Prevent Python call with exception set in __Pyx_AddTraceback() (cytho…

…nGH-4723)

Closes cython#4722

Cython/Utility/Exceptions.c

@@ -778,6 +778,7 @@ static void __Pyx_AddTraceback(const char *funcname, int c_line,
     PyCodeObject *py_code = 0;
     PyFrameObject *py_frame = 0;
     PyThreadState *tstate = __Pyx_PyThreadState_Current;
+    PyObject *ptype, *pvalue, *ptraceback;
 
     if (c_line) {
         c_line = __Pyx_CLineForTraceback(tstate, c_line);
@@ -786,9 +787,18 @@ static void __Pyx_AddTraceback(const char *funcname, int c_line,
     // Negate to avoid collisions between py and c lines.
     py_code = $global_code_object_cache_find(c_line ? -c_line : py_line);
     if (!py_code) {
+        __Pyx_ErrFetchInState(tstate, &ptype, &pvalue, &ptraceback);
         py_code = __Pyx_CreateCodeObjectForTraceback(
             funcname, c_line, py_line, filename);
-        if (!py_code) goto bad;
+        if (!py_code) {
+            /* If the code object creation fails, then we should clear the
+               fetched exception references and propagate the new exception */
+            Py_XDECREF(ptype);
+            Py_XDECREF(pvalue);
+            Py_XDECREF(ptraceback);
+            goto bad;
+        }
+        __Pyx_ErrRestoreInState(tstate, ptype, pvalue, ptraceback);
         $global_code_object_cache_insert(c_line ? -c_line : py_line, py_code);
     }
     py_frame = PyFrame_New(