closes bpo-34471: _datetime: Add missing NULL check to tzinfo_from_isoformat_results. (GH-8869)


Reported by Svace static analyzer.
(cherry picked from commit 498845368ff0f6238750ab1d443e7cf4ec98ccd2)

Co-authored-by: Alexey Izbyshev <izbyshev@ispras.ru>
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 91d6991..41b95b9 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -1290,8 +1290,11 @@
         }
 
         PyObject *delta = new_delta(0, tzoffset, tz_useconds, 1);
+        if (delta == NULL) {
+            return NULL;
+        }
         tzinfo = new_timezone(delta, NULL);
-        Py_XDECREF(delta);
+        Py_DECREF(delta);
     } else {
         tzinfo = Py_None;
         Py_INCREF(Py_None);