Avoid unwraps in more places

src/backend/mod.rs

@@ -38,10 +38,10 @@ impl Backend {
         }
     }
 
-    pub fn renderer(&mut self) -> &mut GlesRenderer {
+    pub fn renderer(&mut self) -> Option<&mut GlesRenderer> {
         match self {
             Backend::Tty(tty) => tty.renderer(),
-            Backend::Winit(winit) => winit.renderer(),
+            Backend::Winit(winit) => Some(winit.renderer()),
         }
     }
 

src/backend/tty.rs

@@ -327,7 +327,7 @@ impl Tty {
         let mut dmabuf_state = DmabufState::new();
         let default_feedback = DmabufFeedbackBuilder::new(device_id, gles.dmabuf_formats())
             .build()
-            .unwrap();
+            .context("error building default dmabuf feedback")?;
         let dmabuf_global = dmabuf_state
             .create_global_with_default_feedback::<State>(&niri.display_handle, &default_feedback);
 
@@ -426,11 +426,14 @@ impl Tty {
             .cloned()
             .unwrap_or_default();
 
-        let device = self.output_device.as_mut().unwrap();
+        let device = self
+            .output_device
+            .as_mut()
+            .context("missing output device")?;
 
         let mut mode = connector.modes().get(0);
         connector.modes().iter().for_each(|m| {
-            debug!("mode: {m:?}");
+            trace!("mode: {m:?}");
 
             if m.mode_type().contains(ModeTypeFlags::PREFERRED) {
                 // Pick the highest refresh rate.
@@ -514,7 +517,7 @@ impl Tty {
         let dmabuf_feedback = DmabufFeedbackBuilder::new(device.id, device.formats.clone())
             .add_preference_tranche(device.id, Some(TrancheFlags::Scanout), scanout_formats)
             .build()
-            .unwrap();
+            .context("error building dmabuf feedback")?;
 
         let vblank_frame_name =
             tracy_client::FrameName::new_leak(format!("vblank on {output_name}"));
@@ -554,7 +557,10 @@ impl Tty {
         crtc: crtc::Handle,
     ) {
         debug!("disconnecting connector: {connector:?}");
-        let device = self.output_device.as_mut().unwrap();
+        let Some(device) = self.output_device.as_mut() else {
+            error!("missing output device");
+            return;
+        };
 
         let Some(surface) = device.surfaces.remove(&crtc) else {
             debug!("crtc wasn't enabled");
@@ -568,10 +574,12 @@ impl Tty {
                 let tty_state: &TtyOutputState = output.user_data().get().unwrap();
                 tty_state.device_id == device.id && tty_state.crtc == crtc
             })
-            .unwrap()
-            .clone();
-
+            .cloned();
+        if let Some(output) = output {
             niri.remove_output(&output);
+        } else {
+            error!("missing output for crtc {crtc:?}");
+        };
 
         self.connectors.lock().unwrap().remove(&surface.name);
     }
@@ -692,8 +700,8 @@ impl Tty {
         self.session.seat()
     }
 
-    pub fn renderer(&mut self) -> &mut GlesRenderer {
-        &mut self.output_device.as_mut().unwrap().gles
+    pub fn renderer(&mut self) -> Option<&mut GlesRenderer> {
+        self.output_device.as_mut().map(|d| &mut d.gles)
     }
 
     pub fn render(
@@ -705,13 +713,20 @@ impl Tty {
     ) -> Option<&DmabufFeedback> {
         let span = tracy_client::span!("Tty::render");
 
-        let device = self.output_device.as_mut().unwrap();
+        let Some(device) = self.output_device.as_mut() else {
+            error!("missing output device");
+            return None;
+        };
+
         let tty_state: &TtyOutputState = output.user_data().get().unwrap();
-        let surface = device.surfaces.get_mut(&tty_state.crtc).unwrap();
-        let drm_compositor = &mut surface.compositor;
+        let Some(surface) = device.surfaces.get_mut(&tty_state.crtc) else {
+            error!("missing surface");
+            return None;
+        };
 
         span.emit_text(&surface.name);
 
