Fixed #17760 -- Implemented callable database features as cached properties (aa423575) · Commits · Dom Sekotill / django

django/contrib/gis/db/backends/spatialite/creation.py

+0 −3

Original line number	Diff line number	Diff line
		@@ -31,9 +31,6 @@ class SpatiaLiteCreation(DatabaseCreation):
		self.connection.close()
		self.connection.settings_dict["NAME"] = test_database_name

		# Confirm the feature set of the test database
		self.connection.features.confirm()

		# Need to load the SpatiaLite initialization SQL before running `syncdb`.
		self.load_spatialite_sql()

django/db/backends/init.py

+9 −22

Original line number	Diff line number	Diff line
		@@ -10,6 +10,7 @@ from django.conf import settings
		from django.db import DEFAULT_DB_ALIAS
		from django.db.backends import util
		from django.db.transaction import TransactionManagementError
		from django.utils.functional import cached_property
		from django.utils.importlib import import_module
		from django.utils.timezone import is_aware

		@@ -402,12 +403,10 @@ class BaseDatabaseFeatures(object):
		# Does the backend reset sequences between tests?
		supports_sequence_reset = True

		# Features that need to be confirmed at runtime
		# Cache whether the confirmation has been performed.
		_confirmed = False
		supports_transactions = None
		supports_stddev = None
		can_introspect_foreign_keys = None
		# Confirm support for introspected foreign keys
		# Every database can do this reliably, except MySQL,
		# which can't do it for MyISAM tables
		can_introspect_foreign_keys = True

		# Support for the DISTINCT ON clause
		can_distinct_on_fields = False
		@@ -415,15 +414,8 @@ class BaseDatabaseFeatures(object):
		def __init__(self, connection):
		self.connection = connection

		def confirm(self):
		"Perform manual checks of any database features that might vary between installs"
		if not self._confirmed:
		self._confirmed = True
		self.supports_transactions = self._supports_transactions()
		self.supports_stddev = self._supports_stddev()
		self.can_introspect_foreign_keys = self._can_introspect_foreign_keys()

		def _supports_transactions(self):
		@cached_property
		def supports_transactions(self):
		"Confirm support for transactions"
		cursor = self.connection.cursor()
		cursor.execute('CREATE TABLE ROLLBACK_TEST (X INT)')
		@@ -436,7 +428,8 @@ class BaseDatabaseFeatures(object):
		self.connection._commit()
		return count == 0

		def _supports_stddev(self):
		@cached_property
		def supports_stddev(self):
		"Confirm support for STDDEV and related stats functions"
		class StdDevPop(object):
		sql_function = 'STDDEV_POP'
		@@ -447,12 +440,6 @@ class BaseDatabaseFeatures(object):
		except NotImplementedError:
		return False

		def _can_introspect_foreign_keys(self):
		"Confirm support for introspected foreign keys"
		# Every database can do this reliably, except MySQL,
		# which can't do it for MyISAM tables
		return True


		class BaseDatabaseOperations(object):
		"""

django/db/backends/creation.py

+0 −3

Original line number	Diff line number	Diff line
		@@ -264,9 +264,6 @@ class BaseDatabaseCreation(object):
		self.connection.close()
		self.connection.settings_dict["NAME"] = test_database_name

		# Confirm the feature set of the test database
		self.connection.features.confirm()

		# Report syncdb messages at one level lower than that requested.
		# This ensures we don't get flooded with messages during testing
		# (unless you really ask to be flooded)

django/db/backends/mysql/base.py

+16 −16

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@ from django.db.backends.mysql.client import DatabaseClient
		from django.db.backends.mysql.creation import DatabaseCreation
		from django.db.backends.mysql.introspection import DatabaseIntrospection
		from django.db.backends.mysql.validation import DatabaseValidation
		from django.utils.functional import cached_property
		from django.utils.safestring import SafeString, SafeUnicode
		from django.utils import timezone

		@@ -170,11 +171,10 @@ class DatabaseFeatures(BaseDatabaseFeatures):

		def __init__(self, connection):
		super(DatabaseFeatures, self).__init__(connection)
		self._storage_engine = None

		@cached_property
		def _mysql_storage_engine(self):
		"Internal method used in Django tests. Don't rely on this from your code"
		if self._storage_engine is None:
		cursor = self.connection.cursor()
		cursor.execute('CREATE TABLE INTROSPECT_TEST (X INT)')
		# This command is MySQL specific; the second column
		@@ -184,12 +184,12 @@ class DatabaseFeatures(BaseDatabaseFeatures):
		cursor.execute("SHOW TABLE STATUS WHERE Name='INTROSPECT_TEST'")
		result = cursor.fetchone()
		cursor.execute('DROP TABLE INTROSPECT_TEST')
		self._storage_engine = result[1]
		return self._storage_engine
		return result[1]

		def _can_introspect_foreign_keys(self):
		@cached_property
		def can_introspect_foreign_keys(self):
		"Confirm support for introspected foreign keys"
		return self._mysql_storage_engine() != 'MyISAM'
		return self._mysql_storage_engine != 'MyISAM'

		class DatabaseOperations(BaseDatabaseOperations):
		compiler_module = "django.db.backends.mysql.compiler"

django/db/backends/sqlite3/base.py

+3 −1

Original line number	Diff line number	Diff line
		@@ -19,6 +19,7 @@ from django.db.backends.sqlite3.client import DatabaseClient
		from django.db.backends.sqlite3.creation import DatabaseCreation
		from django.db.backends.sqlite3.introspection import DatabaseIntrospection
		from django.utils.dateparse import parse_date, parse_datetime, parse_time
		from django.utils.functional import cached_property
		from django.utils.safestring import SafeString
		from django.utils import timezone

		@@ -86,7 +87,8 @@ class DatabaseFeatures(BaseDatabaseFeatures):
		has_bulk_insert = True
		can_combine_inserts_with_and_without_auto_increment_pk = True

		def _supports_stddev(self):
		@cached_property
		def supports_stddev(self):
		"""Confirm support for STDDEV and related stats functions

		SQLite supports STDDEV as an extension package; so