我应该使用隐式转换到返回类型以帮助调试吗？

Question

I have the following method in my API

 public bool CheckSignature(string data, string key)
 { ... }

In the event that I return false (for an invalid signature), I'd like the ability to cleanly get the debug data without changing all my callers code.

If I was returning an object, I would simply add a debug type like this

public class SignatureResult
{
     public bool Validation {get;set;}
     public SpecialDebugObject Debug {get;set;}
} 

• Is it a bad idea for me to change my API so that it returns a SignatureResult but with an implicit conversion to bool so the existing clients don't break?

• Would this be OK to do for a new API?

Answer 1

Existing clients will break, this is a breaking change.

The code written against CheckSignature expects a bool to be returned. Even if there's an implicit conversion between your type and bool, the compiled IL is missing the proper conversion instruction.

This is analogous to changing a field to be a property instead: you lose binary compatibility .

Would this be OK to do for a new API?

I wouldn't. You're exposing debugging logic.

---

Here's a good guide for what's considered a breaking change in .NET: A definitive guide to API-breaking changes in .NET . As you can see, method signatures are very sensible. Changing the return type, and even the argument's names are considered breaking changes.