updated child validation for ListSerializer

Author: p-r-a-v-i-n

rest_framework/serializers.py

@@ -652,6 +652,14 @@ def run_child_validation(self, data):
         self.child.initial_data = data
         return super().run_child_validation(data)
         """
+        instance = None
+        if self.instance is not None:
+            instance_map = {getattr(obj, 'pk', None): obj for obj in self.instance}
+            obj_id = data.get('pk') if isinstance(data, dict) else None
+            instance = instance_map.get(obj_id)
+
+        self.child.instance = instance
+        self.child.initial_data = data
         return self.child.run_validation(data)
 
     def to_internal_value(self, data):

tests/models.py

@@ -150,3 +150,8 @@ def __new__(cls, *args, **kwargs):
                                    help_text='OneToOneTarget',
                                    verbose_name='OneToOneTarget',
                                    on_delete=models.CASCADE)
+
+
+class TestListModel(models.Model):
+    name = models.CharField(max_length=50)
+    value = models.IntegerField()

tests/test_serializer_lists.py

@@ -5,7 +5,7 @@
 from rest_framework import serializers
 from rest_framework.exceptions import ErrorDetail
 from tests.models import (
-    CustomManagerModel, NullableOneToOneSource, OneToOneTarget
+    CustomManagerModel, NullableOneToOneSource, OneToOneTarget, TestListModel
 )
 
 
@@ -775,3 +775,47 @@ def test(self):
         queryset = NullableOneToOneSource.objects.all()
         serializer = self.serializer(queryset, many=True)
         assert serializer.data
+
+
+class TestManyTrueValidationCheck:
+    """
+    Tests ListSerializer validation with many=True for both valid and invalid model data.
+    """
+
+    @pytest.mark.django_db
+    def test_run_child_validation_with_many_true(self):
+        obj1 = TestListModel.objects.create(name="A", value=1)
+        obj2 = TestListModel.objects.create(name="B", value=2)
+
+        class TestListModelSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = TestListModel
+                fields = ["id", "name", "value"]
+
+        input_data = [
+            {"id": obj1.id, "name": "Updated A", "value": 10},
+            {"id": obj2.id, "name": "Updated B", "value": 20},
+        ]
+
+        serializer = TestListModelSerializer([obj1, obj2], data=input_data, many=True)
+        assert serializer.is_valid(), serializer.errors
+
+        serializer = TestListModelSerializer(TestListModel.objects.all(), data=input_data, many=True)
+        assert serializer.is_valid(), serializer.errors
+
+    @pytest.mark.django_db
+    def test_validation_error_for_invalid_data(self):
+        obj = TestListModel.objects.create(name="C", value=5)
+
+        class TestListModelSerializer(serializers.ModelSerializer):
+            class Meta:
+                model = TestListModel
+                fields = ["id", "name", "value"]
+
+        input_data = [
+            {"id": obj.pk, "name": "", "value": -1},
+        ]
+
+        serializer = TestListModelSerializer([obj], data=input_data, many=True)
+        assert not serializer.is_valid()
+        assert "name" in serializer.errors[0]