Fixed #21216 -- Allow OneToOneField reverse accessor to be hidden.

django/db/models/fields/related.py

@@ -960,6 +960,7 @@ class ManyToManyRel(object):
 class ForeignObject(RelatedField):
     requires_unique_target = True
     generate_reverse_relation = True
+    related_accessor_class = ForeignRelatedObjectsDescriptor
 
     def __init__(self, to, from_fields, to_fields, **kwargs):
         self.from_fields = from_fields
@@ -1160,7 +1161,7 @@ class ForeignObject(RelatedField):
         # Internal FK's - i.e., those with a related name ending with '+' -
         # and swapped models don't get a related descriptor.
         if not self.rel.is_hidden() and not related.model._meta.swapped:
-            setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
+            setattr(cls, related.get_accessor_name(), self.related_accessor_class(related))
             if self.rel.limit_choices_to:
                 cls._meta.related_fkey_lookups.append(self.rel.limit_choices_to)
 
@@ -1334,6 +1335,7 @@ class OneToOneField(ForeignKey):
     always returns the object pointed to (since there will only ever be one),
     rather than returning a list.
     """
+    related_accessor_class = SingleRelatedObjectDescriptor
     description = _("One-to-one relationship")
 
     def __init__(self, to, to_field=None, **kwargs):
@@ -1346,10 +1348,6 @@ class OneToOneField(ForeignKey):
             del kwargs['unique']
         return name, path, args, kwargs
 
-    def contribute_to_related_class(self, cls, related):
-        setattr(cls, related.get_accessor_name(),
-                SingleRelatedObjectDescriptor(related))
-
     def formfield(self, **kwargs):
         if self.rel.parent_link:
             return None