[ISSUE #10419] Fix NPE when class filter route data is missing

[yin-bo-Final]

Which Issue(s) This PR Fixes

• Fixes [Bug] PullAPIWrapper throws NPE when class filter topic route data is missing #10419

Brief Description

This PR avoids a potential NullPointerException in PullAPIWrapper#computePullFromWhichFilterServer when class filter is enabled but the local topic route table does not contain route data for the target topic.

Instead of dereferencing a missing TopicRouteData, the code falls through to the existing MQClientException path.

How Did You Test This Change?

• Added a targeted unit test for missing topic route data.
• Ran:

mvn -pl client -Dtest=org.apache.rocketmq.client.impl.consumer.PullAPIWrapperTest -Djacoco.skip=true test

The test passed with Tests run: 8, Failures: 0, Errors: 0, Skipped: 0.

[oss-taishan-ai]

Review by github-manager-bot

Summary

Fixes NPE in PullAPIWrapper#computePullFromWhichFilterServer when topicRouteData is null, allowing the method to fall through to the existing MQClientException error path.

Findings

• [Correctness] ✅ The null check on topicRouteData (line 302) correctly addresses the NPE reported in #10419. The additional null check on getFilterServerTable() is a good defensive measure.
• [Correctness] ✅ The control flow after the fix is correct: when route data or filter server table is missing, the method falls through to the existing MQClientException("Find Filter Server Failed, ...") at the bottom of the method.
• [Tests] ✅ testPullKernelImplWithMissingTopicRouteDataForClassFilter validates the fix well — empty ConcurrentHashMap ensures get(topic) returns null, and the assertion checks for MQClientException with the expected message.
• [Compatibility] ✅ No public API changes. Backward compatible.

Verdict

LGTM. Clean, minimal fix that aligns with the existing error handling pattern. Test coverage is adequate.

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Automated review by github-manager-bot

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 47.94%. Comparing base (2a9560c) to head (65c20fc).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10420      +/-   ##
=============================================
- Coverage      48.05%   47.94%   -0.11%     
+ Complexity     13303    13279      -24     
=============================================
  Files           1377     1377              
  Lines         100611   100614       +3     
  Branches       12991    12993       +2     
=============================================
- Hits           48347    48240     -107     
- Misses         46348    46431      +83     
- Partials        5916     5943      +27     

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[RongtongJin]

LGTM