Error Capture Functionality Only Works for Explicit error Return Types

[korECM]

It appears that when using the //dd:span tag, the error capture functionality only activates when the return type is explicitly error. However, in some cases, functions return a different type or an interface that implements error, and the error capture does not seem to work in these cases.

Could you please let us know if there are plans to address this issue? Alternatively, is there a workaround or recommended solution for users encountering this problem?

Thank you!

[eliottness]

👋 Thanks for reaching out and trying out orchestrion @korECM

It appears that when using the //dd:span tag, the error capture functionality only activates when the return type is explicitly error. However, in some cases, functions return a different type or an interface that implements error, and the error capture does not seem to work in these cases.

Overall I don't see any problem to implement this. The code that does this type check is in dd-trace-go. There, the template helper ResultOfType "error" only does a formal check of the error type but in theory we could implement something like ResultHasError using types.Implements to check for error types. Would this fit your usecase?

Alternatively, is there a workaround or recommended solution for users encountering this problem?

I believe the only thing possible right now is to either change the signature of your function or to use the standard dd-trace-go API to add errors on Spans.

[korECM]

@eliottness

Based on my thoughts, simply modifying the dd-trace-go code should be sufficient. Would it be possible to open an issue directly on dd-trace-go and work on it? From your explanation, it seems that only modifying the relevant template code would be enough and shouldn’t be too challenging. I think I can do that work. Alternatively, is there any plan in place for this work?

[korECM]

DataDog/dd-trace-go#3168
I created an issue about this.