From c9ac70fc456f5a8b7e8d217c27f3f6f6f782c967 Mon Sep 17 00:00:00 2001
From: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
Date: Wed, 18 Mar 2026 12:58:08 +0000
Subject: [PATCH] gh-146076: Fix crash when a `ZoneInfo` subclass is missing a
 `_weak_cache` (GH-146082) (cherry picked from commit
 3b06d68d8a3cc1f37359af1d7ebb3d09e1222296)

Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
---
 Lib/test/test_zoneinfo/test_zoneinfo.py              | 12 ++++++++++++
 .../2026-03-17-20-41-27.gh-issue-146076.yoBNnB.rst   |  2 ++
 Modules/_zoneinfo.c                                  |  6 ++++++
 3 files changed, 20 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2026-03-17-20-41-27.gh-issue-146076.yoBNnB.rst

diff --git a/Lib/test/test_zoneinfo/test_zoneinfo.py b/Lib/test/test_zoneinfo/test_zoneinfo.py
index 8a58c7d68acf82..7201c16b3e8551 100644
--- a/Lib/test/test_zoneinfo/test_zoneinfo.py
+++ b/Lib/test/test_zoneinfo/test_zoneinfo.py
@@ -1595,6 +1595,18 @@ class ZI(self.klass):
             "Unexpected instance of int in ZI weak cache for key 'America/Los_Angeles'"
         )
 
+    def test_deleted_weak_cache(self):
+        class ZI(self.klass):
+            pass
+        delattr(ZI, '_weak_cache')
+
+        # These should not segfault
+        with self.assertRaises(AttributeError):
+            ZI("UTC")
+
+        with self.assertRaises(AttributeError):
+            ZI.clear_cache()
+
     def test_inconsistent_weak_cache_setdefault(self):
         class Cache:
             def get(self, key, default=None):
diff --git a/Misc/NEWS.d/next/Library/2026-03-17-20-41-27.gh-issue-146076.yoBNnB.rst b/Misc/NEWS.d/next/Library/2026-03-17-20-41-27.gh-issue-146076.yoBNnB.rst
new file mode 100644
index 00000000000000..746f5b278829bd
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-03-17-20-41-27.gh-issue-146076.yoBNnB.rst
@@ -0,0 +1,2 @@
+:mod:`zoneinfo`: fix crashes when deleting ``_weak_cache`` from a
+:class:`zoneinfo.ZoneInfo` subclass.
diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
index 25f7eb7a44d827..976b653c77a9f5 100644
--- a/Modules/_zoneinfo.c
+++ b/Modules/_zoneinfo.c
@@ -321,6 +321,9 @@ zoneinfo_ZoneInfo_impl(PyTypeObject *type, PyObject *key)
     }
 
     PyObject *weak_cache = get_weak_cache(state, type);
+    if (weak_cache == NULL) {
+        return NULL;
+    }
     instance = PyObject_CallMethod(weak_cache, "get", "O", key, Py_None);
     if (instance == NULL) {
         Py_DECREF(weak_cache);
@@ -505,6 +508,9 @@ zoneinfo_ZoneInfo_clear_cache_impl(PyTypeObject *type, PyTypeObject *cls,
 {
     zoneinfo_state *state = zoneinfo_get_state_by_cls(cls);
     PyObject *weak_cache = get_weak_cache(state, type);
+    if (weak_cache == NULL) {
+        return NULL;
+    }
 
     if (only_keys == NULL || only_keys == Py_None) {
         PyObject *rv = PyObject_CallMethod(weak_cache, "clear", NULL);