knx/examples/knxPython/pybind11/tests/test_embed/test_interpreter.cpp

#include <pybind11/embed.h>

// Silence MSVC C++17 deprecation warning from Catch regarding std::uncaught_exceptions (up to
// catch 2.0.1; this should be fixed in the next catch release after 2.0.1).
PYBIND11_WARNING_DISABLE_MSVC(4996)

#include <catch.hpp>
#include <cstdlib>
#include <fstream>
#include <functional>
#include <thread>
#include <utility>

namespace py = pybind11;
using namespace py::literals;

size_t get_sys_path_size()
{
    auto sys_path = py::module::import("sys").attr("path");
    return py::len(sys_path);
}

class Widget
{
    public:
        explicit Widget(std::string message) : message(std::move(message)) {}
        virtual ~Widget() = default;

        std::string the_message() const
        {
            return message;
        }
        virtual int the_answer() const = 0;
        virtual std::string argv0() const = 0;

    private:
        std::string message;
};

class PyWidget final : public Widget
{
        using Widget::Widget;

        int the_answer() const override
        {
            PYBIND11_OVERRIDE_PURE(int, Widget, the_answer);
        }
        std::string argv0() const override
        {
            PYBIND11_OVERRIDE_PURE(std::string, Widget, argv0);
        }
};

class test_override_cache_helper
{

    public:
        virtual int func()
        {
            return 0;
        }

        test_override_cache_helper() = default;
        virtual ~test_override_cache_helper() = default;
        // Non-copyable
        test_override_cache_helper& operator=(test_override_cache_helper const& Right) = delete;
        test_override_cache_helper(test_override_cache_helper const& Copy) = delete;
};

class test_override_cache_helper_trampoline : public test_override_cache_helper
{
        int func() override
        {
            PYBIND11_OVERRIDE(int, test_override_cache_helper, func);
        }
};

PYBIND11_EMBEDDED_MODULE(widget_module, m)
{
    py::class_<Widget, PyWidget>(m, "Widget")
    .def(py::init<std::string>())
    .def_property_readonly("the_message", &Widget::the_message);

    m.def("add", [](int i, int j)
    {
        return i + j;
    });
}

PYBIND11_EMBEDDED_MODULE(trampoline_module, m)
{
    py::class_<test_override_cache_helper,
    test_override_cache_helper_trampoline,
    std::shared_ptr<test_override_cache_helper>>(m, "test_override_cache_helper")
    .def(py::init_alias<>())
    .def("func", &test_override_cache_helper::func);
}

PYBIND11_EMBEDDED_MODULE(throw_exception, )
{
    throw std::runtime_error("C++ Error");
}

PYBIND11_EMBEDDED_MODULE(throw_error_already_set, )
{
    auto d = py::dict();
    d["missing"].cast<py::object>();
}

TEST_CASE("PYTHONPATH is used to update sys.path")
{
    // The setup for this TEST_CASE is in catch.cpp!
    auto sys_path = py::str(py::module_::import("sys").attr("path")).cast<std::string>();
    REQUIRE_THAT(sys_path,
                 Catch::Matchers::Contains("pybind11_test_embed_PYTHONPATH_2099743835476552"));
}

TEST_CASE("Pass classes and data between modules defined in C++ and Python")
{
    auto module_ = py::module_::import("test_interpreter");
    REQUIRE(py::hasattr(module_, "DerivedWidget"));

    auto locals = py::dict("hello"_a = "Hello, World!", "x"_a = 5, **module_.attr("__dict__"));
    py::exec(R"(
        widget = DerivedWidget("{} - {}".format(hello, x))
        message = widget.the_message
    )",
             py::globals(),
             locals);
    REQUIRE(locals["message"].cast<std::string>() == "Hello, World! - 5");

    auto py_widget = module_.attr("DerivedWidget")("The question");
    auto message = py_widget.attr("the_message");
    REQUIRE(message.cast<std::string>() == "The question");

    const auto& cpp_widget = py_widget.cast<const Widget&>();
    REQUIRE(cpp_widget.the_answer() == 42);
}

TEST_CASE("Override cache")
{
    auto module_ = py::module_::import("test_trampoline");
    REQUIRE(py::hasattr(module_, "func"));
    REQUIRE(py::hasattr(module_, "func2"));

    auto locals = py::dict(**module_.attr("__dict__"));

    int i = 0;

    for (; i < 1500; ++i)
    {
        std::shared_ptr<test_override_cache_helper> p_obj;
        std::shared_ptr<test_override_cache_helper> p_obj2;

        py::object loc_inst = locals["func"]();
        p_obj = py::cast<std::shared_ptr<test_override_cache_helper>>(loc_inst);

        int ret = p_obj->func();

