[3.8] bpo-37994: Fix silencing all errors if an attribute lookup fails. (GH-15630) (GH-15635)

Only AttributeError should be silenced.
(cherry picked from commit 41c57b335330ff48af098d47e379e0f9ba09d233)

1 files changed, 6 insertions, 8 deletions

diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 93ffce2..11c20cf 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -201,16 +201,12 @@ PySys_Audit(const char *event, const char *argFormat, ...)
         ts->tracing++;
         ts->use_tracing = 0;
         while ((hook = PyIter_Next(hooks)) != NULL) {
+            _Py_IDENTIFIER(__cantrace__);
             PyObject *o;
-            int canTrace = -1;
-            o = PyObject_GetAttrString(hook, "__cantrace__");
+            int canTrace = _PyObject_LookupAttrId(hook, &PyId___cantrace__, &o);
             if (o) {
                 canTrace = PyObject_IsTrue(o);
                 Py_DECREF(o);
-            } else if (PyErr_Occurred() &&
-                       PyErr_ExceptionMatches(PyExc_AttributeError)) {
-                PyErr_Clear();
-                canTrace = 0;
             }
             if (canTrace < 0) {
                 break;
@@ -538,7 +534,10 @@ sys_displayhook_unencodable(PyObject *outf, PyObject *o)
     if (encoded == NULL)
         goto error;
 
-    buffer = _PyObject_GetAttrId(outf, &PyId_buffer);
+    if (_PyObject_LookupAttrId(outf, &PyId_buffer, &buffer) < 0) {
+        Py_DECREF(encoded);
+        goto error;
+    }
     if (buffer) {
         result = _PyObject_CallMethodIdObjArgs(buffer, &PyId_write, encoded, NULL);
         Py_DECREF(buffer);
@@ -548,7 +547,6 @@ sys_displayhook_unencodable(PyObject *outf, PyObject *o)
         Py_DECREF(result);
     }
     else {
-        PyErr_Clear();
         escaped_str = PyUnicode_FromEncodedObject(encoded,
                                                   stdout_encoding_str,
                                                   "strict");