Function WithMessagef

errors.go:229–237

WithMessagef annotates err with the format specifier. If err is nil, WithMessagef returns nil.

(err error, format string, args ...interface{})

// WithMessagef annotates err with the format specifier.
// If err is nil, WithMessagef returns nil.
func WithMessagef(err error, format string, args ...interface{}) error {
	if err == nil {
		return nil
	}
	return &withMessage{
		cause: err,
		msg:   fmt.Sprintf(format, args...),
	}
}

type withMessage struct {
	cause error