bpo-42006: Stop using PyDict_GetItem, PyDict_GetItemString and _PyDict_GetItemId. (GH-22648)

These functions are considered not safe because they suppress all internal errors
and can return wrong result.  PyDict_GetItemString and _PyDict_GetItemId can
also silence current exception in rare cases.

Remove no longer used _PyDict_GetItemId.
Add _PyDict_ContainsId and rename _PyDict_Contains into
_PyDict_Contains_KnownHash.

1 files changed, 7 insertions, 11 deletions

diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
index bee59b8..76b667d 100644
--- a/Modules/_zoneinfo.c
+++ b/Modules/_zoneinfo.c
@@ -722,17 +722,16 @@ zoneinfo__unpickle(PyTypeObject *cls, PyObject *args)
 static PyObject *
 load_timedelta(long seconds)
 {
-    PyObject *rv = NULL;
+    PyObject *rv;
     PyObject *pyoffset = PyLong_FromLong(seconds);
     if (pyoffset == NULL) {
         return NULL;
     }
-    int contains = PyDict_Contains(TIMEDELTA_CACHE, pyoffset);
-    if (contains == -1) {
-        goto error;
-    }
-
-    if (!contains) {
+    rv = PyDict_GetItemWithError(TIMEDELTA_CACHE, pyoffset);
+    if (rv == NULL) {
+        if (PyErr_Occurred()) {
+            goto error;
+        }
         PyObject *tmp = PyDateTimeAPI->Delta_FromDelta(
             0, seconds, 0, 1, PyDateTimeAPI->DeltaType);
 
@@ -743,12 +742,9 @@ load_timedelta(long seconds)
         rv = PyDict_SetDefault(TIMEDELTA_CACHE, pyoffset, tmp);
         Py_DECREF(tmp);
     }
-    else {
-        rv = PyDict_GetItem(TIMEDELTA_CACHE, pyoffset);
-    }
 
+    Py_XINCREF(rv);
     Py_DECREF(pyoffset);
-    Py_INCREF(rv);
     return rv;
 error:
     Py_DECREF(pyoffset);