Function PopulateErrorDetails

pkg/sql/parser/lexer.go:421–458

PopulateErrorDetails properly wraps the "last error" field in the lexer.

(
	tokID int32, lastTokStr string, lastTokPos int32, lastErr error, lIn string,
)

// PopulateErrorDetails properly wraps the "last error" field in the lexer.
func PopulateErrorDetails(
	tokID int32, lastTokStr string, lastTokPos int32, lastErr error, lIn string,
) error {
	var retErr error

	if tokID == ERROR {
		// This is a tokenizer (lexical) error: the scanner
		// will have stored the error message in the string field.
		err := pgerror.WithCandidateCode(errors.Newf("lexical error: %s", lastTokStr), pgcode.Syntax)
		retErr = errors.WithSecondaryError(err, lastErr)
	} else {
		// This is a contextual error. Print the provided error message
		// and the error context.
		if !strings.Contains(lastErr.Error(), "syntax error") {
			// "syntax error" is already prepended when the yacc-generated
			// parser encounters a parsing error.
			lastErr = errors.Wrap(lastErr, "syntax error")
		}
		retErr = errors.Wrapf(lastErr, "at or near \"%s\"", lastTokStr)
	}

	// Find the end of the line containing the last token.
	i := strings.IndexByte(lIn[lastTokPos:], '\n')
	if i == -1 {
		i = len(lIn)
	} else {
		i += int(lastTokPos)
	}
	// Find the beginning of the line containing the last token. Note that
	// LastIndexByte returns -1 if '\n' could not be found.
	j := strings.LastIndexByte(lIn[:lastTokPos], '\n') + 1
	// Output everything up to and including the line containing the last token.
	var buf bytes.Buffer
	fmt.Fprintf(&buf, "source SQL:\n%s\n", lIn[:i])
	// Output a caret indicating where the last token starts.
	fmt.Fprintf(&buf, "%s^", strings.Repeat(" ", int(lastTokPos)-j))
	return errors.WithDetail(retErr, buf.String())
}

func (l *lexer) populateErrorDetails() {
	lastTok := l.lastToken()