fix generic invalidation in record class, for issue #3156#4027
fix generic invalidation in record class, for issue #3156#4027jujn wants to merge 2 commits intoalibaba:mainfrom
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Code Review 修复思路正确，通过在 ASM 路径中检测 Number.class 擦除场景并降级到反射模式，避免了 readNumber() 将小数默认解析为 BigDecimal 导致的 建议
// 当前写法 // 建议改为（与周围代码风格一致）
Options 和 Options2 是非静态内部类，会持有外部类 Issue3156 的隐式引用，可能影响反序列化框架的实例构造。建议改为： public static class Options { ... } Options2 中的 Parameter 同理。
当前只测试了 Double，建议增加 中 T 为 Integer 的场景，以及整数值的解析验证，确保不会被错误解析为 BigDecimal。 |
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Pull request overview
Improves fastjson2’s ASM-based ObjectReader selection to avoid incorrect handling of generic Number-typed fields (e.g., T extends Number), and adds regression tests to ensure numeric values are materialized with the expected boxed type.
Changes:
- Adds a matching guard in
ObjectReaderCreatorASMto fall back from ASM readers whenfieldClassisNumberbut the reflectivefieldTypecarries different generic information. - Extends
Issue3156tests to cover generic numeric fields for both record-based (no default ctor) and POJO-based (default ctor) parameter containers.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
test-jdk17/src/test/java/com/alibaba/fastjson2/issues/Issue3156.java |
Adds new JUnit coverage for generic Number value deserialization (expects Double). |
core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderCreatorASM.java |
Adjusts ASM eligibility checks to avoid JIT readers in a Number + generic-type mismatch scenario. |
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done. |
What this PR does / why we need it?
修复了泛型字段擦除为 Number.class 时，asm 解析器未考虑真实泛型上下文而调用 readNumber()，导致小数被默认解析为 BigDecimal 从而引发 ClassCastException 的缺陷。修复逻辑是在 ObjectReaderCreatorASM 中增加校验，当字段擦除类型为 Number.class ，降级为反射模式进行动态解析。
Summary of your change
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