Handle Select widget specifically otherwise field.widget.format_value will return a list. #617

Author: adamghill

django_unicorn/components/unicorn_view.py

@@ -11,7 +11,7 @@
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.db.models import Model
-from django.forms.widgets import CheckboxInput
+from django.forms.widgets import CheckboxInput, Select
 from django.http import HttpRequest
 from django.utils.decorators import classonlymethod
 from django.views.generic.base import TemplateView
@@ -457,20 +457,23 @@ def get_frontend_context_variables(self) -> str:
         form = self._get_form(attributes)
 
         if form:
-            form.is_valid()
-
             for key in attributes.keys():
                 if key in form.fields:
                     field = form.fields[key]
 
                     if key in form.cleaned_data:
                         cleaned_value = form.cleaned_data[key]
-                        value = field.widget.format_value(cleaned_value)
 
                         if isinstance(field.widget, CheckboxInput) and isinstance(cleaned_value, bool):
                             # Handle booleans for checkboxes explicitly because `format_value`
-                            # returns `None` in this case
+                            # returns `None`
+                            value = cleaned_value
+                        elif isinstance(field.widget, Select) and not field.widget.allow_multiple_selected:
+                            # Handle value for Select widgets explicitly because `format_value`
+                            # returns a list of stringified values
                             value = cleaned_value
+                        else:
+                            value = field.widget.format_value(cleaned_value)
 
                         # Don't update the frontend variable if the only change is
                         # stripping off the whitespace from the field value

example/books/migrations/0004_book_type.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.5 on 2023-10-29 22:53
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("books", "0003_auto_20221110_0400"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="book",
+            name="type",
+            field=models.IntegerField(choices=[(1, "Hardcover"), (2, "Softcover")], default=1),
+        ),
+    ]

example/books/models.py

@@ -2,8 +2,10 @@
 
 
 class Book(models.Model):
+    TYPES = ((1, "Hardcover"), (2, "Softcover"))
     title = models.CharField(max_length=255)
     date_published = models.DateField()
+    type = models.IntegerField(choices=TYPES, default=1)
 
 
 class Author(models.Model):

tests/components/test_component.py

@@ -291,7 +291,7 @@ def test_get_frontend_context_variables_form_with_boolean_field(component):
     frontend_context_variables = component.get_frontend_context_variables()
     frontend_context_variables_dict = orjson.loads(frontend_context_variables)
 
-    assert frontend_context_variables_dict.get("permanent")
+    assert frontend_context_variables_dict.get("permanent") is not None
 
 
 def test_get_frontend_context_variables_authentication_form(component):

tests/views/fake_components.py

@@ -13,6 +13,7 @@
     PollUpdate,
     UnicornView,
 )
+from example.books.models import Book
 from example.coffee.models import Flavor
 
 
@@ -65,6 +66,21 @@ def test_validation_error_list(self):
         raise ValidationError([ValidationError({"check": "Check is required"}, code="required")])
 
 
+class FakeModelForm(forms.ModelForm):
+    class Meta:
+        model = Book
+        fields = ("title", "date_published", "type")
+
+
+class FakeModelFormComponent(UnicornView):
+    template_name = "templates/test_component.html"
+    form_class = FakeModelForm
+
+    title = None
+    date_published = None
+    type = None  # noqa: A003
+
+
 class FakeModelComponent(UnicornView):
     template_name = "templates/test_component.html"
     flavors = Flavor.objects.all()

tests/views/message/test_sync_input.py

@@ -18,3 +18,28 @@ def test_message_nested_sync_input(client):
 
     assert not response["errors"]
     assert response["data"].get("dictionary") == {"name": "test1"}
+
+
+def test_message_sync_input_choices_with_select_widget(client):
+    """
+    ModelForms with a Model that have a field with `choices` and the form's field uses a Select widget.
+    Need to handle Select widget specifically otherwise `field.widget.format_value` will return a list
+    that only contains one object.
+    """
+
+    data = {"type": 1}
+    action_queue = [
+        {
+            "payload": {"name": "type", "value": 2},
+            "type": "syncInput",
+        }
+    ]
+    response = post_and_get_response(
+        client,
+        url="/message/tests.views.fake_components.FakeModelFormComponent",
+        data=data,
+        action_queue=action_queue,
+    )
+
+    assert not response["errors"]
+    assert response["data"].get("type") == 2