Comparison of DB migrations and models assumes, that String and Text are equal types.

[Viktor Serhieiev]

If column type declared as sqlalchemy.Text in migration script and as sqlalchemy.String (without length) in model description, comparison of DB migrations and models supposes, that these types are equal. This can be ok in some use cases, but if we will try to initialize MySQL database schema from models medtadata, we will get an exception "CompileError: (in table '...', column '...'): VARCHAR requires a length on dialect mysql". See an example of the full traceback in [1]

[1] - http://paste.openstack.org/show/123942/