[3.13] gh-154892: Fix PyLong_AsLong() error checks in _zoneinfo (GH-154901) (#155058)

(cherry picked from commit 7b4165b)

Co-authored-by: Bhuvansh <bhuvanshkataria@gmail.com>
Co-authored-by: Stan Ulbrych <stan@python.org>

Author: 3 people

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -316,6 +316,18 @@ def test_unambiguous(self):
                 self.assertEqual(dt.utcoffset(), offset.utcoffset, dt)
                 self.assertEqual(dt.dst(), offset.dst, dt)
 
+    def test_datetime_subclass_negative_components(self):
+        class MinusOneDateTime(datetime):
+            hour = minute = second = -1
+
+        zi = self.zone_from_key("UTC")
+        dt = MinusOneDateTime(2024, 1, 1, tzinfo=zi)
+
+        self.assertEqual(dt.utcoffset(), ZERO)
+        self.assertEqual(dt.dst(), ZERO)
+        self.assertEqual(dt.tzname(), "UTC")
+        self.assertEqual(zi.fromutc(dt), datetime(2024, 1, 1, tzinfo=zi))
+
     def test_folds_and_gaps(self):
         test_cases = []
         for key in self.zones():

Misc/NEWS.d/next/Library/2026-07-29-21-37-39.gh-issue-154892.eQyJ3Z.rst

@@ -0,0 +1,3 @@
+Fix a bug in the C accelerator for :mod:`zoneinfo` where
+:class:`datetime.datetime` subclasses returning ``-1`` for ``hour``,
+``minute``, or ``second`` could incorrectly raise a :exc:`SystemError`.

Modules/_zoneinfo.c

@@ -2309,7 +2309,7 @@ get_local_timestamp(PyObject *dt, int64_t *local_ts)
         }
         hour = PyLong_AsLong(num);
         Py_DECREF(num);
-        if (hour == -1) {
+        if (hour == -1 && PyErr_Occurred()) {
             return -1;
         }
 
@@ -2319,7 +2319,7 @@ get_local_timestamp(PyObject *dt, int64_t *local_ts)
         }
         minute = PyLong_AsLong(num);
         Py_DECREF(num);
-        if (minute == -1) {
+        if (minute == -1 && PyErr_Occurred()) {
             return -1;
         }
 
@@ -2329,7 +2329,7 @@ get_local_timestamp(PyObject *dt, int64_t *local_ts)
         }
         second = PyLong_AsLong(num);
         Py_DECREF(num);
-        if (second == -1) {
+        if (second == -1 && PyErr_Occurred()) {
             return -1;
         }
     }