Refs #24397 -- Sped up model reloading in ProjectState. (039d7881) · Commits · Dom Sekotill / django

django/db/migrations/state.py

+33 −25

Original line number	Diff line number	Diff line
		@@ -2,6 +2,7 @@ from __future__ import unicode_literals

		import copy
		from collections import OrderedDict
		from contextlib import contextmanager

		from django.apps import AppConfig
		from django.apps.registry import Apps, apps as global_apps
		@@ -111,11 +112,9 @@ class ProjectState(object):
		related_models.add((app_label, model_name))

		# Unregister all related models
		with self.apps.bulk_update():
		for rel_app_label, rel_model_name in related_models:
		self.apps.unregister_model(rel_app_label, rel_model_name)
		# Need to do it once all models are unregistered to avoid corrupting
		# existing models' _meta
		self.apps.clear_cache()

		states_to_be_rendered = []
		# Gather all models states of those models that will be rerendered.
		@@ -226,6 +225,18 @@ class StateApps(Apps):
		labels = (".".join(model_key) for model_key in self._pending_operations)
		raise ValueError(msg % ", ".join(labels))

		@contextmanager
		def bulk_update(self):
		# Avoid clearing each model's cache for each change. Instead, clear
		# all caches when we're finished updating the model instances.
		ready = self.ready
		self.ready = False
		try:
		yield
		finally:
		self.ready = ready
		self.clear_cache()

		def render_multiple(self, model_states):
		# We keep trying to render the models in a loop, ignoring invalid
		# base errors, until the size of the unrendered models doesn't
		@@ -234,7 +245,7 @@ class StateApps(Apps):
		if not model_states:
		return
		# Prevent that all model caches are expired for each render.
		self.ready = False
		with self.bulk_update():
		unrendered_models = model_states
		while unrendered_models:
		new_unrendered_models = []
		@@ -244,7 +255,6 @@ class StateApps(Apps):
		except InvalidBasesError:
		new_unrendered_models.append(model)
		if len(new_unrendered_models) == len(unrendered_models):
		self.ready = True
		raise InvalidBasesError(
		"Cannot resolve bases for %r\nThis can happen if you are inheriting models from an "
		"app with migrations (e.g. contrib.auth)\n in an app with no migrations; see "
		@@ -252,8 +262,6 @@ class StateApps(Apps):
		"for more" % (new_unrendered_models, get_docs_version())
		)
		unrendered_models = new_unrendered_models
		self.ready = True
		self.clear_cache()

		def clone(self):
		"""

tests/migrations/test_state.py

+16 −0

Original line number	Diff line number	Diff line
		@@ -160,6 +160,22 @@ class StateTests(TestCase):
		self.assertEqual([mgr.args for name, mgr in food_order_manager_state.managers],
		[('a', 'b', 1, 2), ('x', 'y', 3, 4)])

		def test_apps_bulk_update(self):
		"""
		StateApps.bulk_update() should update apps.ready to False and reset
		the value afterwards.
		"""
		project_state = ProjectState()
		apps = project_state.apps
		with apps.bulk_update():
		self.assertFalse(apps.ready)
		self.assertTrue(apps.ready)
		with self.assertRaises(ValueError):
		with apps.bulk_update():
		self.assertFalse(apps.ready)
		raise ValueError()
		self.assertTrue(apps.ready)

		def test_render(self):
		"""
		Tests rendering a ProjectState into an Apps.