Function extractPrefix

errbase/encode.go:197–216

extractPrefix extracts the prefix from a wrapper's error message. For example, err := errors.New("bar") err = errors.Wrap(err, "foo") extractPrefix(err) returns "foo". If a presumed wrapper does not have a message prefix, it is assumed to override the entire error message and `extractPrefix` r

(err, cause error)

// the entire message and the boolean `true` to signify that the causes
// should not be appended to it.
func extractPrefix(err, cause error) (string, MessageType) {
	causeSuffix := cause.Error()
	errMsg := err.Error()

	if strings.HasSuffix(errMsg, causeSuffix) {
		prefix := errMsg[:len(errMsg)-len(causeSuffix)]
		// If error msg matches exactly then this is a wrapper
		// with no message of its own.
		if len(prefix) == 0 {
			return "", Prefix
		}
		if strings.HasSuffix(prefix, ": ") {
			return prefix[:len(prefix)-2], Prefix
		}
	}
	// If we don't have the cause as a suffix, then we have
	// some other string as our error msg, preserve that and
	// mark as override
	return errMsg, FullMessage
}

func getTypeDetails(
	err error, onlyFamily bool,