https://github.com/python/cpython/commit/e46d403d59ab28b49d2056b55cc871600816a2bb
commit: e46d403d59ab28b49d2056b55cc871600816a2bb
branch: main
author: Pieter Eendebak <[email protected]>
committer: kumaraditya303 <[email protected]>
date: 2025-09-04T13:20:23+05:30
summary:
gh-132657: improve `deepcopy` and `copy` scaling on free-threading (#138429)
files:
A Misc/NEWS.d/next/Library/2025-09-03-09-03-11.gh-issue-132657.cbAIDh.rst
M Lib/copy.py
diff --git a/Lib/copy.py b/Lib/copy.py
index c64fc0761793f5..fff7e93c2a1b89 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -100,14 +100,14 @@ def copy(x):
return _reconstruct(x, None, *rv)
-_copy_atomic_types = {types.NoneType, int, float, bool, complex, str, tuple,
+_copy_atomic_types = frozenset({types.NoneType, int, float, bool, complex,
str, tuple,
bytes, frozenset, type, range, slice, property,
types.BuiltinFunctionType, types.EllipsisType,
types.NotImplementedType, types.FunctionType, types.CodeType,
- weakref.ref, super}
-_copy_builtin_containers = {list, dict, set, bytearray}
+ weakref.ref, super})
+_copy_builtin_containers = frozenset({list, dict, set, bytearray})
-def deepcopy(x, memo=None, _nil=[]):
+def deepcopy(x, memo=None):
"""Deep copy operation on arbitrary Python objects.
See the module's __doc__ string for more info.
@@ -122,8 +122,8 @@ def deepcopy(x, memo=None, _nil=[]):
if memo is None:
memo = {}
else:
- y = memo.get(d, _nil)
- if y is not _nil:
+ y = memo.get(d, None)
+ if y is not None:
return y
copier = _deepcopy_dispatch.get(cls)
@@ -162,9 +162,9 @@ def deepcopy(x, memo=None, _nil=[]):
_keep_alive(x, memo) # Make sure x lives at least as long as d
return y
-_atomic_types = {types.NoneType, types.EllipsisType, types.NotImplementedType,
+_atomic_types = frozenset({types.NoneType, types.EllipsisType,
types.NotImplementedType,
int, float, bool, complex, bytes, str, types.CodeType, type, range,
- types.BuiltinFunctionType, types.FunctionType, weakref.ref, property}
+ types.BuiltinFunctionType, types.FunctionType, weakref.ref,
property})
_deepcopy_dispatch = d = {}
diff --git
a/Misc/NEWS.d/next/Library/2025-09-03-09-03-11.gh-issue-132657.cbAIDh.rst
b/Misc/NEWS.d/next/Library/2025-09-03-09-03-11.gh-issue-132657.cbAIDh.rst
new file mode 100644
index 00000000000000..8f07f8fc8d1372
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-09-03-09-03-11.gh-issue-132657.cbAIDh.rst
@@ -0,0 +1 @@
+Improve the scaling of :func:`copy.copy` and :func:`copy.deepcopy` in the
free-threading build.
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