[1.9.x] Fixed #26186 -- Documented how app relative relationships of abstract models behave.

This partially reverts commit bc7d201bdbaeac14a49f51a9ef292d6312b4c45e.

Thanks Tim for the review.

Refs #25858.

Backport of 0223e213dd690b6b6e0669f836a20efb10998c83 from master

1 files changed, 6 insertions, 15 deletions

diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 31434864cd..5d9b881c16 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -40,7 +40,7 @@ from .reverse_related import (
 RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
 
 
-def resolve_relation(scope_model, relation, resolve_recursive_relationship=True):
+def resolve_relation(scope_model, relation):
     """
     Transform relation into a model or fully-qualified model string of the form
     "app_label.ModelName", relative to scope_model.
@@ -55,11 +55,12 @@ def resolve_relation(scope_model, relation, resolve_recursive_relationship=True)
     """
     # Check for recursive relations
     if relation == RECURSIVE_RELATIONSHIP_CONSTANT:
-        if resolve_recursive_relationship:
-            relation = scope_model
+        relation = scope_model
+
     # Look for an "app.Model" relation
-    elif isinstance(relation, six.string_types) and '.' not in relation:
-        relation = "%s.%s" % (scope_model._meta.app_label, relation)
+    if isinstance(relation, six.string_types):
+        if "." not in relation:
+            relation = "%s.%s" % (scope_model._meta.app_label, relation)
 
     return relation
 
@@ -303,11 +304,6 @@ class RelatedField(Field):
                 field.remote_field.model = related
                 field.do_related_class(related, model)
             lazy_related_operation(resolve_related_class, cls, self.remote_field.model, field=self)
-        else:
-            # Bind a lazy reference to the app in which the model is defined.
-            self.remote_field.model = resolve_relation(
-                cls, self.remote_field.model, resolve_recursive_relationship=False
-            )
 
     def get_forward_related_filter(self, obj):
         """
@@ -1584,11 +1580,6 @@ class ManyToManyField(RelatedField):
                 lazy_related_operation(resolve_through_model, cls, self.remote_field.through, field=self)
             elif not cls._meta.swapped:
                 self.remote_field.through = create_many_to_many_intermediary_model(self, cls)
-        else:
-            # Bind a lazy reference to the app in which the model is defined.
-            self.remote_field.through = resolve_relation(
-                cls, self.remote_field.through, resolve_recursive_relationship=False
-            )
 
         # Add the descriptor for the m2m relation.
         setattr(cls, self.name, ManyToManyDescriptor(self.remote_field, reverse=False))