Gate overlap zones on node world

backend/routes/analytics.py

@@ -125,6 +125,14 @@ async def association_status():
     return {
         "registered_nodes": len(_a.node_geometries),
         "overlap_zones": len(_a.overlap_zones),
+        # Node pairs that got no grid because the two nodes are in different
+        # worlds (node_world above).  Read next to overlap_zones: on a fleet
+        # of 50 synthetic nodes over the same city as 8 receivers it is the
+        # 400 sim/real pairs whose grids could only ever have paired a
+        # simulated echo with a real one.  Counted per pair considered, so it
+        # keeps rising as nodes re-register — zero means the fleet is single-
+        # world (or untagged), not that the gate is off.
+        "assoc_world_skipped_pairs": getattr(_a, "assoc_world_skipped_pairs", 0),
         # Confirmed single-node tracks each node last submitted; these are what
         # pairings are drawn from.
         "pending_tracks": {nid: len(tracks) for nid, tracks in list(_a._pending_tracks.items())},

backend/tests/test_adsb_seed_backend.py

@@ -605,3 +605,32 @@ def test_associator_gets_the_state_world_resolver(self):
         must consult the same resolver claiming and the auto-tag filter use,
         or one consumer accepts what another rejects."""
         assert state.node_associator.node_world_provider is state.node_world
+
+    def test_a_sim_and_a_real_node_over_one_footprint_get_no_overlap_zone(self):
+        """The same resolver, one level down: bottom-up pairing must not build
+        a grid across worlds either.  Registering a synthetic node and a
+        hardware node on overlapping coverage used to leave a zone whose only
+        possible pairing was a simulated echo against a real one — which is how
+        real node ids reached the synthetic fleet's dark solves."""
+        _a = state.node_associator
+        try:
+            _a.register_node("synth-GVL-9001", dict(_NODE_CFG))
+            _a.register_node("hw-9001", dict(_NODE_CFG, rx_lat=34.86, rx_lon=-82.36))
+
+            assert _a.overlap_zones == {}
+            assert _a._neighbors.get("synth-GVL-9001", set()) == set()
+            assert _a.assoc_world_skipped_pairs == 1
+        finally:
+            state._reset_for_tests()
+
+    def test_two_synthetic_nodes_over_one_footprint_still_pair(self):
+        """The gate is the world difference, not the registration."""
+        _a = state.node_associator
+        try:
+            _a.register_node("synth-GVL-9001", dict(_NODE_CFG))
+            _a.register_node("synth-GVL-9002", dict(_NODE_CFG, rx_lat=34.86, rx_lon=-82.36))
+
+            assert _a.overlap_zones
+            assert _a.assoc_world_skipped_pairs == 0
+        finally:
+            state._reset_for_tests()

backend/tests/test_analytics_routes.py

@@ -129,6 +129,18 @@ def test_status_returns_expected_fields(self, client):
         assert "overlap_zones" in body
         assert "overlaps" in body
 
+    def test_status_reports_world_skipped_pairs(self, client):
+        """The world gate on overlap zones is otherwise invisible: a fleet
+        whose sim/real pairs are being refused looks exactly like a fleet whose
+        pairs never overlapped, and only this counter separates them."""
+        _a = state.node_associator
+        _a.assoc_world_skipped_pairs += 7
+        try:
+            body = client.get("/api/radar/association/status").json()
+            assert body["assoc_world_skipped_pairs"] == 7
+        finally:
+            state._reset_for_tests()
+
     def test_status_includes_claiming_block(self, client):
         """Top-down claiming (ASSOC_CLAIM_MODE) since boot — off by default
         in tests, so this pins the shape rather than any particular mode."""