Hacker News Reader

Comment by bootsmann | Hacker News Reader

Do you really do that in practice, or do you just blindly go 'if err != nil return nil, err'?

Because fundamentally the function you called can return different errors at any point so if you just propagate the error the code paths are in fact not spelled out at all because the function one above in the hierarchy has to deal with all the possible errors two calls down which are not transparent at all.

View on HN

In Go, no one really blindly returns nil, err. People very clearly think about errors—if an error may need to be actioned on up the stack, people will either create a named error value (e.g., `ErrInvalidInput = errors.New(“invalid input”)` or a named error type that downstream users can check against. Moreover, even when propagating errors many programmers will attach error context: `return nil, fmt.Errorf(“searching for the flux capacitor `%s`: %w”, fluxCap, err)`. I think there’s room for improvement, but Go error handling (and Rust error handling for that matter) seem to be eminently thoughtful.

Coming from dotnet, I rather like the Go pattern as you've described it. I would normally catch and error and then write out a custom message with relevant information, anyway, and I hate the ergonomics of the try{}catch(Exception ex){} syntax. And yes, it is tempting to let the try block encompass more code than it really should.

Yeah, I was pretty skeptical when they added the error wrapping stuff to the standard library, and it still feels a little too squishy, but in practice it works very well. I prefer Go’s error handling even to Rust’s much more explicit error handling.

I don't see how it's possible to do it blindly unless the code gets autogenerated. If you're typing the `if err != nil` then you've clearly understood that an error path is there.

There's no requirement for the calling function to handle each possible type of error of the callee. It can, as long as the callee properly wrapped the error, but it's relatively rare for that to be required. Usually the exact error is not important, just that there was one, so it gets handled generically.

Their point was writing `if err != nil return nil, err` is the same thing that stack traces from exceptions do, but with even less information. And if that's most of a Golang codebases error handling, it's not a compelling argument against exceptions.

Reply on news.ycombinator.com