[Python-checkins] bpo-39142: Avoid converting namedtuple instances to ConvertingTuple. (GH-17773)
Vinay Sajip
webhook-mailer at python.org
Wed Jan 1 14:32:25 EST 2020
https://github.com/python/cpython/commit/46abfc1416ff8e450999611ef8f231ff871ab133
commit: 46abfc1416ff8e450999611ef8f231ff871ab133
branch: master
author: Vinay Sajip <vinay_sajip at yahoo.co.uk>
committer: GitHub <noreply at github.com>
date: 2020-01-01T19:32:11Z
summary:
bpo-39142: Avoid converting namedtuple instances to ConvertingTuple. (GH-17773)
This uses the heuristic of assuming a named tuple is a subclass of
tuple with a _fields attribute. This change means that contents of
a named tuple wouldn't be converted - if a user wants to have
ConvertingTuple functionality from a namedtuple, they will have to
implement it themselves.
files:
A Misc/NEWS.d/next/Library/2019-12-31-19-27-23.bpo-39142.oqU5iD.rst
M Lib/logging/config.py
M Lib/test/test_logging.py
diff --git a/Lib/logging/config.py b/Lib/logging/config.py
index 4a3b8966ede1c..fd3aded7608cb 100644
--- a/Lib/logging/config.py
+++ b/Lib/logging/config.py
@@ -448,7 +448,7 @@ def convert(self, value):
value = ConvertingList(value)
value.configurator = self
elif not isinstance(value, ConvertingTuple) and\
- isinstance(value, tuple):
+ isinstance(value, tuple) and not hasattr(value, '_fields'):
value = ConvertingTuple(value)
value.configurator = self
elif isinstance(value, str): # str for py3k
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 4feed03fec2a8..c38fdae03385e 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -3379,6 +3379,37 @@ def test_baseconfig(self):
self.assertRaises(ValueError, bc.convert, 'cfg://!')
self.assertRaises(KeyError, bc.convert, 'cfg://adict[2]')
+ def test_namedtuple(self):
+ # see bpo-39142
+ from collections import namedtuple
+
+ class MyHandler(logging.StreamHandler):
+ def __init__(self, resource, *args, **kwargs):
+ super().__init__(*args, **kwargs)
+ self.resource: namedtuple = resource
+
+ def emit(self, record):
+ record.msg += f' {self.resource.type}'
+ return super().emit(record)
+
+ Resource = namedtuple('Resource', ['type', 'labels'])
+ resource = Resource(type='my_type', labels=['a'])
+
+ config = {
+ 'version': 1,
+ 'handlers': {
+ 'myhandler': {
+ '()': MyHandler,
+ 'resource': resource
+ }
+ },
+ 'root': {'level': 'INFO', 'handlers': ['myhandler']},
+ }
+ with support.captured_stderr() as stderr:
+ self.apply_config(config)
+ logging.info('some log')
+ self.assertEqual(stderr.getvalue(), 'some log my_type\n')
+
class ManagerTest(BaseTest):
def test_manager_loggerclass(self):
logged = []
diff --git a/Misc/NEWS.d/next/Library/2019-12-31-19-27-23.bpo-39142.oqU5iD.rst b/Misc/NEWS.d/next/Library/2019-12-31-19-27-23.bpo-39142.oqU5iD.rst
new file mode 100644
index 0000000000000..508d1338d7c31
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-12-31-19-27-23.bpo-39142.oqU5iD.rst
@@ -0,0 +1,5 @@
+A change was made to logging.config.dictConfig to avoid converting instances
+of named tuples to ConvertingTuple. It's assumed that named tuples are too
+specialised to be treated like ordinary tuples; if a user of named tuples
+requires ConvertingTuple functionality, they will have to implement that
+themselves in their named tuple class.
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