[3.11] gh-110875: Handle '.' properties in logging formatter configuration correctly. (GH-110943) (GH-111914)

Co-authored-by: Vinay Sajip <vinay_sajip@yahoo.co.uk>

Lib/logging/config.py

@@ -1,4 +1,4 @@
-# Copyright 2001-2019 by Vinay Sajip. All Rights Reserved.
+# Copyright 2001-2023 by Vinay Sajip. All Rights Reserved.
 #
 # Permission to use, copy, modify, and distribute this software and its
 # documentation for any purpose and without fee is hereby granted,
@@ -19,7 +19,7 @@
 is based on PEP 282 and comments thereto in comp.lang.python, and influenced
 by Apache's log4j system.
 
-Copyright (C) 2001-2019 Vinay Sajip. All Rights Reserved.
+Copyright (C) 2001-2023 Vinay Sajip. All Rights Reserved.
 
 To use, simply 'import logging' and log away!
 """
@@ -477,10 +477,10 @@ def configure_custom(self, config):
         c = config.pop('()')
         if not callable(c):
             c = self.resolve(c)
-        props = config.pop('.', None)
         # Check for valid identifiers
-        kwargs = {k: config[k] for k in config if valid_ident(k)}
+        kwargs = {k: config[k] for k in config if (k != '.' and valid_ident(k))}
         result = c(**kwargs)
+        props = config.pop('.', None)
         if props:
             for name, value in props.items():
                 setattr(result, name, value)
@@ -752,8 +752,7 @@ def configure_handler(self, config):
                 'address' in config:
                 config['address'] = self.as_tuple(config['address'])
             factory = klass
-        props = config.pop('.', None)
-        kwargs = {k: config[k] for k in config if valid_ident(k)}
+        kwargs = {k: config[k] for k in config if (k != '.' and valid_ident(k))}
         try:
             result = factory(**kwargs)
         except TypeError as te:
@@ -771,6 +770,7 @@ def configure_handler(self, config):
             result.setLevel(logging._checkLevel(level))
         if filters:
             self.add_filters(result, filters)
+        props = config.pop('.', None)
         if props:
             for name, value in props.items():
                 setattr(result, name, value)

Lib/test/test_logging.py

@@ -1,4 +1,4 @@
-# Copyright 2001-2022 by Vinay Sajip. All Rights Reserved.
+# Copyright 2001-2023 by Vinay Sajip. All Rights Reserved.
 #
 # Permission to use, copy, modify, and distribute this software and its
 # documentation for any purpose and without fee is hereby granted,
@@ -16,7 +16,7 @@
 
 """Test harness for the logging module. Run all tests.
 
-Copyright (C) 2001-2022 Vinay Sajip. All Rights Reserved.
+Copyright (C) 2001-2023 Vinay Sajip. All Rights Reserved.
 """
 
 import logging
@@ -2881,6 +2881,39 @@ class ConfigDictTest(BaseTest):
         },
     }
 
+    class CustomFormatter(logging.Formatter):
+        custom_property = "."
+
+        def format(self, record):
+            return super().format(record)
+
+    config17 = {
+        'version': 1,
+        'formatters': {
+            "custom": {
+                "()": CustomFormatter,
+                "style": "{",
+                "datefmt": "%Y-%m-%d %H:%M:%S",
+                "format": "{message}", # <-- to force an exception when configuring
+                ".": {
+                    "custom_property": "value"
+                }
+            }
+        },
+        'handlers' : {
+            'hand1' : {
+                'class' : 'logging.StreamHandler',
+                'formatter' : 'custom',
+                'level' : 'NOTSET',
+                'stream'  : 'ext://sys.stdout',
+            },
+        },
+        'root' : {
+            'level' : 'WARNING',
+            'handlers' : ['hand1'],
+        },
+    }
+
     out_of_order = {
         "version": 1,
         "formatters": {
@@ -3295,6 +3328,11 @@ def cleanup(h1, fn):
         handler = logging.root.handlers[0]
         self.addCleanup(cleanup, handler, fn)
 
+    def test_config17_ok(self):
+        self.apply_config(self.config17)
+        h = logging._handlers['hand1']
+        self.assertEqual(h.formatter.custom_property, 'value')
+
     def setup_via_listener(self, text, verify=None):
         text = text.encode("utf-8")
         # Ask for a randomly assigned port (by using port 0)