cube-js/cube · error · std::io::Error (ErrorKind::InvalidData)

Unable to parse bytes as a UTF-8 string

Error message

Unable to parse bytes as a UTF-8 string

What it means

While reading a null-terminated (C-style) string from the PostgreSQL wire protocol, the accumulated bytes were not valid UTF-8. PostgreSQL transmits strings as UTF-8, so this indicates a misbehaving or incompatible client sending non-UTF-8 bytes in a startup parameter, statement, or other string field.

Source

Thrown at rust/cubesql/pg-srv/src/buffer.rs:171

}

pub async fn read_string<Reader: AsyncReadExt + Unpin>(
    reader: &mut Reader,
) -> Result<String, Error> {
    let mut bytes = Vec::with_capacity(64);

    loop {
        // PostgreSQL uses a null-terminated string (C-style string)
        let byte = reader.read_u8().await?;
        if byte == 0 {
            break;
        }

        bytes.push(byte);
    }

    let string = String::from_utf8(bytes).map_err(|_| {
        Error::new(
            ErrorKind::InvalidData,
            "Unable to parse bytes as a UTF-8 string",
        )
    })?;

    Ok(string)
}

pub async fn read_format<Reader: AsyncReadExt + Unpin>(
    reader: &mut Reader,
) -> Result<protocol::Format, ProtocolError> {
    match reader.read_i16().await? {
        0 => Ok(protocol::Format::Text),
        1 => Ok(protocol::Format::Binary),
        format_code => Err(protocol::ErrorResponse::error(
            protocol::ErrorCode::ProtocolViolation,
            format!("Unknown format code: {}", format_code),
        )

View on GitHub (pinned to 7d981676b3)

Solutions

1. Ensure the connecting client sends protocol strings encoded as UTF-8
2. Check for middleware or proxies corrupting the byte stream
3. Verify the client driver version is compatible with the PostgreSQL message format

When it happens

Trigger: Thrown at rust/cubesql/pg-srv/src/buffer.rs:171 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of cube-js/cube@7d981676b3 (2026-09-02). Data as JSON: /api/errors/791e0deb7db0c73c. Report an issue: GitHub.