Django 1.10 / AttributeError: 'list' objec

Question

I got this error:

Internal Server Error: /QOP/1/editar/ Traceback (most recent call last): ... opts = instance._meta AttributeError: 'list' object has no attribute '_meta' [25/Nov/2016 19:17:00] "GET /QOP/1/editar/ HTTP/1.1" 500 77572

models.py

from django.db import models
from smart_selects.db_fields import ChainedForeignKey
from django.core.urlresolvers import reverse
from modulos.modPessoas.models import Postos


# Quadro Orgânico Pessoal

class Qop(models.Model):
    class Meta:
        ordering = ['qop_ref']
        verbose_name = 'Quadro Orgânico Pessoal'
        verbose_name_plural = 'Quadro Orgânico Pessoal'

    qop_ref = models.CharField(max_length=255, null=True, blank=True, verbose_name='Referência')
    qop_nome = models.CharField(max_length=255, null=True, blank=True, verbose_name='QOP Nome')
    qop_dt_arov = models.DateField(null=True, blank=True, verbose_name='Data de Aprovação')
    qop_atv = models.BooleanField(default=True, verbose_name='Ativo?')

    def __str__(self):
        return '{} {}'.format(self.qop_ref, self.qop_nome)

    def get_absulute_url(self):
        return reverse("QOP:detalhe", kwargs={"pk": self.id})

views.py

def qop_editar(request, pk=None):
    instance = get_list_or_404(Qop, id=pk)
    form = QopForm(request.POST or None, request.FILES or None, instance=instance)
    if form.is_valid():
        instance = form.save(commit=False)
        instance.save()
    contexto = {
        "titulo": "QOP Editar",
        "instance": instance,
        "form": form
    }
    return render(request, "modQOP/editar.html", contexto)

urls.py

from django.conf.urls import url
from .views import (index,
                    qop_lista,
                    qop_detalhe,
                    qop_criar,
                    qop_editar)

urlpatterns = [
    url(r'^$', index),
    url(r'^criar/$', qop_criar),
    url(r'^lista/$', qop_lista),
    url(r'^(?P<pk>\d+)/detalhe/$', qop_detalhe, name='detalhe'),
    url(r'^(?P<pk>\d+)/editar/$', qop_editar, name='editar'),
]

template

<form method="post" action="" enctype="multipart/form-data">
{% csrf_token %}
    Nome: {{ form.qop_nome }}<br>
    Nº de Referência: {{ form.qop_ref }}<br>
    Data de Aprovação: {{ form.qop_dt_arov }}<br>
    Ativo? {{ form.qop_atv }}<br>
<button type="submit" class="button">Guardar</button>
</form>

What is wrong with code?

Thanks in advance!

edit: Full traceback:

Environment:


Request Method: GET
Request URL: http://127.0.0.1:8000/QOP/1/editar/

Django Version: 1.10.3
Python Version: 3.5.2
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'smart_selects',
 'modulos.modAutenticacao',
 'modulos.modQOP',
 'modulos.modPessoas']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "C:\Users\Filipe\envRTm\lib\site-packages\django\core\handlers\exception.py" in inner
  39.             response = get_response(request)

File "C:\Users\Filipe\envRTm\lib\site-packages\django\core\handlers\base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "C:\Users\Filipe\envRTm\lib\site-packages\django\core\handlers\base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "C:\Users\Filipe\Documents\GitHub\rhead\modulos\modQOP\views.py" in qop_editar
  36.     form = QopForm(request.POST or None, request.FILES or None, instance=instance)

File "C:\Users\Filipe\envRTm\lib\site-packages\django\forms\models.py" in __init__
  282.             object_data = model_to_dict(instance, opts.fields, opts.exclude)

File "C:\Users\Filipe\envRTm\lib\site-packages\django\forms\models.py" in model_to_dict
  87.     opts = instance._meta

Exception Type: AttributeError at /QOP/1/editar/
Exception Value: 'list' object has no attribute '_meta'

Answer 1

You can't pass the result from get_list_or_404 to a ModelForm instance as it will return an QuerySet. You need to use get_object_or_404 to return an instance of the model.