Pumpkin-MC/Pumpkin · error · PacketDecodeError

failed to decode packet ID

Error message

failed to decode packet ID

What it means

`PacketDecodeError::DecodeID` is returned when the incoming packet's ID VarInt could not be read — the very first field of every framed packet. Failure here means the stream is empty, truncated, or desynchronized before any packet content was parsed.

Solutions

1. Treat as a connection-level failure: close and clean up the session.
2. Check whether a previous decode error desynchronized the stream; resync or reconnect.
3. Verify the framing (length prefix) is being consumed correctly before the ID read.
4. Log the connection state to distinguish clean disconnects from corruption.

match read_packet(&mut reader) {
    Ok(p) => handle(p),
    Err(PacketDecodeError::DecodeID) | Err(PacketDecodeError::OutOfBounds) => {
        log::info!("stream ended or desynced; closing connection");
    }
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Reading a packet from a stream that closed/ended mid-frame; a corrupted length field causing a short read; reading from an already-closed connection.

Common situations: Client disconnecting abruptly; network interruption mid-packet; a prior decode error leaving the reader at the wrong offset.

Understand the failure class

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

Related errors

• IO error
• JSON error
• Authentication servers are down
• item string array length out of bounds
• Failed to verify username

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/8debeeb6ad164ff5. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-protocol/src/lib.rs:301

pub trait BServerPacket: Packet + Sized {
    fn read(read: impl Read) -> Result<Self, Error>;
}

/// Errors that can occur during packet encoding.
#[derive(Error, Debug)]
pub enum PacketEncodeError {
    #[error("Packet exceeds maximum length: {0}")]
    TooLong(usize),
    #[error("Compression failed {0}")]
    CompressionFailed(String),
    #[error("Writing packet failed: {0}")]
    Message(String),
}

#[derive(Error, Debug)]
pub enum PacketDecodeError {
    #[error("failed to decode packet ID")]
    DecodeID,
    #[error("packet exceeds maximum length")]
    TooLong,
    #[error("packet length is out of bounds")]
    OutOfBounds,
    #[error("malformed packet length VarInt: {0}")]
    MalformedLength(String),
    #[error("failed to decompress packet: {0}")]
    FailedDecompression(String), // Updated to include error details
    #[error("packet is uncompressed but greater than the threshold")]
    NotCompressed,
    #[error("the connection has closed")]
    ConnectionClosed,
    #[error("{0}")]
    Message(String),
}

impl From<ReadingError> for PacketDecodeError {

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