[ISSUE #11423] fix(proxy): report a missing local topic as TOPIC_NOT_EXIST

[iloveeyjafjalla]

Which Issue(s) This PR Fixes

• Fixes [Bug] LOCAL-mode proxy throws NullPointerException for a topic that is not in the broker's topic config table #11423

Brief Description

LocalTopicRouteService.getCurrentMessageQueueView looked the topic up in the local broker's topic config table and passed the result straight into the route-data builder, so a topic that is not in the table produced a NullPointerException while building the queue data:

TopicConfig topicConfig = this.brokerController.getTopicConfigManager().getTopicConfigTable().get(topic);
return new MessageQueueView(topic, toTopicRouteData(topicConfig), null);   // topicConfig may be null -> NPE at topicConfig.getPerm()

The cluster implementation of the same method already answers with a client error — getAllMessageQueueView → TopicRouteService.getCacheMessageQueueWrapper throws MQClientException(ResponseCode.TOPIC_NOT_EXIST, "No topic route info in name server for the topic: …"), and ClusterTopicRouteServiceTest pins that behaviour. This change mirrors it for LOCAL mode:

if (topicConfig == null) {
    throw new MQClientException(ResponseCode.TOPIC_NOT_EXIST,
        "No topic route info in local broker for the topic: " + topic);
}

so the callers can produce their designed responses instead of an internal error — ConsumerProcessor.popMessage reaches FORBIDDEN, "no readable queue" handling and ProducerProcessor.sendMessage (FORBIDDEN, "no writable queue") for topics that exist, while a genuinely missing topic is reported as TOPIC_NOT_EXIST.

How Did You Test This Change?

New test LocalTopicRouteServiceTest#testGetCurrentMessageQueueViewForUnknownTopic: calls getCurrentMessageQueueView for a topic that is not in the broker's topic config table and asserts a MQClientException with ResponseCode.TOPIC_NOT_EXIST (the existing testGetCurrentMessageQueueView covers the topic-present case).

Results on Temurin JDK 8 (the JDK CI uses), base a7edeecfb plus this patch:

• before the fix: java.lang.AssertionError — the call throws NullPointerException instead of MQClientException
• after the fix: LocalTopicRouteServiceTest — Tests run: 3, Failures: 0, Errors: 0
• mvn -B -ntp -pl proxy clean package -Dtest='!ProxyChannelTest': BUILD SUCCESS, 453 tests / 0 failures / 4 skipped, You have 0 Checkstyle violations., BugInstance size is 0

Disclosure: ProxyChannelTest#testWriteAndFlush is excluded from that run because it fails on the unmodified base as well (documented in earlier local verification); skipAfterFailureCount=1 is configured for this module, so leaving it in would hide the rest of the suite.

This change was prepared with AI assistance (analysis, patch and test drafting); the diff and every result above were reproduced locally by running the module's tests against the base commit and the patched tree.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

[RockteMQ-AI]

Review by github-manager-bot

Summary

Fixes NPE in LocalTopicRouteService.getCurrentMessageQueueView when a topic is not found in the local broker's config table, replacing it with a proper MQClientException(TOPIC_NOT_EXIST) — consistent with the cluster-mode behavior.

Findings

• [Info] LocalTopicRouteService.java:58 — The null check is correctly placed immediately after the get(topic) lookup and before toTopicRouteData(topicConfig). Clean and minimal.

• [Info] LocalTopicRouteService.java:59 — Error message includes the topic name, which is helpful for debugging. Consider also logging the event at WARN level if the proxy module has a logger available, so operators can detect misconfigured clients attempting to consume from non-existent topics. This is optional and not a blocker.

• [Info] LocalTopicRouteServiceTest.java:95-101 — Test correctly uses catchThrowableOfType and verifies both the exception type and response code. Good coverage of the negative path.

Assessment

Dimension	Verdict
Correctness	✅ Null check prevents NPE; error code matches cluster-mode semantics
Performance	✅ No concern — single null check
Tests	✅ New test covers unknown-topic path; existing test covers happy path
Compatibility	✅ Improves error reporting without breaking API contract

This is a well-prepared fix. LGTM.

---

Automated review by github-manager-bot