Fixed #23745 -- Reused states as much as possible in migrations (1aa3e09c) · Commits · Dom Sekotill / django

django/db/migrations/executor.py

+13 −11

Original line number	Diff line number	Diff line
		@@ -98,13 +98,13 @@ class MigrationExecutor(object):
		self.progress_callback("apply_start", migration, fake)
		if not fake:
		# Test to see if this is an already-applied initial migration
		if self.detect_soft_applied(state, migration):
		applied, state = self.detect_soft_applied(state, migration)
		if applied:
		fake = True
		else:
		# Alright, do it normally
		with self.connection.schema_editor() as schema_editor:
		project_state = self.loader.project_state((migration.app_label, migration.name), at_end=False)
		migration.apply(project_state, schema_editor)
		state = migration.apply(state, schema_editor)
		# For replacement migrations, record individual statuses
		if migration.replaces:
		for app_label, name in migration.replaces:
		@@ -124,8 +124,7 @@ class MigrationExecutor(object):
		self.progress_callback("unapply_start", migration, fake)
		if not fake:
		with self.connection.schema_editor() as schema_editor:
		project_state = self.loader.project_state((migration.app_label, migration.name), at_end=False)
		migration.unapply(project_state, schema_editor)
		state = migration.unapply(state, schema_editor)
		# For replacement migrations, record individual statuses
		if migration.replaces:
		for app_label, name in migration.replaces:
		@@ -143,12 +142,15 @@ class MigrationExecutor(object):
		tables it would create exist. This is intended only for use
		on initial migrations (as it only looks for CreateModel).
		"""
		project_state = self.loader.project_state((migration.app_label, migration.name), at_end=True)
		apps = project_state.apps
		found_create_migration = False
		# Bail if the migration isn't the first one in its app
		if [name for app, name in migration.dependencies if app == migration.app_label]:
		return False
		return False, project_state
		if project_state is None:
		after_state = self.loader.project_state((migration.app_label, migration.name), at_end=True)
		else:
		after_state = migration.mutate_state(project_state)
		apps = after_state.apps
		found_create_migration = False
		# Make sure all create model are done
		for operation in migration.operations:
		if isinstance(operation, migrations.CreateModel):
		@@ -158,8 +160,8 @@ class MigrationExecutor(object):
		# main app cache, as it's not a direct dependency.
		model = global_apps.get_model(model._meta.swapped)
		if model._meta.db_table not in self.connection.introspection.table_names(self.connection.cursor()):
		return False
		return False, project_state
		found_create_migration = True
		# If we get this far and we found at least one CreateModel migration,
		# the migration is considered implicitly applied.
		return found_create_migration
		return found_create_migration, after_state

django/db/migrations/migration.py

+8 −11

Original line number	Diff line number	Diff line
		@@ -97,19 +97,17 @@ class Migration(object):
		schema_editor.collected_sql.append("-- %s" % operation.describe())
		schema_editor.collected_sql.append("--")
		continue
		# Get the state after the operation has run
		new_state = project_state.clone()
		operation.state_forwards(self.app_label, new_state)
		# Save the state before the operation has run
		old_state = project_state.clone()
		operation.state_forwards(self.app_label, project_state)
		# Run the operation
		if not schema_editor.connection.features.can_rollback_ddl and operation.atomic:
		# We're forcing a transaction on a non-transactional-DDL backend
		with atomic(schema_editor.connection.alias):
		operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
		operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
		else:
		# Normal behaviour
		operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
		# Switch states
		project_state = new_state
		operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
		return project_state

		def unapply(self, project_state, schema_editor, collect_sql=False):
		@@ -133,10 +131,9 @@ class Migration(object):
		# If it's irreversible, error out
		if not operation.reversible:
		raise Migration.IrreversibleError("Operation %s in %s is not reversible" % (operation, self))
		new_state = project_state.clone()
		operation.state_forwards(self.app_label, new_state)
		to_run.append((operation, project_state, new_state))
		project_state = new_state
		old_state = project_state.clone()
		operation.state_forwards(self.app_label, project_state)
		to_run.append((operation, old_state, project_state))
		# Now run them in reverse
		to_run.reverse()
		for operation, to_state, from_state in to_run:

