prestodb/presto · error · PrestoException

GENERIC_INTERNAL_ERROR

GENERIC_INTERNAL_ERROR

Error message

Invalid InetAddress length:

What it means

castFromVarcharToIpPrefix expects the resolved InetAddress to be either 4 bytes (IPv4) or 16 bytes (IPv6). Any other length indicates an unexpected internal state in address parsing, so Presto throws GENERIC_INTERNAL_ERROR. This is a defensive branch, not a user-input validation error.

Source

Thrown at presto-main-base/src/main/java/com/facebook/presto/type/IpPrefixOperators.java:177

            }
            bytes[10] = (byte) 0xff;
            bytes[11] = (byte) 0xff;
            arraycopy(address, 0, bytes, 12, 4);
            bytes[IPPREFIX.getFixedSize() - 1] = (byte) subnetSize;
        }
        else if (address.length == 16) {
            if (subnetSize < 0 || 128 < subnetSize) {
                throw new PrestoException(INVALID_CAST_ARGUMENT, "Cannot cast value to IPPREFIX: " + slice.toStringUtf8());
            }

            for (int i = 0; i < 16; i++) {
                address[15 - i] &= (byte) -0x1 << min(max((128 - subnetSize) - 8 * i, 0), 8);
            }
            arraycopy(address, 0, bytes, 0, 16);
            bytes[IPPREFIX.getFixedSize() - 1] = (byte) subnetSize;
        }
        else {
            throw new PrestoException(GENERIC_INTERNAL_ERROR, "Invalid InetAddress length: " + address.length);
        }

        return wrappedBuffer(bytes);
    }

    @ScalarOperator(CAST)
    @SqlType(StandardTypes.VARCHAR)
    public static Slice castFromIpPrefixToVarchar(@SqlType(StandardTypes.IPPREFIX) Slice slice)
    {
        try {
            String addrString = InetAddresses.toAddrString(InetAddress.getByAddress(slice.getBytes(0, 2 * Long.BYTES)));
            String prefixString = Integer.toString(slice.getByte(2 * Long.BYTES) & 0xff);
            return utf8Slice(addrString + "/" + prefixString);
        }
        catch (UnknownHostException e) {
            throw new PrestoException(INVALID_CAST_ARGUMENT, "Invalid IP address binary length: " + slice.length(), e);
        }
    }

View on GitHub (pinned to 55bb57d202)

Solutions

  1. Verify the standard JDK is being used (no custom InetAddress providers)
  2. File a bug with the query and value that triggered it
  3. Work around by pre-parsing with try_cast or explicit IP parsing before the cast
Defensive patterns

Strategy: try-catch

Try / catch

// In custom engine/plugin code invoking the cast operator:
try {
    Slice prefix = IpPrefixOperators.castFromVarcharToIpPrefix(input);
} catch (PrestoException e) {
    if (e.getErrorCode().getCode() == StandardErrorCode.GENERIC_INTERNAL_ERROR.toErrorCode().getCode()) {
        // log and report bug; not a user-input problem
    }
    throw e;
}

Prevention

When it happens

Trigger: Calling CAST(varchar AS IPPREFIX) when InetAddress.getAddress() returns a byte array of length other than 4 or 16 — an internal invariant violation in JDK address parsing.

Common situations: Extremely rare; typically surfaces only with a patched/non-standard JDK InetAddress implementation or custom code paths feeding unexpected binary forms. Not caused by normal user input.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/11afa2996ac9e36c. Report an issue: GitHub.