#25332: migrate fails for CharField if max_length is omitted
----------------------------+------------------------------------------
Reporter: ryselis | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Keywords: max_length CharField migrate
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+------------------------------------------
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.
--
Ticket URL: <https://code.djangoproject.com/ticket/25332>
Django <https://code.djangoproject.com/>
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