Handle subclasses of PolymorphicModel being abstract

nested_admin/polymorphic.py

@@ -32,14 +32,52 @@ def get_base_polymorphic_models(child_model):
  return models
 
 
-def get_child_polymorphic_models(model):
- models = []
- for m in model.__subclasses__():
- if (isinstance(model, PolymorphicModelBase)
- and model is not PolymorphicModel
- and not model._meta.abstract):
- models.append(model)
- return models
+def get_all_subclasses(python_class):
+ """
+ Helper function to get all the subclasses of a class.
+
+ Taken from: https://gist.github.com/pzrq/460424c9382dd50d02b8
+ :param python_class: Any Python class that implements __subclasses__()
+ """
+ python_class.__subclasses__()
+ subclasses = set()
+ check_these = [python_class]
+ while check_these:
+ parent = check_these.pop()
+ for child in parent.__subclasses__():
+ if child not in subclasses:
+ subclasses.add(child)
+ check_these.append(child)
+ return subclasses
+
+
+def get_child_concrete_polymorphic_models(base_model):
+ """
+ Helper function to get all concrete models
+ that are subclasses of base_model
+ in sorted order by name.
+
+ Taken and modified from: https://gist.github.com/pzrq/460424c9382dd50d02b8
+
+ :param base_model: A Django models.Model instance.
+ """
+ found = get_all_subclasses(base_model)
+ def filter_func(model):
+ meta = getattr(model, '_meta', '')
+ if getattr(meta, 'abstract', True):
+ # Skip meta classes
+ return False
+ if not isinstance(model, PolymorphicModelBase):
+ return False
+ if model is PolymorphicModel:
+ return False
+ if '_Deferred_' in model.__name__:
+ # See deferred_class_factory() in django.db.models.query_utils
+ # Catches when you do .only('attr') on a queryset
+ return False
+ return True
+ subclasses = list(filter(filter_func, found))
+ return subclasses
 
 
 def get_polymorphic_related_models(model):
@@ -79,10 +117,10 @@ def inline_formset_data(self):
  formset_fk_model = ''
  parent_models = []
  compatible_parents = get_compatible_parents(self.formset.model)
- sub_models = self.formset.model()._get_inheritance_relation_fields_and_models()
+ sub_models = get_child_concrete_polymorphic_models(self.formset.model)
  data['nestedOptions'].update({
  'parentModel': get_model_id(formset_fk_model),
- 'childModels': [get_model_id(m) for m in sub_models.values()],
+ 'childModels': [get_model_id(m) for m in sub_models],
  'parentModels': [get_model_id(m) for m in parent_models],
  'compatibleParents': {
  get_model_id(k): [get_model_id(m) for m in v]

nested_admin/tests/nested_polymorphic/test_polymorphic_abstract_classes/admin.py

@@ -0,0 +1,44 @@
+from django.contrib import admin
+from django.db import models
+from django import forms
+
+import nested_admin
+
+from .models import (
+ FreeTextBlock, PollBlock, QuestionBlock, Survey, SurveyBlock, )
+
+
+class SurveyBlockInline(nested_admin.NestedStackedPolymorphicInline):
+ class QuestionInline(nested_admin.NestedStackedPolymorphicInline.Child):
+ model = QuestionBlock
+ sortable_field_name = "position"
+ formfield_overrides = {
+ models.PositiveSmallIntegerField: {'widget': forms.HiddenInput},
+ }
+
+ class FreeTextInline(nested_admin.NestedStackedPolymorphicInline.Child):
+ model = FreeTextBlock
+ sortable_field_name = "position"
+ formfield_overrides = {
+ models.PositiveSmallIntegerField: {'widget': forms.HiddenInput},
+ }
+
+ class PollInline(nested_admin.NestedStackedPolymorphicInline.Child):
+ model = PollBlock
+ sortable_field_name = "position"
+ formfield_overrides = {
+ models.PositiveSmallIntegerField: {'widget': forms.HiddenInput},
+ }
+
+ model = SurveyBlock
+ extra = 0
+ sortable_field_name = "position"
+ child_inlines = (FreeTextInline, PollInline, QuestionInline)
+ formfield_overrides = {
+ models.PositiveSmallIntegerField: {'widget': forms.HiddenInput},
+ }
+
+
+@admin.register(Survey)
+class SurveyAdmin(nested_admin.NestedPolymorphicModelAdmin):
+ inlines = (SurveyBlockInline,)

nested_admin/tests/nested_polymorphic/test_polymorphic_abstract_classes/models.py

