Emergency dump rules on failure

src/beanify/gui/mainwindow.py

@@ -219,9 +219,17 @@ class MainWindow(ThemedTk):
         self.rebuild_account_cache()
 
     def do_save_rules(self):
-        self.ruleset.save_rules()
-        self.update_status("Rules saved!")
-        # TODO: Feedback and confirmation
+        try:
+            self.ruleset.save_rules()
+            self.update_status("Rules saved!")
+            # TODO: Feedback and confirmation
+        except Exception:
+            # Emergency dump
+            import pickle
+
+            with open("ruleset-crashdump.pickle", "wb") as f:
+                pickle.dump(self.ruleset.rules, f)
+
         # TODO Raw dump if we can't save for some reason
 
     def do_export_txn(self):