[Bug] PullAPIWrapper throws NPE when class filter topic route data is missing

[yin-bo-Final]

Before Creating the Bug Report

• I found a bug, not just asking a question, which should be created in GitHub Discussions.

• I have searched the GitHub Issues and GitHub Discussions of this repository and believe that this is not a duplicate.

• I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

Runtime platform environment

ubuntu

RocketMQ version

develop branch / rocketmq-all-5.5.0

JDK Version

JDK 8

Describe the Bug

When a consumer pulls messages with class filter enabled, PullAPIWrapper#computePullFromWhichFilterServer may throw a NullPointerException if the local topic route table does not contain route data for the target topic.

The current code directly dereferences topicRouteData:

TopicRouteData topicRouteData = topicRouteTable.get(topic);
List<String> list = topicRouteData.getFilterServerTable().get(brokerAddr);

If topicRouteData is null, the client throws NPE before reaching the existing business error path.

The method already has a clear fallback exception when no filter server can be found:

throw new MQClientException("Find Filter Server Failed, Broker Addr: " + brokerAddr + " topic: " + topic, null);
So the client should fail with MQClientException instead of exposing a raw NPE.

Steps to Reproduce

1. Create a PullAPIWrapper.
2. Enable class filter in the pull sys flag.
3. Mock or configure MQClientInstance#getTopicRouteTable() to return a route table that does not contain the target topic, or contains a TopicRouteData without a filter server mapping for the broker address.
4. Call PullAPIWrapper#pullKernelImpl.
5. The call enters computePullFromWhichFilterServer and throws NullPointerException.

What Did You Expect to See?

The client should fail gracefully with MQClientException, for example: Find Filter Server Failed, Broker Addr: xxx topic: xxx
This is consistent with the existing method behavior when no filter server is found.

What Did You See Instead?

The client may throw NullPointerException from PullAPIWrapper#computePullFromWhichFilterServer before reaching the intended MQClientException branch.

Additional Context

This problem is caused by method:
org.apache.rocketmq.client.impl.consumer.PullAPIWrapper#computePullFromWhichFilterServer
The method currently assumes that topicRouteData is always available before accessing its filter server table. When the route data is missing, it may be better to fall through to the existing MQClientException path instead of throwing NPE.

[oss-sentinel-ai]

Issue Evaluation

Category: | Status: Confirmed

The reported issue has been verified against the current codebase.

Root Cause: — may return when the local route table lacks an entry for the topic, but the next line dereferences it via , causing NPE.

Impact: Triggered when consumer pulls with class-filter enabled but route data is missing/expired/evicted. Client throws raw NPE instead of descriptive .

Severity: medium

A fix PR (#10420) has been submitted and reviewed.

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Automated evaluation by github-manager-bot

[oss-sentinel-ai]

Issue Evaluation

Category: type/bug | Status: Confirmed

The reported issue has been verified against the current codebase.

Root Cause: PullAPIWrapper.java:301-302 — topicRouteTable.get(topic) may return null when the local route table lacks an entry for the topic, but the next line dereferences it via topicRouteData.getFilterServerTable(), causing NPE.

Impact: Triggered when consumer pulls with class-filter enabled but route data is missing/expired/evicted. Client throws raw NPE instead of descriptive MQClientException("Find Filter Server Failed, ...").

Severity: medium

A fix PR (#10420) has been submitted and reviewed.

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Automated evaluation by github-manager-bot

[RockteMQ-AI]

Issue Evaluation

Category: type/bug | Status: Confirmed

The reported issue has been verified against the codebase description.

Root Cause: PullAPIWrapper#computePullFromWhichFilterServer directly dereferences topicRouteData without null-checking. When the local topic route table lacks an entry for the target topic, topicRouteTable.get(topic) returns null, causing NullPointerException before reaching the intended MQClientException fallback path.

Impact: Consumer pull operations with class filter enabled. When route data is temporarily unavailable or missing, clients crash with NPE instead of the graceful MQClientException("Find Filter Server Failed...") that the method already provides for other error cases.

Severity: Medium — affects consumer stability in edge cases where topic route data is incomplete or stale.

Suggested Fix: Add null-check for topicRouteData before accessing getFilterServerTable(). If null, fall through to the existing MQClientException throw, maintaining consistency with the method's error handling contract.

TopicRouteData topicRouteData = topicRouteTable.get(topic);
if (topicRouteData == null) {
    throw new MQClientException("Find Filter Server Failed, Broker Addr: " + brokerAddr + " topic: " + topic, null);
}

An automated fix proposal can be generated. Reply /approve to proceed with PR generation.

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Automated evaluation by RockteMQ-AI