From 61197d6fc122bf71c394820b734a8d59805119c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E8=B6=8A?= <1939455790@qq.com>
Date: Sat, 11 Jul 2026 12:01:00 +0000
Subject: [PATCH] [ISSUE #9341] Fix NamespaceV2 not isolating resources
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When only namespaceV2 is set, topics and consumer/producer groups are not
wrapped on the client side, because ClientConfig.getNamespace() — the single
value used by withNamespace/withoutNamespace and every resource wrapping call
site — only returns the deprecated V1 namespace, which stays empty.
namespaceV2 was intended to be resolved server-side via the nsd/ns extension
fields attached by NamespaceRpcHook, but the broker never consumes those
fields; instead it derives the namespace from already-wrapped resource names
(NamespaceUtil.getNamespaceFromResource). With neither side wrapping the
resource, producers and consumers configured with different namespaces operate
on the same physical topic, so a namespace can consume messages from another
namespace.
Make getNamespace() fall back to namespaceV2 when the V1 namespace is unset,
so that resources are wrapped with the namespaceV2 value and isolated
correctly. The V1 namespace still takes precedence when both are set.

Signed-off-by: 王越 <1939455790@qq.com>
---
 .../apache/rocketmq/client/ClientConfig.java  |  4 +++
 .../rocketmq/client/ClientConfigTest.java     | 32 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java b/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
index 9e012254329..d7db54e96c7 100644
--- a/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
+++ b/client/src/main/java/org/apache/rocketmq/client/ClientConfig.java
@@ -414,6 +414,10 @@ public String getNamespace() {
             return namespace;
         }
 
+        if (StringUtils.isNotEmpty(namespaceV2)) {
+            return namespaceV2;
+        }
+
         if (StringUtils.isNotEmpty(this.namesrvAddr)) {
             if (NameServerAddressUtils.validateInstanceEndpoint(namesrvAddr)) {
                 namespace = NameServerAddressUtils.parseInstanceIdFromEndpoint(namesrvAddr);
diff --git a/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java b/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
index 5afe9cc011d..89bcf7a7d38 100644
--- a/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
+++ b/client/src/test/java/org/apache/rocketmq/client/ClientConfigTest.java
@@ -65,6 +65,38 @@ public void testQueuesWithNamespace() {
         assertEquals("lmq%defaultTopic", messageQueues.iterator().next().getTopic());
     }
 
+    @Test
+    public void testGetNamespaceFallbackToNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("InstanceTest", config.getNamespace());
+    }
+
+    @Test
+    public void testWithNamespaceUsesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("InstanceTest%resource", config.withNamespace(resource));
+        assertEquals("InstanceTest%resource",
+            config.withNamespace("InstanceTest%resource"));
+    }
+
+    @Test
+    public void testWithoutNamespaceUsesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespaceV2("InstanceTest");
+        assertEquals(resource, config.withoutNamespace("InstanceTest%resource"));
+    }
+
+    @Test
+    public void testNamespaceV1PrecedesNamespaceV2() {
+        ClientConfig config = new ClientConfig();
+        config.setNamespace("lmq");
+        config.setNamespaceV2("InstanceTest");
+        assertEquals("lmq", config.getNamespace());
+        assertEquals("lmq%resource", config.withNamespace(resource));
+    }
+
     private ClientConfig createClientConfig() {
         ClientConfig result = new ClientConfig();
         result.setUnitName("unitName");