Fixed #26064 -- Moved operation reduction logic to their own class. (49f4c9f4) · Commits · Dom Sekotill / django

django/db/migrations/operations/base.py

+8 −0

Original line number	Diff line number	Diff line
		@@ -111,6 +111,14 @@ class Operation(object):

		return router.allow_migrate_model(connection_alias, model)

		def reduce(self, operation, in_between, app_label=None):
		"""
		Return either a list of operations the actual operation should be
		replaced with or a boolean that indicates whether or not the specified
		operation can be optimized across.
		"""
		return False

		def __repr__(self):
		return "<%s %s%s>" % (
		self.__class__.__name__,

django/db/migrations/operations/fields.py

+80 −42

Original line number	Diff line number	Diff line
		@@ -7,24 +7,38 @@ from django.utils.functional import cached_property
		from .base import Operation


		class AddField(Operation):
		"""
		Adds a field to a model.
		"""

		def __init__(self, model_name, name, field, preserve_default=True):
		class FieldOperation(Operation):
		def __init__(self, model_name, name):
		self.model_name = model_name
		self.name = name
		self.field = field
		self.preserve_default = preserve_default

		@cached_property
		def model_name_lower(self):
		return self.model_name.lower()

		@cached_property
		def name_lower(self):
		return self.name.lower()

		@cached_property
		def model_name_lower(self):
		return self.model_name.lower()
		def is_same_model_operation(self, operation):
		return self.model_name_lower == operation.model_name_lower

		def is_same_field_operation(self, operation):
		return self.is_same_model_operation(operation) and self.name_lower == operation.name_lower

		def reduce(self, operation, in_between, app_label=None):
		return not operation.references_field(self.model_name, self.name, app_label)


		class AddField(FieldOperation):
		"""
		Adds a field to a model.
		"""

		def __init__(self, model_name, name, field, preserve_default=True):
		self.field = field
		self.preserve_default = preserve_default
		super(AddField, self).__init__(model_name, name)

		def deconstruct(self):
		kwargs = {
		@@ -78,24 +92,34 @@ class AddField(Operation):
		def references_field(self, model_name, name, app_label=None):
		return self.references_model(model_name) and name.lower() == self.name_lower

		def reduce(self, operation, in_between, app_label=None):
		if isinstance(operation, FieldOperation) and self.is_same_field_operation(operation):
		if isinstance(operation, AlterField):
		return [
		AddField(
		model_name=self.model_name,
		name=operation.name,
		field=operation.field,
		),
		]
		elif isinstance(operation, RemoveField):
		return []
		elif isinstance(operation, RenameField):
		return [
		AddField(
		model_name=self.model_name,
		name=operation.new_name,
		field=self.field,
		),
		]
		return super(AddField, self).reduce(operation, in_between, app_label=app_label)


		class RemoveField(Operation):
		class RemoveField(FieldOperation):
		"""
		Removes a field from a model.
		"""

		def __init__(self, model_name, name):
		self.model_name = model_name
		self.name = name

		@cached_property
		def name_lower(self):
		return self.name.lower()

		@cached_property
		def model_name_lower(self):
		return self.model_name.lower()

		def deconstruct(self):
		kwargs = {
		'model_name': self.model_name,
		@@ -136,24 +160,15 @@ class RemoveField(Operation):
		return self.references_model(model_name) and name.lower() == self.name_lower


		class AlterField(Operation):
		class AlterField(FieldOperation):
		"""
		Alters a field's database column (e.g. null, max_length) to the provided new field
		"""

		def __init__(self, model_name, name, field, preserve_default=True):
		self.model_name = model_name
		self.name = name
		self.field = field
		self.preserve_default = preserve_default

		@cached_property
		def name_lower(self):
		return self.name.lower()

		@cached_property
		def model_name_lower(self):
		return self.model_name.lower()
		super(AlterField, self).__init__(model_name, name)

		def deconstruct(self):
		kwargs = {
		@@ -214,16 +229,30 @@ class AlterField(Operation):
		def references_field(self, model_name, name, app_label=None):
		return self.references_model(model_name) and name.lower() == self.name_lower

		def reduce(self, operation, in_between, app_label=None):
		if isinstance(operation, RemoveField) and self.is_same_field_operation(operation):
		return [operation]
		elif isinstance(operation, RenameField) and self.is_same_field_operation(operation):
		return [
		operation,
		AlterField(
		model_name=self.model_name,
		name=operation.new_name,
		field=self.field,
		),
		]
		return super(AlterField, self).reduce(operation, in_between, app_label=app_label)


		class RenameField(Operation):
		class RenameField(FieldOperation):
		"""
		Renames a field on the model. Might affect db_column too.
		"""

		def __init__(self, model_name, old_name, new_name):
		self.model_name = model_name
		self.old_name = old_name
		self.new_name = new_name
		super(RenameField, self).__init__(model_name, old_name)

		@cached_property
		def old_name_lower(self):
		@@ -233,10 +262,6 @@ class RenameField(Operation):
		def new_name_lower(self):
		return self.new_name.lower()

