Fixed #23938 -- Added migration support for m2m to concrete fields and vice versa (623ccdd5) · Commits · Dom Sekotill / django

django/db/migrations/autodetector.py

+80 −77

Original line number	Diff line number	Diff line
		@@ -773,6 +773,9 @@ class MigrationAutodetector(object):
		Fields that have been added
		"""
		for app_label, model_name, field_name in sorted(self.new_field_keys - self.old_field_keys):
		self._generate_added_field(app_label, model_name, field_name)

		def _generate_added_field(self, app_label, model_name, field_name):
		field = self.new_apps.get_model(app_label, model_name)._meta.get_field_by_name(field_name)[0]
		# Fields that are foreignkeys/m2ms depend on stuff
		dependencies = []
		@@ -791,32 +794,24 @@ class MigrationAutodetector(object):
		field.rel.through._meta.app_label,
		field.rel.through._meta.object_name,
		None,
		True
		True,
		))
		# You can't just add NOT NULL fields with no default or fields
		# which don't allow empty strings as default.
		preserve_default = True
		if (not field.null and not field.has_default() and
		not isinstance(field, models.ManyToManyField) and
		not (field.blank and field.empty_strings_allowed)):
		field = field.clone()
		field.default = self.questioner.ask_not_null_addition(field_name, model_name)
		preserve_default = False
		self.add_operation(
		app_label,
		operations.AddField(
		model_name=model_name,
		name=field_name,
		field=field,
		preserve_default=False,
		),
		dependencies=dependencies,
		)
		else:
		self.add_operation(
		app_label,
		operations.AddField(
		model_name=model_name,
		name=field_name,
		field=field,
		preserve_default=preserve_default,
		),
		dependencies=dependencies,
		)
		@@ -826,6 +821,9 @@ class MigrationAutodetector(object):
		Fields that have been removed.
		"""
		for app_label, model_name, field_name in sorted(self.old_field_keys - self.new_field_keys):
		self._generate_removed_field(app_label, model_name, field_name)

		def _generate_removed_field(self, app_label, model_name, field_name):
		self.add_operation(
		app_label,
		operations.RemoveField(
		@@ -863,6 +861,8 @@ class MigrationAutodetector(object):
		old_field_dec = self.deep_deconstruct(old_field)
		new_field_dec = self.deep_deconstruct(new_field)
		if old_field_dec != new_field_dec:
		if (not isinstance(old_field, models.ManyToManyField) and
		not isinstance(new_field, models.ManyToManyField)):
		preserve_default = True
		if (old_field.null and not new_field.null and not new_field.has_default() and
		not isinstance(new_field, models.ManyToManyField)):
		@@ -882,6 +882,9 @@ class MigrationAutodetector(object):
		preserve_default=preserve_default,
		)
		)
		else:
		self._generate_removed_field(app_label, model_name, field_name)
		self._generate_added_field(app_label, model_name, field_name)

		def _generate_altered_foo_together(self, operation):
		option_name = operation.option_name

docs/releases/1.7.2.txt

+6 −3

Original line number	Diff line number	Diff line
		@@ -44,7 +44,7 @@ Bugfixes
		* Fixed a migration crash that prevented changing a nullable field with a
		default to non-nullable with the same default (:ticket:`23738`).

		* Fixed a migrations crash when adding ``GeometryField``\s with ``blank=True``
		* Fixed a migration crash when adding ``GeometryField``\s with ``blank=True``
		on PostGIS (:ticket:`23731`).

		* Allowed usage of ``DateTimeField()`` as ``Transform.output_field``
		@@ -144,7 +144,7 @@ Bugfixes
		* ``makemigrations`` no longer prompts for a default value when adding
		``TextField()`` or ``CharField()`` without a ``default`` (:ticket:`23405`).

		* Fixed migration crash when adding ``order_with_respect_to`` to a table
		* Fixed a migration crash when adding ``order_with_respect_to`` to a table
		with existing rows (:ticket:`23983`).

		* Restored the ``pre_migrate`` signal if all apps have migrations
		@@ -181,3 +181,6 @@ Bugfixes

		* Supported strings escaped by third-party libraries with the ``__html__``
		convention in the template engine (:ticket:`23831`).

		* Fixed a migration crash when changing a ``ManyToManyField`` into a concrete
		field and vice versa (:ticket:`23938`).

tests/migrations/test_autodetector.py

+37 −0

Original line number	Diff line number	Diff line
		@@ -126,6 +126,10 @@ class AutodetectorTests(TestCase):
		("id", models.AutoField(primary_key=True)),
		("publishers", models.ManyToManyField("testapp.Publisher", through="testapp.Contract")),
		])
		author_with_former_m2m = ModelState("testapp", "Author", [
		("id", models.AutoField(primary_key=True)),
		("publishers", models.CharField(max_length=100)),
		])
		author_with_options = ModelState("testapp", "Author", [
		("id", models.AutoField(primary_key=True)),
		], {
		@@ -1326,6 +1330,39 @@ class AutodetectorTests(TestCase):
		self.assertOperationAttributes(changes, "testapp", 0, 3, name="Author")
		self.assertOperationAttributes(changes, "testapp", 0, 4, name="Contract")

		def test_concrete_field_changed_to_many_to_many(self):
		"""
		#23938 - Tests that changing a concrete field into a ManyToManyField
		first removes the concrete field and then adds the m2m field.
		"""
		before = self.make_project_state([self.author_with_former_m2m])
		after = self.make_project_state([self.author_with_m2m, self.publisher])
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		# Right number/type of migrations?
		self.assertNumberMigrations(changes, "testapp", 1)
		self.assertOperationTypes(changes, "testapp", 0, ["CreateModel", "RemoveField", "AddField"])
		self.assertOperationAttributes(changes, 'testapp', 0, 0, name='Publisher')
		self.assertOperationAttributes(changes, 'testapp', 0, 1, name="publishers", model_name='author')
		self.assertOperationAttributes(changes, 'testapp', 0, 2, name="publishers", model_name='author')

		def test_many_to_many_changed_to_concrete_field(self):
		"""
		#23938 - Tests that changing a ManyToManyField into a concrete field
		first removes the m2m field and then adds the concrete field.
		"""
		before = self.make_project_state([self.author_with_m2m, self.publisher])
		after = self.make_project_state([self.author_with_former_m2m])
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		# Right number/type of migrations?
		self.assertNumberMigrations(changes, "testapp", 1)
		self.assertOperationTypes(changes, "testapp", 0, ["RemoveField", "AddField", "DeleteModel"])
		self.assertOperationAttributes(changes, 'testapp', 0, 0, name="publishers", model_name='author')
		self.assertOperationAttributes(changes, 'testapp', 0, 1, name="publishers", model_name='author')
		self.assertOperationAttributes(changes, 'testapp', 0, 2, name='Publisher')
		self.assertOperationFieldAttributes(changes, 'testapp', 0, 1, max_length=100)

		def test_non_circular_foreignkey_dependency_removal(self):
		"""
		If two models with a ForeignKey from one to the other are removed at the