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
25332	migrate fails for CharField if max_length is omitted	Karolis Ryselis	nobody	"When adding a CharField to model and leaving out max_length undefined Django migration is created but fails when is run.

Consider this model:


{{{
class Order(Model):
    foo = models.DateField(verbose_name=_(""Foo""))
}}}

We change it to this:

{{{
class Order(Model):
    foo = models.DateField(verbose_name=_(""Foo""))
    payment_terms = models.CharField(verbose_name=_(""Payment terms""), blank=True)
}}}
note that I omit max_length parameter. I run makemigrations for my app, the migration is created with the following operation:

{{{
        migrations.AddField(
            model_name='order',
            name='payment_terms',
            field=models.CharField(verbose_name='Payment terms', blank=True),
            preserve_default=True,
        )
}}}

When I run the migration, it spits the following error:
{{{
 File ""/usr/lib/python3.4/runpy.py"", line 182, in run_module
    return _run_module_code(code, init_globals, run_name, mod_spec)
  File ""/usr/lib/python3.4/runpy.py"", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File ""/usr/lib/python3.4/runpy.py"", line 85, in _run_code
    exec(code, run_globals)
  File ""/home/ryselis/PycharmProjects/ez_demo/manage.py"", line 14, in <module>
    execute_from_command_line(sys.argv)
  File ""/usr/local/lib/python3.4/dist-packages/django/core/management/__init__.py"", line 385, in execute_from_command_line
    utility.execute()
  File ""/usr/local/lib/python3.4/dist-packages/django/core/management/__init__.py"", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File ""/usr/local/lib/python3.4/dist-packages/django/core/management/base.py"", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File ""/usr/local/lib/python3.4/dist-packages/django/core/management/base.py"", line 338, in execute
    output = self.handle(*args, **options)
  File ""/usr/local/lib/python3.4/dist-packages/django/core/management/commands/migrate.py"", line 161, in handle
    executor.migrate(targets, plan, fake=options.get(""fake"", False))
  File ""/usr/local/lib/python3.4/dist-packages/django/db/migrations/executor.py"", line 68, in migrate
    self.apply_migration(migration, fake=fake)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/migrations/executor.py"", line 102, in apply_migration
    migration.apply(project_state, schema_editor)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/migrations/migration.py"", line 108, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/migrations/operations/fields.py"", line 37, in database_forwards
    field,
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/django/schema.py"", line 49, in add_field
    super(DatabaseSchemaEditor, self).add_field(model, field)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/backends/schema.py"", line 388, in add_field
    self.execute(sql, params)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/backends/schema.py"", line 111, in execute
    cursor.execute(sql, params)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/backends/utils.py"", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File ""/usr/local/lib/python3.4/dist-packages/django/db/backends/utils.py"", line 65, in execute
    return self.cursor.execute(sql, params)
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/django/base.py"", line 133, in execute
    return self._execute_wrapper(self.cursor.execute, query, args)
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/django/base.py"", line 116, in _execute_wrapper
    utils.ProgrammingError(err.msg), sys.exc_info()[2])
  File ""/usr/local/lib/python3.4/dist-packages/django/utils/six.py"", line 658, in reraise
    raise value.with_traceback(tb)
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/django/base.py"", line 113, in _execute_wrapper
    return method(query, args)
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/cursor.py"", line 507, in execute
    self._handle_result(self._connection.cmd_query(stmt))
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/connection.py"", line 720, in cmd_query
    result = self._handle_result(self._send_cmd(ServerCmd.QUERY, query))
  File ""/usr/local/lib/python3.4/dist-packages/mysql/connector/connection.py"", line 638, in _handle_result
    raise errors.get_exception(packet)
django.db.utils.ProgrammingError: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'None) DEFAULT '' NOT NULL' at line 1
}}}

The SQL generated is 

{{{
ALTER TABLE `myapp_order` ADD COLUMN `payment_terms` varchar(None) DEFAULT '' NOT NULL
}}}

The docs say that ""The max_length is enforced at the database level and in Django’s validation.""

I suppose this is not the correct behaviour. It used to generate a reasonable error messsage in earlier Django versions."	Bug	closed	Migrations	1.7	Normal	worksforme	max_length CharField migrate		Unreviewed	0	0	0	0	0	0