		@cached_property
		def model_name_lower(self):
		return self.model_name.lower()

		def deconstruct(self):
		kwargs = {
		'model_name': self.model_name,
		@@ -296,3 +321,16 @@ class RenameField(Operation):
		name.lower() == self.old_name_lower or
		name.lower() == self.new_name_lower
		)

		def reduce(self, operation, in_between, app_label=None):
		if (isinstance(operation, RenameField) and
		self.is_same_model_operation(operation) and
		self.new_name_lower == operation.old_name_lower):
		return [
		RenameField(
		self.model_name,
		self.old_name,
		operation.new_name,
		),
		]
		return not operation.references_field(self.model_name, self.new_name, app_label)

django/db/migrations/operations/models.py

+156 −52

Original line number	Diff line number	Diff line
		@@ -7,8 +7,24 @@ from django.db.models.options import normalize_together
		from django.utils import six
		from django.utils.functional import cached_property

		from .fields import (
		AddField, AlterField, FieldOperation, RemoveField, RenameField,
		)


		class ModelOperation(Operation):
		def __init__(self, name):
		self.name = name

		@cached_property
		def name_lower(self):
		return self.name.lower()

		def reduce(self, operation, in_between, app_label=None):
		return not operation.references_model(self.name, app_label)

		class CreateModel(Operation):

		class CreateModel(ModelOperation):
		"""
		Create a model's table.
		"""
		@@ -16,15 +32,11 @@ class CreateModel(Operation):
		serialization_expand_args = ['fields', 'options', 'managers']

		def __init__(self, name, fields, options=None, bases=None, managers=None):
		self.name = name
		self.fields = fields
		self.options = options or {}
		self.bases = bases or (models.Model,)
		self.managers = managers or []

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(CreateModel, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -83,18 +95,101 @@ class CreateModel(Operation):
		return True
		return False


		class DeleteModel(Operation):
		def model_to_key(self, model):
		"""
		Drops a model's table.
		Take either a model class or an "app_label.ModelName" string
		and return (app_label, object_name).
		"""
		if isinstance(model, six.string_types):
		return model.split(".", 1)
		else:
		return model._meta.app_label, model._meta.object_name

		def reduce(self, operation, in_between, app_label=None):
		if (isinstance(operation, DeleteModel) and
		self.name_lower == operation.name_lower and
		not self.options.get("proxy", False)):
		return []
		elif isinstance(operation, RenameModel) and self.name_lower == operation.old_name_lower:
		return [
		CreateModel(
		operation.new_name,
		fields=self.fields,
		options=self.options,
		bases=self.bases,
		managers=self.managers,
		),
		]
		elif isinstance(operation, FieldOperation) and self.name_lower == operation.model_name_lower:
		if isinstance(operation, AddField):
		# Don't allow optimizations of FKs through models they reference
		if hasattr(operation.field, "remote_field") and operation.field.remote_field:
		for between in in_between:
		# Check that it doesn't point to the model
		app_label, object_name = self.model_to_key(operation.field.remote_field.model)
		if between.references_model(object_name, app_label):
		return False
		# Check that it's not through the model
		if getattr(operation.field.remote_field, "through", None):
		app_label, object_name = self.model_to_key(operation.field.remote_field.through)
		if between.references_model(object_name, app_label):
		return False
		return [
		CreateModel(
		self.name,
		fields=self.fields + [(operation.name, operation.field)],
		options=self.options,
		bases=self.bases,
		managers=self.managers,
		),
		]
		elif isinstance(operation, AlterField):
		return [
		CreateModel(
		self.name,
		fields=[
		(n, operation.field if n == operation.name else v)
		for n, v in self.fields
		],
		options=self.options,
		bases=self.bases,
		managers=self.managers,
		),
		]
		elif isinstance(operation, RemoveField):
		return [
		CreateModel(
		self.name,
		fields=[
		(n, v)
		for n, v in self.fields
		if n.lower() != operation.name_lower
		],
		options=self.options,
		bases=self.bases,
		managers=self.managers,
		),
		]
		elif isinstance(operation, RenameField):
		return [
		CreateModel(
		self.name,
		fields=[
		(operation.new_name if n == operation.old_name else n, v)
		for n, v in self.fields
		],
		options=self.options,
		bases=self.bases,
		managers=self.managers,
		),
		]
		return super(CreateModel, self).reduce(operation, in_between, app_label=app_label)

		def __init__(self, name):
		self.name = name

		@cached_property
		def name_lower(self):
		return self.name.lower()
		class DeleteModel(ModelOperation):
		"""
		Drops a model's table.
		"""

		def deconstruct(self):
		kwargs = {
		@@ -126,7 +221,7 @@ class DeleteModel(Operation):
		return "Delete model %s" % (self.name, )


		class RenameModel(Operation):
		class RenameModel(ModelOperation):
		"""
		Renames a model.
		"""
		@@ -134,6 +229,7 @@ class RenameModel(Operation):
		def __init__(self, old_name, new_name):
		self.old_name = old_name
		self.new_name = new_name
		super(RenameModel, self).__init__(old_name)

