[Bug] Boolean-to-string filter comparison throws ClassCastException

[yuluo-yx]

Before Creating the Bug Report

• I found a bug, not just a question.
• I searched open GitHub Issues and pull requests and found no duplicate.
• I confirmed that this bug belongs to Apache RocketMQ.

Runtime platform environment

macOS (Darwin), reproduced with an isolated local unit test.

RocketMQ version

Branch: develop
Git commit: fd0c959

JDK Version

Zulu OpenJDK 8 (8.94.0.17)

Describe the Bug

ComparisonExpression handles a Boolean left operand and String right operand by casting the Boolean left value to String. With string-expression conversion enabled by the selector parser, this branch always throws ClassCastException.

Steps to Reproduce

1. Parse a selector expression such as TRUE=a.
2. Evaluate it with string property a=true.
3. Observe the Boolean-to-String cast failure.

What Did You Expect to See?

The string right operand should be converted to Boolean and compared normally.

What Did You See Instead?

The Boolean left operand is cast to String and evaluation throws ClassCastException.

Additional Context

The reverse String-to-Boolean branch already converts the string operand correctly.

[RockteMQ-AI]

Issue Evaluation

Category: type/bug | Status: Confirmed

Root Cause: ComparisonExpression handles a Boolean left operand and String right operand by casting the Boolean to String, but with string-expression conversion enabled by the selector parser, this branch always throws ClassCastException.
Impact: Message filtering — SQL92 selector expressions like TRUE=a will crash instead of evaluating correctly.
Severity: medium

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Automated evaluation by github-manager-bot

[RockteMQ-AI]

Issue Evaluation

Category: bug | Status: Confirmed

The reported issue has been verified against the current codebase.

Root Cause: The SQL/property filter comparison logic attempts to cast a Boolean value to String for comparison, throwing ClassCastException. The filter evaluation does not handle type coercion between Boolean and String operands.

Impact: Message filtering fails with an unhandled exception when filter expressions compare boolean-typed properties against string literals, causing message consumption failures for affected consumers.

Severity: Medium — affects consumers using property-based filtering with mixed-type comparisons.

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

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Automated evaluation by RockteMQ-AI