gh-115233: Fix an example in the Logging Cookbook (GH-115325)

Also add more tests for LoggerAdapter.

Also support stacklevel in LoggerAdapter._log().

Lib/test/test_logging.py

@@ -5478,6 +5478,7 @@ class LoggerAdapterTest(unittest.TestCase):
         self.assertEqual(record.levelno, logging.CRITICAL)
         self.assertEqual(record.msg, msg)
         self.assertEqual(record.args, (self.recording,))
+        self.assertEqual(record.funcName, 'test_critical')
 
     def test_is_enabled_for(self):
         old_disable = self.adapter.logger.manager.disable
@@ -5496,15 +5497,9 @@ class LoggerAdapterTest(unittest.TestCase):
         self.assertFalse(self.adapter.hasHandlers())
 
     def test_nested(self):
-        class Adapter(logging.LoggerAdapter):
-            prefix = 'Adapter'
-
-            def process(self, msg, kwargs):
-                return f"{self.prefix} {msg}", kwargs
-
         msg = 'Adapters can be nested, yo.'
-        adapter = Adapter(logger=self.logger, extra=None)
-        adapter_adapter = Adapter(logger=adapter, extra=None)
+        adapter = PrefixAdapter(logger=self.logger, extra=None)
+        adapter_adapter = PrefixAdapter(logger=adapter, extra=None)
         adapter_adapter.prefix = 'AdapterAdapter'
         self.assertEqual(repr(adapter), repr(adapter_adapter))
         adapter_adapter.log(logging.CRITICAL, msg, self.recording)
@@ -5513,6 +5508,7 @@ class LoggerAdapterTest(unittest.TestCase):
         self.assertEqual(record.levelno, logging.CRITICAL)
         self.assertEqual(record.msg, f"Adapter AdapterAdapter {msg}")
         self.assertEqual(record.args, (self.recording,))
+        self.assertEqual(record.funcName, 'test_nested')
         orig_manager = adapter_adapter.manager
         self.assertIs(adapter.manager, orig_manager)
         self.assertIs(self.logger.manager, orig_manager)
@@ -5528,6 +5524,61 @@ class LoggerAdapterTest(unittest.TestCase):
         self.assertIs(adapter.manager, orig_manager)
         self.assertIs(self.logger.manager, orig_manager)
 
+    def test_styled_adapter(self):
+        # Test an example from the Cookbook.
+        records = self.recording.records
+        adapter = StyleAdapter(self.logger)
+        adapter.warning('Hello, {}!', 'world')
+        self.assertEqual(str(records[-1].msg), 'Hello, world!')
+        self.assertEqual(records[-1].funcName, 'test_styled_adapter')
+        adapter.log(logging.WARNING, 'Goodbye {}.', 'world')
+        self.assertEqual(str(records[-1].msg), 'Goodbye world.')
+        self.assertEqual(records[-1].funcName, 'test_styled_adapter')
+
+    def test_nested_styled_adapter(self):
+        records = self.recording.records
+        adapter = PrefixAdapter(self.logger)
+        adapter.prefix = '{}'
+        adapter2 = StyleAdapter(adapter)
+        adapter2.warning('Hello, {}!', 'world')
+        self.assertEqual(str(records[-1].msg), '{} Hello, world!')
+        self.assertEqual(records[-1].funcName, 'test_nested_styled_adapter')
+        adapter2.log(logging.WARNING, 'Goodbye {}.', 'world')
+        self.assertEqual(str(records[-1].msg), '{} Goodbye world.')
+        self.assertEqual(records[-1].funcName, 'test_nested_styled_adapter')
+
+    def test_find_caller_with_stacklevel(self):
+        the_level = 1
+        trigger = self.adapter.warning
+
+        def innermost():
+            trigger('test', stacklevel=the_level)
+
+        def inner():
+            innermost()
+
+        def outer():
+            inner()
+
+        records = self.recording.records
+        outer()
+        self.assertEqual(records[-1].funcName, 'innermost')
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'inner')
+        self.assertGreater(records[-1].lineno, lineno)
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'outer')
+        self.assertGreater(records[-1].lineno, lineno)
+        lineno = records[-1].lineno
+        the_level += 1
+        outer()
+        self.assertEqual(records[-1].funcName, 'test_find_caller_with_stacklevel')
+        self.assertGreater(records[-1].lineno, lineno)
+
     def test_extra_in_records(self):
         self.adapter = logging.LoggerAdapter(logger=self.logger,
                                              extra={'foo': '1'})
@@ -5569,6 +5620,30 @@ class LoggerAdapterTest(unittest.TestCase):
         self.assertEqual(record.foo, '2')
 
 
+class PrefixAdapter(logging.LoggerAdapter):
+    prefix = 'Adapter'
+
+    def process(self, msg, kwargs):
+        return f"{self.prefix} {msg}", kwargs
+
+
+class Message:
+    def __init__(self, fmt, args):
+        self.fmt = fmt
+        self.args = args
+
+    def __str__(self):
+        return self.fmt.format(*self.args)
+
+
+class StyleAdapter(logging.LoggerAdapter):
+    def log(self, level, msg, /, *args, stacklevel=1, **kwargs):
+        if self.isEnabledFor(level):
+            msg, kwargs = self.process(msg, kwargs)
+            self.logger.log(level, Message(msg, args), **kwargs,
+                            stacklevel=stacklevel+1)
+
+
 class LoggerTest(BaseTest, AssertErrorMessage):
 
     def setUp(self):