Fixed #36086 -- Fixed crash when using GeneratedField with non-AutoField pk.

The previous logic was systematically attempting to retrieve last_insert_id
even for models without an AutoField primary key when they had a GeneratedField
on backends that can't return columns from INSERT.

The issue affected MySQL, SQLite < 3.35, and Oracle when the use_returning_into
option was disabled and could result in either crashes when the non-auto
primary key wasn't an IntegerField subclass or silent misassignment of bogus
insert ids (0 or the previous auto primary key insert value) to the first
defined generated field value.

2 files changed, 20 insertions, 0 deletions

diff --git a/tests/model_fields/models.py b/tests/model_fields/models.py
index 599efafe7e..fdea06b23d 100644
--- a/tests/model_fields/models.py
+++ b/tests/model_fields/models.py
@@ -527,6 +527,19 @@ class GeneratedModel(models.Model):
         required_db_features = {"supports_stored_generated_columns"}
 
 
+class GeneratedModelNonAutoPk(models.Model):
+    id = models.IntegerField(primary_key=True)
+    a = models.IntegerField()
+    b = models.GeneratedField(
+        expression=F("a"),
+        output_field=models.IntegerField(),
+        db_persist=True,
+    )
+
+    class Meta:
+        required_db_features = {"supports_stored_generated_columns"}
+
+
 class GeneratedModelVirtual(models.Model):
     a = models.IntegerField()
     b = models.IntegerField()
diff --git a/tests/model_fields/test_generatedfield.py b/tests/model_fields/test_generatedfield.py
index c185e19d8b..e00a665ec8 100644
--- a/tests/model_fields/test_generatedfield.py
+++ b/tests/model_fields/test_generatedfield.py
@@ -22,6 +22,7 @@ from .models import (
     GeneratedModelCheckConstraint,
     GeneratedModelCheckConstraintVirtual,
     GeneratedModelFieldWithConverters,
+    GeneratedModelNonAutoPk,
     GeneratedModelNull,
     GeneratedModelNullVirtual,
     GeneratedModelOutputFieldDbCollation,
@@ -356,6 +357,12 @@ class StoredGeneratedFieldTests(GeneratedFieldTestMixin, TestCase):
         obj = self._refresh_if_needed(obj)
         self.assertEqual(obj.field, obj.field_copy)
 
+    def test_create_with_non_auto_pk(self):
+        obj = GeneratedModelNonAutoPk.objects.create(id=1, a=2)
+        self.assertEqual(obj.id, 1)
+        self.assertEqual(obj.a, 2)
+        self.assertEqual(obj.b, 2)
+
 
 @skipUnlessDBFeature("supports_virtual_generated_columns")
 class VirtualGeneratedFieldTests(GeneratedFieldTestMixin, TestCase):