bpo-41991: Remove _PyObject_HasAttrId (GH-22629)

It can silence arbitrary exceptions.

2 files changed, 21 insertions, 4 deletions

diff --git a/Python/errors.c b/Python/errors.c
index 720f18b..02cf479 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -1593,9 +1593,18 @@ PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)
             }
             Py_DECREF(tmp);
         }
+        else {
+            _PyErr_Clear(tstate);
+        }
     }
     if (exc != PyExc_SyntaxError) {
-        if (!_PyObject_HasAttrId(v, &PyId_msg)) {
+        if (_PyObject_LookupAttrId(v, &PyId_msg, &tmp) < 0) {
+            _PyErr_Clear(tstate);
+        }
+        else if (tmp) {
+            Py_DECREF(tmp);
+        }
+        else {
             tmp = PyObject_Str(v);
             if (tmp) {
                 if (_PyObject_SetAttrId(v, &PyId_msg, tmp)) {
@@ -1607,7 +1616,13 @@ PyErr_SyntaxLocationObject(PyObject *filename, int lineno, int col_offset)
                 _PyErr_Clear(tstate);
             }
         }
-        if (!_PyObject_HasAttrId(v, &PyId_print_file_and_line)) {
+        if (_PyObject_LookupAttrId(v, &PyId_print_file_and_line, &tmp) < 0) {
+            _PyErr_Clear(tstate);
+        }
+        else if (tmp) {
+            Py_DECREF(tmp);
+        }
+        else {
             if (_PyObject_SetAttrId(v, &PyId_print_file_and_line,
                                     Py_None)) {
                 _PyErr_Clear(tstate);
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index ff80103..a45ca3b 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -770,7 +770,7 @@ static void
 print_exception(PyObject *f, PyObject *value)
 {
     int err = 0;
-    PyObject *type, *tb;
+    PyObject *type, *tb, *tmp;
     _Py_IDENTIFIER(print_file_and_line);
 
     if (!PyExceptionInstance_Check(value)) {
@@ -789,10 +789,12 @@ print_exception(PyObject *f, PyObject *value)
     if (tb && tb != Py_None)
         err = PyTraceBack_Print(tb, f);
     if (err == 0 &&
-        _PyObject_HasAttrId(value, &PyId_print_file_and_line))
+        (err = _PyObject_LookupAttrId(value, &PyId_print_file_and_line, &tmp)) > 0)
     {
         PyObject *message, *filename, *text;
         Py_ssize_t lineno, offset;
+        err = 0;
+        Py_DECREF(tmp);
         if (!parse_syntax_error(value, &message, &filename,
                                 &lineno, &offset, &text))
             PyErr_Clear();