python · lgeiger · Jun 30, 2024 · Jun 30, 2024 · Jun 30, 2024 · Jul 1, 2024
diff --git a/Lib/copy.py b/Lib/copy.py
@@ -126,10 +126,13 @@ def deepcopy(x, memo=None, _nil=[]):
    if cls in _atomic_types:
        return x

-    d = id(x)
    if memo is None:
+        if cls in _builtin_iterables and not x:
+            return cls()
+        d = id(x)
        memo = {}
    else:
+        d = id(x)
        y = memo.get(d, _nil)
        if y is not _nil:
            return y
@@ -173,6 +176,7 @@ def deepcopy(x, memo=None, _nil=[]):
 _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}
+_builtin_iterables = {tuple, list, dict, set, frozenset}

 _deepcopy_dispatch = d = {}


diff --git a/Misc/NEWS.d/next/Library/2024-07-01-00-32-33.gh-issue-121192.RZFhQP.rst b/Misc/NEWS.d/next/Library/2024-07-01-00-32-33.gh-issue-121192.RZFhQP.rst
@@ -0,0 +1,2 @@
+Add fast path to :func:`copy.deepcopy` for empty lists, tuples, dicts, sets
+or frozensets.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Add fast path to :func:`copy.deepcopy` for empty lists, tuples, dicts, sets
		or frozensets.