Revert "Fixed #22397 -- Issues removing M2M field with explicit through model." (0d397e5a) · Commits · Dom Sekotill / django

django/db/backends/sqlite3/schema.py

+4 −8

Original line number	Diff line number	Diff line
		@@ -121,14 +121,10 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
		Removes a field from a model. Usually involves deleting a column,
		but for M2Ms may involve deleting a table.
		"""
		# M2M fields are a special case
		if isinstance(field, ManyToManyField):
		# For implicit M2M tables, delete the auto-created table
		if field.rel.through._meta.auto_created:
		self.delete_model(field.rel.through)
		# For explicit "through" M2M fields, do nothing
		# Special-case implicit M2M tables
		if isinstance(field, ManyToManyField) and field.rel.through._meta.auto_created:
		return self.delete_model(field.rel.through)
		# For everything else, remake.
		else:
		self._remake_table(model, delete_fields=[field])

		def alter_field(self, model, old_field, new_field, strict=False):

django/db/migrations/autodetector.py

+10 −10

Original line number	Diff line number	Diff line
		@@ -223,6 +223,16 @@ class MigrationAutodetector(object):
		unique_together=unique_together
		)
		)
		# Removing models
		removed_models = set(old_model_keys) - set(new_model_keys)
		for app_label, model_name in removed_models:
		model_state = self.from_state.models[app_label, model_name]
		self.add_to_migration(
		app_label,
		operations.DeleteModel(
		model_state.name,
		)
		)
		# Changes within models
		kept_models = set(old_model_keys).intersection(new_model_keys)
		old_fields = set()
		@@ -338,16 +348,6 @@ class MigrationAutodetector(object):
		)
		for app_label, operation in unique_together_operations:
		self.add_to_migration(app_label, operation)
		# Removing models
		removed_models = set(old_model_keys) - set(new_model_keys)
		for app_label, model_name in removed_models:
		model_state = self.from_state.models[app_label, model_name]
		self.add_to_migration(
		app_label,
		operations.DeleteModel(
		model_state.name,
		)
		)
		# Alright, now add internal dependencies
		for app_label, migrations in self.migrations.items():
		for m1, m2 in zip(migrations, migrations[1:]):

django/db/migrations/migration.py

+0 −1

Original line number	Diff line number	Diff line
		@@ -127,7 +127,6 @@ class Migration(object):
		to_run.reverse()
		for operation, to_state, from_state in to_run:
		operation.database_backwards(self.app_label, schema_editor, from_state, to_state)
		return project_state


		def swappable_dependency(value):

django/db/migrations/state.py

+0 −10

Original line number	Diff line number	Diff line
		@@ -51,16 +51,6 @@ class ProjectState(object):
		if len(new_unrendered_models) == len(unrendered_models):
		raise InvalidBasesError("Cannot resolve bases for %r" % new_unrendered_models)
		unrendered_models = new_unrendered_models
		# make sure apps has no dangling references
		if self.apps._pending_lookups:
		# Raise an error with a best-effort helpful message
		# (only for the first issue). Error message should look like:
		# "ValueError: Lookup failed for model referenced by
		# field migrations.Book.author: migrations.Author"
		dangling_lookup = list(self.apps._pending_lookups.items())[0]
		raise ValueError("Lookup failed for model referenced by field {field}: {model[0]}.{model[1]}".format(
		field=dangling_lookup[1][0][1],
		model=dangling_lookup[0]))
		return self.apps

