[3.9] bpo-47022: Document asynchat, asyncore and smtpd removals in 3.12 (pythonGH-31891)

Document the deprecation of asyncore, asynchat, and smtpd with a slated removal in Python 3.12 thanks to PEP 594..
(cherry picked from commit 7747384)

Co-authored-by: Hugo van Kemenade <[email protected]>

Author: hugovk

Doc/library/asynchat.rst

@@ -3,13 +3,15 @@
 
 .. module:: asynchat
    :synopsis: Support for asynchronous command/response protocols.
+   :deprecated:
 
 .. moduleauthor:: Sam Rushing <[email protected]>
 .. sectionauthor:: Steve Holden <[email protected]>
 
 **Source code:** :source:`Lib/asynchat.py`
 
 .. deprecated:: 3.6
+   :mod:`asynchat` will be removed in Python 3.12 (:pep:`594`).
    Please use :mod:`asyncio` instead.
 
 --------------

Doc/library/asyncore.rst

@@ -4,6 +4,7 @@
 .. module:: asyncore
    :synopsis: A base class for developing asynchronous socket handling
               services.
+   :deprecated:
 
 .. moduleauthor:: Sam Rushing <[email protected]>
 .. sectionauthor:: Christopher Petrilli <[email protected]>
@@ -13,6 +14,7 @@
 **Source code:** :source:`Lib/asyncore.py`
 
 .. deprecated:: 3.6
+   :mod:`asyncore` will be removed in Python 3.12 (:pep:`594`).
    Please use :mod:`asyncio` instead.
 
 --------------

Doc/library/smtpd.rst

@@ -3,6 +3,7 @@
 
 .. module:: smtpd
    :synopsis: A SMTP server implementation in Python.
+   :deprecated:
 
 .. moduleauthor:: Barry Warsaw <[email protected]>
 .. sectionauthor:: Moshe Zadka <[email protected]>
@@ -13,11 +14,11 @@
 
 This module offers several classes to implement SMTP (email) servers.
 
-.. seealso::
-
-    The `aiosmtpd <http://aiosmtpd.readthedocs.io/>`_ package is a recommended
-    replacement for this module.  It is based on :mod:`asyncio` and provides a
-    more straightforward API.  :mod:`smtpd` should be considered deprecated.
+.. deprecated:: 3.6
+   :mod:`smtpd` will be removed in Python 3.12 (:pep:`594`).
+   The `aiosmtpd <https://aiosmtpd.readthedocs.io/>`_ package is a recommended
+   replacement for this module.  It is based on :mod:`asyncio` and provides a
+   more straightforward API.
 
 Several server implementations are present; one is a generic
 do-nothing implementation, which can be overridden, while the other two offer

Doc/library/superseded.rst

@@ -10,5 +10,8 @@ backwards compatibility. They have been superseded by other modules.
 
 .. toctree::
 
-   optparse.rst
+   asynchat.rst
+   asyncore.rst
+   smtpd.rst
    imp.rst
+   optparse.rst

Misc/NEWS.d/next/Library/2022-03-15-09-29-52.bpo-47022.uaEDcI.rst

@@ -0,0 +1,3 @@
+The :mod:`asynchat`, :mod:`asyncore` and  :mod:`smtpd` modules have been
+deprecated since at least Python 3.6. Their documentation has now been
+updated to note they will removed in Python 3.12 (:pep:`594`).