Fixed #30397 -- Added app_label/class interpolation for names of indexes and constraints.

django/db/models/options.py

@@ -180,6 +180,12 @@ class Options:
 
             self.unique_together = normalize_together(self.unique_together)
             self.index_together = normalize_together(self.index_together)
+            # App label/class name interpolation for names of constraints and
+            # indexes.
+            if not getattr(cls._meta, 'abstract', False):
+                for attr_name in {'constraints', 'indexes'}:
+                    objs = getattr(self, attr_name, [])
+                    setattr(self, attr_name, self._format_names_with_class(cls, objs))
 
             # verbose_name_plural is a special case because it uses a 's'
             # by default.
@@ -201,6 +207,18 @@ class Options:
             self.db_table = "%s_%s" % (self.app_label, self.model_name)
             self.db_table = truncate_name(self.db_table, connection.ops.max_name_length())
 
+    def _format_names_with_class(self, cls, objs):
+        """App label/class name interpolation for object names."""
+        new_objs = []
+        for obj in objs:
+            obj = obj.clone()
+            obj.name = obj.name % {
+                'app_label': cls._meta.app_label.lower(),
+                'class': cls.__name__.lower(),
+            }
+            new_objs.append(obj)
+        return new_objs
+
     def _prepare(self, model):
         if self.order_with_respect_to:
             # The app registry will not be ready at this point, so we cannot

docs/ref/models/constraints.txt

@@ -25,8 +25,11 @@ option.
     cannot normally specify a constraint on an abstract base class, since the
     :attr:`Meta.constraints <django.db.models.Options.constraints>` option is
     inherited by subclasses, with exactly the same values for the attributes
-    (including ``name``) each time. Instead, specify the ``constraints`` option
-    on subclasses directly, providing a unique name for each constraint.
+    (including ``name``) each time. To work around name collisions, part of the
+    name may contain ``'%(app_label)s'`` and ``'%(class)s'``, which are
+    replaced, respectively, by the lowercased app label and class name of the
+    concrete model. For example ``CheckConstraint(check=Q(age__gte=18),
+    name='%(app_label)s_%(class)s_is_adult')``.
 
 .. admonition:: Validation of Constraints
 
@@ -63,6 +66,10 @@ ensures the age field is never less than 18.
 
 The name of the constraint.
 
+.. versionchanged:: 3.0
+
+   Interpolation of  ``'%(app_label)s'`` and ``'%(class)s'`` was added.
+
 ``UniqueConstraint``
 ====================
 
@@ -89,6 +96,10 @@ date.
 
 The name of the constraint.
 
+.. versionchanged:: 3.0
+
+   Interpolation of  ``'%(app_label)s'`` and ``'%(class)s'`` was added.
+
 ``condition``
 -------------
 

docs/ref/models/indexes.txt

@@ -55,9 +55,15 @@ than 30 characters and shouldn't start with a number (0-9) or underscore (_).
     cannot normally specify a partial index on an abstract base class, since
     the :attr:`Meta.indexes <django.db.models.Options.indexes>` option is
     inherited by subclasses, with exactly the same values for the attributes
-    (including ``name``) each time. Instead, specify the ``indexes`` option
-    on subclasses directly, providing a unique name for each index.
+    (including ``name``) each time. To work around name collisions, part of the
+    name may contain ``'%(app_label)s'`` and ``'%(class)s'``, which are
+    replaced, respectively, by the lowercased app label and class name of the
+    concrete model. For example ``Index(fields=['title'],
+    name='%(app_label)s_%(class)s_title_index')``.
 
+.. versionchanged:: 3.0
+
+    Interpolation of  ``'%(app_label)s'`` and ``'%(class)s'`` was added.
 
 ``db_tablespace``
 -----------------

docs/releases/3.0.txt

@@ -263,6 +263,11 @@ Models
 * Allowed symmetrical intermediate table for self-referential
   :class:`~django.db.models.ManyToManyField`.
 