+        let drm_compositor = &mut surface.compositor;
         match drm_compositor.render_frame::<_, _, GlesTexture>(
             &mut device.gles,
             elements,
@@ -785,7 +800,10 @@ impl Tty {
     }
 
     pub fn dmabuf_state(&mut self) -> &mut DmabufState {
-        &mut self.output_device.as_mut().unwrap().dmabuf_state
+        let device = self.output_device.as_mut().expect(
+            "the dmabuf global must be created and destroyed together with the output device",
+        );
+        &mut device.dmabuf_state
     }
 
     pub fn connectors(&self) -> Arc<Mutex<HashMap<String, Output>>> {

src/handlers/mod.rs

@@ -89,7 +89,10 @@ impl DmabufHandler for State {
         _global: &DmabufGlobal,
         dmabuf: Dmabuf,
     ) -> Result<(), ImportError> {
-        match self.backend.renderer().import_dmabuf(&dmabuf, None) {
+        let renderer = self.backend.renderer().expect(
+            "the dmabuf global must be created and destroyed together with the output device",
+        );
+        match renderer.import_dmabuf(&dmabuf, None) {
             Ok(_texture) => Ok(()),
             Err(err) => {
                 debug!("error importing dmabuf: {err:?}");

src/input.rs

@@ -153,13 +153,13 @@ impl State {
                         Action::Screenshot => {
                             let active = self.niri.monitor_set.active_output().cloned();
                             if let Some(active) = active {
-                                if let Err(err) =
-                                    self.niri.screenshot(self.backend.renderer(), &active)
-                                {
+                                if let Some(renderer) = self.backend.renderer() {
+                                    if let Err(err) = self.niri.screenshot(renderer, &active) {
                                         warn!("error taking screenshot: {err:?}");
                                     }
                                 }
                             }
+                        }
                         Action::CloseWindow => {
                             if let Some(window) = self.niri.monitor_set.focus() {
                                 window.toplevel().send_close();

src/niri.rs

@@ -361,7 +361,14 @@ impl Niri {
                 calloop::channel::Event::Msg(ScreenshotToNiri::TakeScreenshot {
                     include_cursor,
                 }) => {
-                    let renderer = state.backend.renderer();
+                    let Some(renderer) = state.backend.renderer() else {
+                        let msg = NiriToScreenshot::ScreenshotResult(None);
+                        if let Err(err) = to_screenshot.send_blocking(msg) {
+                            warn!("error sending None to screenshot: {err:?}");
+                        }
+                        return;
+                    };
+
                     let on_done = {
                         let to_screenshot = to_screenshot.clone();
                         move |path| {
@@ -938,6 +945,10 @@ impl Niri {
     fn redraw(&mut self, backend: &mut Backend, output: &Output) {
         let _span = tracy_client::span!("Niri::redraw");
 
+        let Some(renderer) = backend.renderer() else {
+            return;
+        };
+
         let state = self.output_state.get_mut(output).unwrap();
         let presentation_time = state.frame_clock.next_presentation_time();
 
@@ -948,7 +959,7 @@ impl Niri {
         self.monitor_set.advance_animations(presentation_time);
 
         // Render the elements.
-        let elements = self.render(backend.renderer(), output, true);
+        let elements = self.render(renderer, output, true);
 
         // Hand it over to the backend.
         let dmabuf_feedback = backend.render(self, output, &elements, presentation_time);
@@ -962,7 +973,10 @@ impl Niri {
         self.send_frame_callbacks(output);
 
         // Render and send to PipeWire screencast streams.
-        self.send_for_screen_cast(backend, output, &elements, presentation_time);
+        let renderer = backend
+            .renderer()
+            .expect("renderer must not have disappeared");
+        self.send_for_screen_cast(renderer, output, &elements, presentation_time);
     }
 
     fn send_dmabuf_feedbacks(&self, output: &Output, feedback: &DmabufFeedback) {
@@ -1072,7 +1086,7 @@ impl Niri {
 
     fn send_for_screen_cast(
         &mut self,
-        backend: &mut Backend,
+        renderer: &mut GlesRenderer,
         output: &Output,
         elements: &[OutputRenderElements<GlesRenderer>],
         presentation_time: Duration,
@@ -1116,7 +1130,10 @@ impl Niri {
                 let dmabuf = cast.dmabufs.borrow()[&fd].clone();
 
                 // FIXME: Hidden / embedded / metadata cursor
-                render_to_dmabuf(backend.renderer(), dmabuf, size, scale, elements).unwrap();
+                if let Err(err) = render_to_dmabuf(renderer, dmabuf, size, scale, elements) {
+                    error!("error rendering to dmabuf: {err:?}");
+                    continue;
+                }
 
                 let maxsize = data.as_raw().maxsize;
                 let chunk = data.chunk_mut();