FileField / ImageField crash with WTForms >= 2.0

[Mathieu Virbel]

The current dependency for Flask-SuperAdmin is Flask-WTF>=0.9 which itself install wtforms >= 1.0.4.

As for today, version for Flask-WTF is 0.11, and wtforms is 2.0.2.

The following model crash:

class Agenda(Document):
    image = ImageField()

Here is the crash:

Traceback (most recent call last):
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/model/base.py", line 266, in add
    % self.model.__name__)
Exception: The database model for 'Agenda' should have an __init__ with all arguments set to defaults.

But flask-superadmin is hiding the original error with a custom raise. After just changing the source code, the original exception is:

Traceback (most recent call last):
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/base.py", line 37, in inner
    return f(self, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/model/base.py", line 260, in add
    form = Form(obj=self.model())
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/form.py", line 212, in __call__
    return type.__call__(cls, *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/form.py", line 18, in __init__
    super(BaseForm, self).__init__(obj=obj, prefix=prefix, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_wtf/form.py", line 96, in __init__
    *args, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/ext/csrf/form.py", line 21, in __init__
    super(SecureForm, self).__init__(formdata, obj, prefix, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/form.py", line 272, in __init__
    super(Form, self).__init__(self._unbound_fields, meta=meta_obj, prefix=prefix)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/form.py", line 52, in __init__
    field = meta.bind_field(self, unbound_field, options)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/meta.py", line 27, in bind_field
    return unbound_field.bind(form=form, **options)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/fields/core.py", line 346, in bind
    return self.field_class(*self.args, **kw)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/flask_superadmin/form.py", line 125, in __init__
    self._clear = self.clear_field.bind(form=None, name=self._clear_name, prefix=self._prefix, id=self._clear_id)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/fields/core.py", line 346, in bind
    return self.field_class(*self.args, **kw)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/fields/core.py", line 693, in __init__
    super(BooleanField, self).__init__(label, validators, **kwargs)
  File "/home/tito/.envs/2caps-backend/lib/python2.7/site-packages/wtforms/fields/core.py", line 92, in __init__
    raise TypeError("Must provide one of _form or _meta")
TypeError: Must provide one of _form or _meta

Which look like something new from the wforms in 2.0: "Class Meta paradigm allows customization of many aspects of WTForms".

See http://wtforms.readthedocs.org/en/latest/meta.html

[Mathieu Virbel]

I tried to debug it, but got lost into all the layers of abstraction in flask superadmin. The current fix is to downgrade wtforms to a version before 2.0, like 1.0.5.

Ie: pip install --upgrade wtforms==1.0.5

[genxstylez]

+1