tonhowtf/omniget · info

Download cancelled during session creation

Error message

Download cancelled during session creation

What it means

During download() the torrent session (librqbit Session) is created lazily and cached; creation races against the cancellation token. If cancellation fires before the session finishes initializing, the select! arm picks cancelled() and bails with this error. It is a normal, expected abort path, not a fault.

Solutions

1. No fix needed — this is the intended cancellation path; propagate the error as Cancelled
2. In the caller, match on the error message/cancellation state and treat it as success-abort rather than failure
3. Ensure the cancellation token isn't cancelled prematurely by an overly eager timeout or UI handler

Example fix

// before
match download(...).await { Err(e) => report_error(e), ... }
// after
match download(...).await {
    Err(e) if e.to_string().contains("cancelled") => tracing::info!("user cancelled"),
    Err(e) => report_error(e),
    Ok(r) => handle(r),
}

match download(...).await {
    Err(e) if format!("{e:#}").contains("cancelled") => info!("download aborted by user"),
    Err(e) => error!("download failed: {e:#}"),
    Ok(r) => handle(r),
}

When it happens

Trigger: The user (or caller) cancels the download (CancellationToken cancelled) while the first-time session initialization is still in flight in the tokio::select! between session creation and cancel_rx.cancelled().

Common situations: User closes a dialog or hits stop while the torrent engine is starting up; app shutdown during first download; timeouts cancelling slow disk-heavy session init.

Understand the failure class

Background: "Invalid state transition" errors: "status must be X, actually Y", "already rejected/charging/uninstalled", "cannot ... while running" — what they mean when a library rejects your call — this error's family across 31 libraries.

Related errors

• Download cancelled
• Download cancelled by user
• Send cancelled while waiting for receiver
• Send cancelled while paused
• Download cancelled

AI-assisted analysis of tonhowtf/omniget@8600b91f42 (2026-09-12). Data as JSON: /api/errors/06509066bec31aa5. Report an issue: GitHub.

Appendix: source

Thrown at src-tauri/src/platforms/magnet/mod.rs:156

                                    e
                                );
                                match Session::new_with_opts(output_pb.clone(), make_opts(true, false)).await {
                                    Ok(s) => Ok(s),
                                    Err(e2) => {
                                        tracing::warn!(
                                            "[magnet] DHT init failed ({}); retrying with DHT disabled (trackers/PEX only)",
                                            e2
                                        );
                                        Session::new_with_opts(output_pb, make_opts(true, true)).await
                                    }
                                }
                            }
                        }
                    } => {
                        result.map_err(|e| anyhow::anyhow!("Failed to initialize torrent session: {}", e))?
                    }
                    _ = cancel_rx.cancelled() => {
                        anyhow::bail!("Download cancelled during session creation");
                    }
                };
                *guard = Some(s.clone());
                *dir_guard = Some(output_dir.clone());
                s
            } else {
                tracing::info!("[magnet] reusing existing session");
                guard.as_ref().unwrap().clone()
            }
        };

        let add_torrent = if url.starts_with("magnet:")
            || url.starts_with("http://")
            || url.starts_with("https://")
        {
            AddTorrent::from_url(url)
        } else {
            let path = std::path::Path::new(url);

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