Fixed #32095 -- Made QuerySet.update_or_create() save only fields passed in defaults or with custom pre_save().

Thanks Florian Apolloner for the initial patch.

django/db/models/query.py

@@ -20,7 +20,7 @@ from django.db import (
     router,
     transaction,
 )
-from django.db.models import AutoField, DateField, DateTimeField, sql
+from django.db.models import AutoField, DateField, DateTimeField, Field, sql
 from django.db.models.constants import LOOKUP_SEP, OnConflict
 from django.db.models.deletion import Collector
 from django.db.models.expressions import Case, F, Ref, Value, When
@@ -963,7 +963,25 @@ class QuerySet:
                 return obj, created
             for k, v in resolve_callables(defaults):
                 setattr(obj, k, v)
-            obj.save(using=self.db)
+
+            update_fields = set(defaults)
+            concrete_field_names = self.model._meta._non_pk_concrete_field_names
+            # update_fields does not support non-concrete fields.
+            if concrete_field_names.issuperset(update_fields):
+                # Add fields which are set on pre_save(), e.g. auto_now fields.
+                # This is to maintain backward compatibility as these fields
+                # are not updated unless explicitly specified in the
+                # update_fields list.
+                for field in self.model._meta.local_concrete_fields:
+                    if not (
+                        field.primary_key or field.__class__.pre_save is Field.pre_save
+                    ):
+                        update_fields.add(field.name)
+                        if field.name != field.attname:
+                            update_fields.add(field.attname)
+                obj.save(using=self.db, update_fields=update_fields)
+            else:
+                obj.save(using=self.db)
         return obj, False
 
     async def aupdate_or_create(self, defaults=None, **kwargs):

tests/get_or_create/models.py

@@ -63,3 +63,4 @@ class Book(models.Model):
         related_name="books",
         db_column="publisher_id_column",
     )
+    updated = models.DateTimeField(auto_now=True)

tests/get_or_create/tests.py

@@ -6,6 +6,7 @@ from threading import Thread
 from django.core.exceptions import FieldError
 from django.db import DatabaseError, IntegrityError, connection
 from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature
+from django.test.utils import CaptureQueriesContext
 from django.utils.functional import lazy
 
 from .models import (
@@ -513,6 +514,31 @@ class UpdateOrCreateTests(TestCase):
         self.assertIs(created, False)
         self.assertEqual(journalist.name, "John")
 
+    def test_update_only_defaults_and_pre_save_fields_when_local_fields(self):
+        publisher = Publisher.objects.create(name="Acme Publishing")
+        book = Book.objects.create(publisher=publisher, name="The Book of Ed & Fred")
+
+        for defaults in [{"publisher": publisher}, {"publisher_id": publisher}]:
+            with self.subTest(defaults=defaults):
+                with CaptureQueriesContext(connection) as captured_queries:
+                    book, created = Book.objects.update_or_create(
+                        pk=book.pk,
+                        defaults=defaults,
+                    )
+                self.assertIs(created, False)
+                update_sqls = [
+                    q["sql"] for q in captured_queries if q["sql"].startswith("UPDATE")
+                ]
+                self.assertEqual(len(update_sqls), 1)
+                update_sql = update_sqls[0]
+                self.assertIsNotNone(update_sql)
+                self.assertIn(
+                    connection.ops.quote_name("publisher_id_column"), update_sql
+                )
+                self.assertIn(connection.ops.quote_name("updated"), update_sql)
+                # Name should not be updated.
+                self.assertNotIn(connection.ops.quote_name("name"), update_sql)
+
 
 class UpdateOrCreateTestsWithManualPKs(TestCase):
     def test_create_with_duplicate_primary_key(self):