zellij-org/zellij · error · anyhow::Error

Missing pixel_dimensions

Error message

Missing pixel_dimensions

What it means

Thrown while converting a ClientToServerMsg::TerminalPixelDimensions frame (zellij-utils/src/ipc/protobuf_conversion.rs): the outer message was present but its nested pixel_dimensions field (the PixelDimensions message with height/width/character_cell_size) was None. Optional message-typed fields do not get proto3 defaults, so an unset nested message is indistinguishable from an absent one and conversion refuses to invent values.

Source

Thrown at zellij-utils/src/ipc/protobuf_conversion.rs:211

    }
}

// Convert protobuf ClientToServerMsg to Rust
impl TryFrom<ProtoClientToServerMsg> for ClientToServerMsg {
    type Error = anyhow::Error;

    fn try_from(msg: ProtoClientToServerMsg) -> Result<Self> {
        match msg.message {
            Some(client_to_server_msg::Message::DetachSession(detach)) => {
                Ok(ClientToServerMsg::DetachSession {
                    client_ids: detach.client_ids.into_iter().map(|id| id as u16).collect(),
                })
            },
            Some(client_to_server_msg::Message::TerminalPixelDimensions(pixel_dims)) => {
                Ok(ClientToServerMsg::TerminalPixelDimensions {
                    pixel_dimensions: pixel_dims
                        .pixel_dimensions
                        .ok_or_else(|| anyhow!("Missing pixel_dimensions"))?
                        .try_into()?,
                })
            },
            Some(client_to_server_msg::Message::BackgroundColor(bg_color)) => {
                Ok(ClientToServerMsg::BackgroundColor {
                    color: bg_color.color,
                })
            },
            Some(client_to_server_msg::Message::ForegroundColor(fg_color)) => {
                Ok(ClientToServerMsg::ForegroundColor {
                    color: fg_color.color,
                })
            },
            Some(client_to_server_msg::Message::ColorRegisters(color_regs)) => {
                Ok(ClientToServerMsg::ColorRegisters {
                    color_registers: color_regs
                        .color_registers
                        .into_iter()

View on GitHub (pinned to e839bfffa5)

Solutions

1. Always populate pixel_dimensions (with character_cell_size where known) when sending the TerminalPixelDimensions variant.
2. Update the zellij client on the sending side to a release matching the server.
3. On the receiving side, treat a missing nested field as a protocol violation: skip/log the frame rather than propagating the error.

Example fix

// before
let msg = client_to_server_msg::Message::TerminalPixelDimensions(TerminalPixelDimensions::default());

// after: set the nested message
let msg = client_to_server_msg::Message::TerminalPixelDimensions(TerminalPixelDimensions {
    pixel_dimensions: Some(PixelDimensions { height: Some(1080), width: Some(1920), character_cell_size: Some(SizeInPixels { width: 9, height: 18 }) }),
});

// receiver side: skip frames that lack the nested message
let Some(pixel_dimensions) = pixel_dims.pixel_dimensions else {
    log::warn!("TerminalPixelDimensions without pixel_dimensions; ignored");
    return Ok(None);
};

fn has_pixel_dimensions(m: &TerminalPixelDimensions) -> bool {
    m.pixel_dimensions.is_some()
}

match ClientToServerMsg::try_from(proto_msg) {
    Ok(msg) => Some(msg),
    Err(e) if e.to_string().contains("Missing pixel_dimensions") => {
        log::warn!("peer sent pixel-dims frame without payload; frame ignored");
        None
    },
    Err(e) => return Err(e),
}

When it happens

Trigger: A client sends the TerminalPixelDimensions variant without setting the nested pixel_dimensions message — older zellij client that predates the field, custom/web clients constructing the oneof member with defaults, or a test fixture omission.

Common situations: Version-mixed sessions (old client, new server); first implementations of custom clients copying the message shape incompletely; refactors that drop the nested assignment.

Related errors

• Missing new_size
• Invalid BareKey value: {}
• Invalid KeyModifier value: {}
• Character key needs character data
• Unspecified bare key

AI-assisted analysis of zellij-org/zellij@e839bfffa5 (2026-08-19). Data as JSON: /api/errors/0e235fb8177212c0. Report an issue: GitHub.