		@cached_property
		def old_name_lower(self):
		@@ -260,19 +356,26 @@ class RenameModel(Operation):
		def describe(self):
		return "Rename model %s to %s" % (self.old_name, self.new_name)

		def reduce(self, operation, in_between, app_label=None):
		if (isinstance(operation, RenameModel) and
		self.new_name_lower == operation.old_name_lower):
		return [
		RenameModel(
		self.old_name,
		operation.new_name,
		),
		]
		return not operation.references_model(self.new_name, app_label)


		class AlterModelTable(Operation):
		class AlterModelTable(ModelOperation):
		"""
		Renames a model's table
		"""

		def __init__(self, name, table):
		self.name = name
		self.table = table

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterModelTable, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -316,8 +419,29 @@ class AlterModelTable(Operation):
		def describe(self):
		return "Rename table for %s to %s" % (self.name, self.table)

		def reduce(self, operation, in_between, app_label=None):
		if isinstance(operation, (AlterModelTable, DeleteModel)) and self.name_lower == operation.name_lower:
		return [operation]
		return super(AlterModelTable, self).reduce(operation, in_between, app_label=app_label)


		class ModelOptionOperation(ModelOperation):
		def reduce(self, operation, in_between, app_label=None):
		if isinstance(operation, (self.__class__, DeleteModel)) and self.name_lower == operation.name_lower:
		return [operation]
		return super(ModelOptionOperation, self).reduce(operation, in_between, app_label=app_label)


		class AlterUniqueTogether(Operation):
		class FieldRelatedOptionOperation(ModelOptionOperation):
		def reduce(self, operation, in_between, app_label=None):
		if (isinstance(operation, FieldOperation) and
		self.name_lower == operation.model_name_lower and
		not self.references_field(operation.model_name, operation.name)):
		return [operation, self]
		return super(FieldRelatedOptionOperation, self).reduce(operation, in_between, app_label=app_label)


		class AlterUniqueTogether(FieldRelatedOptionOperation):
		"""
		Changes the value of unique_together to the target one.
		Input value of unique_together must be a set of tuples.
		@@ -325,13 +449,9 @@ class AlterUniqueTogether(Operation):
		option_name = "unique_together"

		def __init__(self, name, unique_together):
		self.name = name
		unique_together = normalize_together(unique_together)
		self.unique_together = set(tuple(cons) for cons in unique_together)

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterUniqueTogether, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -378,7 +498,7 @@ class AlterUniqueTogether(Operation):
		return "Alter %s for %s (%s constraint(s))" % (self.option_name, self.name, len(self.unique_together or ''))


		class AlterIndexTogether(Operation):
		class AlterIndexTogether(FieldRelatedOptionOperation):
		"""
		Changes the value of index_together to the target one.
		Input value of index_together must be a set of tuples.
		@@ -386,13 +506,9 @@ class AlterIndexTogether(Operation):
		option_name = "index_together"

		def __init__(self, name, index_together):
		self.name = name
		index_together = normalize_together(index_together)
		self.index_together = set(tuple(cons) for cons in index_together)

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterIndexTogether, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -439,18 +555,14 @@ class AlterIndexTogether(Operation):
		return "Alter %s for %s (%s constraint(s))" % (self.option_name, self.name, len(self.index_together or ''))


		class AlterOrderWithRespectTo(Operation):
		class AlterOrderWithRespectTo(FieldRelatedOptionOperation):
		"""
		Represents a change with the order_with_respect_to option.
		"""

		def __init__(self, name, order_with_respect_to):
		self.name = name
		self.order_with_respect_to = order_with_respect_to

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterOrderWithRespectTo, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -505,7 +617,7 @@ class AlterOrderWithRespectTo(Operation):
		return "Set order_with_respect_to on %s to %s" % (self.name, self.order_with_respect_to)


		class AlterModelOptions(Operation):
		class AlterModelOptions(ModelOptionOperation):
		"""
		Sets new model options that don't directly affect the database schema
		(like verbose_name, permissions, ordering). Python code in migrations
		@@ -525,12 +637,8 @@ class AlterModelOptions(Operation):
		]

		def __init__(self, name, options):
		self.name = name
		self.options = options

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterModelOptions, self).__init__(name)

		def deconstruct(self):
		kwargs = {
		@@ -565,7 +673,7 @@ class AlterModelOptions(Operation):
		return "Change Meta options on %s" % (self.name, )


		class AlterModelManagers(Operation):
		class AlterModelManagers(ModelOptionOperation):
		"""
		Alters the model's managers
		"""
		@@ -573,12 +681,8 @@ class AlterModelManagers(Operation):
		serialization_expand_args = ['managers']

		def __init__(self, name, managers):
		self.name = name
		self.managers = managers

		@cached_property
		def name_lower(self):
		return self.name.lower()
		super(AlterModelManagers, self).__init__(name)

		def deconstruct(self):
		return (

django/db/migrations/optimizer.py

+6 −305

File changed.

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