Fixed #24133 -- Replaced formatting syntax in success_url placeholders

Thanks Laurent Payot for the report, and Markus Holtermann, Tim Graham
for the reviews.

3 files changed, 29 insertions, 2 deletions

diff --git a/docs/internals/deprecation.txt b/docs/internals/deprecation.txt
index 4e03378f06..0a460b7739 100644
--- a/docs/internals/deprecation.txt
+++ b/docs/internals/deprecation.txt
@@ -158,6 +158,9 @@ details on these changes.
   and ``Storage.save()`` to be defined without a ``max_length`` argument will
   be removed.
 
+* Support for the legacy ``%(<foo>)s`` syntax in ``ModelFormMixin.success_url``
+  will be removed.
+
 .. _deprecation-removed-in-1.9:
 
 1.9
diff --git a/docs/ref/class-based-views/mixins-editing.txt b/docs/ref/class-based-views/mixins-editing.txt
index 3dcf28dae3..0bfbcbd3f7 100644
--- a/docs/ref/class-based-views/mixins-editing.txt
+++ b/docs/ref/class-based-views/mixins-editing.txt
@@ -160,9 +160,15 @@ ModelFormMixin
 
         ``success_url`` may contain dictionary string formatting, which
         will be interpolated against the object's field attributes. For
-        example, you could use ``success_url="/polls/%(slug)s/"`` to
+        example, you could use ``success_url="/polls/{slug}/"`` to
         redirect to a URL composed out of the ``slug`` field on a model.
 
+        .. versionchanged:: 1.8
+
+            Support for the new brace-based Python formatting syntax has been
+            added. The old ``%(slug)s`` placeholder syntax support has been
+            deprecated and will be removed in Django 2.0.
+
     .. method:: get_form_class()
 
         Retrieve the form class to instantiate. If
@@ -248,9 +254,15 @@ DeletionMixin
 
         ``success_url`` may contain dictionary string formatting, which will be
         interpolated against the object's field attributes. For example, you
-        could use ``success_url="/parent/%(parent_id)s/"`` to redirect to a URL
+        could use ``success_url="/parent/{parent_id}/"`` to redirect to a URL
         composed out of the ``parent_id`` field on a model.
 
+        .. versionchanged:: 1.8
+
+            Support for the new brace-based Python formatting syntax has been
+            added. The old ``%(slug)s`` placeholder syntax support has been
+            deprecated and will be removed in Django 2.0.
+
     .. method:: get_success_url()
 
         Returns the url to redirect to when the nominated object has been
diff --git a/docs/releases/1.8.txt b/docs/releases/1.8.txt
index a07a209347..cd9a5de682 100644
--- a/docs/releases/1.8.txt
+++ b/docs/releases/1.8.txt
@@ -388,6 +388,11 @@ Generic Views
   require a ``form_class`` to be provided anymore. If not provided ``form_class``
   defaults to :meth:`~django.views.generic.edit.FormMixin.get_form_class()`.
 
+* Placeholders in :attr:`ModelFormMixin.success_url
+  <django.views.generic.edit.ModelFormMixin.success_url>` now support the Python
+  :py:meth:`str.format()` syntax. The legacy ``%(<foo>)s`` syntax is still
+  supported but will be removed in Django 2.0.
+
 Internationalization
 ^^^^^^^^^^^^^^^^^^^^
 
@@ -1550,6 +1555,13 @@ will be removed in Django 2.0.
 Using a single equals sign with the ``{% if %}`` template tag for equality
 testing was undocumented and untested. It's now deprecated in favor of ``==``.
 
+``%(<foo>)s`` syntax in ``ModelFormMixin.success_url``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The legacy ``%(<foo>)s`` syntax in :attr:`ModelFormMixin.success_url
+ <django.views.generic.edit.ModelFormMixin.success_url>` is deprecated and
+will be removed in Django 2.0.
+
 .. removed-features-1.8:
 
 Features removed in 1.8