From 899f92f53a0bf6ccce8b06b161dee690b7bf93d9 Mon Sep 17 00:00:00 2001
From: blag <blag@users.noreply.github.com>
Date: Sun, 24 May 2020 15:58:44 -0700
Subject: [PATCH] Return an HTTP 400 if the queryset size has changed since the
 page was loaded

---
 adminsortable/admin.py | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/adminsortable/admin.py b/adminsortable/admin.py
index cd855c1..50ef603 100644
--- a/adminsortable/admin.py
+++ b/adminsortable/admin.py
@@ -314,6 +314,15 @@ class SortableAdmin(SortableAdminBase, ModelAdmin):
 
                 objects_dict = {str(obj.pk): obj for obj in qs}
                 objects_list = list(objects_dict.keys())
+                if len(indexes) != len(objects_dict):
+                    return HttpResponseBadRequest(
+                        json.dumps({
+                            'objects_sorted': False,
+                            'reason': _("An object has been added or removed "
+                                        "since the last load. Please refresh "
+                                        "the page and try reordering again."),
+                        }, ensure_ascii=False),
+                        content_type='application/json')
                 order_field_name = klass._meta.ordering[0]
 
                 if order_field_name.startswith('-'):