Fixed #30661 -- Added models.SmallAutoField.

7 files changed, 120 insertions, 14 deletions

diff --git a/tests/db_functions/comparison/test_cast.py b/tests/db_functions/comparison/test_cast.py
index c5698d6d0e..988eaa4dad 100644
--- a/tests/db_functions/comparison/test_cast.py
+++ b/tests/db_functions/comparison/test_cast.py
@@ -55,6 +55,7 @@ class CastTests(TestCase):
         for field_class in (
             models.AutoField,
             models.BigAutoField,
+            models.SmallAutoField,
             models.IntegerField,
             models.BigIntegerField,
             models.SmallIntegerField,
diff --git a/tests/introspection/models.py b/tests/introspection/models.py
index fa663de2fd..d069c5820e 100644
--- a/tests/introspection/models.py
+++ b/tests/introspection/models.py
@@ -9,6 +9,11 @@ class City(models.Model):
         return self.name
 
 
+class Country(models.Model):
+    id = models.SmallAutoField(primary_key=True)
+    name = models.CharField(max_length=50)
+
+
 class District(models.Model):
     city = models.ForeignKey(City, models.CASCADE, primary_key=True)
     name = models.CharField(max_length=50)
diff --git a/tests/introspection/tests.py b/tests/introspection/tests.py
index 7edb01a4b7..4a7ce11e7a 100644
--- a/tests/introspection/tests.py
+++ b/tests/introspection/tests.py
@@ -5,7 +5,9 @@ from django.db.models import Index
 from django.db.utils import DatabaseError
 from django.test import TransactionTestCase, skipUnlessDBFeature
 
-from .models import Article, ArticleReporter, City, Comment, District, Reporter
+from .models import (
+    Article, ArticleReporter, City, Comment, Country, District, Reporter,
+)
 
 
 class IntrospectionTests(TransactionTestCase):
@@ -115,6 +117,15 @@ class IntrospectionTests(TransactionTestCase):
             [connection.introspection.get_field_type(r[1], r) for r in desc],
         )
 
+    @skipUnlessDBFeature('can_introspect_autofield')
+    def test_smallautofield(self):
+        with connection.cursor() as cursor:
+            desc = connection.introspection.get_table_description(cursor, Country._meta.db_table)
+        self.assertIn(
+            connection.features.introspected_small_auto_field_type,
+            [connection.introspection.get_field_type(r[1], r) for r in desc],
+        )
+
     # Regression test for #9991 - 'real' types in postgres
     @skipUnlessDBFeature('has_real_datatype')
     def test_postgresql_real_type(self):
diff --git a/tests/many_to_one/models.py b/tests/many_to_one/models.py
index 6230129bbd..6e00fb18fa 100644
--- a/tests/many_to_one/models.py
+++ b/tests/many_to_one/models.py
@@ -27,8 +27,14 @@ class Article(models.Model):
         return self.headline
 
 
+class Country(models.Model):
+    id = models.SmallAutoField(primary_key=True)
+    name = models.CharField(max_length=50)
+
+
 class City(models.Model):
     id = models.BigAutoField(primary_key=True)
+    country = models.ForeignKey(Country, models.CASCADE, related_name='cities', null=True)
     name = models.CharField(max_length=50)
 
     def __str__(self):
diff --git a/tests/many_to_one/tests.py b/tests/many_to_one/tests.py
index e3121a7701..a926574b15 100644
--- a/tests/many_to_one/tests.py
+++ b/tests/many_to_one/tests.py
@@ -8,8 +8,9 @@ from django.test import TestCase
 from django.utils.translation import gettext_lazy
 
 from .models import (
-    Article, Category, Child, ChildNullableParent, City, District, First,
-    Parent, Record, Relation, Reporter, School, Student, Third, ToFieldChild,
+    Article, Category, Child, ChildNullableParent, City, Country, District,
+    First, Parent, Record, Relation, Reporter, School, Student, Third,
+    ToFieldChild,
 )
 
 
@@ -576,6 +577,15 @@ class ManyToOneTests(TestCase):
         District.objects.create(city=ny, name='Brooklyn')
         District.objects.create(city=ny, name='Manhattan')
 
