[pull] main from django:main

AUTHORS

@@ -683,6 +683,7 @@ answer newbie questions, and generally made Django that much better:
     Marc Seguí Coll <metarizard@gmail.com>
     Marc Tamlyn <marc.tamlyn@gmail.com>
     Marc-Aurèle Brothier <ma.brothier@gmail.com>
+    Margaret Fero <maggiefero@gmail.com>
     Marian Andre <django@andre.sk>
     Marijke Luttekes <mail@marijkeluttekes.dev>
     Marijn Vriens <marijn@metronomo.cl>

README.rst

@@ -24,8 +24,10 @@ here's how we recommend you read the docs:
 * See ``docs/README`` for instructions on building an HTML version of the docs.
 
 Docs are updated rigorously. If you find any problems in the docs, or think
-they should be clarified in any way, please take 30 seconds to fill out a
-ticket here: https://code.djangoproject.com/newticket
+they should be clarified in any way, please take 30 seconds to
+`fill out a ticket <https://code.djangoproject.com/newticket>`_. You can log in
+with your GitHub account, or with a DjangoProject account if you have one. Once
+you log in, a New Ticket button is available next to View Tickets.
 
 To get more help:
 

django/db/models/query.py

@@ -37,7 +37,7 @@
     resolve_callables,
 )
 from django.utils import timezone
-from django.utils.deprecation import RemovedInDjango70Warning
+from django.utils.deprecation import RemovedInDjango70Warning, RemovedInDjango71Warning
 from django.utils.functional import cached_property
 from django.utils.warnings import django_file_prefixes
 
@@ -577,18 +577,36 @@ def iterator(self, chunk_size=None):
         )
         return self._iterator(use_chunked_fetch, chunk_size)
 
-    async def aiterator(self, chunk_size=2000):
+    async def aiterator(self, chunk_size=None):
         """
         An asynchronous iterator over the results from applying this QuerySet
         to the database.
         """
-        if chunk_size <= 0:
+        if chunk_size is None:
+            if self._prefetch_related_lookups:
+                # RemovedInDjango71Warning: Replace the warning with:
+                # raise ValueError(
+                #     "chunk_size must be provided when using "
+                #     "QuerySet.aiterator() after prefetch_related()."
+                # )
+                warnings.warn(
+                    "Using QuerySet.aiterator() after prefetch_related() without "
+                    "providing a chunk_size is deprecated and will raise a "
+                    "ValueError in Django 7.1.",
+                    category=RemovedInDjango71Warning,
+                    skip_file_prefixes=django_file_prefixes(),
+                )
+                # RemovedInDjango71Warning: When the deprecation ends, remove.
+                chunk_size = 2000
+        elif chunk_size <= 0:
             raise ValueError("Chunk size must be strictly positive.")
         use_chunked_fetch = not connections[self.db].settings_dict.get(
             "DISABLE_SERVER_SIDE_CURSORS"
         )
         iterable = self._iterable_class(
-            self, chunked_fetch=use_chunked_fetch, chunk_size=chunk_size
+            self,
+            chunked_fetch=use_chunked_fetch,
+            chunk_size=chunk_size or 2000,
         )
         if self._prefetch_related_lookups:
             results = []

docs/internals/deprecation.txt

@@ -17,6 +17,9 @@ details on these changes.
 
 * The ``safe`` parameter of :class:`~django.http.JsonResponse` will be removed.
 
+* Calling ``QuerySet.aiterator()`` after ``prefetch_related()`` without
+  providing a ``chunk_size`` will raise :exc:`ValueError`.
+
 .. _deprecation-removed-in-7.0:
 
 7.0

docs/releases/6.2.txt

@@ -278,3 +278,8 @@ Miscellaneous
 
 * The ``safe`` parameter is deprecated from :class:`~django.http.JsonResponse`.
   Omitting the argument is equivalent to the prior ``safe=False`` usage.
+
+* Calling :meth:`.QuerySet.aiterator` after ``prefetch_related()`` without
+  providing a ``chunk_size`` is deprecated. It currently falls back to a
+  ``chunk_size`` of 2000, but a ``ValueError`` will be raised in
+  Django 7.1.

tests/async/test_async_queryset.py

@@ -7,6 +7,7 @@
 from django.db import NotSupportedError, connection
 from django.db.models import Prefetch, Sum
 from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature
+from django.utils.deprecation import RemovedInDjango71Warning
 
 from .models import RelatedModel, SimpleModel
 
@@ -54,10 +55,31 @@ async def test_aiterator_prefetch_related(self):
         results = []
         async for s in SimpleModel.objects.prefetch_related(
             Prefetch("relatedmodel_set", to_attr="prefetched_relatedmodel")
-        ).aiterator():
+        ).aiterator(chunk_size=2000):
             results.append(s.prefetched_relatedmodel)
         self.assertCountEqual(results, [[self.r1], [self.r2], [self.r3]])
 
+    async def test_aiterator_prefetch_related_chunk_size_none(self):
+        msg = (
+            "Using QuerySet.aiterator() after prefetch_related() without "
+            "providing a chunk_size is deprecated"
+        )
+        qs = SimpleModel.objects.prefetch_related("relatedmodel_set").aiterator()
+
+        # RemovedInDjango71Warning: When the deprecation ends, replace with:
+        # with self.assertRaisesMessage(
+        #     ValueError,
+        #     "chunk_size must be provided when using QuerySet.aiterator() "
+        #     "after prefetch_related().",
+        # ):
+        #     async for _ in qs:
+        #         pass
+        results = []
+        with self.assertWarnsMessage(RemovedInDjango71Warning, msg):
+            async for s in qs:
+                results.append(s)
+        self.assertCountEqual(results, [self.s1, self.s2, self.s3])
+
     async def test_aiterator_invalid_chunk_size(self):
         msg = "Chunk size must be strictly positive."
         for size in [0, -1]:

tests/field_defaults/tests.py

@@ -98,6 +98,17 @@ def test_both_default(self):
         obj2 = DBDefaults.objects.create()
         self.assertEqual(obj2.both, 1)
 
+    def test_db_default_blind_overwrite(self):
+        """
+        Perform a blind overwrite: instantiate an object with a known pk
+        without fetching it, and overwrite some values. The db_default is used.
+        """
+        obj1 = DBDefaults.objects.create(null=1.2)
+        unfetched_instance = DBDefaults(pk=obj1.pk)
+        unfetched_instance.save()
+        obj1.refresh_from_db()
+        self.assertEqual(obj1.null, 1.1)
+
     def test_pk_db_default(self):
         obj1 = DBDefaultsPK.objects.create()
         if not connection.features.can_return_columns_from_insert: