[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-sentinel-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 8 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

[RockteMQ-AI]

Review by github-manager-bot

Summary

Adds null checks for topicRouteData and topicRouteData.getFilterServerTable() in PullAPIWrapper.computePullFromWhichFilterServer() to prevent NPE when class filter route data is missing.

Findings

• [Critical] PullAPIWrapper.java:302 — Without the null check, topicRouteData.getFilterServerTable() throws NPE when topicRouteData is null (route not yet populated) or when getFilterServerTable() returns null (no filter server registered). The fix is correct and minimal.
• [Info] PullAPIWrapperTest.java — Excellent test coverage: 4 test cases covering null route data, null filter server table, missing broker entry, and empty list. Each scenario is isolated and verifies the expected fallback behavior.

Suggestions

No concerns. This is a clean, defensive null check with thorough test coverage.

Verdict: LGTM.

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Automated review by github-manager-bot