        REQUIRE(ret == 42);

        loc_inst = locals["func2"]();

        p_obj2 = py::cast<std::shared_ptr<test_override_cache_helper>>(loc_inst);

        p_obj2->func();
    }
}

TEST_CASE("Import error handling")
{
    REQUIRE_NOTHROW(py::module_::import("widget_module"));
    REQUIRE_THROWS_WITH(py::module_::import("throw_exception"), "ImportError: C++ Error");
    REQUIRE_THROWS_WITH(py::module_::import("throw_error_already_set"),
                        Catch::Contains("ImportError: initialization failed"));

    auto locals = py::dict("is_keyerror"_a = false, "message"_a = "not set");
    py::exec(R"(
        try:
            import throw_error_already_set
        except ImportError as e:
            is_keyerror = type(e.__cause__) == KeyError
            message = str(e.__cause__)
    )",
             py::globals(),
             locals);
    REQUIRE(locals["is_keyerror"].cast<bool>() == true);
    REQUIRE(locals["message"].cast<std::string>() == "'missing'");
}

TEST_CASE("There can be only one interpreter")
{
    static_assert(std::is_move_constructible<py::scoped_interpreter>::value, "");
    static_assert(!std::is_move_assignable<py::scoped_interpreter>::value, "");
    static_assert(!std::is_copy_constructible<py::scoped_interpreter>::value, "");
    static_assert(!std::is_copy_assignable<py::scoped_interpreter>::value, "");

    REQUIRE_THROWS_WITH(py::initialize_interpreter(), "The interpreter is already running");
    REQUIRE_THROWS_WITH(py::scoped_interpreter(), "The interpreter is already running");

    py::finalize_interpreter();
    REQUIRE_NOTHROW(py::scoped_interpreter());
    {
        auto pyi1 = py::scoped_interpreter();
        auto pyi2 = std::move(pyi1);
    }
    py::initialize_interpreter();
}

#if PY_VERSION_HEX >= PYBIND11_PYCONFIG_SUPPORT_PY_VERSION_HEX
TEST_CASE("Custom PyConfig")
{
    py::finalize_interpreter();
    PyConfig config;
    PyConfig_InitPythonConfig(&config);
    REQUIRE_NOTHROW(py::scoped_interpreter{&config});
    {
        py::scoped_interpreter p{&config};
        REQUIRE(py::module_::import("widget_module").attr("add")(1, 41).cast<int>() == 42);
    }
    py::initialize_interpreter();
}

TEST_CASE("scoped_interpreter with PyConfig_InitIsolatedConfig and argv")
{
    py::finalize_interpreter();
    {
        PyConfig config;
        PyConfig_InitIsolatedConfig(&config);
        char* argv[] = {strdup("a.out")};
        py::scoped_interpreter argv_scope{&config, 1, argv};
        std::free(argv[0]);
        auto module = py::module::import("test_interpreter");
        auto py_widget = module.attr("DerivedWidget")("The question");
        const auto& cpp_widget = py_widget.cast<const Widget&>();
        REQUIRE(cpp_widget.argv0() == "a.out");
    }
    py::initialize_interpreter();
}

TEST_CASE("scoped_interpreter with PyConfig_InitPythonConfig and argv")
{
    py::finalize_interpreter();
    {
        PyConfig config;
        PyConfig_InitPythonConfig(&config);

        // `initialize_interpreter() overrides the default value for config.parse_argv (`1`) by
        // changing it to `0`. This test exercises `scoped_interpreter` with the default config.
        char* argv[] = {strdup("a.out"), strdup("arg1")};
        py::scoped_interpreter argv_scope(&config, 2, argv);
        std::free(argv[0]);
        std::free(argv[1]);
        auto module = py::module::import("test_interpreter");
        auto py_widget = module.attr("DerivedWidget")("The question");
        const auto& cpp_widget = py_widget.cast<const Widget&>();
        REQUIRE(cpp_widget.argv0() == "arg1");
    }
    py::initialize_interpreter();
}
#endif

TEST_CASE("Add program dir to path pre-PyConfig")
{
    py::finalize_interpreter();
    size_t path_size_add_program_dir_to_path_false = 0;
    {
        py::scoped_interpreter scoped_interp{true, 0, nullptr, false};
        path_size_add_program_dir_to_path_false = get_sys_path_size();
    }
    {
        py::scoped_interpreter scoped_interp{};
        REQUIRE(get_sys_path_size() == path_size_add_program_dir_to_path_false + 1);
    }
    py::initialize_interpreter();
}

#if PY_VERSION_HEX >= PYBIND11_PYCONFIG_SUPPORT_PY_VERSION_HEX
TEST_CASE("Add program dir to path using PyConfig")
{
    py::finalize_interpreter();
    size_t path_size_add_program_dir_to_path_false = 0;
    {
        PyConfig config;
        PyConfig_InitPythonConfig(&config);
        py::scoped_interpreter scoped_interp{&config, 0, nullptr, false};
        path_size_add_program_dir_to_path_false = get_sys_path_size();
    }
    {
        PyConfig config;
        PyConfig_InitPythonConfig(&config);
        py::scoped_interpreter scoped_interp{&config};
        REQUIRE(get_sys_path_size() == path_size_add_program_dir_to_path_false + 1);
    }
    py::initialize_interpreter();
}
#endif

bool has_state_dict_internals_obj()
{
    return bool(
               py::detail::get_internals_obj_from_state_dict(py::detail::get_python_state_dict()));
}

bool has_pybind11_internals_static()
{
    auto**& ipp = py::detail::get_internals_pp();
    return (ipp != nullptr) && (*ipp != nullptr);
}

