1 files changed, 50 insertions, 40 deletions

diff --git a/Python/errors.c b/Python/errors.c
index b0ad9aa58b..6cc0c20cd5 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -74,11 +74,11 @@ PyErr_SetObject(PyObject *exception, PyObject *value)
         if (value == NULL || !PyExceptionInstance_Check(value)) {
             /* We must normalize the value right now */
             PyObject *args, *fixed_value;
-#ifdef Py_DEBUG
-            /* in debug mode, PyEval_EvalFrameEx() fails with an assertion
-               error if an exception is set when it is called */
+
+            /* Issue #23571: PyEval_CallObject() must not be called with an
+               exception set */
             PyErr_Clear();
-#endif
+
             if (value == NULL || value == Py_None)
                 args = PyTuple_New(0);
             else if (PyTuple_Check(value)) {
@@ -152,13 +152,7 @@ PyErr_SetString(PyObject *exception, const char *string)
 PyObject *
 PyErr_Occurred(void)
 {
-    /* If there is no thread state, PyThreadState_GET calls
-       Py_FatalError, which calls PyErr_Occurred.  To avoid the
-       resulting infinite loop, we inline PyThreadState_GET here and
-       treat no thread as no error. */
-    PyThreadState *tstate =
-        ((PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current));
-
+    PyThreadState *tstate = _PyThreadState_UncheckedGet();
     return tstate == NULL ? NULL : tstate->curexc_type;
 }
 
@@ -315,14 +309,11 @@ finally:
     tstate = PyThreadState_GET();
     if (++tstate->recursion_depth > Py_GetRecursionLimit()) {
         --tstate->recursion_depth;
-        /* throw away the old exception... */
-        Py_DECREF(*exc);
-        Py_DECREF(*val);
-        /* ... and use the recursion error instead */
-        *exc = PyExc_RuntimeError;
-        *val = PyExc_RecursionErrorInst;
-        Py_INCREF(*exc);
-        Py_INCREF(*val);
+        /* throw away the old exception and use the recursion error instead */
+        Py_INCREF(PyExc_RecursionError);
+        Py_SETREF(*exc, PyExc_RecursionError);
+        Py_INCREF(PyExc_RecursionErrorInst);
+        Py_SETREF(*val, PyExc_RecursionErrorInst);
         /* just keeping the old traceback */
         return;
     }
@@ -397,8 +388,11 @@ _PyErr_ChainExceptions(PyObject *exc, PyObject *val, PyObject *tb)
         PyObject *exc2, *val2, *tb2;
         PyErr_Fetch(&exc2, &val2, &tb2);
         PyErr_NormalizeException(&exc, &val, &tb);
+        if (tb != NULL) {
+            PyException_SetTraceback(val, tb);
+            Py_DECREF(tb);
+        }
         Py_DECREF(exc);
-        Py_XDECREF(tb);
         PyErr_NormalizeException(&exc2, &val2, &tb2);
         PyException_SetContext(val2, val);
         PyErr_Restore(exc2, val2, tb2);
@@ -736,9 +730,9 @@ PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
     PyTuple_SET_ITEM(args, 0, msg);
 
     if (PyDict_SetItemString(kwargs, "name", name) < 0)
-        return NULL;
+        goto done;
     if (PyDict_SetItemString(kwargs, "path", path) < 0)
-        return NULL;
+        goto done;
 
     error = PyObject_Call(PyExc_ImportError, args, kwargs);
     if (error != NULL) {
@@ -746,9 +740,9 @@ PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
         Py_DECREF(error);
     }
 
+done:
     Py_DECREF(args);
     Py_DECREF(kwargs);
-
     return NULL;
 }
 
@@ -773,34 +767,38 @@ PyErr_BadInternalCall(void)
 #define PyErr_BadInternalCall() _PyErr_BadInternalCall(__FILE__, __LINE__)
 
 
+PyObject *
+PyErr_FormatV(PyObject *exception, const char *format, va_list vargs)
+{
+    PyObject* string;
+
+    /* Issue #23571: PyUnicode_FromFormatV() must not be called with an
+       exception set, it calls arbitrary Python code like PyObject_Repr() */
+    PyErr_Clear();
+
+    string = PyUnicode_FromFormatV(format, vargs);
+
+    PyErr_SetObject(exception, string);
+    Py_XDECREF(string);
+    return NULL;
+}
+
 
 PyObject *
 PyErr_Format(PyObject *exception, const char *format, ...)
 {
     va_list vargs;
-    PyObject* string;
-
 #ifdef HAVE_STDARG_PROTOTYPES
     va_start(vargs, format);
 #else
     va_start(vargs);
 #endif
-
-#ifdef Py_DEBUG
-    /* in debug mode, PyEval_EvalFrameEx() fails with an assertion error
-       if an exception is set when it is called */
-    PyErr_Clear();
-#endif
-
-    string = PyUnicode_FromFormatV(format, vargs);
-    PyErr_SetObject(exception, string);
-    Py_XDECREF(string);
+    PyErr_FormatV(exception, format, vargs);
     va_end(vargs);
     return NULL;
 }
 
 
-
 PyObject *
 PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
 {
@@ -905,8 +903,12 @@ PyErr_WriteUnraisable(PyObject *obj)
     if (obj) {
         if (PyFile_WriteString("Exception ignored in: ", f) < 0)
             goto done;
-        if (PyFile_WriteObject(obj, f, 0) < 0)
-            goto done;
+        if (PyFile_WriteObject(obj, f, 0) < 0) {
+            PyErr_Clear();
+            if (PyFile_WriteString("<object repr() failed>", f) < 0) {
+                goto done;
+            }
+        }
         if (PyFile_WriteString("\n", f) < 0)
             goto done;
     }
@@ -951,8 +953,12 @@ PyErr_WriteUnraisable(PyObject *obj)
     if (v && v != Py_None) {
         if (PyFile_WriteString(": ", f) < 0)
             goto done;
-        if (PyFile_WriteObject(v, f, Py_PRINT_RAW) < 0)
-            goto done;
+        if (PyFile_WriteObject(v, f, Py_PRINT_RAW) < 0) {
+            PyErr_Clear();
+            if (PyFile_WriteString("<exception str() failed>", f) < 0) {
+                goto done;
+            }
+        }
     }
     if (PyFile_WriteString("\n", f) < 0)
         goto done;
@@ -1121,6 +1127,10 @@ PyErr_ProgramTextObject(PyObject *filename, int lineno)
     if (filename == NULL || lineno <= 0)
         return NULL;
     fp = _Py_fopen_obj(filename, "r" PY_STDIOTEXTMODE);
+    if (fp == NULL) {
+        PyErr_Clear();
+        return NULL;
+    }
     return err_programtext(fp, lineno);
 }