pybind11/tests/test_exceptions.cpp

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/*
tests/test_custom-exceptions.cpp -- exception translation
Copyright (c) 2016 Pim Schellart <P.Schellart@princeton.edu>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#include "pybind11_tests.h"
// A type that should be raised as an exeption in Python
class MyException : public std::exception {
public:
explicit MyException(const char * m) : message{m} {}
virtual const char * what() const noexcept override {return message.c_str();}
private:
std::string message = "";
};
// A type that should be translated to a standard Python exception
class MyException2 : public std::exception {
public:
explicit MyException2(const char * m) : message{m} {}
virtual const char * what() const noexcept override {return message.c_str();}
private:
std::string message = "";
};
// A type that is not derived from std::exception (and is thus unknown)
class MyException3 {
public:
explicit MyException3(const char * m) : message{m} {}
virtual const char * what() const noexcept {return message.c_str();}
private:
std::string message = "";
};
// A type that should be translated to MyException
// and delegated to its exception translator
class MyException4 : public std::exception {
public:
explicit MyException4(const char * m) : message{m} {}
virtual const char * what() const noexcept override {return message.c_str();}
private:
std::string message = "";
};
void throws1() {
throw MyException("this error should go to a custom type");
}
void throws2() {
throw MyException2("this error should go to a standard Python exception");
}
void throws3() {
throw MyException3("this error cannot be translated");
}
void throws4() {
throw MyException4("this error is rethrown");
}
void throws_logic_error() {
throw std::logic_error("this error should fall through to the standard handler");
}
test_initializer custom_exceptions([](py::module &m) {
// make a new custom exception and use it as a translation target
static py::exception<MyException> ex(m, "MyException");
py::register_exception_translator([](std::exception_ptr p) {
try {
if (p) std::rethrow_exception(p);
} catch (const MyException &e) {
PyErr_SetString(ex.ptr(), e.what());
}
});
// register new translator for MyException2
// no need to store anything here because this type will
// never by visible from Python
py::register_exception_translator([](std::exception_ptr p) {
try {
if (p) std::rethrow_exception(p);
} catch (const MyException2 &e) {
PyErr_SetString(PyExc_RuntimeError, e.what());
}
});
// register new translator for MyException4
// which will catch it and delegate to the previously registered
// translator for MyException by throwing a new exception
py::register_exception_translator([](std::exception_ptr p) {
try {
if (p) std::rethrow_exception(p);
} catch (const MyException4 &e) {
throw MyException(e.what());
}
});
m.def("throws1", &throws1);
m.def("throws2", &throws2);
m.def("throws3", &throws3);
m.def("throws4", &throws4);
m.def("throws_logic_error", &throws_logic_error);
});