slug_url_kwarg should default to same as slug_field

rest_framework/fields.py

@@ -494,8 +494,8 @@ class HyperlinkedRelatedField(RelatedField):
     Represents a to-one relationship, using hyperlinking.
     """
     pk_url_kwarg = 'pk'
-    slug_url_kwarg = 'slug'
     slug_field = 'slug'
+    slug_url_kwarg = None  # Defaults to same as `slug_field`
     default_read_only = False
 
     def __init__(self, *args, **kwargs):
@@ -503,8 +503,8 @@ class HyperlinkedRelatedField(RelatedField):
             self.view_name = kwargs.pop('view_name')
         except:
             raise ValueError("Hyperlinked field requires 'view_name' kwarg")
-        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', self.slug_url_kwarg)
         self.slug_field = kwargs.pop('slug_field', self.slug_field)
+        self.slug_url_kwarg = kwargs.pop('slug_url_kwarg', self.slug_field)
         self.format = kwargs.pop('format', None)
         super(HyperlinkedRelatedField, self).__init__(*args, **kwargs)