commit 353053d9ad08fea0e205e6c008b8a4350c0188e6
author Serhiy Storchaka <storchaka@gmail.com> Sun Sep 01 14:01:05 2019 +0300
committer GitHub <noreply@github.com> Sun Sep 01 14:01:05 2019 +0300
tree 3bd4434c152e934fb260c1c1651c080c3df29a14
parent 6922b9e4fce635339cb94c2fdef6bba4e2a99621

[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)

Python/bltinmodule.c

diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index b85bfb2..8f9e813 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2256,16 +2256,12 @@
         return NULL;
     if (v == NULL) {
         d = PyEval_GetLocals();
-        if (d == NULL)
-            return NULL;
-        Py_INCREF(d);
+        Py_XINCREF(d);
     }
     else {
-        d = _PyObject_GetAttrId(v, &PyId___dict__);
-        if (d == NULL) {
+        if (_PyObject_LookupAttrId(v, &PyId___dict__, &d) == 0) {
             PyErr_SetString(PyExc_TypeError,
                 "vars() argument must have __dict__ attribute");
-            return NULL;
         }
     }
     return d;

Python/sysmodule.c

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 @@
         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 @@
     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 @@
         Py_DECREF(result);
     }
     else {
-        PyErr_Clear();
         escaped_str = PyUnicode_FromEncodedObject(encoded,
                                                   stdout_encoding_str,
                                                   "strict");