Restore backtrace when raising Python exceptions

i.e. Python => C++ => Python

Author: ayllon

CMakeLists.txt

@@ -6,4 +6,4 @@ find_package(ElementsProject)
 #---------------------------------------------------------------
 
 # Declare project name and version
-elements_project(SourceXtractorPlusPlus 0.19 USE Alexandria 2.27 DESCRIPTION "SourceXtractor++, the next generation SExtractor")
+elements_project(SourceXtractorPlusPlus 0.19 USE Alexandria 2.28 DESCRIPTION "SourceXtractor++, the next generation SExtractor")

SEPythonModule/src/lib/SePyMain.cpp

@@ -104,6 +104,10 @@ struct std_duration_from_timedelta {
   }
 };
 
+void translate_pyston_exc(const Pyston::Exception& exc) {
+  exc.restore();
+}
+
 }  // namespace
 
 BOOST_PYTHON_MODULE(_SEPythonModule) {
@@ -206,6 +210,9 @@ BOOST_PYTHON_MODULE(_SEPythonModule) {
   // For custom segmentation
   py::def("AllFramesDone", &AllFramesDone::create);
 
+  // Pyston::Exception wrap Python errors, so unwrap them at the Python boundary
+  py::register_exception_translator<Pyston::Exception>(&translate_pyston_exc);
+
   // Import pyston into the interpreter so it is importable without tweaking PYTHONPATH
 #if PY_MAJOR_VERSION >= 3
   PyObject* pyston = PyInit_pyston();