bare-function.ts',
+  'import-style-bare-function-no-binding.ts',
+  'synchronization-removal.ts',
+  'refusals.ts',
+]
+
+export const effectConcurrencySelectionFixtureFiles = Effect.forEach(
+  CONCURRENCY_SELECTION_FIXTURE_NAMES,
+  (name) => Effect.map(effectConcurrencyFixtureContent(name), (content) => ({ name, content })),
+)

packages/stryker-js-instrumenter/tests/opt-in-selection.integration.test.ts

@@ -3,7 +3,11 @@ import { Gherkin, Given, it, makeFeature, Then, When } from '@systemfsoftware/ef
 import { Instrument } from '@systemfsoftware/stryker-js-instrumenter'
 import { Effect } from 'effect'
 
-import { effectConcurrencyFixtureFiles, type FixtureFile } from './__fixtures__/effect-concurrency-files.js'
+import {
+  effectConcurrencyFixtureFiles,
+  effectConcurrencySelectionFixtureFiles,
+  type FixtureFile,
+} from './__fixtures__/effect-concurrency-files.js'
 import { instrument } from './__fixtures__/instrument.js'
 
 const ATOMIC_UPDATE_SPLIT = 'AtomicUpdateSplit'
@@ -165,9 +169,11 @@ Feature('Choosing extra concurrency mutations by name')
     scenario(
       'A run that names some concurrency mutators turns on exactly the ones it named and nothing else',
       Gherkin.Do.pipe(
-        Given('every Effect concurrency fixture has been read from disk')(
+        Given(
+          'the fixtures holding a placement site for each concurrency mutator, and a bare update holding none, have been read from disk',
+        )(
           'fixtures',
-          () => effectConcurrencyFixtureFiles,
+          () => effectConcurrencySelectionFixtureFiles,
         ),
         When('the fixtures are instrumented once without extras and once for every choice of concurrency mutators')(
           'runs',