Gateway: tighten node pending drain semantics (#41429)

Merged via squash.

Prepared head SHA: 361c2eb5c8
Co-authored-by: mbelinky <132747814+mbelinky@users.noreply.github.com>
Co-authored-by: mbelinky <132747814+mbelinky@users.noreply.github.com>
Reviewed-by: @mbelinky

src/gateway/node-pending-work.test.ts

@@ -3,6 +3,7 @@ import {
   acknowledgeNodePendingWork,
   drainNodePendingWork,
   enqueueNodePendingWork,
+  getNodePendingWorkStateCountForTests,
   resetNodePendingWorkForTests,
 } from "./node-pending-work.js";
 
@@ -43,4 +44,24 @@ describe("node pending work", () => {
     const afterAck = drainNodePendingWork("node-2");
     expect(afterAck.items.map((item) => item.id)).toEqual(["baseline-status"]);
   });
+
+  it("keeps hasMore true when the baseline status item is deferred by maxItems", () => {
+    enqueueNodePendingWork({ nodeId: "node-3", type: "location.request" });
+
+    const drained = drainNodePendingWork("node-3", { maxItems: 1 });
+
+    expect(drained.items.map((item) => item.type)).toEqual(["location.request"]);
+    expect(drained.hasMore).toBe(true);
+  });
+
+  it("does not allocate state for drain-only nodes with no queued work", () => {
+    expect(getNodePendingWorkStateCountForTests()).toBe(0);
+
+    const drained = drainNodePendingWork("node-4");
+    const acked = acknowledgeNodePendingWork({ nodeId: "node-4", itemIds: ["baseline-status"] });
+
+    expect(drained.items.map((item) => item.id)).toEqual(["baseline-status"]);
+    expect(acked).toEqual({ revision: 0, removedItemIds: [] });
+    expect(getNodePendingWorkStateCountForTests()).toBe(0);
+  });
 });