I am fully aware of how fmt.Errorf works as well as what's inside the `errors` package in the Golang stdlib, as I do work with the language regularly.
In practice, this ends up with several issues (and I'm just as guilty of doing a bunch of them when I'm writing code not intended for public consumption, to be completely fair).
fmt.Errorf is stupid easy to use. There's a lot of Go code out there that just doesn't use anything else, and we really want to make sure we wrap errors to provide 'context' since there's no backtraces in errors (and nobody wants to force consuming code to pay that runtime cost for every error, given there's no standard way to indicate you want it).
errors.New can be used to create very basic errors, but since it gives you a single instance of a struct implementing `error` there's not a lot you can do with it.
The signature of a function only indicates that it returns `error`, we have to rely on the docs to tell users what specific errors they should expect. Now, to be fair, this is an issue for languages that use exception's - checked exceptions in Java notwithstanding.
Adding a new error type that should be handled means that consumers need to pay attention to the API docs and/or changelog. The compiler, linters, etc don't do anything to help you.
All of this culminates to an infuriating, inconsistent experience with error handling.
In practice, this ends up with several issues (and I'm just as guilty of doing a bunch of them when I'm writing code not intended for public consumption, to be completely fair).
fmt.Errorf is stupid easy to use. There's a lot of Go code out there that just doesn't use anything else, and we really want to make sure we wrap errors to provide 'context' since there's no backtraces in errors (and nobody wants to force consuming code to pay that runtime cost for every error, given there's no standard way to indicate you want it).
errors.New can be used to create very basic errors, but since it gives you a single instance of a struct implementing `error` there's not a lot you can do with it.
The signature of a function only indicates that it returns `error`, we have to rely on the docs to tell users what specific errors they should expect. Now, to be fair, this is an issue for languages that use exception's - checked exceptions in Java notwithstanding.
Adding a new error type that should be handled means that consumers need to pay attention to the API docs and/or changelog. The compiler, linters, etc don't do anything to help you.
All of this culminates to an infuriating, inconsistent experience with error handling.