🔧 Stop using the cgi stdlib module

the module was deprecatied in py 3.11 and removed in py 3.13
there are examples of using the email module to resolve this:
PEP 594
python-babel/babel#873
https://stackoverflow.com/questions/69068527/python-3-cgi-parse-header

This method doesn't seem to work for cherrypy.
The email.message module is trying to create a higher level
object that is intelligent about the headers it has defined. The
cgi.parse_header function is a very low level unintelligent function
that simply parses header content based on structure and does not
inspect the contents. Because of the intelligence of the email.message
object cherrypy can't use it in the very generic way that the
cgi.parse_header function was being used.

Fix #2014

CHANGES.rst

@@ -1,3 +1,9 @@
+v(next)
+-------
+
+* Removed the use of :mod:`cgi` deprecated in Python 3.11
+  -- by :user:`radez`.
+
 v18.9.0
 -------
 

cherrypy/_cpcompat.py

@@ -21,6 +21,43 @@
 import http.client
 
 
+def _cgi_parseparam(s):
+    while s[:1] == ';':
+        s = s[1:]
+        end = s.find(';')
+        while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
+            end = s.find(';', end + 1)
+        if end < 0:
+            end = len(s)
+        f = s[:end]
+        yield f.strip()
+        s = s[end:]
+
+
+def cgi_parse_header(line):
+    """Parse a Content-type like header.
+
+    Return the main content-type and a dictionary of options.
+
+    Copied from removed stdlib cgi module. Couldn't find
+    something to replace it with that provided same functionality
+    from the email module as suggested.
+    """
+    parts = _cgi_parseparam(';' + line)
+    key = parts.__next__()
+    pdict = {}
+    for p in parts:
+        i = p.find('=')
+        if i >= 0:
+            name = p[:i].strip().lower()
+            value = p[i + 1:].strip()
+            if len(value) >= 2 and value[0] == value[-1] == '"':
+                value = value[1:-1]
+                value = value.replace('\\\\', '\\').replace('\\"', '"')
+            pdict[name] = value
+    return key, pdict
+
+
 def ntob(n, encoding='ISO-8859-1'):
     """Return the given native string as a byte string in the given
     encoding.

cherrypy/lib/covercp.py

@@ -22,7 +22,7 @@
 
 import re
 import sys
-import cgi
+import html
 import os
 import os.path
 import urllib.parse
@@ -352,9 +352,9 @@ def annotated_file(self, filename, statements, excluded, missing):
                 buffer.append((lineno, line))
             if empty_the_buffer:
                 for lno, pastline in buffer:
-                    yield template % (lno, cgi.escape(pastline))
+                    yield template % (lno, html.escape(pastline))
                 buffer = []
-                yield template % (lineno, cgi.escape(line))
+                yield template % (lineno, html.escape(line))
 
     @cherrypy.expose
     def report(self, name):

cherrypy/lib/httputil.py

@@ -12,7 +12,7 @@
 import re
 import builtins
 from binascii import b2a_base64
-from cgi import parse_header
+from cherrypy._cpcompat import cgi_parse_header as parse_header
 from email.header import decode_header
 from http.server import BaseHTTPRequestHandler
 from urllib.parse import unquote_plus

pytest.ini

@@ -59,9 +59,6 @@ filterwarnings =
   ignore:the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses:DeprecationWarning
   ignore:the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses:PendingDeprecationWarning
 
-  # TODO: Replace the use of `cgi`. It seems untrivial.
-  ignore:'cgi' is deprecated and slated for removal in Python 3.13:DeprecationWarning
-
   # TODO: Remove once `cheroot.webtest._open_url_once` is fixed to release
   # TODO: connection properly.
   ignore:unclosed <socket.socket fd=:ResourceWarning