Fixed #28593 -- Added a simplified URL routing syntax per DEP 0201.

Thanks Aymeric Augustin for shepherding the DEP and patch review.
Thanks Marten Kenbeek and Tim Graham for contributing to the code.
Thanks Tom Christie, Shai Berger, and Tim Graham for the docs.

2 files changed, 29 insertions, 24 deletions

diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
index 7a4ff947a8..6e4ad180ac 100644
--- a/django/contrib/admin/options.py
+++ b/django/contrib/admin/options.py
@@ -567,7 +567,7 @@ class ModelAdmin(BaseModelAdmin):
         return inline_instances
 
     def get_urls(self):
-        from django.conf.urls import url
+        from django.urls import path
 
         def wrap(view):
             def wrapper(*args, **kwargs):
@@ -578,14 +578,14 @@ class ModelAdmin(BaseModelAdmin):
         info = self.model._meta.app_label, self.model._meta.model_name
 
         urlpatterns = [
-            url(r'^$', wrap(self.changelist_view), name='%s_%s_changelist' % info),
-            url(r'^add/$', wrap(self.add_view), name='%s_%s_add' % info),
-            url(r'^autocomplete/$', wrap(self.autocomplete_view), name='%s_%s_autocomplete' % info),
-            url(r'^(.+)/history/$', wrap(self.history_view), name='%s_%s_history' % info),
-            url(r'^(.+)/delete/$', wrap(self.delete_view), name='%s_%s_delete' % info),
-            url(r'^(.+)/change/$', wrap(self.change_view), name='%s_%s_change' % info),
+            path('', wrap(self.changelist_view), name='%s_%s_changelist' % info),
+            path('add/', wrap(self.add_view), name='%s_%s_add' % info),
+            path('autocomplete/', wrap(self.autocomplete_view), name='%s_%s_autocomplete' % info),
+            path('<path:object_id>/history/', wrap(self.history_view), name='%s_%s_history' % info),
+            path('<path:object_id>/delete/', wrap(self.delete_view), name='%s_%s_delete' % info),
+            path('<path:object_id>/change/', wrap(self.change_view), name='%s_%s_change' % info),
             # For backwards compatibility (was the change url before 1.9)
-            url(r'^(.+)/$', wrap(RedirectView.as_view(
+            path('<path:object_id>/', wrap(RedirectView.as_view(
                 pattern_name='%s:%s_%s_change' % ((self.admin_site.name,) + info)
             ))),
         ]
@@ -1173,8 +1173,7 @@ class ModelAdmin(BaseModelAdmin):
             opts = obj._meta
             to_field = request.POST.get(TO_FIELD_VAR)
             attr = str(to_field) if to_field else opts.pk.attname
-            # Retrieve the `object_id` from the resolved pattern arguments.
-            value = request.resolver_match.args[0]
+            value = request.resolver_match.kwargs['object_id']
             new_value = obj.serializable_value(attr)
             popup_response_data = json.dumps({
                 'action': 'change',
diff --git a/django/contrib/admin/sites.py b/django/contrib/admin/sites.py
index c0767c15ee..2e37ade62e 100644
--- a/django/contrib/admin/sites.py
+++ b/django/contrib/admin/sites.py
@@ -196,11 +196,11 @@ class AdminSite:
             class MyAdminSite(AdminSite):
 
                 def get_urls(self):
-                    from django.conf.urls import url
+                    from django.urls import path
 
                     urls = super().get_urls()
                     urls += [
-                        url(r'^my_view/$', self.admin_view(some_view))
+                        path('my_view/', self.admin_view(some_view))
                     ]
                     return urls
 
@@ -230,7 +230,7 @@ class AdminSite:
         return update_wrapper(inner, view)
 
     def get_urls(self):
-        from django.conf.urls import url, include
+        from django.urls import include, path, re_path
         # Since this module gets imported in the application's root package,
         # it cannot import models from other applications at the module level,
         # and django.contrib.contenttypes.views imports ContentType.
@@ -244,15 +244,21 @@ class AdminSite:
 
         # Admin-site-wide views.
         urlpatterns = [
-            url(r'^$', wrap(self.index), name='index'),
-            url(r'^login/$', self.login, name='login'),
-            url(r'^logout/$', wrap(self.logout), name='logout'),
-            url(r'^password_change/$', wrap(self.password_change, cacheable=True), name='password_change'),
-            url(r'^password_change/done/$', wrap(self.password_change_done, cacheable=True),
-                name='password_change_done'),
-            url(r'^jsi18n/$', wrap(self.i18n_javascript, cacheable=True), name='jsi18n'),
-            url(r'^r/(?P<content_type_id>\d+)/(?P<object_id>.+)/$', wrap(contenttype_views.shortcut),
-                name='view_on_site'),
+            path('', wrap(self.index), name='index'),
+            path('login/', self.login, name='login'),
+            path('logout/', wrap(self.logout), name='logout'),
+            path('password_change/', wrap(self.password_change, cacheable=True), name='password_change'),
+            path(
+                'password_change/done/',
+                wrap(self.password_change_done, cacheable=True),
+                name='password_change_done',
+            ),
+            path('jsi18n/', wrap(self.i18n_javascript, cacheable=True), name='jsi18n'),
+            path(
+                'r/<int:content_type_id>/<path:object_id>/',
+                wrap(contenttype_views.shortcut),
+                name='view_on_site',
+            ),
         ]
 
         # Add in each model's views, and create a list of valid URLS for the
@@ -260,7 +266,7 @@ class AdminSite:
         valid_app_labels = []
         for model, model_admin in self._registry.items():
             urlpatterns += [
-                url(r'^%s/%s/' % (model._meta.app_label, model._meta.model_name), include(model_admin.urls)),
+                path('%s/%s/' % (model._meta.app_label, model._meta.model_name), include(model_admin.urls)),
             ]
             if model._meta.app_label not in valid_app_labels:
                 valid_app_labels.append(model._meta.app_label)
@@ -270,7 +276,7 @@ class AdminSite:
         if valid_app_labels:
             regex = r'^(?P<app_label>' + '|'.join(valid_app_labels) + ')/$'
             urlpatterns += [
-                url(regex, wrap(self.app_index), name='app_list'),
+                re_path(regex, wrap(self.app_index), name='app_list'),
             ]
         return urlpatterns