@@ -0,0 +1,47 @@
+import django
+from django.db import models
+from django.db.models import ForeignKey, CASCADE
+
+try:
+ from polymorphic.models import PolymorphicModel
+except:
+ # Temporary until django-polymorphic supports django 3.1
+ if django.VERSION < (3, 1):
+ raise
+ else:
+ PolymorphicModel = models.Model
+
+
+def NON_POLYMORPHIC_CASCADE(collector, field, sub_objs, using):
+ return CASCADE(collector, field, sub_objs.non_polymorphic(), using)
+
+
+class Survey(models.Model):
+ title = models.CharField(max_length=255)
+
+
+class SurveyBlock(PolymorphicModel):
+ survey = ForeignKey(Survey, related_name='blocks', on_delete=NON_POLYMORPHIC_CASCADE)
+ position = models.PositiveSmallIntegerField(null=True)
+
+ class Meta:
+ ordering = ["position"]
+
+
+class BaseQuestionBlock(SurveyBlock):
+ label = models.CharField(max_length=255)
+
+ class Meta:
+ abstract = True
+
+
+class QuestionBlock(BaseQuestionBlock):
+ is_required = models.BooleanField()
+
+
+class FreeTextBlock(BaseQuestionBlock):
+ pass
+
+
+class PollBlock(BaseQuestionBlock):
+ pass

nested_admin/tests/nested_polymorphic/test_polymorphic_abstract_classes/tests.py

@@ -0,0 +1,76 @@
+from unittest import SkipTest
+from django.test import TestCase
+
+from .models import (
+ FreeTextBlock, PollBlock, QuestionBlock, Survey, SurveyBlock, )
+
+
+try:
+ from nested_admin.tests.nested_polymorphic.base import BaseNestedPolymorphicTestCase
+except ImportError:
+ BaseNestedPolymorphicTestCase = TestCase
+ has_polymorphic = False
+else:
+ has_polymorphic = True
+
+
+class PolymorphicAbstractClassesTestCase(BaseNestedPolymorphicTestCase):
+ root_model = Survey
+ nested_models = (SurveyBlock, )
+
+ @classmethod
+ def setUpClass(cls):
+ if not has_polymorphic:
+ raise SkipTest('django-polymorphic unavailable')
+ super(PolymorphicAbstractClassesTestCase, cls).setUpClass()
+
+ def test_add_level_one_to_empty(self):
+ obj = self.root_model.objects.create(title='test')
+ self.load_admin(obj)
+ self.add_inline(model=QuestionBlock, label='x')
+ self.save_form()
+
+ blocks = obj.blocks.all()
+ self.assertEqual(len(blocks), 1)
+ self.assertIsInstance(blocks[0], QuestionBlock)
+ self.assertEqual(blocks[0].label, 'x')
+ self.assertEqual(blocks[0].is_required, False)
+
+ def test_can_move_children_of_abstract(self):
+ obj = self.root_model.objects.create(title='test')
+ self.load_admin(obj)
+ self.add_inline(model=PollBlock, label='poll')
+ self.add_inline(model=QuestionBlock, label='question')
+ self.add_inline(model=FreeTextBlock, label='free')
+ self.save_form()
+
+ blocks = obj.blocks.all()
+ self.assertEqual(len(blocks), 3)
+ self.assertIsInstance(blocks[0], PollBlock)
+ self.assertEqual(blocks[0].label, 'poll')
+ self.assertEqual(blocks[0].position, 0)
+ self.assertIsInstance(blocks[1], QuestionBlock)
+ self.assertEqual(blocks[1].label, 'question')
+ self.assertEqual(blocks[1].position, 1)
+ self.assertEqual(blocks[1].is_required, False)
+ self.assertIsInstance(blocks[2], FreeTextBlock)
+ self.assertEqual(blocks[2].label, 'free')
+ self.assertEqual(blocks[2].position, 2)
+
+ # Move question block to top
+ self.drag_and_drop_item([1], [0], screenshot_hack=True)
+
+ self.save_form()
+
+ blocks = obj.blocks.all()
+ self.assertEqual(len(blocks), 3)
+ self.assertIsInstance(blocks[0], QuestionBlock)
+ self.assertEqual(blocks[0].label, 'question')
+ self.assertEqual(blocks[0].position, 0)
+ self.assertEqual(blocks[0].is_required, False)
+ self.assertIsInstance(blocks[1], PollBlock)
+ self.assertEqual(blocks[1].label, 'poll')
+ self.assertEqual(blocks[1].position, 1)
+ self.assertIsInstance(blocks[2], FreeTextBlock)
+ self.assertEqual(blocks[2].label, 'free')
+ self.assertEqual(blocks[2].position, 2)