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Fix duplicated and crashing DBus tray icon #21980

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Fix duplicated and crashing DBus tray icon #21980

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aec2e66
Fix duplicated and crashing DBus tray icon
bolikcraft Aug 14, 2026
fdf755a
Track the tray name request instead of an owned flag
bolikcraft Aug 25, 2026
db0484e
Re-check state after every await in CreateTrayIcon
bolikcraft Aug 25, 2026
5cd6efe
Shorten the comments and use Simplified Technical English
bolikcraft Aug 26, 2026
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109 changes: 94 additions & 15 deletions src/Avalonia.FreeDesktop/DBusTrayIconImpl.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,10 @@ internal class DBusTrayIconImpl : ITrayIconImpl
private (int, int, byte[]) _icon;

private string? _sysTrayServiceName;
// This task shows if the name request is in progress, complete, or failed.
private Task? _sysTrayServiceNameRequest;
// The bus keeps the name until the release is complete. A request before that fails.
private Task? _sysTrayServiceNameRelease;
private string? _tooltipText;
private bool _isDisposed;
private bool _serviceConnected;
Expand Down Expand Up @@ -52,8 +56,8 @@ public DBusTrayIconImpl()

MenuExporter = DBusMenuExporter.TryCreateDetachedNativeMenu(dbusMenuPath, _connection);

// CreateTrayIcon exports this object when the connection owns the name.
_statusNotifierItemDbusObj = new StatusNotifierItemDbusObj(_connection, dbusMenuPath);
_connection.AddMethodHandler(_statusNotifierItemDbusObj);

@jsuarezruiz jsuarezruiz Sep 7, 2026

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Confirmed this is the root cause of the duplicate. On main, the object can be inspected through the connection immediately after construction, even before the name is owned. On this branch, it isn’t exposed until the name is acquired. Good catch.

_statusNotifierItemDbusObj.ActivationDelegate += () => OnClicked?.Invoke();

WatchAsync();
Expand Down Expand Up @@ -93,6 +97,10 @@ private async void WatchAsync()
OnOwnerChanged(owner);
}
}
catch (OperationCanceledException)
{
// Dispose cancels this task. The continuation runs after Dispose sets _isDisposed.
}
catch (Exception e) when (!_isDisposed)
{
Logger.TryGet(LogEventLevel.Error, "DBUS")
Expand All @@ -110,8 +118,6 @@ private void OnOwnerChanged(string? newOwner)
_serviceConnected = true;
_statusNotifierWatcher = new StatusNotifierWatcher(_connection, "org.kde.StatusNotifierWatcher", "/StatusNotifierWatcher");

DestroyTrayIcon();

if (_isVisible)
CreateTrayIcon();
}
Expand All @@ -124,40 +130,112 @@ private void OnOwnerChanged(string? newOwner)

private async void CreateTrayIcon()
{
if (_connection is null || !_serviceConnected || _isDisposed || _statusNotifierWatcher is null)
if (_connection is null || !_serviceConnected || _isDisposed || _statusNotifierItemDbusObj is null || _statusNotifierWatcher is null)
return;

Task? request = null;

try
{
// Keep the name for the life of the icon. A new id shows a new item to the host.
if (_sysTrayServiceName is null)
{
#if NET5_0_OR_GREATER
var pid = Environment.ProcessId;
var pid = Environment.ProcessId;
#else
var pid = Process.GetCurrentProcess().Id;
var pid = Process.GetCurrentProcess().Id;
#endif
var tid = s_trayIconInstanceId++;
var tid = s_trayIconInstanceId++;
_sysTrayServiceName = FormattableString.Invariant($"org.kde.StatusNotifierItem-{pid}-{tid}");
}

if (_sysTrayServiceNameRelease is { } release)
{
await release;
if (ReferenceEquals(_sysTrayServiceNameRelease, release))
_sysTrayServiceNameRelease = null;
if (!ShouldShowTrayIcon)
return;
}

_connection.RemoveMethodHandler(_statusNotifierItemDbusObj!.Path);
_connection.AddMethodHandler(_statusNotifierItemDbusObj);
request = _sysTrayServiceNameRequest ??= _connection.RequestNameAsync(_sysTrayServiceName);
await request;

