bpo-32571: Avoid raising unneeded AttributeError and silencing it in C code (GH-5222)

Add two new private APIs: _PyObject_LookupAttr() and _PyObject_LookupAttrId()

1 files changed, 6 insertions, 7 deletions

diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 259fa25..0d25739 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2234,17 +2234,16 @@ dict_update_common(PyObject *self, PyObject *args, PyObject *kwds,
     }
     else if (arg != NULL) {
         _Py_IDENTIFIER(keys);
-        PyObject *func = _PyObject_GetAttrId(arg, &PyId_keys);
-        if (func != NULL) {
+        PyObject *func;
+        if (_PyObject_LookupAttrId(arg, &PyId_keys, &func) < 0) {
+            result = -1;
+        }
+        else if (func != NULL) {
             Py_DECREF(func);
             result = PyDict_Merge(self, arg, 1);
         }
-        else if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
-            PyErr_Clear();
-            result = PyDict_MergeFromSeq2(self, arg, 1);
-        }
         else {
-            result = -1;
+            result = PyDict_MergeFromSeq2(self, arg, 1);
         }
     }