Fix solution upload

apps/participation/views.py

@@ -564,6 +564,7 @@ class SolutionUploadView(LoginRequiredMixin, FormView):
             return self.handle_no_permission()
         return super().dispatch(request, *args, **kwargs)
 
+    @transaction.atomic
     def form_valid(self, form):
         """
         When a solution is submitted, it replaces a previous solution if existing,
@@ -586,7 +587,7 @@ class SolutionUploadView(LoginRequiredMixin, FormView):
             sol.save()
             sol.delete()
         form_sol.participation = self.participation
-        form_sol.final = self.participation.final
+        form_sol.final_solution = self.participation.final
         form_sol.save()
         return super().form_valid(form)