From: Raymond Hettinger <rhettinger@users.noreply.github.com>
Date: Tue, 26 May 2020 04:39:00 +0000 (-0700)
Subject: Simplify creation of the __new__ method in namedtuple() (GH-20361)
X-Git-Tag: v3.10.0a1~819
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3cfe5b7b8fb3a0396e62800f3873d9b1f70da1c2;p=thirdparty%2FPython%2Fcpython.git

Simplify creation of the __new__ method in namedtuple() (GH-20361)
---

diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index c4bff592dc0e..011a0c1e7c19 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -406,11 +406,9 @@ def namedtuple(typename, field_names, *, rename=False, defaults=None, module=Non
 
     # Create all the named tuple methods to be added to the class namespace
 
-    s = f'def __new__(_cls, {arg_list}): return _tuple_new(_cls, ({arg_list}))'
+    s = f'lambda _cls, {arg_list}: _tuple_new(_cls, ({arg_list}))'
     namespace = {'_tuple_new': tuple_new, '__name__': f'namedtuple_{typename}'}
-    # Note: exec() has the side-effect of interning the field names
-    exec(s, namespace)
-    __new__ = namespace['__new__']
+    __new__ = eval(s, namespace)
     __new__.__doc__ = f'Create new instance of {typename}({arg_list})'
     if defaults is not None:
         __new__.__defaults__ = defaults