[Python-checkins] bpo-36321: Fix misspelled attribute in namedtuple() (GH-12375)

Mon Mar 18 03:27:43 EDT 2019

https://github.com/python/cpython/commit/23581c018fceb607fe829a41c6fbe81b4d502cab
commit: 23581c018fceb607fe829a41c6fbe81b4d502cab
branch: master
author: Raymond Hettinger <rhettinger at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2019年03月18日T00:27:39-07:00
summary:
bpo-36321: Fix misspelled attribute in namedtuple() (GH-12375)
files:
A Misc/NEWS.d/next/Library/2019-03-16-13-40-59.bpo-36321.s6crQx.rst
M Doc/library/collections.rst
M Lib/collections/__init__.py
M Lib/test/test_collections.py

diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index daa741428a01..64de970fec94 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -953,14 +953,14 @@ field names, the method and attribute names start with an underscore.
 >>> Pixel(11, 22, 128, 255, 0)
 Pixel(x=11, y=22, red=128, green=255, blue=0)
 
-.. attribute:: somenamedtuple._fields_defaults
+.. attribute:: somenamedtuple._field_defaults
 
 Dictionary mapping field names to default values.
 
 .. doctest::
 
 >>> Account = namedtuple('Account', ['type', 'balance'], defaults=[0])
- >>> Account._fields_defaults
+ >>> Account._field_defaults
 {'balance': 0}
 >>> Account('premium')
 Account(type='premium', balance=0)
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 632a509d316c..cff75a48d627 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -445,6 +445,8 @@ def __getnewargs__(self):
 '__doc__': f'{typename}({arg_list})',
 '__slots__': (),
 '_fields': field_names,
+ '_field_defaults': field_defaults,
+ # alternate spelling for backward compatiblity
 '_fields_defaults': field_defaults,
 '__new__': __new__,
 '_make': _make,
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index dad1b6cd7fb3..1f619bcdac92 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -248,18 +248,18 @@ def test_factory(self):
 
 def test_defaults(self):
 Point = namedtuple('Point', 'x y', defaults=(10, 20)) # 2 defaults
- self.assertEqual(Point._fields_defaults, {'x': 10, 'y': 20})
+ self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
 self.assertEqual(Point(1, 2), (1, 2))
 self.assertEqual(Point(1), (1, 20))
 self.assertEqual(Point(), (10, 20))
 
 Point = namedtuple('Point', 'x y', defaults=(20,)) # 1 default
- self.assertEqual(Point._fields_defaults, {'y': 20})
+ self.assertEqual(Point._field_defaults, {'y': 20})
 self.assertEqual(Point(1, 2), (1, 2))
 self.assertEqual(Point(1), (1, 20))
 
 Point = namedtuple('Point', 'x y', defaults=()) # 0 defaults
- self.assertEqual(Point._fields_defaults, {})
+ self.assertEqual(Point._field_defaults, {})
 self.assertEqual(Point(1, 2), (1, 2))
 with self.assertRaises(TypeError):
 Point(1)
@@ -276,21 +276,21 @@ def test_defaults(self):
 Point = namedtuple('Point', 'x y', defaults=False)
 
 Point = namedtuple('Point', 'x y', defaults=None) # default is None
- self.assertEqual(Point._fields_defaults, {})
+ self.assertEqual(Point._field_defaults, {})
 self.assertIsNone(Point.__new__.__defaults__, None)
 self.assertEqual(Point(10, 20), (10, 20))
 with self.assertRaises(TypeError): # catch too few args
 Point(10)
 
 Point = namedtuple('Point', 'x y', defaults=[10, 20]) # allow non-tuple iterable
- self.assertEqual(Point._fields_defaults, {'x': 10, 'y': 20})
+ self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
 self.assertEqual(Point.__new__.__defaults__, (10, 20))
 self.assertEqual(Point(1, 2), (1, 2))
 self.assertEqual(Point(1), (1, 20))
 self.assertEqual(Point(), (10, 20))
 
 Point = namedtuple('Point', 'x y', defaults=iter([10, 20])) # allow plain iterator
- self.assertEqual(Point._fields_defaults, {'x': 10, 'y': 20})
+ self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
 self.assertEqual(Point.__new__.__defaults__, (10, 20))
 self.assertEqual(Point(1, 2), (1, 2))
 self.assertEqual(Point(1), (1, 20))
diff --git a/Misc/NEWS.d/next/Library/2019-03-16-13-40-59.bpo-36321.s6crQx.rst b/Misc/NEWS.d/next/Library/2019-03-16-13-40-59.bpo-36321.s6crQx.rst
new file mode 100644
index 000000000000..eea6f5418484
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-03-16-13-40-59.bpo-36321.s6crQx.rst
@@ -0,0 +1,5 @@
+collections.namedtuple() misspelled the name of an attribute. To be
+consistent with typing.NamedTuple, the attribute name should have been
+"_field_defaults" instead of "_fields_defaults". For backwards
+compatibility, both spellings are now created. The misspelled version may
+be removed in the future.
