Fixed #36060 -- Prevented IntegrityError in bulk_create() with order_with_respect_to.

django/contrib/contenttypes/fields.py

@@ -55,11 +55,15 @@ class GenericForeignKey(FieldCacheMixin, Field):
         attname, column = super().get_attname_column()
         return attname, None
 
+    @cached_property
+    def ct_field_attname(self):
+        return self.model._meta.get_field(self.ct_field).attname
+
     def get_filter_kwargs_for_object(self, obj):
         """See corresponding method on Field"""
         return {
             self.fk_field: getattr(obj, self.fk_field),
-            self.ct_field: getattr(obj, self.ct_field),
+            self.ct_field_attname: getattr(obj, self.ct_field_attname),
         }
 
     def get_forward_related_filter(self, obj):

django/db/models/query.py

@@ -5,6 +5,7 @@ The main QuerySet implementation. This provides the public API for the ORM.
 import copy
 import operator
 import warnings
+from functools import reduce
 from itertools import chain, islice
 
 from asgiref.sync import sync_to_async
@@ -20,7 +21,7 @@ from django.db import (
     router,
     transaction,
 )
-from django.db.models import AutoField, DateField, DateTimeField, Field, sql
+from django.db.models import AutoField, DateField, DateTimeField, Field, Max, sql
 from django.db.models.constants import LOOKUP_SEP, OnConflict
 from django.db.models.deletion import Collector
 from django.db.models.expressions import Case, DatabaseDefault, F, Value, When
@@ -800,6 +801,7 @@ class QuerySet(AltersData):
         objs = list(objs)
         objs_with_pk, objs_without_pk = self._prepare_for_bulk_create(objs)
         with transaction.atomic(using=self.db, savepoint=False):
+            self._handle_order_with_respect_to(objs)
             if objs_with_pk:
                 returned_columns = self._batched_insert(
                     objs_with_pk,
@@ -840,6 +842,37 @@ class QuerySet(AltersData):
 
         return objs
 
+    def _handle_order_with_respect_to(self, objs):
+        if objs and (order_wrt := self.model._meta.order_with_respect_to):
+            get_filter_kwargs_for_object = order_wrt.get_filter_kwargs_for_object
+            attnames = list(get_filter_kwargs_for_object(objs[0]))
+            group_keys = set()
+            obj_groups = []
+            for obj in objs:
+                group_key = tuple(get_filter_kwargs_for_object(obj).values())
+                group_keys.add(group_key)
+                obj_groups.append((obj, group_key))
+            filters = [
+                Q.create(list(zip(attnames, group_key))) for group_key in group_keys
+            ]
+            next_orders = (
+                self.model._base_manager.using(self.db)
+                .filter(reduce(operator.or_, filters))
+                .values_list(*attnames)
+                .annotate(_order__max=Max("_order") + 1)
+            )
+            # Create mapping of group values to max order.
+            group_next_orders = dict.fromkeys(group_keys, 0)
+            group_next_orders.update(
+                (tuple(group_key), next_order) for *group_key, next_order in next_orders
+            )
+            # Assign _order values to new objects.
+            for obj, group_key in obj_groups:
+                if getattr(obj, "_order", None) is None:
+                    group_next_order = group_next_orders[group_key]
+                    obj._order = group_next_order
+                    group_next_orders[group_key] += 1
+
     bulk_create.alters_data = True
 
     async def abulk_create(