Can't us errors.As to identify an custom error which has been wrapped multiple times

[kjico]

When using a custom error and then wrapping that error with eris.Wrap it's not possible to use errors.As to identify if error is made of target, even if Unwrap is implemented.

package main

import (
	"errors"
	"fmt"

	"github.com/rotisserie/eris"
)

type AnError struct {
	Msg string
	Err error
}

func (ae AnError) Error() string {
	return ae.Msg
}

func (ae AnError) Unwrap() error {
	return ae.Err
}

func main() {
	aerror := AnError{Msg: "invalid", Err: eris.New("eris test error")}
	berr := eris.Wrap(aerror, "the error")

	switch {
	case errors.As(berr, &AnError{}):
		fmt.Println("anerror")
	}
}

I expected this code should print "anerror", if I instead wrap the error with fmt.Errorf and %w, it works as expected.

[morningvera]

Thanks for the bug report! We've been planning to add our own version of As and we'll look into it soon.

[morningvera]

hey @kjico, we merged a fix for this last week, and we're working on adding our own version of As this week. thanks for the feedback!