Properly end winit event loop (#7565)

crates/eframe/src/native/glow_integration.rs

@@ -470,7 +470,7 @@ impl WinitApp for GlowWinitApp<'_> {
         if let Some(running) = &mut self.running {
             Ok(running.on_window_event(window_id, &event))
         } else {
-            Ok(EventResult::Wait)
+            Ok(EventResult::Exit)
         }
     }
 
@@ -747,7 +747,7 @@ impl GlowWinitRunning<'_> {
         }
 
         if integration.should_close() {
-            Ok(EventResult::Exit)
+            Ok(EventResult::CloseRequested)
         } else {
             Ok(EventResult::Wait)
         }
@@ -798,7 +798,7 @@ impl GlowWinitRunning<'_> {
                     log::debug!(
                         "Received WindowEvent::CloseRequested for main viewport - shutting down."
                     );
-                    return EventResult::Exit;
+                    return EventResult::CloseRequested;
                 }
 
                 log::debug!("Received WindowEvent::CloseRequested for viewport {viewport_id:?}");
@@ -818,24 +818,11 @@ impl GlowWinitRunning<'_> {
                     }
                 }
             }
-
-            winit::event::WindowEvent::Destroyed => {
-                log::debug!(
-                    "Received WindowEvent::Destroyed for viewport {:?}",
-                    viewport_id
-                );
-                if viewport_id == Some(ViewportId::ROOT) {
-                    return EventResult::Exit;
-                } else {
-                    return EventResult::Wait;
-                }
-            }
-
             _ => {}
         }
 
         if self.integration.should_close() {
-            return EventResult::Exit;
+            return EventResult::CloseRequested;
         }
 
         let mut event_response = egui_winit::EventResponse {

crates/eframe/src/native/run.rs

@@ -139,6 +139,11 @@ impl<T: WinitApp> WinitAppWrapper<T> {
                 exit = true;
                 event_result
             }
+            EventResult::CloseRequested => {
+                // The windows need to be dropped whilst the event loop is running to allow for proper cleanup.
+                self.winit_app.save_and_destroy();
+                event_result
+            }
         });
 
         if let Err(err) = combined_result {

crates/eframe/src/native/wgpu_integration.rs

@@ -461,7 +461,8 @@ impl WinitApp for WgpuWinitApp<'_> {
         if let Some(running) = &mut self.running {
             Ok(running.on_window_event(window_id, &event))
         } else {
-            Ok(EventResult::Wait)
+            // running is removed to get ready for exiting
+            Ok(EventResult::Exit)
         }
     }
 
@@ -739,7 +740,7 @@ impl WgpuWinitRunning<'_> {
         }
 
         if integration.should_close() {
-            Ok(EventResult::Exit)
+            Ok(EventResult::CloseRequested)
         } else {
             Ok(EventResult::Wait)
         }
@@ -799,7 +800,7 @@ impl WgpuWinitRunning<'_> {
                     log::debug!(
                         "Received WindowEvent::CloseRequested for main viewport - shutting down."
                     );
-                    return EventResult::Exit;
+                    return EventResult::CloseRequested;
                 }
 
                 log::debug!("Received WindowEvent::CloseRequested for viewport {viewport_id:?}");
@@ -833,7 +834,7 @@ impl WgpuWinitRunning<'_> {
             .unwrap_or_default();
 
         if integration.should_close() {
-            EventResult::Exit
+            EventResult::CloseRequested
         } else if event_response.repaint {
             if repaint_asap {
                 EventResult::RepaintNow(window_id)

crates/eframe/src/native/winit_integration.rs

@@ -124,6 +124,25 @@ pub enum EventResult {
     /// Causes a save of the client state when the persistence feature is enabled.
     Save,
 
+    /// Starts the process of ending eframe execution whilst allowing for proper
+    /// clean up of resources.
+    ///
+    /// # Warning
+    /// This event **must** occur before [`Exit`] to correctly exit eframe code.
+    /// If in doubt, return this event.
+    ///
+    /// [`Exit`]: [EventResult::Exit]
+    CloseRequested,
+
+    /// The event loop will exit, now.
+    /// The correct circumstance to return this event is in response to a winit "Destroyed" event.
+    ///
+    /// # Warning
+    /// The [`CloseRequested`] **must** occur before this event to ensure that winit
+    /// is able to remove any open windows. Otherwise the window(s) will remain open
+    /// until the program terminates.
+    ///
+    /// [`CloseRequested`]: EventResult::CloseRequested
     Exit,
 }