Router: Do not automatically adjust lookup_regex when trailing_slash is True

BREAKING CHANGE

When trailing_slash is set to True, the router no longer will adjust the lookup regex to allow it to include periods. To simulate the old behavior, the programmer should specify `lookup_regex = '[^/]+'` on the viewset.

https://github.com/tomchristie/django-rest-framework/pull/1328#issuecomment-31517099

docs/api-guide/routers.md

@@ -83,7 +83,7 @@ This behavior can be modified by setting the `trailing_slash` argument to `False
 
 Trailing slashes are conventional in Django, but are not used by default in some other frameworks such as Rails.  Which style you choose to use is largely a matter of preference, although some javascript frameworks may expect a particular routing style.
 
-With `trailing_slash` set to True, the router will match lookup values containing any characters except slashes and dots. When set to False, dots are allowed.  To restrict the lookup pattern, set the `lookup_field_regex` attribute on the viewset.  For example, you can limit the lookup to valid UUIDs:
+The router will match lookup values containing any characters except slashes and period characters.  For a more restrictive (or lenient) lookup pattern, set the `lookup_field_regex` attribute on the viewset.  For example, you can limit the lookup to valid UUIDs:
 
     class MyModelViewSet(mixins.RetrieveModelMixin, viewsets.GenericViewSet):
         lookup_field = 'my_model_id'

rest_framework/routers.py

@@ -224,9 +224,6 @@ class SimpleRouter(BaseRouter):
         try:
             lookup_value = viewset.lookup_value_regex
         except AttributeError:
-            if self.trailing_slash:
-                lookup_value = '[^/]+'
-            else:
             # Don't consume `.json` style suffixes
             lookup_value = '[^/.]+'
         return base_regex.format(

rest_framework/tests/test_routers.py

@@ -152,7 +152,7 @@ class TestTrailingSlashIncluded(TestCase):
         self.urls = self.router.urls
 
     def test_urls_have_trailing_slash_by_default(self):
-        expected = ['^notes/$', '^notes/(?P<pk>[^/]+)/$']
+        expected = ['^notes/$', '^notes/(?P<pk>[^/.]+)/$']
         for idx in range(len(expected)):
             self.assertEqual(expected[idx], self.urls[idx].regex.pattern)