Fixed #32433 -- Added error message on QuerySet.delete() following distinct().

Author: Egidijus Macijauskas

AUTHORS

@@ -274,6 +274,7 @@ answer newbie questions, and generally made Django that much better:
     [email protected]
     Dustyn Gibson <[email protected]>
     Ed Morley <https://github.com/edmorley>
+    Egidijus Macijauskas <[email protected]>
     [email protected]
     elky <http://elky.me/>
     Emmanuelle Delescolle <https://github.com/nanuxbe>

django/db/models/query.py

@@ -724,6 +724,8 @@ def delete(self):
         assert not self.query.is_sliced, \
             "Cannot use 'limit' or 'offset' with delete."
 
+        if self.query.distinct or self.query.distinct_fields:
+            raise TypeError('Cannot call delete() after .distinct().')
         if self._fields is not None:
             raise TypeError("Cannot call delete() after .values() or .values_list()")
 

tests/delete_regress/tests.py

@@ -1,7 +1,9 @@
 import datetime
 
 from django.db import connection, models, transaction
-from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature
+from django.test import (
+    SimpleTestCase, TestCase, TransactionTestCase, skipUnlessDBFeature,
+)
 
 from .models import (
     Award, AwardNote, Book, Child, Contact, Eaten, Email, File, Food, FooFile,
@@ -352,3 +354,12 @@ def test_foreign_key_delete_nullifies_correct_columns(self):
         self.assertEqual(researcher1.secondary_contact, contact2)
         self.assertEqual(researcher2.primary_contact, contact2)
         self.assertIsNone(researcher2.secondary_contact)
+
+
+class DeleteDistinct(SimpleTestCase):
+    def test_disallowed_delete_distinct(self):
+        msg = 'Cannot call delete() after .distinct().'
+        with self.assertRaisesMessage(TypeError, msg):
+            Book.objects.distinct().delete()
+        with self.assertRaisesMessage(TypeError, msg):
+            Book.objects.distinct('id').delete()