fix(compositor): replace panic-prone unwraps with explicit error handling in winit and DRM backends

- winit backend: client insertion and dispatch_clients failures now log
  and continue instead of unwinding the event loop
- winit backend: bind/render/submit failures in the redraw handler skip
  the frame and log a warning; the compositor stays running
- DRM backend: same client insertion and dispatch_clients treatment
- DRM device_added: use .context()? instead of unwrap() when inserting
  the new device entry after the drm field is known to be initialised
- DRM render_output: use guard-return instead of unwrap() to access drm
  state that was already verified non-None lines above
- compositor state: duplicate layer surface mapping from a misbehaving
  client logs a warning and returns instead of panicking

crates/weft-compositor/src/backend/drm.rs

@@ -137,10 +137,12 @@ pub fn run() -> anyhow::Result<()> {
 
     loop_handle
         .insert_source(listening_socket, |stream, _, state| {
-            state
+            if let Err(e) = state
                 .display_handle
                 .insert_client(stream, Arc::new(WeftClientState::default()))
-                .unwrap();
+            {
+                tracing::warn!(?e, "failed to insert Wayland client");
+            }
         })
         .map_err(|e| anyhow::anyhow!("socket source: {e}"))?;
 
@@ -150,7 +152,9 @@ pub fn run() -> anyhow::Result<()> {
             |_, display, state| {
                 // Safety: Display is owned by this Generic source and outlives the event loop.
                 unsafe {
-                    display.get_mut().dispatch_clients(state).unwrap();
+                    if let Err(e) = display.get_mut().dispatch_clients(state) {
+                        tracing::warn!(?e, "Wayland dispatch error");
+                    }
                 }
                 Ok(PostAction::Continue)
             },
@@ -375,16 +379,21 @@ fn device_added(state: &mut WeftCompositorState, node: DrmNode, path: &Path) ->
         )
         .map_err(|e| anyhow::anyhow!("DRM notifier: {e}"))?;
 
-    state.drm.as_mut().unwrap().devices.insert(
-        node,
-        WeftDrmDevice {
-            drm_output_manager,
-            drm_scanner: DrmScanner::new(),
-            surfaces: HashMap::new(),
-            render_node,
-            registration_token,
-        },
-    );
+    state
+        .drm
+        .as_mut()
+        .context("DRM data missing after initialization")?
+        .devices
+        .insert(
+            node,
+            WeftDrmDevice {
+                drm_output_manager,
+                drm_scanner: DrmScanner::new(),
+                surfaces: HashMap::new(),
+                render_node,
+                registration_token,
+            },
+        );
 
     device_changed(state, node);
     Ok(())
@@ -604,7 +613,7 @@ fn render_output(state: &mut WeftCompositorState, node: DrmNode, crtc: crtc::Han
     };
 
     let render_node = {
-        let d = state.drm.as_ref().unwrap();
+        let Some(d) = state.drm.as_ref() else { return };
         d.devices
             .get(&node)
             .and_then(|d| d.render_node)

crates/weft-compositor/src/backend/winit.rs

@@ -63,10 +63,12 @@ pub fn run() -> anyhow::Result<()> {
 
     loop_handle
         .insert_source(listening_socket, |client_stream, _, state| {
-            state
+            if let Err(e) = state
                 .display_handle
                 .insert_client(client_stream, Arc::new(WeftClientState::default()))
-                .unwrap();
+            {
+                tracing::warn!(?e, "failed to insert Wayland client");
+            }
         })
         .map_err(|e| anyhow::anyhow!("socket source insertion failed: {e}"))?;
 
@@ -78,7 +80,9 @@ pub fn run() -> anyhow::Result<()> {
                 // Safety: the display is owned by this Generic source and is never dropped
                 // while the event loop runs.
                 unsafe {
-                    display.get_mut().dispatch_clients(state).unwrap();
+                    if let Err(e) = display.get_mut().dispatch_clients(state) {
+                        tracing::warn!(?e, "Wayland dispatch error");
+                    }
                 }
                 Ok(PostAction::Continue)
             },
@@ -129,9 +133,8 @@ pub fn run() -> anyhow::Result<()> {
                 let size = backend.window_size();
                 let full_damage = Rectangle::from_size(size);
 
-                {
-                    let (renderer, mut framebuffer) = backend.bind().unwrap();
-                    smithay::desktop::space::render_output::<
+                let render_ok = match backend.bind() {
+                    Ok((renderer, mut framebuffer)) => smithay::desktop::space::render_output::<
                         _,
                         WaylandSurfaceRenderElement<GlesRenderer>,
                         _,
@@ -147,9 +150,18 @@ pub fn run() -> anyhow::Result<()> {
                         &mut damage_tracker,
                         [0.1_f32, 0.1, 0.1, 1.0],
                     )
-                    .unwrap();
+                    .map_err(|e| tracing::warn!(?e, "render_output failed"))
+                    .is_ok(),
+                    Err(e) => {
+                        tracing::warn!(?e, "backend bind failed");
+                        false
+                    }
+                };
+                if render_ok {
+                    if let Err(e) = backend.submit(Some(&[full_damage])) {
+                        tracing::warn!(?e, "backend submit failed");
+                    }
                 }
-                backend.submit(Some(&[full_damage])).unwrap();
 
                 state.space.elements().for_each(|window| {
                     window.send_frame(

crates/weft-compositor/src/state.rs

@@ -294,9 +294,13 @@ impl WlrLayerShellHandler for WeftCompositorState {
     ) {
         let desktop_surface = DesktopLayerSurface::new(surface, namespace);
         if let Some(output) = self.space.outputs().next().cloned() {
-            layer_map_for_output(&output)
+            if layer_map_for_output(&output)
                 .map_layer(&desktop_surface)
-                .expect("layer surface must not already be mapped");
+                .is_err()
+            {
+                tracing::warn!("received duplicate layer surface mapping; ignoring");
+                return;
+            }
             layer_map_for_output(&output).arrange();
         }
     }