What causes "Invalid WKB: empty value" in phalcon/cphalcon?

Treat empty/null geometry as null before parsing: if ($value === '' || $value === null) return null;

phalcon/cphalcon · error · Phalcon\Db\Exceptions\InvalidWkb

Invalid WKB: empty value

Error message

Invalid WKB: empty value

What it means

Phalcon\Db\Geometry\WkbParser::parse() converts WKB/EWKB geometry values from databases into geometry objects. An empty string input is rejected up front with InvalidWkb('empty value') before any parsing, because an empty payload cannot contain a geometry.

Source

Thrown at phalcon/Db/Geometry/WkbParser.zep:42

    /**
     * @var string
     */
    protected buffer = "";
    /**
     * @var int
     */
    protected length = 0;
    /**
     * @var int
     */
    protected position = 0;

    public function parse(string raw) -> <GeometryInterface>
    {
        var srid = 0, body, arr;

        if raw === "" {
            throw new InvalidWkb("empty value");
        }

        /**
         * PostGIS returns EWKB as an even-length ASCII-hex string; MySQL
         * returns binary (4-byte LE SRID prefix + standard WKB). Real binary
         * WKB is not valid ASCII hex (it carries the 0x01 byte-order byte and
         * arbitrary double bytes), so this distinguishes the two.
         */
        if strlen(raw) % 2 === 0 && ctype_xdigit(raw) {
            let body = hex2bin(raw);
        } else {
            if strlen(raw) < 5 {
                throw new InvalidWkb("buffer too short for MySQL prefix");
            }

            let arr  = unpack("V", substr(raw, 0, 4)),
                srid = (int) arr[1],
                body = substr(raw, 4);

View on GitHub (pinned to b7419de9cd)

Solutions

Treat empty/null geometry as null before parsing: if ($value === '' || $value === null) return null;
Fix the query or schema: filter with WHERE geom IS NOT NULL, or stop storing '' in geometry columns
Regenerate fixtures with real WKB from ST_AsBinary/ST_AsEWKB

Example fix

// before
$point = $parser->parse($row['geom']);

// after
$point = ($row['geom'] === '' || $row['geom'] === null)
    ? null
    : $parser->parse($row['geom']);

Defensive patterns

Strategy: validation

Validate before calling

if (!is_string($raw) || '' === $raw) {
    return null; // no geometry on this row
}
return $parser->parse($raw);

Type guard

function isNonEmptyWkb(mixed $value): bool
{
    return is_string($value) && '' !== $value;
}

Try / catch

try {
    $geom = $parser->parse($row['geom']);
} catch (\Phalcon\Db\Exceptions\InvalidWkb $e) {
    $logger->warning('Unparseable geometry', ['id' => $row['id']]);
    $geom = null;
}

Prevention

Filter nullable geometry columns with WHERE geom IS NOT NULL in read queries
Never store '' in geometry columns — use real NULL
Generate fixtures with ST_AsBinary so payloads are real WKB

When it happens

Trigger: Feeding $row['geom'] from a nullable geometry column that returned '' instead of NULL; LEFT JOIN rows where the geometry side is missing; fixtures that insert '' as a placeholder geometry.

Common situations: Drivers or ORMs coercing NULL to ''; batch imports over tables with empty-string defaults on geometry columns; test fixtures hand-written without real WKB.

Related errors

AI-assisted analysis of phalcon/cphalcon@b7419de9cd (2026-08-21). Data as JSON: /api/errors/17a2eeb1d3bb5b72. Report an issue: GitHub.