[Python-checkins] bpo-38191: Accept arbitrary keyword names in NamedTuple() and TypedDict(). (GH-16222)
Serhiy Storchaka
webhook-mailer at python.org
Tue Sep 17 14:22:05 EDT 2019
https://github.com/python/cpython/commit/2bf31ccab3d17f3f35b42dca97f99576dfe2fc7d
commit: 2bf31ccab3d17f3f35b42dca97f99576dfe2fc7d
branch: master
author: Serhiy Storchaka <storchaka at gmail.com>
committer: GitHub <noreply at github.com>
date: 2019-09-17T21:22:00+03:00
summary:
bpo-38191: Accept arbitrary keyword names in NamedTuple() and TypedDict(). (GH-16222)
This includes such names as "cls", "self", "typename", "_typename",
"fields" and "_fields".
Passing positional arguments by keyword is deprecated.
files:
A Misc/NEWS.d/next/Library/2019-09-17-12-28-27.bpo-38191.1TU0HV.rst
M Lib/test/test_typing.py
M Lib/typing.py
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 59b1b4e6d548..5914f314db0a 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -3563,6 +3563,36 @@ def test_namedtuple_keyword_usage(self):
with self.assertRaises(TypeError):
NamedTuple('Name', x=1, y='a')
+ def test_namedtuple_special_keyword_names(self):
+ NT = NamedTuple("NT", cls=type, self=object, typename=str, fields=list)
+ self.assertEqual(NT.__name__, 'NT')
+ self.assertEqual(NT._fields, ('cls', 'self', 'typename', 'fields'))
+ a = NT(cls=str, self=42, typename='foo', fields=[('bar', tuple)])
+ self.assertEqual(a.cls, str)
+ self.assertEqual(a.self, 42)
+ self.assertEqual(a.typename, 'foo')
+ self.assertEqual(a.fields, [('bar', tuple)])
+
+ def test_namedtuple_errors(self):
+ with self.assertRaises(TypeError):
+ NamedTuple.__new__()
+ with self.assertRaises(TypeError):
+ NamedTuple()
+ with self.assertRaises(TypeError):
+ NamedTuple('Emp', [('name', str)], None)
+ with self.assertRaises(ValueError):
+ NamedTuple('Emp', [('_name', str)])
+
+ with self.assertWarns(DeprecationWarning):
+ Emp = NamedTuple(typename='Emp', name=str, id=int)
+ self.assertEqual(Emp.__name__, 'Emp')
+ self.assertEqual(Emp._fields, ('name', 'id'))
+
+ with self.assertWarns(DeprecationWarning):
+ Emp = NamedTuple('Emp', fields=[('name', str), ('id', int)])
+ self.assertEqual(Emp.__name__, 'Emp')
+ self.assertEqual(Emp._fields, ('name', 'id'))
+
def test_pickle(self):
global Emp # pickle wants to reference the class by name
Emp = NamedTuple('Emp', [('name', str), ('id', int)])
@@ -3604,6 +3634,36 @@ def test_basics_keywords_syntax(self):
self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})
self.assertEqual(Emp.__total__, True)
+ def test_typeddict_special_keyword_names(self):
+ TD = TypedDict("TD", cls=type, self=object, typename=str, _typename=int, fields=list, _fields=dict)
+ self.assertEqual(TD.__name__, 'TD')
+ self.assertEqual(TD.__annotations__, {'cls': type, 'self': object, 'typename': str, '_typename': int, 'fields': list, '_fields': dict})
+ a = TD(cls=str, self=42, typename='foo', _typename=53, fields=[('bar', tuple)], _fields={'baz', set})
+ self.assertEqual(a['cls'], str)
+ self.assertEqual(a['self'], 42)
+ self.assertEqual(a['typename'], 'foo')
+ self.assertEqual(a['_typename'], 53)
+ self.assertEqual(a['fields'], [('bar', tuple)])
+ self.assertEqual(a['_fields'], {'baz', set})
+
+ def test_typeddict_create_errors(self):
+ with self.assertRaises(TypeError):
+ TypedDict.__new__()
+ with self.assertRaises(TypeError):
+ TypedDict()
+ with self.assertRaises(TypeError):
+ TypedDict('Emp', [('name', str)], None)
+
+ with self.assertWarns(DeprecationWarning):
+ Emp = TypedDict(_typename='Emp', name=str, id=int)
+ self.assertEqual(Emp.__name__, 'Emp')
+ self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})
+
+ with self.assertWarns(DeprecationWarning):
+ Emp = TypedDict('Emp', _fields={'name': str, 'id': int})
+ self.assertEqual(Emp.__name__, 'Emp')
+ self.assertEqual(Emp.__annotations__, {'name': str, 'id': int})
+
def test_typeddict_errors(self):
Emp = TypedDict('Emp', {'name': str, 'id': int})
self.assertEqual(TypedDict.__module__, 'typing')
diff --git a/Lib/typing.py b/Lib/typing.py
index 32011332127f..43486a7c8ba8 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1653,35 +1653,96 @@ class Employee(NamedTuple):
