fix(run-store): union the id-less pending-waitpoint count so a drain mirror counts once

Author: d-cs

internal-packages/run-store/src/runOpsStore.shardMap.test.ts

@@ -647,6 +647,12 @@ describe("RoutingRunStore countPendingWaitpoints — disjoint-sum partition", ()
     expect(await router.countPendingWaitpoints(["b:w9"], undefined, "a:run")).toBe(0);
   });
 
+  it("id-less count unions a drain-mirrored cuid to one, never sums it to two", async () => {
+    // No runId: fans over distinct stores. A cuid pending on BOTH gen-1 stores is one waitpoint.
+    const { router } = partitionRouter({ new: ["cuid_w1"], legacy: ["cuid_w1"] });
+    expect(await router.countPendingWaitpoints(["cuid_w1"])).toBe(1);
+  });
+
   it("returns the true total for a mixed gen-2 and cuid set with no double count", async () => {
     const { router } = partitionRouter({
       b: ["b:w1"],

internal-packages/run-store/src/runOpsStore.ts

@@ -1402,10 +1402,20 @@ export class RoutingRunStore implements RunStore {
     runId?: string
   ): Promise<number> {
     if (runId === undefined) {
+      // No run id to partition on: query every distinct store and UNION by id, matching the routed
+      // path below. A drain-mirrored cuid pending on both gen-1 stores must count once, not twice —
+      // summing raw counts here would reintroduce the double count this method exists to remove.
       const legs = await this.#fanOut(this.#probeOrder, (store) =>
-        store.countPendingWaitpoints(waitpointIds, RoutingRunStore.#ownPrimary(store, client))
+        store.countPendingWaitpointsWithPresence(
+          waitpointIds,
+          RoutingRunStore.#ownPrimary(store, client)
+        )
       );
-      return legs.reduce((sum, leg) => sum + leg, 0);
+      const union = new Set<string>();
+      for (const leg of legs) {
+        for (const id of leg.pendingIds) union.add(id);
+      }
+      return union.size;
     }
 
     if (waitpointIds.length === 0) {