Pumpkin-MC/Pumpkin · error · PacketDecodeError

malformed packet length VarInt

Error message

malformed packet length VarInt: {0}

What it means

PacketDecodeError variant raised while reading the framed packet's length prefix: the VarInt decoder itself failed while parsing the length field (overflow or malformed continuation). The faulty input is the length VarInt bytes at the start of the frame — truncated or corrupted data on the connection.

Solutions

1. Close the connection; framing cannot be resynchronized
2. Validate VarInt encoding before consuming the body
3. Log the malformed length at debug level

When it happens

Trigger: Thrown at crates/pumpkin-protocol/src/lib.rs:307 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 Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/0650e57292f412b5. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-protocol/src/lib.rs:307

#[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 {
    fn from(value: ReadingError) -> Self {
        Self::FailedDecompression(value.to_string())
    }
}

#[derive(Clone, serde::Serialize)]

View on GitHub (pinned to 8d4639e25a)