		@classmethod

tests/migrations/test_autodetector.py

+3 −54

Original line number	Diff line number	Diff line
		@@ -33,15 +33,11 @@ class AutodetectorTests(TestCase):
		other_stable = ModelState("otherapp", "Stable", [("id", models.AutoField(primary_key=True))])
		third_thing = ModelState("thirdapp", "Thing", [("id", models.AutoField(primary_key=True))])
		book = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Author")), ("title", models.CharField(max_length=200))])
		book_with_no_author = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("title", models.CharField(max_length=200))])
		book_with_author_renamed = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Writer")), ("title", models.CharField(max_length=200))])
		book_with_field_and_author_renamed = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("writer", models.ForeignKey("testapp.Writer")), ("title", models.CharField(max_length=200))])
		book_with_multiple_authors = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("authors", models.ManyToManyField("testapp.Author")), ("title", models.CharField(max_length=200))])
		book_with_multiple_authors_through_attribution = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("authors", models.ManyToManyField("testapp.Author", through="otherapp.Attribution")), ("title", models.CharField(max_length=200))])
		book_unique = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Author")), ("title", models.CharField(max_length=200))], {"unique_together": [("author", "title")]})
		book_unique_2 = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Author")), ("title", models.CharField(max_length=200))], {"unique_together": [("title", "author")]})
		book_unique_3 = ModelState("otherapp", "Book", [("id", models.AutoField(primary_key=True)), ("newfield", models.IntegerField()), ("author", models.ForeignKey("testapp.Author")), ("title", models.CharField(max_length=200))], {"unique_together": [("title", "newfield")]})
		attribution = ModelState("otherapp", "Attribution", [("id", models.AutoField(primary_key=True)), ("author", models.ForeignKey("testapp.Author")), ("book", models.ForeignKey("otherapp.Book"))])
		edition = ModelState("thirdapp", "Edition", [("id", models.AutoField(primary_key=True)), ("book", models.ForeignKey("otherapp.Book"))])
		custom_user = ModelState("thirdapp", "CustomUser", [("id", models.AutoField(primary_key=True)), ("username", models.CharField(max_length=255))])
		knight = ModelState("eggs", "Knight", [("id", models.AutoField(primary_key=True))])
		@@ -556,65 +552,18 @@ class AutodetectorTests(TestCase):
		"""
		# Make state
		before = self.make_project_state([self.author_with_publisher_string])
		after = self.make_project_state([self.author_with_publisher, self.publisher])
		after = self.make_project_state([self.author_with_publisher])
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		# Right number of migrations?
		self.assertEqual(len(changes['testapp']), 1)
		# Right number of actions?
		migration = changes['testapp'][0]
		self.assertEqual(len(migration.operations), 3)
		self.assertEqual(len(migration.operations), 2)
		# Right actions?
		action = migration.operations[0]
		self.assertEqual(action.__class__.__name__, "CreateModel")
		self.assertEqual(action.name, "Publisher")
		action = migration.operations[1]
		self.assertEqual(action.__class__.__name__, "AddField")
		self.assertEqual(action.name, "publisher")
		action = migration.operations[2]
		self.assertEqual(action.__class__.__name__, "RemoveField")
		self.assertEqual(action.name, "publisher_name")

		def test_foreign_key_removed_before_target_model(self):
		"""
		Removing an FK and the model it targets in the same change must remove
		the FK field before the model to maintain consistency.
		"""
		before = self.make_project_state([self.author_with_publisher, self.publisher])
		after = self.make_project_state([self.author_name]) # removes both the model and FK
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		# Right number of migrations?
		self.assertEqual(len(changes['testapp']), 1)
		# Right number of actions?
		migration = changes['testapp'][0]
		self.assertEqual(len(migration.operations), 2)
		# Right actions in right order?
		action = migration.operations[0]
		self.assertEqual(action.__class__.__name__, "RemoveField")
		self.assertEqual(action.name, "publisher")
		action = migration.operations[1]
		self.assertEqual(action.__class__.__name__, "DeleteModel")
		self.assertEqual(action.name, "Publisher")

		def test_many_to_many_removed_before_through_model(self):
		"""
		Removing a ManyToManyField and the "through" model in the same change must remove
		the field before the model to maintain consistency.
		"""
		before = self.make_project_state([self.book_with_multiple_authors_through_attribution, self.author_name, self.attribution])
		after = self.make_project_state([self.book_with_no_author, self.author_name]) # removes both the through model and ManyToMany
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		# Right number of migrations?
		self.assertEqual(len(changes['otherapp']), 1)
		# Right number of actions?
		migration = changes['otherapp'][0]
		self.assertEqual(len(migration.operations), 2)
		# Right actions in right order?
		action = migration.operations[0]
		self.assertEqual(action.__class__.__name__, "RemoveField")
		self.assertEqual(action.name, "authors")
		action = migration.operations[1]
		self.assertEqual(action.__class__.__name__, "DeleteModel")
		self.assertEqual(action.name, "Attribution")
		self.assertEqual(action.name, "publisher_name")