fix(subscriptions): fix edit subscription attached to parent plan

app/services/subscriptions/update_service.rb

@@ -24,11 +24,10 @@ def call
       subscription.ending_at = params[:ending_at] if params.key?(:ending_at)
 
       if params.key?(:plan_overrides)
-        plan_result = Plans::UpdateService.call(
-          plan: subscription.plan,
-          params: params[:plan_overrides].to_h.with_indifferent_access,
-        )
+        plan_result = handle_plan_override
         return plan_result unless plan_result.success?
+
+        subscription.plan = plan_result.plan
       end
 
       if subscription.starting_in_the_future? && params.key?(:subscription_at)
@@ -61,6 +60,22 @@ def process_subscription_at_change(subscription)
       BillSubscriptionJob.perform_later([subscription], Time.current.to_i)
     end
 
+    def handle_plan_override
+      current_plan = subscription.plan
+
+      if current_plan.parent_id
+        Plans::UpdateService.call(
+          plan: current_plan,
+          params: params[:plan_overrides].to_h.with_indifferent_access,
+        )
+      else
+        Plans::OverrideService.call(
+          plan: current_plan,
+          params: params[:plan_overrides].to_h.with_indifferent_access,
+        )
+      end
+    end
+
     def valid?(args)
       Subscriptions::ValidateService.new(result, **args).valid?
     end

spec/services/subscriptions/update_service_spec.rb

@@ -109,6 +109,8 @@
     end
 
     context 'when plan_overrides' do
+      let(:plan) { create(:plan, organization: membership.organization) }
+      let(:subscription) { create(:subscription, plan:, subscription_at: Time.current - 1.year) }
       let(:params) do
         {
           plan_overrides: {
@@ -119,8 +121,23 @@
 
       around { |test| lago_premium!(&test) }
 
-      it 'updates the plan accordingly' do
-        expect { update_service.call }.to change { subscription.plan.reload.name }.to('new name')
+      it 'creates the new plan accordingly' do
+        update_service.call
+
+        expect(subscription.plan.reload.name).to eq('new name')
+        expect(subscription.plan_id).not_to eq(plan.id)
+      end
+
+      context 'with overriden plan' do
+        let(:parent_plan) { create(:plan, organization: membership.organization) }
+        let(:plan) { create(:plan, organization: membership.organization, parent_id: parent_plan.id) }
+
+        it 'updates the plan accordingly' do
+          update_service.call
+
+          expect(subscription.plan.reload.name).to eq('new name')
+          expect(subscription.plan_id).to eq(plan.id)
+        end
       end
     end