From 8d5668151c3efbb757c4421a9fe35e2c35cbd992 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Mon, 1 Jun 2026 02:37:38 +0200
Subject: fix(engine): stop if windowing app thread panics

---
 engine/src/windowing.rs | 69 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 50 insertions(+), 19 deletions(-)

diff --git a/engine/src/windowing.rs b/engine/src/windowing.rs
index a0201db..bf29453 100644
--- a/engine/src/windowing.rs
+++ b/engine/src/windowing.rs
@@ -1,6 +1,7 @@
 use std::borrow::Cow;
 use std::env::consts::EXE_SUFFIX;
 use std::hint::cold_path;
+use std::panic::catch_unwind;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Weak};
 use std::thread::Builder as ThreadBuilder;
@@ -184,6 +185,7 @@ fn update_stuff(
         ref message_from_app_queue,
         ref mut display_handle,
         ref mut windows,
+        ref thread_panicked,
         ..
     } = *context;
 
@@ -288,6 +290,11 @@ fn update_stuff(
             }
         }
     }
+
+    if thread_panicked.load(Ordering::Relaxed) {
+        cold_path();
+        actions.stop();
+    }
 }
 
 fn handle_window_changed(
@@ -344,6 +351,7 @@ pub struct Context
     message_from_app_queue: Arc<ArrayQueue<MessageFromApp>>,
     message_to_app_queue: Arc<ArrayQueue<MessageToApp>>,
     shared_state: Arc<SharedState>,
+    thread_panicked: Arc<AtomicBool>,
     display_handle: Option<OwnedDisplayHandle>,
     windows: MapVec<WindowId, (Arc<winit::window::Window>, Uid)>,
 }
@@ -420,28 +428,22 @@ impl Context
         let shared_state = Arc::new(SharedState::default());
         let shared_state_b = shared_state.clone();
 
+        let thread_panicked = Arc::new(AtomicBool::new(false));
+        let thread_panicked_b = thread_panicked.clone();
+
         ThreadBuilder::new()
             .name("windowing app".to_string())
             .spawn(move || {
-                let mut app = App {
-                    message_from_app_queue: message_from_app_queue_b,
-                    message_to_app_queue: message_to_app_queue_b,
-                    shared_state: shared_state_b,
-                    windows: MapVec::default(),
-                };
-
-                let event_loop = match create_event_loop() {
-                    Ok(event_loop) => event_loop,
-                    Err(err) => {
-                        tracing::error!("Failed to create event loop: {err}");
-                        return;
-                    }
-                };
-
-                event_loop.set_control_flow(EventLoopControlFlow::Poll);
-
-                if let Err(err) = event_loop.run_app(&mut app) {
-                    tracing::error!("Event loop error occurred: {err}");
+                if catch_unwind(move || {
+                    start_app(
+                        message_from_app_queue_b,
+                        message_to_app_queue_b,
+                        shared_state_b,
+                    );
+                })
+                .is_err()
+                {
+                    thread_panicked_b.store(true, Ordering::Relaxed);
                 }
             })
             .expect("Failed to create windowing thread");
@@ -450,6 +452,7 @@ impl Context
             message_from_app_queue,
             message_to_app_queue,
             shared_state,
+            thread_panicked,
             display_handle: None,
             windows: MapVec::default(),
         }
@@ -464,6 +467,34 @@ impl Drop for Context
     }
 }
 
+fn start_app(
+    message_from_app_queue_b: Arc<ArrayQueue<MessageFromApp>>,
+    message_to_app_queue_b: Arc<ArrayQueue<MessageToApp>>,
+    shared_state_b: Arc<SharedState>,
+)
+{
+    let mut app = App {
+        message_from_app_queue: message_from_app_queue_b,
+        message_to_app_queue: message_to_app_queue_b,
+        shared_state: shared_state_b,
+        windows: MapVec::default(),
+    };
+
+    let event_loop = match create_event_loop() {
+        Ok(event_loop) => event_loop,
+        Err(err) => {
+            tracing::error!("Failed to create event loop: {err}");
+            return;
+        }
+    };
+
+    event_loop.set_control_flow(EventLoopControlFlow::Poll);
+
+    if let Err(err) = event_loop.run_app(&mut app) {
+        tracing::error!("Event loop error occurred: {err}");
+    }
+}
+
 fn create_event_loop() -> Result<EventLoop<()>, EventLoopError>
 {
     let mut event_loop_builder = EventLoop::builder();
-- 
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