django/db/migrations/operations/fields.py

+4 −0

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@ class AddField(Operation):
		else:
		field = self.field
		state.models[app_label, self.model_name.lower()].fields.append((self.name, field))
		state.reload_model(app_label, self.model_name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		to_model = to_state.apps.get_model(app_label, self.model_name)
		@@ -94,6 +95,7 @@ class RemoveField(Operation):
		if name != self.name:
		new_fields.append((name, instance))
		state.models[app_label, self.model_name.lower()].fields = new_fields
		state.reload_model(app_label, self.model_name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		from_model = from_state.apps.get_model(app_label, self.model_name)
		@@ -150,6 +152,7 @@ class AlterField(Operation):
		state.models[app_label, self.model_name.lower()].fields = [
		(n, field if n == self.name else f) for n, f in state.models[app_label, self.model_name.lower()].fields
		]
		state.reload_model(app_label, self.model_name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		to_model = to_state.apps.get_model(app_label, self.model_name)
		@@ -220,6 +223,7 @@ class RenameField(Operation):
		[self.new_name if n == self.old_name else n for n in together]
		for together in options[option]
		]
		state.reload_model(app_label, self.model_name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		to_model = to_state.apps.get_model(app_label, self.model_name)

django/db/migrations/operations/models.py

+12 −5

Original line number	Diff line number	Diff line
		@@ -39,14 +39,14 @@ class CreateModel(Operation):
		)

		def state_forwards(self, app_label, state):
		state.models[app_label, self.name.lower()] = ModelState(
		state.add_model(ModelState(
		app_label,
		self.name,
		list(self.fields),
		dict(self.options),
		tuple(self.bases),
		list(self.managers),
		)
		))

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		model = to_state.apps.get_model(app_label, self.name)
		@@ -98,7 +98,7 @@ class DeleteModel(Operation):
		)

		def state_forwards(self, app_label, state):
		del state.models[app_label, self.name.lower()]
		state.remove_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		model = from_state.apps.get_model(app_label, self.name)
		@@ -141,12 +141,13 @@ class RenameModel(Operation):
		# Get all of the related objects we need to repoint
		apps = state.apps
		model = apps.get_model(app_label, self.old_name)
		model._meta.apps = apps
		related_objects = model._meta.get_all_related_objects()
		related_m2m_objects = model._meta.get_all_related_many_to_many_objects()
		# Rename the model
		state.models[app_label, self.new_name.lower()] = state.models[app_label, self.old_name.lower()]
		state.models[app_label, self.new_name.lower()].name = self.new_name
		del state.models[app_label, self.old_name.lower()]
		state.remove_model(app_label, self.old_name)
		# Repoint the FKs and M2Ms pointing to us
		for related_object in (related_objects + related_m2m_objects):
		# Use the new related key for self referential related objects.
		@@ -164,7 +165,8 @@ class RenameModel(Operation):
		field.rel.to = "%s.%s" % (app_label, self.new_name)
		new_fields.append((name, field))
		state.models[related_key].fields = new_fields
		del state.apps # FIXME: this should be replaced by a logic in state (update_model?)
		state.reload_model(*related_key)
		state.reload_model(app_label, self.new_name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		new_model = to_state.apps.get_model(app_label, self.new_name)
		@@ -235,6 +237,7 @@ class AlterModelTable(Operation):

		def state_forwards(self, app_label, state):
		state.models[app_label, self.name.lower()].options["db_table"] = self.table
		state.reload_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		new_model = to_state.apps.get_model(app_label, self.name)
		@@ -290,6 +293,7 @@ class AlterUniqueTogether(Operation):
		def state_forwards(self, app_label, state):
		model_state = state.models[app_label, self.name.lower()]
		model_state.options[self.option_name] = self.unique_together
		state.reload_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		new_model = to_state.apps.get_model(app_label, self.name)
		@@ -337,6 +341,7 @@ class AlterIndexTogether(Operation):
		def state_forwards(self, app_label, state):
		model_state = state.models[app_label, self.name.lower()]
		model_state.options[self.option_name] = self.index_together
		state.reload_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		new_model = to_state.apps.get_model(app_label, self.name)
		@@ -381,6 +386,7 @@ class AlterOrderWithRespectTo(Operation):
		def state_forwards(self, app_label, state):
		model_state = state.models[app_label, self.name.lower()]
		model_state.options['order_with_respect_to'] = self.order_with_respect_to
		state.reload_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		to_model = to_state.apps.get_model(app_label, self.name)
		@@ -451,6 +457,7 @@ class AlterModelOptions(Operation):
		for key in self.ALTER_OPTION_KEYS:
		if key not in self.options and key in model_state.options:
		del model_state.options[key]
		state.reload_model(app_label, self.name)