_sysTrayServiceName = FormattableString.Invariant($"org.kde.StatusNotifierItem-{pid}-{tid}");
await _connection.RequestNameAsync(_sysTrayServiceName);
await _statusNotifierWatcher.RegisterStatusNotifierItemAsync(_sysTrayServiceName);
// The icon can become hidden or disposed while the bus answers. The release then runs
// after this line.
if (!ShouldShowTrayIcon || !ReferenceEquals(_sysTrayServiceNameRequest, request))
return;

_statusNotifierItemDbusObj!.SetTitleAndTooltip(_tooltipText);
_statusNotifierItemDbusObj.SetIcon(_icon);
// Export the object only while the connection owns the name. If not, a host that scans
// the bus adds a second item.
_connection.AddMethodHandler(_statusNotifierItemDbusObj);

@jsuarezruiz jsuarezruiz Sep 7, 2026

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If SetIsVisible toggles quickly (for exampke, false/true/false/true in one turn), two CreateTrayIcon calls end up running at once, both wait on the same release/request, and both reach AddMethodHandler. The second one throws "A method handler is already registered for '/StatusNotifierItem'" and logs "Unable to register the system tray icon."

It is just an error in the log, but it points to CreateTrayIcon not being safe to re enter. On main this never happened because it removed the handler before re adding it.

We could improve with a small guard so re entry skips the add instead of throwing.


await _statusNotifierWatcher.RegisterStatusNotifierItemAsync(_sysTrayServiceName);

if (!ShouldShowTrayIcon)
return;

_statusNotifierItemDbusObj.SetTitleAndTooltip(_tooltipText);
_statusNotifierItemDbusObj.SetIcon(_icon);
}
catch (Exception e)
{
// Clear only this request, and only if it did not complete. The next call then asks for
// the name again.
if (request is { Status: not TaskStatus.RanToCompletion } && ReferenceEquals(_sysTrayServiceNameRequest, request))
_sysTrayServiceNameRequest = null;

if (!_isDisposed)
Logger.TryGet(LogEventLevel.Error, "DBUS")
?.Log(this, "Unable to register the system tray icon.\n{Exception}", e);
}
}

// CreateTrayIcon reads these conditions again after each await.
private bool ShouldShowTrayIcon => !_isDisposed && _isVisible && _serviceConnected;

private void DestroyTrayIcon()
{
if (_connection is null || !_serviceConnected || _isDisposed || _statusNotifierItemDbusObj is null || _sysTrayServiceName is null)
return;

_connection!.ReleaseNameAsync(_sysTrayServiceName);
_connection.RemoveMethodHandler(_statusNotifierItemDbusObj.Path);
}

/// <summary>
/// Releases the bus name. A host removes the item when the name goes away.
/// Call this after <see cref="DestroyTrayIcon"/>, but not when the watcher stops.
/// </summary>
private void ReleaseTrayServiceName()
{
if (_connection is null || _sysTrayServiceName is null || _sysTrayServiceNameRequest is not { } request)
return;

_sysTrayServiceNameRequest = null;
_sysTrayServiceNameRelease = ReleaseTrayServiceName(request, _connection, _sysTrayServiceName);
}

private async Task ReleaseTrayServiceName(Task request, DBusConnection connection, string name)
{
try
{
// Wait for the request. A release before the connection owns the name has no effect.
await request;
await connection.ReleaseNameAsync(name);
}
catch (Exception e)
{
if (!_isDisposed)
Logger.TryGet(LogEventLevel.Error, "DBUS")
?.Log(this, "Unable to release the system tray icon name.\n{Exception}", e);
}
}

public void Dispose()
{
IsActive = false;
DestroyTrayIcon();
ReleaseTrayServiceName();
(MenuExporter as IDisposable)?.Dispose();
_watchCts?.Cancel();
_isDisposed = true;
Expand Down Expand Up @@ -215,6 +293,7 @@ public void SetIsVisible(bool visible)
break;
case false when _isVisible:
DestroyTrayIcon();
ReleaseTrayServiceName();
break;
}

Expand Down