+* The ``name`` attributes of :class:`~django.db.models.CheckConstraint`,
+  :class:`~django.db.models.UniqueConstraint`, and
+  :class:`~django.db.models.Index` now support app label and class
+  interpolation using the ``'%(app_label)s'`` and ``'%(class)s'`` placeholders.
+
 Requests and Responses
 ~~~~~~~~~~~~~~~~~~~~~~
 

tests/check_framework/test_model_checks.py

@@ -131,6 +131,22 @@ class IndexNameTests(SimpleTestCase):
             ),
         ])
 
+    def test_no_collision_abstract_model_interpolation(self):
+        class AbstractModel(models.Model):
+            name = models.CharField(max_length=20)
+
+            class Meta:
+                indexes = [models.Index(fields=['name'], name='%(app_label)s_%(class)s_foo')]
+                abstract = True
+
+        class Model1(AbstractModel):
+            pass
+
+        class Model2(AbstractModel):
+            pass
+
+        self.assertEqual(checks.run_checks(app_configs=self.apps.get_app_configs()), [])
+
     @modify_settings(INSTALLED_APPS={'append': 'basic'})
     @isolate_apps('basic', 'check_framework', kwarg_name='apps')
     def test_collision_across_apps(self, apps):
@@ -154,6 +170,23 @@ class IndexNameTests(SimpleTestCase):
             ),
         ])
 
+    @modify_settings(INSTALLED_APPS={'append': 'basic'})
+    @isolate_apps('basic', 'check_framework', kwarg_name='apps')
+    def test_no_collision_across_apps_interpolation(self, apps):
+        index = models.Index(fields=['id'], name='%(app_label)s_%(class)s_foo')
+
+        class Model1(models.Model):
+            class Meta:
+                app_label = 'basic'
+                constraints = [index]
+
+        class Model2(models.Model):
+            class Meta:
+                app_label = 'check_framework'
+                constraints = [index]
+
+        self.assertEqual(checks.run_checks(app_configs=apps.get_app_configs()), [])
+
 
 @isolate_apps('check_framework', attr_name='apps')
 @override_system_checks([checks.model_checks.check_all_models])
@@ -214,6 +247,22 @@ class ConstraintNameTests(TestCase):
             ),
         ])
 
+    def test_no_collision_abstract_model_interpolation(self):
+        class AbstractModel(models.Model):
+            class Meta:
+                constraints = [
+                    models.CheckConstraint(check=models.Q(id__gt=0), name='%(app_label)s_%(class)s_foo'),
+                ]
+                abstract = True
+
+        class Model1(AbstractModel):
+            pass
+
+        class Model2(AbstractModel):
+            pass
+
+        self.assertEqual(checks.run_checks(app_configs=self.apps.get_app_configs()), [])
+
     @modify_settings(INSTALLED_APPS={'append': 'basic'})
     @isolate_apps('basic', 'check_framework', kwarg_name='apps')
     def test_collision_across_apps(self, apps):
@@ -236,3 +285,20 @@ class ConstraintNameTests(TestCase):
                 id='models.E032',
             ),
         ])
+
+    @modify_settings(INSTALLED_APPS={'append': 'basic'})
+    @isolate_apps('basic', 'check_framework', kwarg_name='apps')
+    def test_no_collision_across_apps_interpolation(self, apps):
+        constraint = models.CheckConstraint(check=models.Q(id__gt=0), name='%(app_label)s_%(class)s_foo')
+
+        class Model1(models.Model):
+            class Meta:
+                app_label = 'basic'
+                constraints = [constraint]
+
+        class Model2(models.Model):
+            class Meta:
+                app_label = 'check_framework'
+                constraints = [constraint]
+
+        self.assertEqual(checks.run_checks(app_configs=apps.get_app_configs()), [])

tests/constraints/models.py

@@ -13,6 +13,10 @@ class Product(models.Model):
                 check=models.Q(price__gt=models.F('discounted_price')),
                 name='price_gt_discounted_price',
             ),
+            models.CheckConstraint(
+                check=models.Q(price__gt=0),
+                name='%(app_label)s_%(class)s_price_gt_0',
+            ),