+    def test_fk_to_smallautofield(self):
+        us = Country.objects.create(name='United States')
+        City.objects.create(country=us, name='Chicago')
+        City.objects.create(country=us, name='New York')
+
+        uk = Country.objects.create(name='United Kingdom', id=2 ** 11)
+        City.objects.create(country=uk, name='London')
+        City.objects.create(country=uk, name='Edinburgh')
+
     def test_multiple_foreignkeys(self):
         # Test of multiple ForeignKeys to the same model (bug #7125).
         c1 = Category.objects.create(name='First')
diff --git a/tests/migrations/test_operations.py b/tests/migrations/test_operations.py
index 3b2129a933..3c321d4cb4 100644
--- a/tests/migrations/test_operations.py
+++ b/tests/migrations/test_operations.py
@@ -2651,9 +2651,13 @@ class OperationTests(OperationTestBase):
             fill_data.state_forwards("fill_data", new_state)
             fill_data.database_forwards("fill_data", editor, project_state, new_state)
 
-    def test_autofield_foreignfield_growth(self):
+    def _test_autofield_foreignfield_growth(self, source_field, target_field, target_value):
         """
-        A field may be migrated from AutoField to BigAutoField.
+        A field may be migrated in the following ways:
+
+        - AutoField to BigAutoField
+        - SmallAutoField to AutoField
+        - SmallAutoField to BigAutoField
         """
         def create_initial_data(models, schema_editor):
             Article = models.get_model("test_article", "Article")
@@ -2665,14 +2669,14 @@ class OperationTests(OperationTestBase):
         def create_big_data(models, schema_editor):
             Article = models.get_model("test_article", "Article")
             Blog = models.get_model("test_blog", "Blog")
-            blog2 = Blog.objects.create(name="Frameworks", id=2 ** 33)
+            blog2 = Blog.objects.create(name="Frameworks", id=target_value)
             Article.objects.create(name="Django", blog=blog2)
-            Article.objects.create(id=2 ** 33, name="Django2", blog=blog2)
+            Article.objects.create(id=target_value, name="Django2", blog=blog2)
 
         create_blog = migrations.CreateModel(
             "Blog",
             [
-                ("id", models.AutoField(primary_key=True)),
+                ("id", source_field(primary_key=True)),
                 ("name", models.CharField(max_length=100)),
             ],
             options={},
@@ -2680,7 +2684,7 @@ class OperationTests(OperationTestBase):
         create_article = migrations.CreateModel(
             "Article",
             [
-                ("id", models.AutoField(primary_key=True)),
+                ("id", source_field(primary_key=True)),
                 ("blog", models.ForeignKey(to="test_blog.Blog", on_delete=models.CASCADE)),
                 ("name", models.CharField(max_length=100)),
                 ("data", models.TextField(default="")),
@@ -2690,8 +2694,8 @@ class OperationTests(OperationTestBase):
         fill_initial_data = migrations.RunPython(create_initial_data, create_initial_data)
         fill_big_data = migrations.RunPython(create_big_data, create_big_data)
 
-        grow_article_id = migrations.AlterField("Article", "id", models.BigAutoField(primary_key=True))
-        grow_blog_id = migrations.AlterField("Blog", "id", models.BigAutoField(primary_key=True))
+        grow_article_id = migrations.AlterField('Article', 'id', target_field(primary_key=True))
+        grow_blog_id = migrations.AlterField('Blog', 'id', target_field(primary_key=True))
 
         project_state = ProjectState()
         new_state = project_state.clone()
@@ -2719,7 +2723,7 @@ class OperationTests(OperationTestBase):
 
         state = new_state.clone()
         article = state.apps.get_model("test_article.Article")
-        self.assertIsInstance(article._meta.pk, models.BigAutoField)
+        self.assertIsInstance(article._meta.pk, target_field)
 
         project_state = new_state
         new_state = new_state.clone()
@@ -2729,7 +2733,7 @@ class OperationTests(OperationTestBase):
 
         state = new_state.clone()
         blog = state.apps.get_model("test_blog.Blog")
-        self.assertIsInstance(blog._meta.pk, models.BigAutoField)
+        self.assertIsInstance(blog._meta.pk, target_field)
 
         project_state = new_state
         new_state = new_state.clone()
@@ -2737,6 +2741,30 @@ class OperationTests(OperationTestBase):
             fill_big_data.state_forwards("fill_big_data", new_state)
             fill_big_data.database_forwards("fill_big_data", editor, project_state, new_state)
 
