id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 27378 Add UUID serialization support to migration writer Yuriy Korobko Tim Graham "Using following model {{{ import uuid from django.db import models # Create your models here. class Student(models.Model): FRESHMAN = uuid.UUID('5c859437-d061-4847-b3f7-e6b78852f8c8') SOPHOMORE = uuid.UUID('c7853ec1-2ea3-4359-b02d-b54e8f1bcee2') JUNIOR = uuid.UUID('94a43637-6dfc-4209-852a-bd9bd8c0101f') SENIOR = uuid.UUID('dfb9cc50-c332-4809-9b4c-69c81a7489d0') MENTOR = uuid.UUID('b8f3897a-0a0a-4630-8f1b-1ca4b0ee37ca') YEAR_IN_SCHOOL_CHOICES = ( (FRESHMAN, 'Freshman'), (SOPHOMORE, 'Sophomore'), (JUNIOR, 'Junior'), (SENIOR, 'Senior'), (MENTOR, 'Mentor'), ) year_in_school = models.UUIDField(choices=YEAR_IN_SCHOOL_CHOICES, default=FRESHMAN) }}} According to documentation it should work, and it works until you try to make migrations for this model, it fails with exception {{{ Migrations for 'testapp': testapp/migrations/0001_initial.py: - Create model Student Traceback (most recent call last): File ""./manage.py"", line 22, in execute_from_command_line(sys.argv) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/__init__.py"", line 367, in execute_from_command_line utility.execute() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/__init__.py"", line 359, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/base.py"", line 294, in run_from_argv self.execute(*args, **cmd_options) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/base.py"", line 345, in execute output = self.handle(*args, **options) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/commands/makemigrations.py"", line 189, in handle self.write_migration_files(changes) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/core/management/commands/makemigrations.py"", line 224, in write_migration_files migration_string = writer.as_string() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/writer.py"", line 163, in as_string operation_string, operation_imports = OperationWriter(operation).serialize() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/writer.py"", line 120, in serialize _write(arg_name, arg_value) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/writer.py"", line 84, in _write arg_string, arg_imports = MigrationWriter.serialize(_arg_value) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/writer.py"", line 293, in serialize return serializer_factory(value).serialize() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/serializer.py"", line 228, in serialize return self.serialize_deconstructed(path, args, kwargs) File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/serializer.py"", line 100, in serialize_deconstructed arg_string, arg_imports = serializer_factory(arg).serialize() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/serializer.py"", line 43, in serialize item_string, item_imports = serializer_factory(item).serialize() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/serializer.py"", line 43, in serialize item_string, item_imports = serializer_factory(item).serialize() File ""/home/yuriy/dev/uuidtest/env/lib/python3.5/site-packages/django/db/migrations/serializer.py"", line 388, in serializer_factory ""topics/migrations/#migration-serializing"" % (value, get_docs_version()) ValueError: Cannot serialize: UUID('5c859437-d061-4847-b3f7-e6b78852f8c8') There are some values Django cannot serialize into migration files. For more, see https://docs.djangoproject.com/en/1.10/topics/migrations/#migration-serializing }}} Here is a small patch that add UUIDSerializer to migration serializers and tells serializer_factory to use it in case of UUID value {{{ --- django/db/migrations/serializer.py.orig 2016-10-24 12:16:21.000000000 +0300 +++ django/db/migrations/serializer.py 2016-10-24 15:32:33.908818046 +0300 @@ -6,6 +6,7 @@ import functools import math import types +import uuid from importlib import import_module from django.db import models @@ -319,6 +320,10 @@ else: return ""%s.%s"" % (module, self.value.__name__), {""import %s"" % module} +class UUIDSerializer(BaseSerializer): + def serialize(self): + return ""uuid.UUID('%s')"" % self.value, {""import uuid""} + def serializer_factory(value): from django.db.migrations.writer import SettingsReference @@ -382,6 +387,8 @@ return IterableSerializer(value) if isinstance(value, (COMPILED_REGEX_TYPE, RegexObject)): return RegexSerializer(value) + if isinstance(value, uuid.UUID): + return UUIDSerializer(value) raise ValueError( ""Cannot serialize: %r\nThere are some values Django cannot serialize into "" ""migration files.\nFor more, see https://docs.djangoproject.com/en/%s/"" }}} After applying this change everything works as expected {{{ (env) yuriy@yuriy-desktop:~/dev/uuidtest/src/uuidtest$ ./manage.py makemigrations Migrations for 'testapp': testapp/migrations/0001_initial.py: - Create model Student (env) yuriy@yuriy-desktop:~/dev/uuidtest/src/uuidtest$ ./manage.py migrate Operations to perform: Apply all migrations: admin, auth, contenttypes, sessions, testapp Running migrations: Applying contenttypes.0001_initial... OK Applying auth.0001_initial... OK Applying admin.0001_initial... OK Applying admin.0002_logentry_remove_auto_add... OK Applying contenttypes.0002_remove_content_type_name... OK Applying auth.0002_alter_permission_name_max_length... OK Applying auth.0003_alter_user_email_max_length... OK Applying auth.0004_alter_user_username_opts... OK Applying auth.0005_alter_user_last_login_null... OK Applying auth.0006_require_contenttypes_0002... OK Applying auth.0007_alter_validators_add_error_messages... OK Applying auth.0008_alter_user_username_max_length... OK Applying sessions.0001_initial... OK Applying testapp.0001_initial... OK (env) yuriy@yuriy-desktop:~/dev/uuidtest/src/uuidtest$ }}} migratin produced is {{{ # -*- coding: utf-8 -*- # Generated by Django 1.10.2 on 2016-10-24 13:30 from __future__ import unicode_literals from django.db import migrations, models import uuid class Migration(migrations.Migration): initial = True dependencies = [ ] operations = [ migrations.CreateModel( name='Student', fields=[ ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')), ('year_in_school', models.UUIDField(choices=[(uuid.UUID('5c859437-d061-4847-b3f7-e6b78852f8c8'), 'Freshman'), (uuid.UUID('c7853ec1-2ea3-4359-b02d-b54e8f1bcee2'), 'Sophomore'), (uuid.UUID('94a43637-6dfc-4209-852a-bd9bd8c0101f'), 'Junior'), (uuid.UUID('dfb9cc50-c332-4809-9b4c-69c81a7489d0'), 'Senior'), (uuid.UUID('b8f3897a-0a0a-4630-8f1b-1ca4b0ee37ca'), 'Mentor')], default=uuid.UUID('5c859437-d061-4847-b3f7-e6b78852f8c8'))), ], ), ] }}} I have no idea if it is correct, but works for me, if it should be fixed in other place could you point me where to look? Thanks " New feature closed Migrations dev Normal fixed uuid choices migration Ready for checkin 1 0 0 0 1 0