https://github.com/python/cpython/commit/9d6604222e9ef4e136ee9ccfa2d4d5ff9feee976
commit: 9d6604222e9ef4e136ee9ccfa2d4d5ff9feee976
branch: main
author: Pieter Eendebak <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2024-06-07T18:42:01+03:00
summary:
gh-114264: Optimize performance of copy.deepcopy by adding a fast path for
atomic types (GH-114266)
files:
A Misc/NEWS.d/next/Library/2024-01-18-21-44-23.gh-issue-114264.DBKn29.rst
M Lib/copy.py
diff --git a/Lib/copy.py b/Lib/copy.py
index a69bc4e78c20b3..7a1907d75494d7 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -121,6 +121,11 @@ def deepcopy(x, memo=None, _nil=[]):
See the module's __doc__ string for more info.
"""
+ cls = type(x)
+
+ if cls in _atomic_types:
+ return x
+
d = id(x)
if memo is None:
memo = {}
@@ -129,14 +134,12 @@ def deepcopy(x, memo=None, _nil=[]):
if y is not _nil:
return y
- cls = type(x)
-
copier = _deepcopy_dispatch.get(cls)
if copier is not None:
y = copier(x, memo)
else:
if issubclass(cls, type):
- y = _deepcopy_atomic(x, memo)
+ y = x # atomic copy
else:
copier = getattr(x, "__deepcopy__", None)
if copier is not None:
@@ -167,26 +170,12 @@ 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,
+ int, float, bool, complex, bytes, str, types.CodeType, type, range,
+ types.BuiltinFunctionType, types.FunctionType, weakref.ref, property}
+
_deepcopy_dispatch = d = {}
-def _deepcopy_atomic(x, memo):
- return x
-d[types.NoneType] = _deepcopy_atomic
-d[types.EllipsisType] = _deepcopy_atomic
-d[types.NotImplementedType] = _deepcopy_atomic
-d[int] = _deepcopy_atomic
-d[float] = _deepcopy_atomic
-d[bool] = _deepcopy_atomic
-d[complex] = _deepcopy_atomic
-d[bytes] = _deepcopy_atomic
-d[str] = _deepcopy_atomic
-d[types.CodeType] = _deepcopy_atomic
-d[type] = _deepcopy_atomic
-d[range] = _deepcopy_atomic
-d[types.BuiltinFunctionType] = _deepcopy_atomic
-d[types.FunctionType] = _deepcopy_atomic
-d[weakref.ref] = _deepcopy_atomic
-d[property] = _deepcopy_atomic
def _deepcopy_list(x, memo, deepcopy=deepcopy):
y = []
diff --git
a/Misc/NEWS.d/next/Library/2024-01-18-21-44-23.gh-issue-114264.DBKn29.rst
b/Misc/NEWS.d/next/Library/2024-01-18-21-44-23.gh-issue-114264.DBKn29.rst
new file mode 100644
index 00000000000000..069ac68b4f3a95
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-01-18-21-44-23.gh-issue-114264.DBKn29.rst
@@ -0,0 +1 @@
+Improve performance of :func:`copy.deepcopy` by adding a fast path for atomic
types.
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