+    def test_autofield__bigautofield_foreignfield_growth(self):
+        """A field may be migrated from AutoField to BigAutoField."""
+        self._test_autofield_foreignfield_growth(
+            models.AutoField,
+            models.BigAutoField,
+            2 ** 33,
+        )
+
+    def test_smallfield_autofield_foreignfield_growth(self):
+        """A field may be migrated from SmallAutoField to AutoField."""
+        self._test_autofield_foreignfield_growth(
+            models.SmallAutoField,
+            models.AutoField,
+            2 ** 22,
+        )
+
+    def test_smallfield_bigautofield_foreignfield_growth(self):
+        """A field may be migrated from SmallAutoField to BigAutoField."""
+        self._test_autofield_foreignfield_growth(
+            models.SmallAutoField,
+            models.BigAutoField,
+            2 ** 33,
+        )
+
     def test_run_python_noop(self):
         """
         #24098 - Tests no-op RunPython operations.
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index a765528d50..7276912c71 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -14,7 +14,8 @@ from django.db.models.deletion import CASCADE, PROTECT
 from django.db.models.fields import (
     AutoField, BigAutoField, BigIntegerField, BinaryField, BooleanField,
     CharField, DateField, DateTimeField, IntegerField, PositiveIntegerField,
-    SlugField, TextField, TimeField, UUIDField,
+    SlugField, SmallAutoField, SmallIntegerField, TextField, TimeField,
+    UUIDField,
 )
 from django.db.models.fields.related import (
     ForeignKey, ForeignObject, ManyToManyField, OneToOneField,
@@ -1179,6 +1180,28 @@ class SchemaTests(TransactionTestCase):
         # Fail on PostgreSQL if sequence is missing an owner.
         self.assertIsNotNone(Author.objects.create(name='Bar'))
 
+    def test_alter_autofield_pk_to_smallautofield_pk_sequence_owner(self):
+        """
+        Converting an implicit PK to SmallAutoField(primary_key=True) should
+        keep a sequence owner on PostgreSQL.
+        """
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+        old_field = Author._meta.get_field('id')
+        new_field = SmallAutoField(primary_key=True)
+        new_field.set_attributes_from_name('id')
+        new_field.model = Author
+        with connection.schema_editor() as editor:
+            editor.alter_field(Author, old_field, new_field, strict=True)
+
+        Author.objects.create(name='Foo', pk=1)
+        with connection.cursor() as cursor:
+            sequence_reset_sqls = connection.ops.sequence_reset_sql(no_style(), [Author])
+            if sequence_reset_sqls:
+                cursor.execute(sequence_reset_sqls[0])
+        # Fail on PostgreSQL if sequence is missing an owner.
+        self.assertIsNotNone(Author.objects.create(name='Bar'))
+
     def test_alter_int_pk_to_autofield_pk(self):
         """
         Should be able to rename an IntegerField(primary_key=True) to
@@ -1211,6 +1234,28 @@ class SchemaTests(TransactionTestCase):
         with connection.schema_editor() as editor:
             editor.alter_field(IntegerPK, old_field, new_field, strict=True)
 
+    @isolate_apps('schema')
+    def test_alter_smallint_pk_to_smallautofield_pk(self):
+        """
+        Should be able to rename an SmallIntegerField(primary_key=True) to
+        SmallAutoField(primary_key=True).
+        """
+        class SmallIntegerPK(Model):
+            i = SmallIntegerField(primary_key=True)
+
+            class Meta:
+                app_label = 'schema'
+
+        with connection.schema_editor() as editor:
+            editor.create_model(SmallIntegerPK)
+        self.isolated_local_models = [SmallIntegerPK]
+        old_field = SmallIntegerPK._meta.get_field('i')
+        new_field = SmallAutoField(primary_key=True)
+        new_field.model = SmallIntegerPK
+        new_field.set_attributes_from_name('i')
+        with connection.schema_editor() as editor:
+            editor.alter_field(SmallIntegerPK, old_field, new_field, strict=True)
+
     def test_alter_int_pk_to_int_unique(self):
         """
         Should be able to rename an IntegerField(primary_key=True) to