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 = "";
};
// Like the above, but declared via the helper function
class MyException5 : public std::logic_error {
public:
explicit MyException5(const std::string &what) : std::logic_error(what) {}
};
// Inherits from MyException5
class MyException5_1 : public MyException5 {
using MyException5::MyException5;
};
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 throws5() {
throw MyException5("this is a helper-defined translated exception");
}
void throws5_1() {
throw MyException5_1("MyException5 subclass");
}
void throws_logic_error() {
throw std::logic_error("this error should fall through to the standard handler");
}
// Test error_already_set::matches() method
void exception_matches() {
py::dict foo;
try {
foo["bar"];
}
catch (py::error_already_set& ex) {
if (ex.matches(PyExc_KeyError))
ex.clear();
else
throw;
}
}
struct PythonCallInDestructor {
PythonCallInDestructor(const py::dict &d) : d(d) {}
~PythonCallInDestructor() { d["good"] = true; }
py::dict d;
};
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) {
// Set MyException as the active python error
ex(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) {
// Translate this exception to a standard RuntimeError
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());
}
});
// A simple exception translation:
auto ex5 = py::register_exception<MyException5>(m, "MyException5");
// A slightly more complicated one that declares MyException5_1 as a subclass of MyException5
py::register_exception<MyException5_1>(m, "MyException5_1", ex5.ptr());
m.def("throws1", &throws1);
m.def("throws2", &throws2);
m.def("throws3", &throws3);
m.def("throws4", &throws4);
m.def("throws5", &throws5);
m.def("throws5_1", &throws5_1);
m.def("throws_logic_error", &throws_logic_error);
m.def("exception_matches", &exception_matches);
m.def("throw_already_set", [](bool err) {
if (err)
PyErr_SetString(PyExc_ValueError, "foo");
try {
throw py::error_already_set();
} catch (const std::runtime_error& e) {
if ((err && e.what() != std::string("ValueError: foo")) ||
(!err && e.what() != std::string("Unknown internal error occurred")))
{
PyErr_Clear();
throw std::runtime_error("error message mismatch");
}
}
PyErr_Clear();
if (err)
PyErr_SetString(PyExc_ValueError, "foo");
throw py::error_already_set();
});
m.def("python_call_in_destructor", [](py::dict d) {
try {
PythonCallInDestructor set_dict_in_destructor(d);
PyErr_SetString(PyExc_ValueError, "foo");
throw py::error_already_set();
} catch (const py::error_already_set&) {
return true;
}
return false;
});
});