Ticket #11882: 11822.diff

docs/ref/contrib/admin/index.txt

@@ -820 +820 @@
 This uses the ``HttpRequest`` instance to filter the ``Car`` foreign key field
 to only the cars owned by the ``User`` instance.
 
+Similarly, the ``formfield_for_manytomany`` method can be overridden.
+For example, if an owner can own multiple cars and cars can belong to
+multiple owners -- a many to many relationship -- you would need to
+override the many to many field::
+
+    class MyModelAdmin(admin.ModelAdmin):
+        def formfield_for_manytomany(self, db_field, request, **kwargs):
+            if db_field.name == "cars":
+                kwargs["queryset"] = Car.objects.filter(owner=request.user)
+                return db_field.formfield(**kwargs)
+            return super(MyModelAdmin, self).formfield_for_manytomany(db_field, request, **kwargs)
+
 Other methods
 ~~~~~~~~~~~~~