gh-154892: Fix PyLong_AsLong() error checks in _zoneinfo

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -499,6 +499,37 @@ def __add__(self, other):
                 self.assertEqual(dt_fromutc.fold, 1)
                 self.assertEqual(dt.fold, 0)
 
+    def test_datetime_subclass_negative_components(self):
+        """Regression test for gh-154892.
+
+        Datetime subclasses may return -1 for time components. The C
+        accelerator should treat -1 as a valid PyLong_AsLong() result unless
+        an exception is set, matching the pure-Python implementation.
+        """
+        class MinusOneDateTime(datetime):
+            @property
+            def hour(self):
+                return -1
+
+            @property
+            def minute(self):
+                return -1
+
+            @property
+            def second(self):
+                return -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),
+        )
+
 
 class ZoneInfoDatetimeSubclassTest(DatetimeSubclassMixin, ZoneInfoTest):
     pass

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

@@ -0,0 +1,3 @@
+Fixed a bug in the C accelerator for :mod:`zoneinfo` where ``datetime``
+subclasses returning ``-1`` for ``hour``, ``minute``, or ``second`` could
+incorrectly raise an error due to ``PyLong_AsLong()`` sentinel handling.

Modules/_zoneinfo.c

@@ -2311,7 +2311,7 @@ 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;
         }
 
@@ -2321,7 +2321,7 @@ 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;
         }
 
@@ -2331,7 +2331,7 @@ 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;
         }
     }