Don't mark orders as pending unnecessarily

src/pretix/api/views/order.py

@@ -627,7 +627,7 @@ class RefundViewSet(CreateModelMixin, viewsets.ReadOnlyModelViewSet):
         if request.data.get('mark_refunded', False):
             mark_order_refunded(refund.order, user=self.request.user if self.request.user.is_authenticated else None,
                                 auth=self.request.auth)
-        else:
+        elif not (refund.order.status == Order.STATUS_PAID and refund.order.pending_sum <= 0):
             refund.order.status = Order.STATUS_PENDING
             refund.order.set_expires(
                 now(),

src/pretix/control/views/orders.py

@@ -464,7 +464,7 @@ class OrderRefundProcess(OrderView):
 
             if self.request.POST.get("action") == "r":
                 mark_order_refunded(self.order, user=self.request.user)
-            else:
+            elif not (self.order.status == Order.STATUS_PAID and self.order.pending_sum <= 0):
                 self.order.status = Order.STATUS_PENDING
                 self.order.set_expires(
                     now(),
@@ -750,13 +750,14 @@ class OrderRefundView(OrderView):
                         if self.start_form.cleaned_data.get('action') == 'mark_refunded':
                             mark_order_refunded(self.order, user=self.request.user)
                         elif self.start_form.cleaned_data.get('action') == 'mark_pending':
-                            self.order.status = Order.STATUS_PENDING
-                            self.order.set_expires(
-                                now(),
-                                self.order.event.subevents.filter(
-                                    id__in=self.order.positions.values_list('subevent_id', flat=True))
-                            )
-                            self.order.save(update_fields=['status', 'expires'])
+                            if not (self.order.status == Order.STATUS_PAID and self.order.pending_sum <= 0):
+                                self.order.status = Order.STATUS_PENDING
+                                self.order.set_expires(
+                                    now(),
+                                    self.order.event.subevents.filter(
+                                        id__in=self.order.positions.values_list('subevent_id', flat=True))
+                                )
+                                self.order.save(update_fields=['status', 'expires'])
 
                     return redirect(self.get_order_url())
                 else:

src/tests/control/test_orders.py

@@ -1078,6 +1078,33 @@ def test_process_refund(client, env):
     assert env[2].status == Order.STATUS_PENDING
 
 
+@pytest.mark.django_db
+def test_process_refund_overpaid_externally(client, env):
+    env[2].payments.first().confirm()
+    env[2].payments.create(
+        state='confirmed',
+        provider='stripe',
+        amount=Decimal('14.00'),
+        payment_date=now()
+    )
+    assert env[2].pending_sum == -14
+    r = env[2].refunds.create(
+        provider='stripe',
+        state='external',
+        source='external',
+        amount=Decimal('14.00'),
+        execution_date=now(),
+    )
+    client.login(email='dummy@dummy.dummy', password='dummy')
+    response = client.post('/control/event/dummy/dummy/orders/FOO/refunds/{}/process'.format(r.pk), {}, follow=True)
+    assert 'alert-success' in response.rendered_content
+    r.refresh_from_db()
+    assert r.state == OrderRefund.REFUND_STATE_DONE
+    env[2].refresh_from_db()
+    assert env[2].status == Order.STATUS_PAID
+    assert env[2].pending_sum == 0
+
+
 @pytest.mark.django_db
 def test_process_refund_invalid_state(client, env):
     r = env[2].refunds.create(