Merge pull request #846 from bckohan/master

fix base_manager resolution

Author: bckohan

docs/changelog/index.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+v4.9.1, v4.10.3 (2026-01-15)
+----------------------------
+
+* Fixed `Meta.base_manager_name is not respected <https://github.com/jazzband/django-polymorphic/issues/845>`_
+
+
 v4.10.2 (2026-01-14)
 --------------------
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "django-polymorphic"
-version = "4.10.2"
+version = "4.10.3"
 description = "Seamless polymorphic inheritance for Django models."
 readme = "README.md"
 license = "BSD-3-Clause"

src/polymorphic/__init__.py

@@ -19,7 +19,7 @@
 Seamless Polymorphic Inheritance for Django Models
 """
 
-VERSION = "4.10.2"
+VERSION = "4.10.3"
 
 __title__ = "Django Polymorphic"
 __version__ = VERSION  # version synonym for backwards compatibility

src/polymorphic/base.py

@@ -71,28 +71,28 @@ class PolymorphicModelBase(ModelBase):
     """
 
     def __new__(cls, model_name, bases, attrs, **kwargs):
-        # create new model
-        new_class = super().__new__(cls, model_name, bases, attrs, **kwargs)
+        # skip special setup for PolymorphicModel itself
+        if attrs.pop("_meta_skip", False):
+            return super().__new__(cls, model_name, bases, attrs, **kwargs)
 
-        if new_class._meta.base_manager_name is None:
-            # by default, use polymorphic manager as the base manager
-            new_class._meta.base_manager_name = new_class._meta.default_manager_name or "objects"
+        from .models import PolymorphicModel
 
-        # ensure base_manager is a plain PolymorphicManager by resetting it if it
-        # was not explicitly set and it defaults to a changed default_manager
-        # the base class manager determination logic is complex enough that we prefer
-        # to observe its application and correct rather than preempting it
-        if (
-            type(new_class._meta.default_manager) is not PolymorphicManager
-            and new_class._meta.base_manager is new_class._meta.default_manager
+        new_class = super().__new__(cls, model_name, bases, attrs, **kwargs)
+
+        if not any(
+            parent._meta.base_manager_name
+            for parent in new_class.mro()
+            if issubclass(parent, PolymorphicModel)
         ):
-            manager = PolymorphicManager()
-            manager.name = "_base_manager"
-            manager.model = new_class
-            manager.auto_created = True
-            new_class._meta.base_manager_name = None
-            # write new manager to property cache
-            new_class._meta.__dict__["base_manager"] = manager
+            if new_class._meta.default_manager.__class__ is PolymorphicManager:
+                new_class._meta.__dict__["base_manager"] = new_class._meta.default_manager
+            else:
+                manager = PolymorphicManager()
+                manager.name = "_base_manager"
+                manager.model = new_class
+                manager.auto_created = True
+                # write new manager to property cache
+                new_class._meta.__dict__["base_manager"] = manager
 
         # wrap on_delete handlers of reverse relations back to this model with the
         # polymorphic deletion guard
@@ -104,8 +104,6 @@ def __new__(cls, model_name, bases, attrs, **kwargs):
 
         # replace the parent/child descriptors
         if new_class._meta.parents and not (new_class._meta.abstract or new_class._meta.proxy):
-            # PolymorphicModel is guaranteed to be defined here
-            from .models import PolymorphicModel
 
             def replace_inheritance_descriptors(model):
                 for super_cls, field_to_super in model._meta.parents.items():

src/polymorphic/models.py

@@ -35,6 +35,8 @@ class PolymorphicModel(models.Model, metaclass=PolymorphicModelBase):
     and provides a polymorphic manager as the default manager (and as 'objects').
     """
 
+    _meta_skip = True
+
     # for PolymorphicModelBase, so it can tell which models are polymorphic and which are not (duck typing)
     polymorphic_model_marker = True