Pumpkin-MC/Pumpkin · error

Invalid ContainerName ID

Error message

Invalid ContainerName ID: {value}

What it means

Returned by ContainerName::try_from/decode when the incoming varint ID does not map to any known ContainerName variant (valid IDs currently run 0..=66). The parser fails with InvalidData rather than inventing an unknown container variant.

Solutions

1. Update the server/protocol crate to a version that maps the new ContainerName IDs.
2. Check client version compatibility; pin or reject clients with unsupported protocol versions.
3. Verify packet parsing alignment upstream — a desynced read turns ordinary data into invalid IDs.
4. If extensibility is needed, add a fallback Unknown(i32) handling path instead of erroring.

Example fix

// before
let name = ContainerName::from_id(value)?; // Err on 67
// after
let name = ContainerName::from_id(value).unwrap_or(ContainerName::Dynamic); // or reject client

fn known_container_id(v: u32) -> bool { v <= 66 }

match ContainerName::decode(buf) {
    Ok(name) => name,
    Err(e) if e.to_string().starts_with("Invalid ContainerName ID") => {
        log::warn!("unknown container id from client — update protocol? ");
        ContainerName::Dynamic
    }
    Err(e) => return Err(e),
}

When it happens

Trigger: Decoding a Bedrock packet that carries a ContainerName ID outside the recognized 0-66 range — newer/older client sending an ID this server build doesn't know, or stream desync producing a garbage value.

Common situations: Client on a newer Bedrock version introduces container IDs unknown to this server; corrupt packet misaligned so random bytes parse as the ID.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• user_data_len exceeds 1MB limit
• extra_data_len exceeds 1MB limit
• item string array length out of bounds
• String::from_utf8 error
• Nbt read error

AI-assisted analysis of Pumpkin-MC/Pumpkin@8d4639e25a (2026-09-09). Data as JSON: /api/errors/92c2dc44b782f6b5. Report an issue: GitHub.

Appendix: source

Thrown at crates/pumpkin-protocol/src/bedrock/network_item.rs:496

            49 => Ok(Self::Trade2ResultPreview),
            50 => Ok(Self::GrindstoneInput),
            51 => Ok(Self::GrindstoneAdditional),
            52 => Ok(Self::GrindstoneResultPreview),
            53 => Ok(Self::StonecutterInput),
            54 => Ok(Self::StonecutterResultPreview),
            55 => Ok(Self::CartographyInput),
            56 => Ok(Self::CartographyAdditional),
            57 => Ok(Self::CartographyResultPreview),
            58 => Ok(Self::Barrel),
            59 => Ok(Self::Cursor),
            60 => Ok(Self::CreatedOutput),
            61 => Ok(Self::SmithingTableTemplate),
            62 => Ok(Self::CrafterLevelEntity),
            63 => Ok(Self::Dynamic),
            64 => Ok(Self::RecipeFood),
            65 => Ok(Self::RecipeBlocks),
            66 => Ok(Self::RecipeFurnaceItems),
            _ => Err(Error::new(
                std::io::ErrorKind::InvalidData,
                format!("Invalid ContainerName ID: {value}"),
            )),
        }
    }
}

impl PacketWrite for ContainerName {
    fn write<W: Write>(&self, writer: &mut W) -> Result<(), Error> {
        (*self as u8).write(writer)?;
        Ok(())
    }
}

impl PacketRead for ContainerName {
    fn read<R: Read>(buf: &mut R) -> Result<Self, Error> {
        let value = u8::read(buf)?;
        Self::try_from(value)

View on GitHub (pinned to 8d4639e25a)