Keep restricted engines reserved through asynchronous retirement

2026-10-08 05:21:10 -07:00
parent dec3aa475a
commit 1b91e21d49
2 changed files with 42 additions and 4 deletions
@@ -686,3 +686,39 @@ test("the shared engine budget evicts idle code families and rejects busy oversu
  }
  assert.equal(engineBudget.stats().engines, 0);
 });
+
+test("engine retirement accounting keeps its admission lease busy", async () => {
+  const observations = [];
+  let idle;
+  const engineBudget = new RestrictedEngineBudget(1, async () => ({
+    usage: async () => {
+      observations.push(idle());
+      await new Promise((done) => setImmediate(done));
+      return { cpuMicroseconds: 0, memoryBytes: 1024 };
+    },
+    release: async () => {},
+  }));
+  const acquire = engineBudget.acquire.bind(engineBudget);
+  engineBudget.acquire = (isIdle, evict) => {
+    idle = isIdle;
+    return acquire(isIdle, evict);
+  };
+  const f = await fixture(registry("return request.input;"), { engineBudget });
+  try {
+    f.start("first");
+    assert.equal((await f.receive()).output, "first");
+    assert.ok(observations.length > 0);
+    assert.ok(
+      observations.every((value) => !value),
+      "An engine must not become evictable during asynchronous retirement accounting",
+    );
+    assert.equal(f.stats().idle, 1);
+    assert.equal(idle(), true);
+    f.start("second");
+    assert.equal((await f.receive()).output, "second");
+    assert.equal(f.stats().starts, 1);
+  } finally {
+    await f.close();
+  }
+  assert.equal(engineBudget.stats().engines, 0);
+});