feat: Flush notebook to disk on restart

frontend/src/components/editor/actions/useRestartKernel.tsx

@@ -5,23 +5,31 @@ import { useImperativeModal } from "@/components/modal/ImperativeModal";
 import { AlertDialogDestructiveAction } from "@/components/ui/alert-dialog";
 import { connectionAtom } from "@/core/network/connection";
 import { useRequestClient } from "@/core/network/requests";
+import { useSaveNotebook } from "@/core/saving/save-component";
 import { WebSocketState } from "@/core/websocket/types";
+import { Logger } from "@/utils/Logger";
 import { reloadSafe } from "@/utils/reload-safe";
 
 export function useRestartKernel() {
   const { openConfirm } = useImperativeModal();
   const setConnection = useSetAtom(connectionAtom);
   const { sendRestart } = useRequestClient();
+  const { saveIfNotebookIsPersistent } = useSaveNotebook();
 
   return () => {
     openConfirm({
       title: "Restart Kernel",
       description:
-        "This will restart the Python kernel. You'll lose all data that's in memory. You will also lose any unsaved changes, so make sure to save your work before restarting.",
+        "This will restart the Python kernel. You'll lose all data that's in memory. Unsaved code changes are saved automatically before restarting.",
       variant: "destructive",
       confirmAction: (
         <AlertDialogDestructiveAction
           onClick={async () => {
+            try {
+              await saveIfNotebookIsPersistent();
+            } catch (error) {
+              Logger.warn("restart: pre-restart save failed", error);
+            }
             setConnection({ state: WebSocketState.CLOSING });
             await sendRestart();
             reloadSafe();

frontend/src/core/saving/save-component.tsx

@@ -160,7 +160,7 @@ export function useSaveNotebook() {
       isNamedPersistentFile(filename) &&
       connection.state === WebSocketState.OPEN
     ) {
-      saveNotebook(filename, userInitiated);
+      return saveNotebook(filename, userInitiated);
     }
   });