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.

7 files changed, 82 insertions, 62 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
 
diff --git a/django/contrib/admindocs/urls.py b/django/contrib/admindocs/urls.py
index bfc9648e83..bc9c3df7cf 100644
--- a/django/contrib/admindocs/urls.py
+++ b/django/contrib/admindocs/urls.py
@@ -1,32 +1,50 @@
-from django.conf.urls import url
 from django.contrib.admindocs import views
+from django.urls import path, re_path
 
 urlpatterns = [
-    url(r'^$',
+    path(
+        '',
         views.BaseAdminDocsView.as_view(template_name='admin_doc/index.html'),
-        name='django-admindocs-docroot'),
-    url(r'^bookmarklets/$',
+        name='django-admindocs-docroot',
+    ),
+    path(
+        'bookmarklets/',
         views.BookmarkletsView.as_view(),
-        name='django-admindocs-bookmarklets'),
-    url(r'^tags/$',
+        name='django-admindocs-bookmarklets',
+    ),
+    path(
+        'tags/',
         views.TemplateTagIndexView.as_view(),
-        name='django-admindocs-tags'),
-    url(r'^filters/$',
+        name='django-admindocs-tags',
+    ),
+    path(
+        'filters/',
         views.TemplateFilterIndexView.as_view(),
-        name='django-admindocs-filters'),
-    url(r'^views/$',
+        name='django-admindocs-filters',
+    ),
+    path(
+        'views/',
         views.ViewIndexView.as_view(),
-        name='django-admindocs-views-index'),
-    url(r'^views/(?P<view>[^/]+)/$',
+        name='django-admindocs-views-index',
+    ),
+    path(
+        'views/<view>/',
         views.ViewDetailView.as_view(),
-        name='django-admindocs-views-detail'),
-    url(r'^models/$',
+        name='django-admindocs-views-detail',
+    ),
+    path(
+        'models/',
         views.ModelIndexView.as_view(),
-        name='django-admindocs-models-index'),
-    url(r'^models/(?P<app_label>[^\.]+)\.(?P<model_name>[^/]+)/$',
+        name='django-admindocs-models-index',
+    ),
+    re_path(
+        r'^models/(?P<app_label>[^\.]+)\.(?P<model_name>[^/]+)/$',
         views.ModelDetailView.as_view(),
-        name='django-admindocs-models-detail'),
-    url(r'^templates/(?P<template>.*)/$',
+        name='django-admindocs-models-detail',
+    ),
+    path(
+        'templates/<path:template>/',
         views.TemplateDetailView.as_view(),
-        name='django-admindocs-templates'),
+        name='django-admindocs-templates',
+    ),
 ]
diff --git a/django/contrib/admindocs/views.py b/django/contrib/admindocs/views.py
index 2b96ee3e8f..e45898c025 100644
--- a/django/contrib/admindocs/views.py
+++ b/django/contrib/admindocs/views.py
@@ -401,13 +401,12 @@ def extract_views_from_urlpatterns(urlpatterns, base='', namespace=None):
                 continue
             views.extend(extract_views_from_urlpatterns(
                 patterns,
-                base + p.regex.pattern,
+                base + str(p.pattern),
                 (namespace or []) + (p.namespace and [p.namespace] or [])
             ))
         elif hasattr(p, 'callback'):
             try:
-                views.append((p.callback, base + p.regex.pattern,
-                              namespace, p.name))
+                views.append((p.callback, base + str(p.pattern), namespace, p.name))
             except ViewDoesNotExist:
                 continue
         else:
diff --git a/django/contrib/auth/admin.py b/django/contrib/auth/admin.py
index 3661d226a7..41df65a72e 100644
--- a/django/contrib/auth/admin.py
+++ b/django/contrib/auth/admin.py
@@ -1,5 +1,4 @@
 from django.conf import settings
-from django.conf.urls import url
 from django.contrib import admin, messages
 from django.contrib.admin.options import IS_POPUP_VAR
 from django.contrib.admin.utils import unquote
@@ -12,7 +11,7 @@ from django.core.exceptions import PermissionDenied
 from django.db import router, transaction
 from django.http import Http404, HttpResponseRedirect
 from django.template.response import TemplateResponse
-from django.urls import reverse
+from django.urls import path, reverse
 from django.utils.decorators import method_decorator
 from django.utils.html import escape
 from django.utils.translation import gettext, gettext_lazy as _
@@ -81,8 +80,8 @@ class UserAdmin(admin.ModelAdmin):
 
     def get_urls(self):
         return [
-            url(
-                r'^(.+)/password/$',
+            path(
+                '<id>/password/',
                 self.admin_site.admin_view(self.user_change_password),
                 name='auth_user_password_change',
             ),
diff --git a/django/contrib/auth/urls.py b/django/contrib/auth/urls.py
index 233eef8fec..c3306807e5 100644
--- a/django/contrib/auth/urls.py
+++ b/django/contrib/auth/urls.py
@@ -3,19 +3,18 @@
 # It is also provided as a convenience to those who want to deploy these URLs
 # elsewhere.
 
-from django.conf.urls import url
 from django.contrib.auth import views
+from django.urls import path
 
 urlpatterns = [
-    url(r'^login/$', views.LoginView.as_view(), name='login'),
-    url(r'^logout/$', views.LogoutView.as_view(), name='logout'),
+    path('login/', views.LoginView.as_view(), name='login'),
+    path('logout/', views.LogoutView.as_view(), name='logout'),
 
-    url(r'^password_change/$', views.PasswordChangeView.as_view(), name='password_change'),
-    url(r'^password_change/done/$', views.PasswordChangeDoneView.as_view(), name='password_change_done'),
+    path('password_change/', views.PasswordChangeView.as_view(), name='password_change'),
+    path('password_change/done/', views.PasswordChangeDoneView.as_view(), name='password_change_done'),
 
-    url(r'^password_reset/$', views.PasswordResetView.as_view(), name='password_reset'),
-    url(r'^password_reset/done/$', views.PasswordResetDoneView.as_view(), name='password_reset_done'),
-    url(r'^reset/(?P<uidb64>[0-9A-Za-z_\-]+)/(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/$',
-        views.PasswordResetConfirmView.as_view(), name='password_reset_confirm'),
-    url(r'^reset/done/$', views.PasswordResetCompleteView.as_view(), name='password_reset_complete'),
+    path('password_reset/', views.PasswordResetView.as_view(), name='password_reset'),
+    path('password_reset/done/', views.PasswordResetDoneView.as_view(), name='password_reset_done'),
+    path('reset/<uidb64>/<token>/', views.PasswordResetConfirmView.as_view(), name='password_reset_confirm'),
+    path('reset/done/', views.PasswordResetCompleteView.as_view(), name='password_reset_complete'),
 ]
diff --git a/django/contrib/flatpages/urls.py b/django/contrib/flatpages/urls.py
index 3437e823b2..a087fe8c1d 100644
--- a/django/contrib/flatpages/urls.py
+++ b/django/contrib/flatpages/urls.py
@@ -1,6 +1,6 @@
-from django.conf.urls import url
 from django.contrib.flatpages import views
+from django.urls import path
 
 urlpatterns = [
-    url(r'^(?P<url>.*)$', views.flatpage, name='django.contrib.flatpages.views.flatpage'),
+    path('<path:url>', views.flatpage, name='django.contrib.flatpages.views.flatpage'),
 ]