Fix lookup_url_kwarg handling in viewsets.

The ``lookup_url_kwarg`` is intended to set the name of a field in the
URL regexps when using custom ``lookup_field``, but the routers ignore
it altogether.

1 files changed, 3 insertions, 2 deletions

diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index b1e39ff7..4df852bf 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -218,14 +218,15 @@ class SimpleRouter(BaseRouter):
 
         https://github.com/alanjds/drf-nested-routers
         """
-        base_regex = '(?P<{lookup_prefix}{lookup_field}>{lookup_value})'
+        base_regex = '(?P<{lookup_prefix}{lookup_url_kwarg}>{lookup_value})'
         # Use `pk` as default field, unset set.  Default regex should not
         # consume `.json` style suffixes and should break at '/' boundaries.
         lookup_field = getattr(viewset, 'lookup_field', 'pk')
+        lookup_url_kwarg = getattr(viewset, 'lookup_url_kwarg', None) or lookup_field
         lookup_value = getattr(viewset, 'lookup_value_regex', '[^/.]+')
         return base_regex.format(
             lookup_prefix=lookup_prefix,
-            lookup_field=lookup_field,
+            lookup_url_kwarg=lookup_url_kwarg,
             lookup_value=lookup_value
         )