zed-industries/zed · info

dialog cancelled

Error message

dialog cancelled

What it means

show_dialog runs the platform dialog on a background thread and can be cancelled (e.g. the window was closed or a timeout fired via CancellationTimer). Before and after invoking the dialog callback, the thread checks the cancellation token; if cancellation was requested it aborts with this anyhow error instead of returning dialog results. It is a deliberate cooperative-cancellation signal, not a bug.

Solutions

1. Treat the error as benign cancellation: filter it out where dialog results are consumed instead of logging it as a failure.
2. Avoid closing/dropping the window that owns the dialog request until the dialog future resolves, or keep a handle so cancellation is intentional.
3. If it fires frequently at startup, investigate slow Apartment::new / thread startup that widens the cancellation race window.
4. Check whether CancellationTimer's timeout is too aggressive for the environment and raise it if dialogs legitimately take long.

Example fix

// before
if let Err(e) = show_dialog(...).await {
    log::error!("dialog failed: {e}");
}
// after
if let Err(e) = show_dialog(...).await {
    if !e.to_string().contains("dialog cancelled") {
        log::error!("dialog failed: {e}");
    }
}

match show_dialog(cx).await {
    Ok(result) => handle(result),
    Err(e) if e.to_string().contains("dialog cancelled") => {}, // benign
    Err(e) => log::error!("dialog failed: {e:#}"),
}

When it happens

Trigger: Calling show_dialog and then closing the window / dropping the requester before the background thread reaches the dialog callback (pre-dialog check at line 122), or the CancellationTimer expiring while the dialog is being spawned.

Common situations: Rapidly closing a window while a file-picker or message box is still opening; slow COM apartment startup on a busy system; teardown races during app shutdown where the dialog request outlives its owner.

Related errors

• Autoupdate failed, nothing to rollback
• Autoupdate failed, rollback successful
• Buffer edited while formatting. Aborting
• Delete operations cannot be rolled back, file
• Device lost

AI-assisted analysis of zed-industries/zed@916fc2b8cb (2026-09-19). Data as JSON: /api/errors/b8ecd7f765fea339. Report an issue: GitHub.

Appendix: source

Thrown at crates/gpui_windows/src/dialog.rs:122

                    Either::Right(((), _)) => return,
                }
            } else {
                None
            };
            if sender.is_canceled() || cancellation.is_requested() {
                return;
            }
            let (result_sender, mut result_receiver) = oneshot::channel();
            let thread = std::thread::Builder::new()
                .name("windows-native-dialog".into())
                .spawn({
                    let cancellation = cancellation.clone();
                    move || {
                        let result = (|| {
                            let _apartment = Apartment::new()?;
                            let _timer = CancellationTimer::new(cancellation.clone())?;
                            if cancellation.is_requested() {
                                return Err(anyhow!("dialog cancelled"));
                            }
                            let result = dialog(hwnd.map(|hwnd| hwnd.as_raw()).unwrap_or_default());
                            if cancellation.is_requested() {
                                return Err(anyhow!("dialog cancelled"));
                            }
                            result
                        })();
                        result_sender.send(result).ok();
                    }
                });
            if let Err(error) = thread {
                drop(serialization);
                sender.send(Err(error.into())).ok();
                return;
            }
            let result = match select(&mut result_receiver, sender.cancellation()).await {
                Either::Left((result, _)) => result,
                Either::Right(((), _)) => {

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