title: Django form instance is missing a field
body: <p>So I have a problem. I have a model form:</p>
  
  <pre><code>class TeamForm(forms.ModelForm):
  
  class Meta:
      model = Team
      fields = ['name','category','association','division','gender','logo','season']
  
  def __init__(self, *args, **kwargs):
      self.user = kwargs.pop('user')
      super(TeamForm, self).__init__(*args, **kwargs)
      instance = getattr(self, 'instance', None)
  
      utils = CPUtils()
      season_utils = SeasonUtils()
  
      if instance and instance.pk is None:
          self.fields['division'].initial = 1
          self.fields['season'].initial = season_utils.getCurrentSeason().id
  
          if user_role != 'admin':
              self.fields['division'].widget.attrs['disabled'] = True
              self.fields['division'].required = False
  
              self.fields['season'].widget.attrs['disabled'] = True
              self.fields['season'].required = False
  </code></pre>
  
  <p>So I am setting the initial of the form for the field season.
  On my form, it is showing just fine.</p>
  
  <p>So now in my clean method, I want to run some validation and I need to get the instance season.</p>
  
  <p>In my clean method:</p>
  
  <pre><code>    if cleaned_data.get('season') is None:
          cleaned_data['season'] = self.instance.season
  </code></pre>
  
  <p>But it says that self.instance.season: DoesNotExist: Team has no season.</p>
  
  <p>I have been trying to figure this out for a while now and I have no idea what's going on...</p>
  
  <p>EDIT: 
  Here my model:</p>
  
  <pre><code>name = models.CharField(max_length=25,verbose_name=_("name"))
  slug = AutoSlugField(unique=True,populate_from='name')
  season = models.ForeignKey(Season,verbose_name=_("season"),blank=False)
  association = models.ForeignKey(Association,blank=False,null=True,verbose_name=_("association"),on_delete=models.SET_NULL)
  category = models.ForeignKey(Category,verbose_name=_("category"),blank=False,null=True,default=1,on_delete=models.SET_NULL)
  division = models.ForeignKey(Division,verbose_name=_("division"),blank=False,null=True,default=1,on_delete=models.SET_NULL)
  </code></pre>
  
  <p>Also, the instance does not have season only during create and not during update...</p>
  
  <p>Thanks,
  Ara</p>