ModelForms calls default on fields that ain't selected.

[skruven96]

Hello,

Every time you create an instance of MyForm in the example below create_a function gets called which creates an instance of ModelA which clutters the database with ModelAs.

# models.py
def create_a():
    return ModelA.objects.create(name='<default-name>').id

class ModelA(models.Model):
    pass

class ModelB(models.Model):
    name = models.CharField(max_length=123)
    reference = models.ForeignKey(ModelA, default=create_a)

# views.py
class MyForm(ModelForm):
    class Meta:
        model = ModelB
        fields = ['name']

[Simon Charette]

Hello there,

That's expected as your ModelForm subclass will create a ModelB instance ​on initialization as you didn't provide one yourself.

You should pass an instance=ModelB(reference=None) when creating a MyForm instance yourself and then make sure to assign a ModelA instance to form.instance.reference before saving it.

For such usage questions please use our support channels instead as this bug tracker is exclusively devoted to serve the development of Django itself.