             models.UniqueConstraint(fields=['name', 'color'], name='name_color_uniq'),
             models.UniqueConstraint(
                 fields=['name'],
@@ -20,3 +24,20 @@ class Product(models.Model):
                 condition=models.Q(color__isnull=True),
             ),
         ]
+
+
+class AbstractModel(models.Model):
+    age = models.IntegerField()
+
+    class Meta:
+        abstract = True
+        constraints = [
+            models.CheckConstraint(
+                check=models.Q(age__gte=18),
+                name='%(app_label)s_%(class)s_adult',
+            ),
+        ]
+
+
+class ChildModel(AbstractModel):
+    pass

tests/constraints/tests.py

@@ -3,7 +3,7 @@ from django.db import IntegrityError, connection, models
 from django.db.models.constraints import BaseConstraint
 from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature
 
-from .models import Product
+from .models import ChildModel, Product
 
 
 def get_constraints(table):
@@ -76,8 +76,17 @@ class CheckConstraintTests(TestCase):
     @skipUnlessDBFeature('supports_table_check_constraints')
     def test_name(self):
         constraints = get_constraints(Product._meta.db_table)
-        expected_name = 'price_gt_discounted_price'
-        self.assertIn(expected_name, constraints)
+        for expected_name in (
+            'price_gt_discounted_price',
+            'constraints_product_price_gt_0',
+        ):
+            with self.subTest(expected_name):
+                self.assertIn(expected_name, constraints)
+
+    @skipUnlessDBFeature('supports_table_check_constraints')
+    def test_abstract_name(self):
+        constraints = get_constraints(ChildModel._meta.db_table)
+        self.assertIn('constraints_childmodel_adult', constraints)
 
 
 class UniqueConstraintTests(TestCase):

tests/model_indexes/models.py

@@ -7,20 +7,26 @@ class Book(models.Model):
     pages = models.IntegerField(db_column='page_count')
     shortcut = models.CharField(max_length=50, db_tablespace='idx_tbls')
     isbn = models.CharField(max_length=50, db_tablespace='idx_tbls')
+    barcode = models.CharField(max_length=31)
 
     class Meta:
         indexes = [
             models.Index(fields=['title']),
             models.Index(fields=['isbn', 'id']),
+            models.Index(fields=['barcode'], name='%(app_label)s_%(class)s_barcode_idx'),
         ]
 
 
 class AbstractModel(models.Model):
     name = models.CharField(max_length=50)
+    shortcut = models.CharField(max_length=3)
 
     class Meta:
         abstract = True
-        indexes = [models.Index(fields=['name'])]
+        indexes = [
+            models.Index(fields=['name']),
+            models.Index(fields=['shortcut'], name='%(app_label)s_%(class)s_idx'),
+        ]
 
 
 class ChildModel1(AbstractModel):

tests/model_indexes/tests.py

@@ -134,13 +134,26 @@ class SimpleIndexesTests(SimpleTestCase):
 
     def test_name_set(self):
         index_names = [index.name for index in Book._meta.indexes]
-        self.assertCountEqual(index_names, ['model_index_title_196f42_idx', 'model_index_isbn_34f975_idx'])
+        self.assertCountEqual(
+            index_names,
+            [
+                'model_index_title_196f42_idx',
+                'model_index_isbn_34f975_idx',
+                'model_indexes_book_barcode_idx',
+            ],
+        )
 
     def test_abstract_children(self):
         index_names = [index.name for index in ChildModel1._meta.indexes]
-        self.assertEqual(index_names, ['model_index_name_440998_idx'])
+        self.assertEqual(
+            index_names,
+            ['model_index_name_440998_idx', 'model_indexes_childmodel1_idx'],
+        )
         index_names = [index.name for index in ChildModel2._meta.indexes]
-        self.assertEqual(index_names, ['model_index_name_b6c374_idx'])
+        self.assertEqual(
+            index_names,
+            ['model_index_name_b6c374_idx', 'model_indexes_childmodel2_idx'],
+        )
 
 
 class IndexesTests(TestCase):