Django Exception DoesNotExist

I have a model that has Django's model fields AND python properties at the same time. Ex:

Edit2: Updated with actual models (sorry for the portuguese names)

#On Produto.models.py
from django.db          import models
from django.forms       import ModelForm
from openshift.models   import AbstractModel

from openshift.produto.models import app_name


class Produto(models.Model):

    class Meta:
        app_label = app_name


    descricao = models.CharField(max_length=128)    
    und_choices = (
        ('UND', 'Unidade'),
        ('M',     'Metro'),
        ('Kg',     'Quilograma'),
        ('PC',     'Peça'),
    )
    unidade   = models.CharField(max_length=3, choices=und_choices, default='UND')

#On Estoque.models.py

from django.db          import models
from django.forms       import ModelForm
from openshift.models   import AbstractModel
from produto.models     import Produto

from openshift.estoque.models import app_name

class Estoque(models.Model):

    class Meta:
        app_label = app_name

    id = models.IntegerField(primary_key=True)
    produtoid   = models.ForeignKey(Produto, unique=True)
    quantidade  = models.DecimalField(max_digits=20, decimal_places=4)
    valorunit   = models.DecimalField(max_digits=20, decimal_places=4)
    valortotal  = models.DecimalField(max_digits=20, decimal_places=2)   


    _field_labels = {
        "id" : r"Código", 
        "produtoid"  : r"Produto", 
        "quantidade" : r"Quantidade",
        "valorunit" : r"Valor Unitário",
        "valortotal" : r"Valor Total"
    }

    _view_order = ['id', 'produtoid', 'quantidade', 'valorunit', 'valortotal']

    @property
    def Vars(self):
        return {'field_labels': self._field_labels, 'view_order': self._view_order}

#on project.views.main_request

obj = get_model('Estoque', 'Estoque')().Vars #Here is where the Exception triggers.

If i try to call the property "Vars" before I call the save() method (during the creation of the model's record), django keeps raising a DoesNotExist exception, even though the "Vars" property isnt part of the django model.

Can anyone explain why is this happening?

Edit: As Requested:

Django Trace:

Traceback:

File "/home/gleal/cbengine/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response 111. response = callback(request, *callback_args, **callback_kwargs)

File "/home/gleal/cbengine/engine/wsgi/openshift/views.py" in req 48. return browse(request, app, model, var_dict, False)

File "/home/gleal/cbengine/engine/wsgi/openshift/../openshift/subviews/browse.py" in _browse 32. custom_vars['TableColspan'] = len(obj.Vars.get('VIEW_ORDER', {}))

File "/home/gleal/cbengine/engine/wsgi/openshift/../openshift/models.py" in Vars 40. curr_vals[field.name] = getattr(self, field.name) File "/home/gleal/cbengine/local/lib/python2.7/site-packages/django/db/models/fields/related.py" in get 343. raise self.field.rel.to.DoesNotExist

Exception Type: DoesNotExist at /estoque/estoque/browse/ Exception Value:

---

Just figured out that the great villain was the @property decorator on the method Vars .

It was making django try to get values from the instance of the class, and in some cases, it might trigger some querys on the DB made by the Django's ORM (basically, in cases where i tried to get values from the current instance).

I changed the @property to a @classmethod and everything worked like a charm. Like this:

#before
@property
def Vars(self):
    return {'field_labels': self._field_labels, 'view_order': self._view_order}

#after
@classmethod
def Vars(self):
    return {'field_labels': self._field_labels, 'view_order': self._view_order}

Thanks to anyone who tried to help!

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