"""
_root = True
- def __new__(self, typename, fields=None, **kwargs):
+ def __new__(*args, **kwargs):
+ if not args:
+ raise TypeError('NamedTuple.__new__(): not enough arguments')
+ cls, *args = args # allow the "cls" keyword be passed
+ if args:
+ typename, *args = args # allow the "typename" keyword be passed
+ elif 'typename' in kwargs:
+ typename = kwargs.pop('typename')
+ import warnings
+ warnings.warn("Passing 'typename' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ raise TypeError("NamedTuple.__new__() missing 1 required positional "
+ "argument: 'typename'")
+ if args:
+ try:
+ fields, = args # allow the "fields" keyword be passed
+ except ValueError:
+ raise TypeError(f'NamedTuple.__new__() takes from 2 to 3 '
+ f'positional arguments but {len(args) + 2} '
+ f'were given') from None
+ elif 'fields' in kwargs and len(kwargs) == 1:
+ fields = kwargs.pop('fields')
+ import warnings
+ warnings.warn("Passing 'fields' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ fields = None
+
if fields is None:
fields = kwargs.items()
elif kwargs:
raise TypeError("Either list of fields or keywords"
" can be provided to NamedTuple, not both")
return _make_nmtuple(typename, fields)
+ __new__.__text_signature__ = '($cls, typename, fields=None, /, **kwargs)'
-def _dict_new(cls, *args, **kwargs):
+def _dict_new(*args, **kwargs):
+ if not args:
+ raise TypeError('TypedDict.__new__(): not enough arguments')
+ cls, *args = args # allow the "cls" keyword be passed
return dict(*args, **kwargs)
-
-
-def _typeddict_new(cls, _typename, _fields=None, **kwargs):
- total = kwargs.pop('total', True)
- if _fields is None:
- _fields = kwargs
+_dict_new.__text_signature__ = '($cls, _typename, _fields=None, /, **kwargs)'
+
+
+def _typeddict_new(*args, total=True, **kwargs):
+ if not args:
+ raise TypeError('TypedDict.__new__(): not enough arguments')
+ cls, *args = args # allow the "cls" keyword be passed
+ if args:
+ typename, *args = args # allow the "_typename" keyword be passed
+ elif '_typename' in kwargs:
+ typename = kwargs.pop('_typename')
+ import warnings
+ warnings.warn("Passing '_typename' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ raise TypeError("TypedDict.__new__() missing 1 required positional "
+ "argument: '_typename'")
+ if args:
+ try:
+ fields, = args # allow the "_fields" keyword be passed
+ except ValueError:
+ raise TypeError(f'TypedDict.__new__() takes from 2 to 3 '
+ f'positional arguments but {len(args) + 2} '
+ f'were given') from None
+ elif '_fields' in kwargs and len(kwargs) == 1:
+ fields = kwargs.pop('_fields')
+ import warnings
+ warnings.warn("Passing '_fields' as keyword argument is deprecated",
+ DeprecationWarning, stacklevel=2)
+ else:
+ fields = None
+
+ if fields is None:
+ fields = kwargs
elif kwargs:
raise TypeError("TypedDict takes either a dict or keyword arguments,"
" but not both")
- ns = {'__annotations__': dict(_fields), '__total__': total}
+ ns = {'__annotations__': dict(fields), '__total__': total}
try:
# Setting correct module is necessary to make typed dict classes pickleable.
ns['__module__'] = sys._getframe(1).f_globals.get('__name__', '__main__')
except (AttributeError, ValueError):
pass
- return _TypedDictMeta(_typename, (), ns)
+ return _TypedDictMeta(typename, (), ns)
+_typeddict_new.__text_signature__ = '($cls, _typename, _fields=None, /, *, total=True, **kwargs)'
def _check_fails(cls, other):
diff --git a/Misc/NEWS.d/next/Library/2019-09-17-12-28-27.bpo-38191.1TU0HV.rst b/Misc/NEWS.d/next/Library/2019-09-17-12-28-27.bpo-38191.1TU0HV.rst
new file mode 100644
index 000000000000..1a6de60e46c1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-09-17-12-28-27.bpo-38191.1TU0HV.rst
@@ -0,0 +1,4 @@
+Constructors of :class:`~typing.NamedTuple` and :class:`~typing.TypedDict`
+types now accept arbitrary keyword argument names, including "cls", "self",
+"typename", "_typename", "fields" and "_fields". Passing positional
+arguments by keyword is deprecated.
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