Django 4.2 - Handling Field-Level Validation in a Custom Model Form with Inline Formsets
I'm having trouble implementing field-level validation in a custom model form that is used within an inline formset in Django 4.2. The scenario arises when I try to validate a field based on the value of another field in the same form. I have a `Product` model and an `Order` model, where each `Order` can have multiple `Product` instances as inline forms. I want to ensure that the `quantity` field of each `Product` want to exceed the `available_stock` defined in the `Product` model. Here's a simplified version of my code: ```python class Product(models.Model): name = models.CharField(max_length=100) available_stock = models.PositiveIntegerField() class Order(models.Model): products = models.ManyToManyField(Product) class ProductForm(forms.ModelForm): class Meta: model = Product fields = ['name', 'quantity'] def clean_quantity(self): quantity = self.cleaned_data.get('quantity') product = self.instance # This should refer to the current Product instance if quantity > product.available_stock: raise forms.ValidationError('Quantity want to exceed available stock.') return quantity class OrderForm(forms.ModelForm): class Meta: model = Order fields = [] # Assuming no fields for Order itself ProductFormSet = inlineformset_factory(Order, Product, form=ProductForm, extra=1) ``` When I submit the formset, I get the following behavior: `ValidationError: ['Quantity want to exceed available stock.']`, but it seems to trigger even when the quantity is within the limits. I've confirmed that the `available_stock` value is correct. I attempted to debug this by printing out the `product.available_stock` value in the `clean_quantity` method, and it correctly shows the available stock, yet the validation fails. I also checked if `self.instance` is pointing to the right product, and it appears to be correct as well. Could the scenario be with how Django handles inline formsets and model instances during validation, or am I missing something in my implementation? I would appreciate any insights or solutions to ensure that the field-level validation works as expected.