bpo-40756: Default second argument of LoggerAdapter.__init__ to None (GH-20362)
The 'extra' argument is not always used by custom logger adapters. For
example:
```python
class IndentAdapter(logging.LoggerAdapter):
def process(self, msg, kwargs):
indent = kwargs.pop(indent, 1)
return ' ' * indent + msg, kwargs
```
It is cleaner and friendlier to default the 'extra' argument to None
instead of either forcing the subclasses of LoggerAdapter to pass a None
value directly or to override the constructor.
This change is backward compatible because existing calls to
`LoggerAdapter.__init__` are already passing a value for the second
argument.
Automerge-Triggered-By: @vsajipdiff --git a/Lib/logging/__init__.py b/Lib/logging/__init__.py
index 403dc81..6d27301 100644
--- a/Lib/logging/__init__.py
+++ b/Lib/logging/__init__.py
@@ -1751,7 +1751,7 @@
information in logging output.
"""
- def __init__(self, logger, extra):
+ def __init__(self, logger, extra=None):
"""
Initialize the adapter with a logger and a dict-like object which
provides contextual information. This constructor signature allows
diff --git a/Misc/NEWS.d/next/Library/2020-05-24-11-06-37.bpo-40756.7ZH83z.rst b/Misc/NEWS.d/next/Library/2020-05-24-11-06-37.bpo-40756.7ZH83z.rst
new file mode 100644
index 0000000..a970f5b
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-05-24-11-06-37.bpo-40756.7ZH83z.rst
@@ -0,0 +1,2 @@
+The second argument (extra) of ``LoggerAdapter.__init__`` now defaults to
+None.
