From c75894a36b13f2dd1bfdd72695dd904260b7ef78 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Sat, 18 Jan 2025 11:17:42 +0100
Subject: [PATCH] [3.13] gh-128961: Fix exhausted array iterator crash in
 __setstate__() (GH-128962) (#128976)

(cherry picked from commit 4dade055f4e18a7e91bc70293abb4db745ad16ca)

Co-authored-by: Tomasz Pytel <tompytel@gmail.com>
---
 Lib/test/test_array.py                            |  8 ++++++++
 ...2025-01-17-21-33-11.gh-issue-128961.XwvyIZ.rst |  1 +
 Modules/arraymodule.c                             | 15 ++++++++++-----
 3 files changed, 19 insertions(+), 5 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2025-01-17-21-33-11.gh-issue-128961.XwvyIZ.rst

diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 47cbe60bfca4e4..f0e32befd6628d 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -1665,5 +1665,13 @@ def test_tolist(self, size):
         self.assertEqual(ls[:8], list(example[:8]))
         self.assertEqual(ls[-8:], list(example[-8:]))
 
+    def test_gh_128961(self):
+        a = array.array('i')
+        it = iter(a)
+        list(it)
+        it.__setstate__(0)
+        self.assertRaises(StopIteration, next, it)
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Misc/NEWS.d/next/Library/2025-01-17-21-33-11.gh-issue-128961.XwvyIZ.rst b/Misc/NEWS.d/next/Library/2025-01-17-21-33-11.gh-issue-128961.XwvyIZ.rst
new file mode 100644
index 00000000000000..9c985df77743da
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-01-17-21-33-11.gh-issue-128961.XwvyIZ.rst
@@ -0,0 +1 @@
+Fix a crash when setting state on an exhausted :class:`array.array` iterator.
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 679222c3f03d23..600302e1183f99 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -3074,11 +3074,16 @@ array_arrayiterator___setstate__(arrayiterobject *self, PyObject *state)
     Py_ssize_t index = PyLong_AsSsize_t(state);
     if (index == -1 && PyErr_Occurred())
         return NULL;
-    if (index < 0)
-        index = 0;
-    else if (index > Py_SIZE(self->ao))
-        index = Py_SIZE(self->ao); /* iterator exhausted */
-    self->index = index;
+    arrayobject *ao = self->ao;
+    if (ao != NULL) {
+        if (index < 0) {
+            index = 0;
+        }
+        else if (index > Py_SIZE(ao)) {
+            index = Py_SIZE(ao); /* iterator exhausted */
+        }
+        self->index = index;
+    }
     Py_RETURN_NONE;
 }