Pumpkin-MC/Pumpkin · error · PacketEncodeError

Writing packet failed

Error message

Writing packet failed: {0}

What it means

`PacketEncodeError::Message` wraps a generic I/O failure that occurred while writing the serialized packet bytes to the underlying writer. The inner io::Error description is embedded in the message. It means packet construction itself was fine but the write step failed.

Solutions

  1. Check connection state before writing; treat this as a dead connection and clean it up.
  2. Inspect the inner io::Error message for the root cause (broken pipe vs reset vs aborted).
  3. Add disconnect handling so write failures are logged and the player/session is removed gracefully.
  4. Avoid sending packets to sessions already flagged as closed.
Defensive patterns

Strategy: try-catch

Try / catch

match write_packet(&packet, version, &mut stream) {
    Ok(()) => {},
    Err(PacketEncodeError::Message(e)) if e.contains("Broken pipe") || e.contains("reset") => {
        log::info!("client disconnected mid-packet; closing session");
        session.close();
    }
    Err(e) => return Err(e.into()),
}

Prevention

When it happens

Trigger: Any io::Error bubbling out of `write_packet`'s writer — a closed socket (broken pipe), a full/failed buffer, or the underlying connection being reset mid-write.

Common situations: Client disconnected while the server was sending a packet; TCP connection reset; writing to a network buffer that failed.

Related errors

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/1476556118bb2c42. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-protocol/src/lib.rs:295

    fn write_packet(&self, writer: impl Write) -> Result<(), Error>;

    fn serialize_packet(&self) -> Result<Bytes, Error> {
        crate::bedrock::packet_encoder::serialize_packet(self)
    }
}

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")]

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