		def database_forwards(self, app_label, schema_editor, from_state, to_state):
		pass

django/db/migrations/state.py

+68 −4

Original line number	Diff line number	Diff line
		from __future__ import unicode_literals
		from collections import OrderedDict
		import copy

		from django.apps import AppConfig
		from django.apps.registry import Apps, apps as global_apps
		@@ -30,15 +32,52 @@ class ProjectState(object):
		# Apps to include from main registry, usually unmigrated ones
		self.real_apps = real_apps or []

		def add_model_state(self, model_state):
		self.models[(model_state.app_label, model_state.name.lower())] = model_state
		def add_model(self, model_state):
		app_label, model_name = model_state.app_label, model_state.name.lower()
		self.models[(app_label, model_name)] = model_state
		if 'apps' in self.__dict__: # hasattr would cache the property
		self.reload_model(app_label, model_name)

		def remove_model(self, app_label, model_name):
		model_name = model_name.lower()
		del self.models[app_label, model_name]
		if 'apps' in self.__dict__: # hasattr would cache the property
		self.apps.unregister_model(app_label, model_name)

		def reload_model(self, app_label, model_name):
		if 'apps' in self.__dict__: # hasattr would cache the property
		# Get relations before reloading the models, as _meta.apps may change
		model_name = model_name.lower()
		try:
		related_old = {
		f.model for f in
		self.apps.get_model(app_label, model_name)._meta.get_all_related_objects()
		}
		except LookupError:
		related_old = set()
		self._reload_one_model(app_label, model_name)
		# Reload models if there are relations
		model = self.apps.get_model(app_label, model_name)
		related_m2m = {f.rel.to for f, _ in model._meta.get_m2m_with_model()}
		for rel_model in related_old.union(related_m2m):
		self._reload_one_model(rel_model._meta.app_label, rel_model._meta.model_name)
		if related_m2m:
		# Re-render this model after related models have been reloaded
		self._reload_one_model(app_label, model_name)

		def _reload_one_model(self, app_label, model_name):
		self.apps.unregister_model(app_label, model_name)
		self.models[app_label, model_name].render(self.apps)

		def clone(self):
		"Returns an exact copy of this ProjectState"
		return ProjectState(
		new_state = ProjectState(
		models={k: v.clone() for k, v in self.models.items()},
		real_apps=self.real_apps,
		)
		if 'apps' in self.__dict__:
		new_state.apps = self.apps.clone()
		return new_state

		@cached_property
		def apps(self):
		@@ -147,6 +186,31 @@ class StateApps(Apps):
		else:
		do_pending_lookups(model)

		def clone(self):
		"""
		Return a clone of this registry, mainly used by the migration framework.
		"""
		clone = StateApps([], {})
		clone.all_models = copy.deepcopy(self.all_models)
		clone.app_configs = copy.deepcopy(self.app_configs)
		return clone

		def register_model(self, app_label, model):
		self.all_models[app_label][model._meta.model_name] = model
		if app_label not in self.app_configs:
		self.app_configs[app_label] = AppConfigStub(app_label)
		self.app_configs[app_label].models = OrderedDict()
		self.app_configs[app_label].models[model._meta.model_name] = model
		self.clear_cache()

		def unregister_model(self, app_label, model_name):
		try:
		del self.all_models[app_label][model_name]
		del self.app_configs[app_label].models[model_name]
		except KeyError:
		pass
		self.clear_cache()


		class ModelState(object):
		"""
		@@ -368,7 +432,7 @@ class ModelState(object):
		for mgr_name, manager in self.managers:
		body[mgr_name] = manager

		# Then, make a Model object
		# Then, make a Model object (apps.register_model is called in __new__)
		return type(
		str(self.name),
		bases,