add support for nested forms

Author: timgraham

django_mongodb_backend/forms/fields/embedded_model_array.py

@@ -22,7 +22,7 @@ def __init__(self, model, *, prefix, max_num=None, extra_forms=3, **kwargs):
     def clean(self, value):
         if not value:
             return []
-        formset = self.formset(value, prefix=self.prefix)
+        formset = self.formset(value, prefix=self.prefix_override or self.prefix)
         if not formset.is_valid():
             raise ValidationError(formset.errors + formset.non_form_errors())
         cleaned_data = []
@@ -39,16 +39,18 @@ def has_changed(self, initial, data):
         return formset.has_changed()
 
     def get_bound_field(self, form, field_name):
-        return EmbeddedModelArrayBoundField(form, self, field_name)
+        # Nested embedded model form fields need a double prefix.
+        self.prefix_override = f"{form.prefix}-{self.prefix}" if form.prefix else None
+        return EmbeddedModelArrayBoundField(form, self, field_name, self.prefix_override)
 
 
 class EmbeddedModelArrayBoundField(forms.BoundField):
-    def __init__(self, form, field, name):
+    def __init__(self, form, field, name, prefix_override):
         super().__init__(form, field, name)
         self.formset = field.formset(
             self.data if form.is_bound else None,
             initial=models_to_dicts(self.initial),
-            prefix=self.html_name,
+            prefix=prefix_override if prefix_override else self.html_name,
         )
 
     def __str__(self):

tests/model_forms_/forms.py

@@ -1,6 +1,6 @@
 from django import forms
 
-from .models import Author, Book, Movie
+from .models import Author, Book, Movie, Store
 
 
 class AuthorForm(forms.ModelForm):
@@ -19,3 +19,9 @@ class MovieForm(forms.ModelForm):
     class Meta:
         fields = "__all__"
         model = Movie
+
+
+class StoreForm(forms.ModelForm):
+    class Meta:
+        fields = "__all__"
+        model = Store

tests/model_forms_/models.py

@@ -44,3 +44,13 @@ class Movie(models.Model):
 
     def __str__(self):
         return self.title
+
+
+class Product(EmbeddedModel):
+    name = models.CharField(max_length=255)
+    reviews = EmbeddedModelArrayField(Review)
+
+
+class Store(models.Model):
+    name = models.CharField(max_length=255)
+    products = EmbeddedModelArrayField(Product)