How to Implement a Version of errors.New That Accepts the Same Parameters as fmt.Sprintf

To implement a version of errors.New that accepts the same parameters as fmt.Sprintf, one can use the NewError function, which is defined as follows:

func NewError(format string, a ...interface{}) error {
    return errors.New(fmt.Sprintf(format, a))
}

However, this function does not work correctly because the variable number of arguments in a becomes a single array parameter in NewError, causing Sprintf to fill out only a single parameter in the format string.

To fix this issue, the final parameter in NewError should be marked as a variable number of arguments with the ... syntax:

func NewError(format string, a ...interface{}) error {
    return errors.New(fmt.Sprintf(format, a...))
}

This allows fmt.Sprintf to interpret a as variable number of arguments.