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gh-128118: Improve performance of copy.copy by using a fast lookup for atomic and container types #128119

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Merged
erlend-aasland merged 4 commits into from
Dec 30, 2024
Merged

gh-128118: Improve performance of copy.copy by using a fast lookup for atomic and container types #128119

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d951b17
Refactor copy.copy
eendebakpt Dec 20, 2024
742aa88
use set instead of tuple
eendebakpt Dec 20, 2024
c2e6a4a
📜🤖 Added by blurb_it.
blurb-it[bot] Dec 20, 2024
9490a23
Update Misc/NEWS.d/next/Library/2024-12-20-10-57-10.gh-issue-128118.m…
eendebakpt Dec 26, 2024
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Refactor copy.copy
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@eendebakpt
eendebakpt committed Dec 20, 2024
commit d951b17e66032285b7418d233afee3aee6055922
27 changes: 9 additions & 18 deletions Lib/copy.py
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Original file line number Diff line number Diff line change
Expand Up @@ -67,13 +67,15 @@ def copy(x):

cls = type(x)

copier = _copy_dispatch.get(cls)
if copier:
return copier(x)
if cls in _copy_atomic_types:
return x
if cls in _copy_builtin_containers:
return cls.copy(x)


if issubclass(cls, type):
# treat it as a regular class:
return _copy_immutable(x)
return x

copier = getattr(cls, "__copy__", None)
if copier is not None:
Expand All @@ -98,23 +100,12 @@ def copy(x):
return _reconstruct(x, None, *rv)


_copy_dispatch = d = {}

def _copy_immutable(x):
return x
for t in (types.NoneType, int, float, bool, complex, str, tuple,
_copy_atomic_types = (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):
d[t] = _copy_immutable

d[list] = list.copy
d[dict] = dict.copy
d[set] = set.copy
d[bytearray] = bytearray.copy

del d, t
weakref.ref, super)
_copy_builtin_containers = (list, dict, set, bytearray)

def deepcopy(x, memo=None, _nil=[]):
"""Deep copy operation on arbitrary Python objects.
Expand Down