fix(control): check native completion before restarting a parent

packages/control-core/src/service.ts

@@ -136,9 +136,13 @@ function sameRequest(left: RunRecordV1, right: RunRecordV1): boolean {
   );
 }
 
-async function readIfPresent(store: ObjectStore, key: string): Promise<unknown | null> {
+async function readIfPresent(
+  store: ObjectStore,
+  key: string,
+  options?: { fresh?: boolean },
+): Promise<unknown | null> {
   try {
-    return await readJson(store, key);
+    return await readJson(store, key, options);
   } catch (error) {
     if ((error as NodeJS.ErrnoException).code === "ENOENT") return null;
     throw error;
@@ -908,6 +912,17 @@ export class ControlService {
           Date.now() - Date.parse(latest.started_at) < this.options.restartDelayMs
         )
           return;
+        // A completed native result can become readable after the projection's
+        // Bucket listings began. Do not start another parent from that stale view.
+        const nativeResult = asRecord(
+          await readIfPresent(
+            this.store,
+            `runs/${projected.record.run_id}/job/result.json`,
+            { fresh: true },
+          ),
+        );
+        if (typeof nativeResult?.finished_at === "string" && nativeResult.finished_at)
+          return;
         let parent: JobObservation;
         try {
           parent = await this.sequenceInference(async () => {

packages/control-core/src/store.ts

@@ -155,8 +155,14 @@ export class FilesystemObjectStore implements ObjectStore {
   }
 }
 
-export async function readJson(store: ObjectStore, key: string): Promise<unknown> {
-  return JSON.parse(new TextDecoder().decode(await store.read(key))) as unknown;
+export async function readJson(
+  store: ObjectStore,
+  key: string,
+  options?: { fresh?: boolean },
+): Promise<unknown> {
+  return JSON.parse(
+    new TextDecoder().decode(await store.read(key, options)),
+  ) as unknown;
 }
 
 export async function createJson(

packages/control-core/test/reconciliation-performance.test.ts

@@ -323,6 +323,46 @@ it.each([4, 16, 64])(
   },
 );
 
+it("does not restart a parent when a finished native result appears after stale listings", async () => {
+  const id = await seed(0, "run");
+  const resultKey = `runs/${id}/job/result.json`;
+  await putJson(store, resultKey, { finished_at: now, n_total_trials: 1 });
+  const list = vi.mocked(store.list).getMockImplementation();
+  if (!list) throw new Error("missing list fixture");
+  let calls = 0;
+  vi.spyOn(store, "list").mockImplementation(async (prefix) => {
+    const entries = await list(prefix);
+    // The direct object is already readable, but both reconciliation listings
+    // started before its upload became visible in the Bucket listing.
+    return ++calls <= 2 ? entries.filter((entry) => entry.key !== resultKey) : entries;
+  });
+
+  await service.reconcile();
+
+  expect(port.startParent).not.toHaveBeenCalled();
+  expect(store.read).toHaveBeenCalledWith(resultKey, { fresh: true });
+  expect(projection.run(id)?.status).toBe("finished");
+});
+
+it("bypasses cached unfinished results before starting a replacement parent", async () => {
+  const id = await seed(0, "run");
+  const resultKey = `runs/${id}/job/result.json`;
+  await putJson(store, resultKey, { finished_at: now, n_total_trials: 1 });
+  const read = vi.mocked(store.read).getMockImplementation();
+  if (!read) throw new Error("missing read fixture");
+  vi.spyOn(store, "read").mockImplementation((key, options) =>
+    key === resultKey && !options?.fresh
+      ? Promise.resolve(new TextEncoder().encode(JSON.stringify({ finished_at: null })))
+      : read(key, options),
+  );
+
+  await service.reconcile();
+
+  expect(port.startParent).not.toHaveBeenCalled();
+  expect(store.read).toHaveBeenCalledWith(resultKey, { fresh: true });
+  expect(projection.run(id)?.status).toBe("queued");
+});
+
 it("does not skip terminal live Jobs present in the initial complete snapshot", async () => {
   const terminal = await seed(0);
   jobs.push(observation(terminal), observation(terminal, "child", "trial"));