From 0863cf49034a82c875be78b45680c1dc19c62e00 Mon Sep 17 00:00:00 2001
From: furkanonder <furkanonder@protonmail.com>
Date: Tue, 31 Jan 2023 18:58:52 +0300
Subject: [PATCH 1/4] Fix duplicate values in the list when copying a subclass
 list

---
 Lib/copy.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Lib/copy.py b/Lib/copy.py
index da2908ef623d8c..6490706732bc7f 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -254,6 +254,33 @@ def _reconstruct(x, memo, func, args,
     if deep:
         memo[id(x)] = y
 
+    if isinstance(state, list):
+        if listiter is not None:
+            if deep:
+                for item in listiter:
+                    item = deepcopy(item, memo)
+                    y.append(item)
+            else:
+                for item in listiter:
+                    y.append(item)
+
+        if state is not None:
+            if deep:
+                state = deepcopy(state, memo)
+            if hasattr(y, '__setstate__'):
+                y.__setstate__(state)
+            else:
+                if isinstance(state, tuple) and len(state) == 2:
+                    state, slotstate = state
+                else:
+                    slotstate = None
+                if state is not None:
+                    y.__dict__.update(state)
+                if slotstate is not None:
+                    for key, value in slotstate.items():
+                        setattr(y, key, value)
+        return y
+
     if state is not None:
         if deep:
             state = deepcopy(state, memo)

From 3e3916d4a9610aecf05b59c22ed0d70062acdc52 Mon Sep 17 00:00:00 2001
From: furkanonder <furkanonder@protonmail.com>
Date: Tue, 31 Jan 2023 19:04:42 +0300
Subject: [PATCH 2/4] Add new list subclass test cases to the copy module

---
 Lib/test/test_copy.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
index 826e46824e004c..68465bcfdda95f 100644
--- a/Lib/test/test_copy.py
+++ b/Lib/test/test_copy.py
@@ -761,6 +761,18 @@ class C(list):
         self.assertIsNot(x[0], y[0])
         self.assertIsNot(x.foo, y.foo)
 
+        class L(list):
+            def __getstate__(self):
+                return list(self)
+
+            def __setstate__(self, state):
+                self[:] = state
+
+        l1 = L([1, 2])
+        l2 = copy.deepcopy(l1)
+        self.assertEqual(list(l1), list(l2))
+        self.assertEqual(len(l1), len(l2))
+
     def test_copy_tuple_subclass(self):
         class C(tuple):
             pass

From 9d4d7a6c408e9eeb3a77782130ac33396921be9b Mon Sep 17 00:00:00 2001
From: Furkan Onder <furkanonder@protonmail.com>
Date: Tue, 31 Jan 2023 19:08:58 +0300
Subject: [PATCH 3/4] don't cast list to list

---
 Lib/test/test_copy.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
index 68465bcfdda95f..5b9899804249f6 100644
--- a/Lib/test/test_copy.py
+++ b/Lib/test/test_copy.py
@@ -770,7 +770,7 @@ def __setstate__(self, state):
 
         l1 = L([1, 2])
         l2 = copy.deepcopy(l1)
-        self.assertEqual(list(l1), list(l2))
+        self.assertEqual(l1, l2)
         self.assertEqual(len(l1), len(l2))
 
     def test_copy_tuple_subclass(self):

From 6131f8a42763a0d69dedb8ddf72b603a29626ba1 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Tue, 31 Jan 2023 16:48:57 +0000
Subject: [PATCH 4/4] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Library/2023-01-31-16-48-54.gh-issue-48962.RvwDsB.rst   | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2023-01-31-16-48-54.gh-issue-48962.RvwDsB.rst

diff --git a/Misc/NEWS.d/next/Library/2023-01-31-16-48-54.gh-issue-48962.RvwDsB.rst b/Misc/NEWS.d/next/Library/2023-01-31-16-48-54.gh-issue-48962.RvwDsB.rst
new file mode 100644
index 00000000000000..235929e5fbe333
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-01-31-16-48-54.gh-issue-48962.RvwDsB.rst
@@ -0,0 +1 @@
+Fix duplicate values in the list when deepcopying a subclass list in the copy module.