Fixed cached_properties that share a common property.

The aliases aren't cached and thus the old usage will be an error after
refs #29478.

django/db/backends/mysql/features.py

@@ -1,3 +1,5 @@
+import operator
+
 from django.db.backends.base.features import BaseDatabaseFeatures
 from django.utils.functional import cached_property
 
@@ -91,7 +93,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     def has_select_for_update_skip_locked(self):
         return not self.connection.mysql_is_mariadb and self.connection.mysql_version >= (8, 0, 1)
 
-    has_select_for_update_nowait = has_select_for_update_skip_locked
+    has_select_for_update_nowait = property(operator.attrgetter('has_select_for_update_skip_locked'))
 
     @cached_property
     def needs_explain_extended(self):

django/db/backends/postgresql/features.py

@@ -1,3 +1,5 @@
+import operator
+
 from django.db.backends.base.features import BaseDatabaseFeatures
 from django.db.utils import InterfaceError
 from django.utils.functional import cached_property
@@ -64,10 +66,10 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     def is_postgresql_10(self):
         return self.connection.pg_version >= 100000
 
-    has_select_for_update_skip_locked = is_postgresql_9_5
-    has_brin_index_support = is_postgresql_9_5
-    has_jsonb_agg = is_postgresql_9_5
-    has_brin_autosummarize = is_postgresql_10
-    has_gin_pending_list_limit = is_postgresql_9_5
-    supports_ignore_conflicts = is_postgresql_9_5
-    has_phraseto_tsquery = is_postgresql_9_6
+    has_select_for_update_skip_locked = property(operator.attrgetter('is_postgresql_9_5'))
+    has_brin_index_support = property(operator.attrgetter('is_postgresql_9_5'))
+    has_jsonb_agg = property(operator.attrgetter('is_postgresql_9_5'))
+    has_brin_autosummarize = property(operator.attrgetter('is_postgresql_10'))
+    has_gin_pending_list_limit = property(operator.attrgetter('is_postgresql_9_5'))
+    supports_ignore_conflicts = property(operator.attrgetter('is_postgresql_9_5'))
+    has_phraseto_tsquery = property(operator.attrgetter('is_postgresql_9_6'))

tests/postgres_tests/test_indexes.py

@@ -219,14 +219,14 @@ class SchemaTests(PostgreSQLTestCase):
             editor.remove_index(IntegerArrayModel, index)
         self.assertNotIn(index_name, self.get_constraints(IntegerArrayModel._meta.db_table))
 
+    @mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_gin_pending_list_limit', False)
     def test_gin_parameters_exception(self):
         index_name = 'gin_options_exception'
         index = GinIndex(fields=['field'], name=index_name, gin_pending_list_limit=64)
         msg = 'GIN option gin_pending_list_limit requires PostgreSQL 9.5+.'
         with self.assertRaisesMessage(NotSupportedError, msg):
-            with mock.patch('django.db.connection.features.has_gin_pending_list_limit', False):
-                with connection.schema_editor() as editor:
-                    editor.add_index(IntegerArrayModel, index)
+            with connection.schema_editor() as editor:
+                editor.add_index(IntegerArrayModel, index)
         self.assertNotIn(index_name, self.get_constraints(IntegerArrayModel._meta.db_table))
 
     @skipUnlessDBFeature('has_brin_index_support')
@@ -259,7 +259,7 @@ class SchemaTests(PostgreSQLTestCase):
         index_name = 'brin_index_exception'
         index = BrinIndex(fields=['field'], name=index_name)
         with self.assertRaisesMessage(NotSupportedError, 'BRIN indexes require PostgreSQL 9.5+.'):
-            with mock.patch('django.db.connection.features.has_brin_index_support', False):
+            with mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_brin_index_support', False):
                 with connection.schema_editor() as editor:
                     editor.add_index(CharFieldModel, index)
         self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))
@@ -269,7 +269,7 @@ class SchemaTests(PostgreSQLTestCase):
         index_name = 'brin_options_exception'
         index = BrinIndex(fields=['field'], name=index_name, autosummarize=True)
         with self.assertRaisesMessage(NotSupportedError, 'BRIN option autosummarize requires PostgreSQL 10+.'):
-            with mock.patch('django.db.connection.features.has_brin_autosummarize', False):
+            with mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_brin_autosummarize', False):
                 with connection.schema_editor() as editor:
                     editor.add_index(CharFieldModel, index)
         self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))