Update the Scrapy 2.8 release notes up to b337c98

docs/news.rst

@@ -76,6 +76,12 @@ New features
     avoid confusion.
     (:issue:`5717`, :issue:`5722`, :issue:`5727`)
 
+-   The ``callback`` parameter of :class:`~scrapy.http.Request` can now be set
+    to :func:`scrapy.http.request.NO_CALLBACK`, to distinguish it from
+    ``None``, as the latter indicates that the default spider callback
+    (:meth:`~scrapy.Spider.parse`) is to be used.
+    (:issue:`5798`)
+
 
 Bug fixes
 ~~~~~~~~~

docs/topics/request-response.rst

@@ -39,9 +39,7 @@ Request objects
        -   ``None`` (default), which indicates that the spider's
            :meth:`~scrapy.Spider.parse` method must be used.
 
-       -   :py:data:`scrapy.http.request.NO_CALLBACK`
-
-            .. autodata:: scrapy.http.request.NO_CALLBACK
+       -   :func:`~scrapy.http.request.NO_CALLBACK`
 
        For more information, see
        :ref:`topics-request-response-ref-request-callback-arguments`.
@@ -247,6 +245,8 @@ Request objects
 Other functions related to requests
 -----------------------------------
 
+.. autofunction:: scrapy.http.request.NO_CALLBACK
+
 .. autofunction:: scrapy.utils.request.request_from_dict
 
 

scrapy/http/request/__init__.py

@@ -25,6 +25,12 @@ def NO_CALLBACK(*args, **kwargs):
     :class:`~scrapy.http.Request`, it indicates that the request is not meant
     to have a spider callback at all.
 
+    For example:
+
+    .. code-block:: python
+
+       Request("https://example.com", callback=NO_CALLBACK)
+
     This value should be used by :ref:`components <topics-components>` that
     create and handle their own requests, e.g. through
     :meth:`scrapy.core.engine.ExecutionEngine.download`, so that downloader