From eb3d9e200aff536aa7b180c5ef154a9e25fc53ac Mon Sep 17 00:00:00 2001
From: Steve Stagg <stestagg@gmail.com>
Date: Tue, 7 Jul 2026 00:19:47 +0100
Subject: [PATCH 1/3] gh-153210: Do not DECREF ArryaType in array_modexc
 because it's initialized on the array mod state, so GC / module cleanup will
 do this. (Ownership belongs to the state struct)

---
 Lib/test/test_array.py | 19 +++++++++++++++++++
 Modules/arraymodule.c  |  2 --
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 23d9f3c9667d868..998358ff23cae86 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -9,11 +9,13 @@
 from test.support import os_helper
 from test.support import _2G
 from test.support import subTests
+from test.support.script_helper import assert_python_ok
 import weakref
 import pickle
 import operator
 import struct
 import sys
+import textwrap
 
 import array
 from array import _array_reconstructor as array_reconstructor
@@ -35,6 +37,23 @@ def test_array_is_sequence(self):
         self.assertIsInstance(array.array("B"), collections.abc.MutableSequence)
         self.assertIsInstance(array.array("B"), collections.abc.Reversible)
 
+    @support.cpython_only
+    def test_module_init_mutablesequence_register_failure(self):
+        # gh-153210: Check that when collections.abc.MutableSequence is unavailable
+        # The refcount of ArrayType is decremented correctly.
+        # This test only catches the issue in a debug build.
+        script = textwrap.dedent("""
+            import collections.abc
+            del collections.abc.MutableSequence
+            try:
+                import array
+            except AttributeError:
+                pass
+            else:
+                raise SystemExit("import array should have failed")
+        """)
+        assert_python_ok("-c", script)
+
     def test_bad_constructor(self):
         self.assertRaises(TypeError, array.array)
         self.assertRaises(TypeError, array.array, spam=42)
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 9f613927be63159..528d1b287612fef 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -3409,14 +3409,12 @@ array_modexec(PyObject *m)
     PyObject *mutablesequence = PyImport_ImportModuleAttrString(
             "collections.abc", "MutableSequence");
     if (!mutablesequence) {
-        Py_DECREF((PyObject *)state->ArrayType);
         return -1;
     }
     PyObject *res = PyObject_CallMethod(mutablesequence, "register", "O",
                                         (PyObject *)state->ArrayType);
     Py_DECREF(mutablesequence);
     if (!res) {
-        Py_DECREF((PyObject *)state->ArrayType);
         return -1;
     }
     Py_DECREF(res);

From a8da27b604cebaa3fb4fba7610c06bbc013ef2f9 Mon Sep 17 00:00:00 2001
From: Steve Stagg <stestagg@gmail.com>
Date: Tue, 7 Jul 2026 00:26:10 +0100
Subject: [PATCH 2/3] Add blurb

---
 .../next/Library/2026-07-07-00-26-06.gh-issue-153210.HRwj-j.rst | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2026-07-07-00-26-06.gh-issue-153210.HRwj-j.rst

diff --git a/Misc/NEWS.d/next/Library/2026-07-07-00-26-06.gh-issue-153210.HRwj-j.rst b/Misc/NEWS.d/next/Library/2026-07-07-00-26-06.gh-issue-153210.HRwj-j.rst
new file mode 100644
index 000000000000000..ef3279fee8061e6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-07-07-00-26-06.gh-issue-153210.HRwj-j.rst
@@ -0,0 +1,2 @@
+:mod:`array`: Fix incorrect handling of reference counts when errors occur
+during module import

From 84c0da3e09b60d3b2888b8a9b433b31ba2b85069 Mon Sep 17 00:00:00 2001
From: Steve Stagg <stestagg@gmail.com>
Date: Tue, 7 Jul 2026 00:33:24 +0100
Subject: [PATCH 3/3] Tighten up the inline script in the test a bit

---
 Lib/test/test_array.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Lib/test/test_array.py b/Lib/test/test_array.py
index 998358ff23cae86..122957dc58f6c15 100755
--- a/Lib/test/test_array.py
+++ b/Lib/test/test_array.py
@@ -49,8 +49,6 @@ def test_module_init_mutablesequence_register_failure(self):
                 import array
             except AttributeError:
                 pass
-            else:
-                raise SystemExit("import array should have failed")
         """)
         assert_python_ok("-c", script)