kamilsk/retry

package retry

const internal Error = "have no any try"

// Error defines a string-based error without a different root cause.
type Error string

// Error returns a string representation of an error.
func (err Error) Error() string { return string(err) }

// Unwrap always returns nil means that an error doesn't have other root cause.
func (err Error) Unwrap() error { return nil }

func unwrap(err error) error {
    for err != nil {
        layer, is := err.(wrapper)
        if is {
            err = layer.Unwrap()
            continue
        }
        cause, is := err.(causer)
        if is {
            err = cause.Cause()
            continue
        }
        break
    }
    return err
}

// compatible with github.com/pkg/errors
type causer interface {
    Cause() error
}

// compatible with built-in errors since 1.13
type wrapper interface {
    Unwrap() error
}