Fix migration autodector to work correctly with custom deconstructed values (a0c4b846) · Commits · Dom Sekotill / django

django/db/migrations/autodetector.py

+22 −5

Original line number	Diff line number	Diff line
		@@ -64,6 +64,23 @@ class MigrationAutodetector(object):
		if not model._meta.proxy and model._meta.managed and al not in self.to_state.real_apps:
		new_model_keys.append((al, mn))

		def _deep_deconstruct(obj, field=True):
		"""
		Recursive deconstruction for a field and its arguments.
		"""
		if not hasattr(obj, 'deconstruct'):
		return obj
		deconstructed = obj.deconstruct()
		if field:
		deconstructed = deconstructed[1:]
		name, args, kwargs = deconstructed
		return (
		name,
		[_deep_deconstruct(value, field=False) for value in args],
		dict([(key, _deep_deconstruct(value, field=False))
		for key, value in kwargs.items()])
		)

		def _rel_agnostic_fields_def(fields):
		"""
		Return a definition of the fields that ignores field names and
		@@ -71,7 +88,7 @@ class MigrationAutodetector(object):
		"""
		fields_def = []
		for name, field in fields:
		deconstruction = field.deconstruct()[1:]
		deconstruction = _deep_deconstruct(field)
		if field.rel and field.rel.to:
		del deconstruction[2]['to']
		fields_def.append(deconstruction)
		@@ -255,11 +272,11 @@ class MigrationAutodetector(object):
		new_model_state = self.to_state.models[app_label, model_name]
		field = new_model_state.get_field_by_name(field_name)
		# Scan to see if this is actually a rename!
		field_dec = field.deconstruct()[1:]
		field_dec = _deep_deconstruct(field)
		found_rename = False
		for rem_app_label, rem_model_name, rem_field_name in (old_fields - new_fields):
		if rem_app_label == app_label and rem_model_name == model_name:
		old_field_dec = old_model_state.get_field_by_name(rem_field_name).deconstruct()[1:]
		old_field_dec = _deep_deconstruct(old_model_state.get_field_by_name(rem_field_name))
		if field.rel and field.rel.to and 'to' in old_field_dec[2]:
		old_rel_to = old_field_dec[2]['to']
		if old_rel_to in renamed_models_rel:
		@@ -326,8 +343,8 @@ class MigrationAutodetector(object):
		old_model_state = self.from_state.models[app_label, old_model_name]
		new_model_state = self.to_state.models[app_label, model_name]
		old_field_name = renamed_fields.get((app_label, model_name, field_name), field_name)
		old_field_dec = old_model_state.get_field_by_name(old_field_name).deconstruct()[1:]
		new_field_dec = new_model_state.get_field_by_name(field_name).deconstruct()[1:]
		old_field_dec = _deep_deconstruct(old_model_state.get_field_by_name(old_field_name))
		new_field_dec = _deep_deconstruct(new_model_state.get_field_by_name(field_name))
		if old_field_dec != new_field_dec:
		self.add_to_migration(
		app_label,

tests/migrations/test_autodetector.py

+22 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,15 @@ from django.db.migrations.graph import MigrationGraph
		from django.db import models


		class DeconstructableObject(object):
		"""
		A custom deconstructable object.
		"""

		def deconstruct(self):
		return self.__module__ + '.' + self.__class__.__name__, [], {}


		class AutodetectorTests(TestCase):
		"""
		Tests the migration autodetector.
		@@ -17,6 +26,8 @@ class AutodetectorTests(TestCase):
		author_name_longer = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=400))])
		author_name_renamed = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("names", models.CharField(max_length=200))])
		author_name_default = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200, default='Ada Lovelace'))])
		author_name_deconstructable_1 = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200, default=DeconstructableObject()))])
		author_name_deconstructable_2 = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200, default=DeconstructableObject()))])
		author_with_book = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200)), ("book", models.ForeignKey("otherapp.Book"))])
		author_renamed_with_book = ModelState("testapp", "Writer", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200)), ("book", models.ForeignKey("otherapp.Book"))])
		author_with_publisher_string = ModelState("testapp", "Author", [("id", models.AutoField(primary_key=True)), ("name", models.CharField(max_length=200)), ("publisher_name", models.CharField(max_length=200))])
		@@ -550,6 +561,17 @@ class AutodetectorTests(TestCase):
		self.assertEqual(action.__class__.__name__, "AddField")
		self.assertEqual(action.name, "name")

		def test_custom_deconstructable(self):
		"""
		Two instances which deconstruct to the same value aren't considered a
		change.
		"""
		before = self.make_project_state([self.author_name_deconstructable_1])
		after = self.make_project_state([self.author_name_deconstructable_2])
		autodetector = MigrationAutodetector(before, after)
		changes = autodetector._detect_changes()
		self.assertEqual(changes, {})

		def test_replace_string_with_foreignkey(self):
		"""
		Adding an FK in the same "spot" as a deleted CharField should work. (#22300).