From 793d44e1e92649739ddd6eabb1e40a7caef58694 Mon Sep 17 00:00:00 2001
From: liaodongnian <361485583@qq.com>
Date: Thu, 27 Aug 2026 19:21:08 +0800
Subject: [PATCH] Fix duplicate local delivery results by prioritizing
 NO_RECEIVER

---
 .../mqtt/service/LocalDistService.java        |  1 +
 .../mqtt/service/LocalDistServiceTest.java    | 46 +++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/bifromq-mqtt/bifromq-mqtt-server/src/main/java/org/apache/bifromq/mqtt/service/LocalDistService.java b/bifromq-mqtt/bifromq-mqtt-server/src/main/java/org/apache/bifromq/mqtt/service/LocalDistService.java
index 6422b802c..a7f849d13 100644
--- a/bifromq-mqtt/bifromq-mqtt-server/src/main/java/org/apache/bifromq/mqtt/service/LocalDistService.java
+++ b/bifromq-mqtt/bifromq-mqtt-server/src/main/java/org/apache/bifromq/mqtt/service/LocalDistService.java
@@ -194,6 +194,7 @@ public CompletableFuture<DeliveryReply> dist(DeliveryRequest request) {
             tenantMeter.recordSummary(MqttTransientFanOutBytes, totalFanOutBytes);
             // don't include duplicated matchInfo in the result
             // treat skip as ok
+            noSub.removeAll(noReceiver);
             Sets.difference(Sets.union(ok, skip), Sets.union(noSub, noReceiver)).forEach(matchInfo ->
                 resultsBuilder.addResult(
                     DeliveryResult.newBuilder().setMatchInfo(matchInfo).setCode(DeliveryResult.Code.OK).build()));
diff --git a/bifromq-mqtt/bifromq-mqtt-server/src/test/java/org/apache/bifromq/mqtt/service/LocalDistServiceTest.java b/bifromq-mqtt/bifromq-mqtt-server/src/test/java/org/apache/bifromq/mqtt/service/LocalDistServiceTest.java
index 60ea83091..2d611601d 100644
--- a/bifromq-mqtt/bifromq-mqtt-server/src/test/java/org/apache/bifromq/mqtt/service/LocalDistServiceTest.java
+++ b/bifromq-mqtt/bifromq-mqtt-server/src/test/java/org/apache/bifromq/mqtt/service/LocalDistServiceTest.java
@@ -403,6 +403,52 @@ public void deliverToNoLocalRoute() {
         assertEquals(result.getCode(), DeliveryResult.Code.NO_RECEIVER);
     }
 
+    @Test
+    public void noReceiverWinsNoSubAcrossDeliveryPacksRegardlessOfOrder() {
+        String noSubFirstTenantId = "noSubFirst";
+        String noReceiverFirstTenantId = "noReceiverFirst";
+        String topicFilter = "testTopic/#";
+        String channelId = "channel0";
+        MatchInfo matchInfo = MatchInfo.newBuilder()
+            .setMatcher(TopicUtil.from(topicFilter))
+            .setReceiverId("receiverId")
+            .build();
+        DeliveryPack deliveryPack = DeliveryPack.newBuilder()
+            .setMessagePack(TopicMessagePack.newBuilder().setTopic("testTopic").build())
+            .addMatchInfo(matchInfo)
+            .build();
+        DeliveryPackage deliveryPackage = DeliveryPackage.newBuilder()
+            .addPack(deliveryPack)
+            .addPack(deliveryPack)
+            .build();
+        DeliveryRequest request = DeliveryRequest.newBuilder()
+            .putPackage(noSubFirstTenantId, deliveryPackage)
+            .putPackage(noReceiverFirstTenantId, deliveryPackage)
+            .build();
+
+        IMQTTTransientSession session = mock(IMQTTTransientSession.class);
+        when(session.publish(any(), any())).thenAnswer(invocation -> invocation.getArgument(1));
+        when(localSessionRegistry.get(channelId)).thenReturn(session);
+        ILocalTopicRouter.ILocalRoutes localRoutes = mock(ILocalTopicRouter.ILocalRoutes.class);
+        when(localRoutes.localReceiverId()).thenReturn("receiverId");
+        when(localRoutes.routesInfo()).thenReturn(Map.of(channelId, 1L));
+        when(localTopicRouter.getTopicRoutes(noSubFirstTenantId, matchInfo))
+            .thenReturn(Optional.of(CompletableFuture.completedFuture(localRoutes)))
+            .thenReturn(Optional.empty());
+        when(localTopicRouter.getTopicRoutes(noReceiverFirstTenantId, matchInfo))
+            .thenReturn(Optional.empty())
+            .thenReturn(Optional.of(CompletableFuture.completedFuture(localRoutes)));
+
+        DeliveryReply reply = localDistService.dist(request).join();
+
+        DeliveryResults noSubFirstResults = reply.getResultMap().get(noSubFirstTenantId);
+        assertEquals(noSubFirstResults.getResultCount(), 1);
+        assertEquals(noSubFirstResults.getResult(0).getCode(), DeliveryResult.Code.NO_RECEIVER);
+        DeliveryResults noReceiverFirstResults = reply.getResultMap().get(noReceiverFirstTenantId);
+        assertEquals(noReceiverFirstResults.getResultCount(), 1);
+        assertEquals(noReceiverFirstResults.getResult(0).getCode(), DeliveryResult.Code.NO_RECEIVER);
+    }
+
     @Test
     public void deliverToEmptyLocalRoutes() {
         String tenantId = "tenant1";