failed to spawn egui_inspection connection thread

Error message

failed to spawn egui_inspection connection thread

What it means

Error "failed to spawn egui_inspection connection thread" thrown in emilk/egui.

Solutions

The inspection connection thread failed to spawn (resource exhaustion): limit concurrent inspection connections or check OS thread limits.

Example fix

// Accept connections on a single listener thread and reuse it instead of spawning per connection.

When it happens

Trigger: Thrown at crates/egui_inspection/src/plugin.rs:380 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emilk/egui@8fb03c9ae9 (2026-08-19). Data as JSON: /api/errors/83de35510fe30d9e. Report an issue: GitHub.

Appendix: source

Thrown at crates/egui_inspection/src/plugin.rs:398

        .spawn(move || {
            for stream in listener.incoming() {
                let Ok(stream) = stream else { continue };
                let ctx = ctx.clone();
                std::thread::Builder::new()
                    .name("egui_inspection_conn".into())
                    .spawn(move || {
                        if let Err(err) = serve_connection(stream, &ctx) {
                            log::warn!("egui_inspection: connection ended: {err}");
                        }
                    })
                    .expect("failed to spawn egui_inspection connection thread");
            }
        })?;
    Ok(())
}

/// Connection handler: write the handshake, then read framed requests, submit each to the
/// plugin via the context, and write the framed response back. Returns once the client
/// disconnects.
///
/// # Errors
/// On any socket I/O failure.
#[cfg(not(target_arch = "wasm32"))]
fn serve_connection(stream: std::net::TcpStream, ctx: &Context) -> std::io::Result<()> {
    use crate::protocol::{read_message, write_handshake, write_message};

    let mut reader = std::io::BufReader::new(stream.try_clone()?);
    let mut writer = std::io::BufWriter::new(stream);

    // Identify ourselves and our protocol version before any framed messages.
    write_handshake(&mut writer)?;

    loop {
        let req: Request = match read_message(&mut reader) {
            Ok(req) => req,
            Err(err) if err.kind() == std::io::ErrorKind::UnexpectedEof => return Ok(()), // client gone

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