Fix missing crash dialog for panics thrown inside requestAnimationFrame loop

frontend/wasm/src/editor_api.rs

@@ -5,7 +5,7 @@
 // on the dispatcher messaging system and more complex Rust data types.
 //
 use crate::helpers::translate_key;
-use crate::{EDITOR_HANDLE, EDITOR_HAS_CRASHED, Error, MESSAGE_BUFFER};
+use crate::{EDITOR_HANDLE, EDITOR_HAS_CRASHED, Error, MESSAGE_BUFFER, PANIC_DIALOG_MESSAGE_CALLBACK};
 use editor::consts::FILE_EXTENSION;
 use editor::messages::clipboard::utility_types::ClipboardContentRaw;
 use editor::messages::input_mapper::utility_types::input_keyboard::ModifierKeys;
@@ -78,6 +78,16 @@ impl EditorHandle {
 	pub fn send_frontend_message_to_js_rust_proxy(&self, message: FrontendMessage) {
 		self.send_frontend_message_to_js(message);
 	}
+
+	fn initialize_handle(frontend_message_handler_callback: js_sys::Function) -> EditorHandle {
+		let panic_callback = frontend_message_handler_callback.clone();
+		let editor_handle = EditorHandle { frontend_message_handler_callback };
+		if EDITOR_HANDLE.with(|handle| handle.lock().ok().map(|mut guard| *guard = Some(editor_handle.clone()))).is_none() {
+			log::error!("Attempted to initialize the editor handle more than once");
+		}
+		PANIC_DIALOG_MESSAGE_CALLBACK.with_borrow_mut(|callback| *callback = Some(panic_callback));
+		editor_handle
+	}
 }
 
 #[wasm_bindgen]
@@ -97,23 +107,16 @@ impl EditorHandle {
 			uuid_random_seed,
 		);
 
-		let editor_handle = EditorHandle { frontend_message_handler_callback };
 		if EDITOR.with(|handle| handle.lock().ok().map(|mut guard| *guard = Some(editor))).is_none() {
 			log::error!("Attempted to initialize the editor more than once");
 		}
-		if EDITOR_HANDLE.with(|handle| handle.lock().ok().map(|mut guard| *guard = Some(editor_handle.clone()))).is_none() {
-			log::error!("Attempted to initialize the editor handle more than once");
-		}
-		editor_handle
+
+		Self::initialize_handle(frontend_message_handler_callback)
 	}
 
 	#[cfg(feature = "native")]
 	pub fn create(_platform: String, _uuid_random_seed: u64, frontend_message_handler_callback: js_sys::Function) -> EditorHandle {
-		let editor_handle = EditorHandle { frontend_message_handler_callback };
-		if EDITOR_HANDLE.with(|handle| handle.lock().ok().map(|mut guard| *guard = Some(editor_handle.clone()))).is_none() {
-			log::error!("Attempted to initialize the editor handle more than once");
-		}
-		editor_handle
+		Self::initialize_handle(frontend_message_handler_callback)
 	}
 
 	// Sends a message to the dispatcher in the Editor Backend

frontend/wasm/src/lib.rs

@@ -24,6 +24,7 @@ thread_local! {
 	pub static EDITOR: Mutex<Option<editor::application::Editor>> = const { Mutex::new(None) };
 	pub static MESSAGE_BUFFER: std::cell::RefCell<Vec<Message>> = const { std::cell::RefCell::new(Vec::new()) };
 	pub static EDITOR_HANDLE: Mutex<Option<editor_api::EditorHandle>> = const { Mutex::new(None) };
+	pub static PANIC_DIALOG_MESSAGE_CALLBACK: std::cell::RefCell<Option<js_sys::Function>> = const { std::cell::RefCell::new(None) };
 }
 
 /// Initialize the backend
@@ -72,12 +73,80 @@ pub fn panic_hook(info: &panic::PanicHookInfo) {
 
 	log::error!("{info}");
 
+	// Prefer using the raw JS callback to avoid mutex lock contention inside the panic hook.
+	// Fall back to the editor handle path if needed.
+	if let Err(info) = send_panic_dialog_via_callback(info) {
+		if let Err(info) = send_panic_dialog(info) {
+			send_panic_dialog_deferred(info);
+		}
+	}
+}
+
+fn send_panic_dialog_via_callback(panic_info: String) -> Result<(), String> {
+	let message = FrontendMessage::DisplayDialogPanic { panic_info };
+	let message_type = message.to_discriminant().local_name();
+	let Ok(message_data) = serde_wasm_bindgen::to_value(&message) else {
+		log::error!("Failed to serialize crash dialog panic message");
+		let FrontendMessage::DisplayDialogPanic { panic_info } = message else {
+			unreachable!("Message variant changed unexpectedly")
+		};
+		return Err(panic_info);
+	};
+
+	PANIC_DIALOG_MESSAGE_CALLBACK.with(|callback| {
+		let callback_ref = callback.borrow();
+		let Some(callback) = callback_ref.as_ref() else {
+			let FrontendMessage::DisplayDialogPanic { panic_info } = message else {
+				unreachable!("Message variant changed unexpectedly")
+			};
+			return Err(panic_info);
+		};
+
+		if let Err(error) = callback.call2(&JsValue::null(), &JsValue::from(message_type), &message_data) {
+			log::error!("Failed to send crash dialog panic message to JS: {:?}", error);
+			let FrontendMessage::DisplayDialogPanic { panic_info } = message else {
+				unreachable!("Message variant changed unexpectedly")
+			};
+			return Err(panic_info);
+		}
+
+		Ok(())
+	})
+}
+
+fn send_panic_dialog(panic_info: String) -> Result<(), String> {
 	EDITOR_HANDLE.with(|editor_handle| {
-		let mut guard = editor_handle.lock();
-		if let Ok(Some(handle)) = guard.as_deref_mut() {
-			handle.send_frontend_message_to_js_rust_proxy(FrontendMessage::DisplayDialogPanic { panic_info: info.to_string() });
+		let mut guard = editor_handle.try_lock();
+		let Ok(Some(handle)) = guard.as_deref_mut() else {
+			return Err(panic_info);
+		};
+
+		handle.send_frontend_message_to_js_rust_proxy(FrontendMessage::DisplayDialogPanic { panic_info });
+		Ok(())
+	})
+}
+
+#[cfg(not(feature = "native"))]
+fn send_panic_dialog_deferred(panic_info: String) {
+	let callback = Closure::once_into_js(move || {
+		if send_panic_dialog(panic_info).is_err() {
+			log::error!("Failed to send crash dialog after panic because the editor handle is unavailable");
 		}
 	});
+
+	let Some(window) = web_sys::window() else {
+		log::error!("Failed to schedule crash dialog after panic because no window exists");
+		return;
+	};
+
+	if window.set_timeout_with_callback_and_timeout_and_arguments_0(callback.unchecked_ref(), 0).is_err() {
+		log::error!("Failed to schedule crash dialog after panic with setTimeout");
+	}
+}
+
+#[cfg(feature = "native")]
+fn send_panic_dialog_deferred(_panic_info: String) {
+	// Native builds do not use `setTimeout`, so just log the failure in the caller's context.
 }
 
 #[wasm_bindgen]