feat(repo): wire dry-run module evidence into closure analysis

[systemfsoftware-maker]

Summary

Layer 3 of 3. This wires the dry run's testFileModules into every closure analysis and persists it in the incremental report. With it, the last 3 open stryker-js test closures close (src/conclude-run.ts, src/mutation-reporting.service.ts, src/run/instrument.ts). Those were open only because they reach the computed import(moduleName) in src/drivers/config.ts.

Wiring

• Persist. dryRunCoverage.testFileModules stores original project paths, mapped from the sandbox the same way as globalTestInputs. A reused dry run carries it forward unchanged.
  • A sandbox-only value with no project original is dropped. That is the runner's generated setup module; otherwise it would open every closure.
  • Values outside the sandbox (data: URLs, store realpaths) pass through verbatim, so a data: target still opens the closure.
• Feed. Evidence goes into both closureAnalysisOf calls in the dry-run cell: the prior coverage before the reuse decision, and the fresh evidence after a run. It also goes into the incremental-reuse analysis and the plan path.
• Soundness, by induction. A key computed from the evidence of run N matches at run N+1 only if every module the test loaded at N is byte-identical. In that case the test loads the same modules again. A changed observation can only refuse reuse, never reuse a stale verdict. Known boundary, same as today's fs reads: a mutant that changes a computed specifier may load a module the dry run never saw.

Proof (real dry runs with the layer-1 runner, not hand-fed evidence)

tests/incremental-reuse.integration.test.ts. A test file statically imports src/left.mjs and, in its body, runs await load(new URL('../src/plugin.mjs', import.meta.url).href).

• Editing the dynamic target src/plugin.mjs re-runs left's covered mutants.
• Editing an unrelated src/unrelated.mjs keeps them.
• A runtime data: target keeps the closure open, so the unrelated edit re-runs them.
• The fix(repo): key a module-level mutant on its whole-suite closure digest #219 open-closure scenario used an uncalled import(name). With evidence, an uncalled import loads nothing, so it closes. The scenario now imports a data: URL at runtime, which keeps the soundness case meaningful.

Failing-before: "A runtime module a test file loads keeps the closure closed around an unreached edit". With layer 2's engine sources in a scratch worktree, it got kept: false, reran: true against expected kept: true, reran: false (1 failed, 13 passed). 14 of 14 pass here.

Projected effect (no mutation run; main CI measures after release)

Evidence was collected exactly as the runner collects it, reading the worker module map in each test file's afterAll during a plain vitest run of the package's mutation test set: 184 files, 1081 tests. Closures were computed with this branch's analyzeImportClosure. Mutants come from the merged report of main run 37574914218 (2624 reusable mutants), and the projection covers one-file edits of each of the 243 source files under main's keys (#216 plus #219).

	open closures	re-runs per one-file edit (mean / median / max)	mean recorded cost
main today	3 / 177	273 / 258 / 478	19.2 min
this stack	0 / 177	225 / 258 / 478	15.7 min

The median holds at 258 because #219's whole-suite key re-runs every static mutant whenever any test reaches the edited file. That is most files; 42 of 243 edits now keep everything. With no open closures left, the held reach key (stryker/static-reach-closure) projects 165 / 211 / 431 at 12.0 min.

Validation

• Full stryker-js suite: 231 files, 1250 tests. Vitest-runner: 23 tests. Plugin-interface: 270 tests.
• pnpm check:ci: 111 of 112. The only failure is stryker-js#api:check, whose single diff is the machine-dependent Node_2 as Node alias. The committed report keeps the rendering that CI passes on main.
• guard:projects reports Verdict-Semantics: unchanged, and both changeset checks exit 0.
• Changeset: minor.

[kiro-systemf]

Layer 3: wires dry-run module evidence into closures; unresolved evidence keeps closures open.