Ticket #15884: ticket_15884-patch_1.diff

django/core/management/validation.py

@@ -40 +40 @@
                 e.add(opts, '"%s": You can\'t use "id" as a field name, because each model automatically gets an "id" field if none of the fields have primary_key=True. You need to either remove/rename your "id" field or add primary_key=True to a field.' % f.name)
             if f.name.endswith('_'):
                 e.add(opts, '"%s": Field names cannot end with underscores, because this would lead to ambiguous queryset filters.' % f.name)
+            if f.primary_key and f.null:
+                e.add(opts, '"%s: Primary key fields do not accept null values.' % f.name)
             if isinstance(f, models.CharField):
                 try:
                     max_length = int(f.max_length)