Summary

Key Insight

InternalSerializer.internalMarshal uses reflection to detect types implementing json.Marshaler and delegates to json.Marshal. However, it passes the result of rv.Interface() — a non-addressable struct value. Go's method dispatch requires an addressable value to call pointer-receiver methods. Since ToolInfo.MarshalJSON is defined on *ToolInfo, the non-addressable ToolInfo value does NOT satisfy json.Marshaler. json.Marshal falls back to default struct encoding, which cannot access the unexported ParamsOneOf fields — causing silent data loss.

The fix ensures we always pass a pointer to json.Marshal:

• If rv.CanAddr(): use rv.Addr().Interface() directly
• Otherwise: allocate a temporary reflect.New(rt), copy the value, and pass the pointer

Changes

internal/serialization/serialization.go — In the checkMarshaler branch of internalMarshal, ensure json.Marshal always receives a pointer so that pointer-receiver MarshalJSON methods are invoked.

Testing

• Existing adk interrupt/cancel tests pass with -race (200+ iterations)
• Existing compose tests pass with -race
• The fix is exercised whenever any type with pointer-receiver MarshalJSON is stored in graph state and checkpointed

摘要

核心洞察

InternalSerializer.internalMarshal 通过反射检测实现了 json.Marshaler 的类型，然后委托给 json.Marshal。但它传递的是 rv.Interface() 的结果——一个不可寻址的结构体值。Go 的方法分派要求可寻址的值才能调用指针接收者方法。由于 ToolInfo.MarshalJSON 定义在 *ToolInfo 上，不可寻址的 ToolInfo 值不满足 json.Marshaler 接口。json.Marshal 回退到默认结构体编码，无法访问未导出的 ParamsOneOf 字段——导致静默数据丢失。

修复确保始终传递指针给 json.Marshal：

• 若 rv.CanAddr()：直接使用 rv.Addr().Interface()
• 否则：分配临时 reflect.New(rt)，复制值，传递指针

变更

internal/serialization/serialization.go — 在 internalMarshal 的 checkMarshaler 分支中，确保 json.Marshal 始终接收指针，以调用指针接收者 MarshalJSON 方法。