chore(bluetooth): handle DBus service unknown error

cosmic-settings/src/pages/bluetooth/mod.rs

@@ -47,6 +47,8 @@ pub struct Page {
     selected_adapter: Option<OwnedObjectPath>,
     heading: String,
     devices: HashMap<OwnedObjectPath, Device>,
+    // Set to true when the org.bluez dbus service is unknown.
+    bluez_service_unknown: bool,
     popup_setting: bool,
     popup_device: Option<OwnedObjectPath>,
     subscription: Option<tokio::sync::oneshot::Sender<()>>,
@@ -157,6 +159,7 @@ pub enum Message {
         tokio::sync::mpsc::Sender<crate::pages::Message>,
     ),
     DBusError(String),
+    DBusServiceUnknown,
     DeviceFailed(OwnedObjectPath),
     DisconnectDevice(OwnedObjectPath),
     ForgetDevice(OwnedObjectPath),
@@ -491,6 +494,9 @@ impl Page {
             Message::DBusError(why) => {
                 tracing::error!("dbus connection failed. {why}");
             }
+            Message::DBusServiceUnknown => {
+                self.bluez_service_unknown = true;
+            }
         };
         cosmic::Task::none()
     }
@@ -575,6 +581,14 @@ fn status() -> Section<crate::pages::Message> {
         .show_while::<Page>(|page| !page.adapters.is_empty())
         .view::<Page>(move |_binder, page, section| {
             let descriptions = &section.descriptions;
+
+            if page.bluez_service_unknown {
+                return widget::text::body(
+                    "The org.bluez DBus service could not be activated. Is bluez installed?",
+                )
+                .apply(Element::from);
+            }
+
             let status = page
                 .get_selected_adapter()
                 .map_or(page.active, |(_, adapter)| adapter.enabled);

cosmic-settings/src/pages/bluetooth/subscription.rs

@@ -7,7 +7,7 @@ use std::pin::Pin;
 use bluez_zbus::BluetoothDevice;
 use cosmic::iced::futures::{SinkExt, StreamExt};
 use futures::{channel::mpsc, stream::FusedStream};
-use zbus::zvariant::OwnedObjectPath;
+use zbus::{fdo, zvariant::OwnedObjectPath};
 
 enum DevicePropertyWatcherTask {
     Add(OwnedObjectPath),
@@ -201,14 +201,26 @@ pub async fn watch(
         }.await;
 
         if let Err(why) = result {
-            tracing::error!("failed to watch bluetooth event: {why}");
-            if let Err(why) = tx
+            _ = tx
                 .send(bluetooth::Message::DBusError(why.to_string()))
-                .await
-            {
-                tracing::error!("failed to communicate error to app: {why}");
+                .await;
+
+            tracing::error!("failed to watch bluetooth event: {why}.");
+
+            // Exit if the dbus service is not found.
+            if let zbus::Error::FDO(fdo_error) = why {
+                match *fdo_error {
+                    fdo::Error::ServiceUnknown(_) => {
+                        tracing::error!(
+                            "The org.bluez dbus service is unknown. Is the bluez service installed and activatable?"
+                        );
+                        _ = tx.send(bluetooth::Message::DBusServiceUnknown).await;
+                        return;
+                    }
+
+                    _ => (),
+                }
             }
-            tracing::error!("failed to watch bluetooth event: {why}. Restarting...");
         }
     }
 }