remove class hierarchy walks

Author: bckohan

src/polymorphic/admin/helpers.py

@@ -63,7 +63,6 @@ def __iter__(self):
         for form in self.formset.extra_forms + self.formset.empty_forms:
             model = form._meta.model
             child_inline = self.opts.get_child_inline_instance(model)
-
             yield PolymorphicInlineAdminForm(
                 formset=self.formset,
                 form=form,
@@ -142,26 +141,3 @@ def get_inline_formsets(self, request, formsets, inline_instances, obj=None, *ar
                 admin_formset.request = request
                 admin_formset.obj = obj
         return inline_admin_formsets
-
-
-def get_leaf_subclasses(cls, exclude=None):
-    "Get leaf subclasses of `cls` class"
-
-    if exclude is None:
-        exclude = ()
-
-    elif not isinstance(exclude, (list, tuple)):
-        # Accept single instance in `exclude`
-        exclude = (exclude,)
-
-    result = []
-
-    subclasses = cls.__subclasses__()
-
-    if subclasses:
-        for subclass in subclasses:
-            result.extend(get_leaf_subclasses(subclass, exclude))
-    elif not (cls in exclude or (hasattr(cls, "_meta") and cls._meta.abstract)):
-        result.append(cls)
-
-    return result

src/polymorphic/admin/inlines.py

@@ -20,7 +20,7 @@
 )
 from polymorphic.formsets.utils import add_media
 
-from .helpers import PolymorphicInlineSupportMixin, get_leaf_subclasses
+from .helpers import PolymorphicInlineSupportMixin
 
 
 class PolymorphicInlineModelAdmin(InlineModelAdmin):
@@ -86,35 +86,14 @@ def __init__(self, parent_model, admin_site):
 
     def get_child_inlines(self):
         """
-        Return the derived inline classes which this admin should handle
+        Return the derived inline classes which this admin should handle.
 
         This should return a list of tuples, exactly like
         :attr:`child_inlines` is.
-
-        The inline classes can be retrieved as
-        ``base_inline.__subclasses__()``, a setting in a config file, or
-        a query of a plugin registration system at your option
         """
         if self.child_inlines is not None:
             return self.child_inlines
-
-        child_inlines = get_leaf_subclasses(
-            PolymorphicInlineModelAdmin.Child, self.exclude_children
-        )
-        child_inlines = tuple(
-            inline
-            for inline in child_inlines
-            if (inline.model is not None and issubclass(inline.model, self.model))
-        )
-
-        if child_inlines:
-            return child_inlines
-
-        raise ImproperlyConfigured(
-            f"No child inlines found for '{self.model.__name__}', please "
-            "define the 'child_inlines' attribute or overwrite the "
-            "'get_child_inlines()' method."
-        )
+        return ()
 
     def get_child_inline_instances(self):
         """

src/polymorphic/admin/parentadmin.py

@@ -19,7 +19,6 @@
 from polymorphic.utils import get_base_polymorphic_model
 
 from .forms import PolymorphicModelChoiceForm
-from .helpers import get_leaf_subclasses
 
 
 class RegistrationClosed(RuntimeError):
@@ -52,13 +51,6 @@ class PolymorphicParentModelAdmin(admin.ModelAdmin):
     #: The child models that should be displayed
     child_models = None
 
-    #: The models that should be excluded from the auto-discovered child
-    #: leaf models that should be displayed. This can be a list of
-    #: models or a single model. It's useful to exclude non-abstract
-    #: base models (abstract models are always excluded) when they don't
-    #: have defined any child models.
-    exclude_children = None
-
     #: Whether the list should be polymorphic too, leave to ``False`` to optimize
     polymorphic_list = False
 
@@ -117,41 +109,24 @@ def register_child(self, model, model_admin):
     def get_child_models(self):
         """
         Return the derived model classes which this admin should handle.
+        This should return a list of tuples, exactly like :attr:`child_models` is.
 
-        This should return a list of tuples, exactly like
-        :attr:`child_models` is.
-
-        The model classes can be retrieved as
-        ``base_model.__subclasses__()``, a setting in a config file, or
-        a query of a plugin registration system at your option
+        The model classes can be retrieved as ``base_model.__subclasses__()``,
+        a setting in a config file, or a query of a plugin registration system at your option
         """
-        if self.child_models is not None:
-            return self.child_models
+        if self.child_models is None:
+            raise NotImplementedError("Implement get_child_models() or child_models")
 
-        child_models = get_leaf_subclasses(self.base_model, self.exclude_children)
-
-        if child_models:
-            return child_models
-
-        raise ImproperlyConfigured(
-            f"No child models found for '{self.base_model.__name__}', please "
-            "define the 'child_models' attribute or overwrite the "
-            "'get_child_models' method."
-        )
+        return self.child_models
 
     def get_child_type_choices(self, request, action):
         """
         Return a list of polymorphic types for which the user has the permission to perform the given action.
         """
         self._lazy_setup()
-
-        child_models = self._child_models
-        if not child_models:
-            raise ImproperlyConfigured("No child models are available.")
-
         choices = []
         content_types = ContentType.objects.get_for_models(
-            *child_models, for_concrete_models=False
+            *self.get_child_models(), for_concrete_models=False
         )
 
         for model, ct in content_types.items():