Go errors with source file and line number

errors.go

package errors

import (
	"errors"
	"fmt"
	"runtime"
)

type errorDebug struct {
	error
	file string
	line int
}

func New(s string) error {
	err := errors.New(s)
	_, file, line, _ := runtime.Caller(1)

	return &errorDebug{err, file, line}
}

func Errorf(format string, a ...interface{}) error {
	// We can not simply do: return New(fmt.Sprintf(format, a...))
	err := fmt.Errorf(format, a...)
	_, file, line, _ := runtime.Caller(1)

	return &errorDebug{err, file, line}
}

func (e *errorDebug) Error() string {
	return fmt.Sprintf("%s (%s:%d)", e.error, e.file, e.line)
}

func Clone(err error) error {
	_, file, line, _ := runtime.Caller(1)

	return &errorDebug{err, file, line}
}

func Equal(lhs, rhs error) bool {
	if lhs == rhs {
		return true
	}

	if err, ok := lhs.(*errorDebug); ok && err.error == rhs {
		return true
	}

	if err, ok := rhs.(*errorDebug); ok && err.error == lhs {
		return true
	}

	return false
}