[Merged by Bors] - TaskPool Panic Handling

crates/bevy_ecs/src/system/system_piping.rs

@@ -202,7 +202,7 @@ pub mod adapter {
     /// // Building a new schedule/app...
     /// # use bevy_ecs::schedule::SystemStage;
     /// # let mut sched = Schedule::default(); sched
-    /// #     .add_stage(CoreStage::Update, SystemStage::single_threaded())
+    /// #     .add_stage(CoreStage::Update, SystemStage::parallel())
     ///     .add_system_to_stage(
     ///         CoreStage::Update,
     ///         // Panic if the load system returns an error.
@@ -246,7 +246,7 @@ pub mod adapter {
     /// // Building a new schedule/app...
     /// # use bevy_ecs::schedule::SystemStage;
     /// # let mut sched = Schedule::default(); sched
-    /// #     .add_stage(CoreStage::Update, SystemStage::single_threaded())
+    /// #     .add_stage(CoreStage::Update, SystemStage::parallel())
     ///     .add_system_to_stage(
     ///         CoreStage::Update,
     ///         // If the system fails, just move on and try again next frame.

crates/bevy_tasks/src/task_pool.rs

@@ -118,14 +118,21 @@ impl TaskPool {
                 thread_builder
                     .spawn(move || {
                         TaskPool::LOCAL_EXECUTOR.with(|local_executor| {
-                            let tick_forever = async move {
-                                loop {
-                                    local_executor.tick().await;
+                            loop {
+                                let res = std::panic::catch_unwind(|| {
+                                    let tick_forever = async move {
+                                        loop {
+                                            local_executor.tick().await;
+                                        }
+                                    };
+                                    future::block_on(ex.run(tick_forever.or(shutdown_rx.recv())))
+                                });
+                                if let Ok(value) = res {
+                                    // Use unwrap_err because we expect a Closed error
+                                    value.unwrap_err();
+                                    break;
                                 }
-                            };
-                            let shutdown_future = ex.run(tick_forever.or(shutdown_rx.recv()));
-                            // Use unwrap_err because we expect a Closed error
-                            future::block_on(shutdown_future).unwrap_err();
+                            }
                         });
                     })
                     .expect("Failed to spawn thread.")

crates/bevy_time/src/time.rs

@@ -120,7 +120,7 @@ impl Time {
     ///     world.insert_resource(time);
     ///     world.insert_resource(Health { health_value: 0.2 });
     ///
-    ///     let mut update_stage = SystemStage::single_threaded();
+    ///     let mut update_stage = SystemStage::parallel();
     ///     update_stage.add_system(health_system);
     ///
     ///     // Simulate that 30 ms have passed

crates/bevy_transform/src/systems.rs

@@ -318,8 +318,8 @@ mod test {
         let mut temp = World::new();
         let mut app = App::new();
 
-        // Adding the system in a single threaded stage. As the system will panic, this will
-        // only bring down the current test thread.
+        // FIXME: Parallel executors seem to have some odd interaction with the other
+        // tests in this crate. Using single_threaded until a root cause can be found.
         app.add_stage("single", SystemStage::single_threaded())
             .add_system_to_stage("single", transform_propagate_system);