Fixes #10408: Fix validation when attempting to add redundant contact assignments

netbox/templates/tenancy/contactassignment_edit.html

@@ -3,6 +3,9 @@
 {% load form_helpers %}
 
 {% block form %}
+  {% for field in form.hidden_fields %}
+    {{ field }}
+  {% endfor %}
   <div class="field-group my-5">
     <div class="row mb-2">
       <h5 class="offset-sm-3">Contact Assignment</h5>

netbox/tenancy/forms/models.py

@@ -119,8 +119,10 @@ class ContactAssignmentForm(BootstrapMixin, forms.ModelForm):
     class Meta:
         model = ContactAssignment
         fields = (
-            'group', 'contact', 'role', 'priority',
+            'content_type', 'object_id', 'group', 'contact', 'role', 'priority',
         )
         widgets = {
+            'content_type': forms.HiddenInput(),
+            'object_id': forms.HiddenInput(),
             'priority': StaticSelect(),
         }