TEST_CASE("Restart the interpreter")
{
    // Verify pre-restart state.
    REQUIRE(py::module_::import("widget_module").attr("add")(1, 2).cast<int>() == 3);
    REQUIRE(has_state_dict_internals_obj());
    REQUIRE(has_pybind11_internals_static());
    REQUIRE(py::module_::import("external_module").attr("A")(123).attr("value").cast<int>()
            == 123);

    // local and foreign module internals should point to the same internals:
    REQUIRE(reinterpret_cast<uintptr_t>(*py::detail::get_internals_pp())
            == py::module_::import("external_module").attr("internals_at")().cast<uintptr_t>());

    // Restart the interpreter.
    py::finalize_interpreter();
    REQUIRE(Py_IsInitialized() == 0);

    py::initialize_interpreter();
    REQUIRE(Py_IsInitialized() == 1);

    // Internals are deleted after a restart.
    REQUIRE_FALSE(has_state_dict_internals_obj());
    REQUIRE_FALSE(has_pybind11_internals_static());
    pybind11::detail::get_internals();
    REQUIRE(has_state_dict_internals_obj());
    REQUIRE(has_pybind11_internals_static());
    REQUIRE(reinterpret_cast<uintptr_t>(*py::detail::get_internals_pp())
            == py::module_::import("external_module").attr("internals_at")().cast<uintptr_t>());

    // Make sure that an interpreter with no get_internals() created until finalize still gets the
    // internals destroyed
    py::finalize_interpreter();
    py::initialize_interpreter();
    bool ran = false;
    py::module_::import("__main__").attr("internals_destroy_test")
        = py::capsule(&ran, [](void* ran)
    {
        py::detail::get_internals();
        *static_cast<bool*>(ran) = true;
    });
    REQUIRE_FALSE(has_state_dict_internals_obj());
    REQUIRE_FALSE(has_pybind11_internals_static());
    REQUIRE_FALSE(ran);
    py::finalize_interpreter();
    REQUIRE(ran);
    py::initialize_interpreter();
    REQUIRE_FALSE(has_state_dict_internals_obj());
    REQUIRE_FALSE(has_pybind11_internals_static());

    // C++ modules can be reloaded.
    auto cpp_module = py::module_::import("widget_module");
    REQUIRE(cpp_module.attr("add")(1, 2).cast<int>() == 3);

    // C++ type information is reloaded and can be used in python modules.
    auto py_module = py::module_::import("test_interpreter");
    auto py_widget = py_module.attr("DerivedWidget")("Hello after restart");
    REQUIRE(py_widget.attr("the_message").cast<std::string>() == "Hello after restart");
}

TEST_CASE("Subinterpreter")
{
    // Add tags to the modules in the main interpreter and test the basics.
    py::module_::import("__main__").attr("main_tag") = "main interpreter";
    {
        auto m = py::module_::import("widget_module");
        m.attr("extension_module_tag") = "added to module in main interpreter";

        REQUIRE(m.attr("add")(1, 2).cast<int>() == 3);
    }
    REQUIRE(has_state_dict_internals_obj());
    REQUIRE(has_pybind11_internals_static());

    /// Create and switch to a subinterpreter.
    auto* main_tstate = PyThreadState_Get();
    auto* sub_tstate = Py_NewInterpreter();

    // Subinterpreters get their own copy of builtins. detail::get_internals() still
    // works by returning from the static variable, i.e. all interpreters share a single
    // global pybind11::internals;
    REQUIRE_FALSE(has_state_dict_internals_obj());
    REQUIRE(has_pybind11_internals_static());

    // Modules tags should be gone.
    REQUIRE_FALSE(py::hasattr(py::module_::import("__main__"), "tag"));
    {
        auto m = py::module_::import("widget_module");
        REQUIRE_FALSE(py::hasattr(m, "extension_module_tag"));

        // Function bindings should still work.
        REQUIRE(m.attr("add")(1, 2).cast<int>() == 3);
    }

    // Restore main interpreter.
    Py_EndInterpreter(sub_tstate);
    PyThreadState_Swap(main_tstate);

    REQUIRE(py::hasattr(py::module_::import("__main__"), "main_tag"));
    REQUIRE(py::hasattr(py::module_::import("widget_module"), "extension_module_tag"));
}

TEST_CASE("Execution frame")
{
    // When the interpreter is embedded, there is no execution frame, but `py::exec`
    // should still function by using reasonable globals: `__main__.__dict__`.
    py::exec("var = dict(number=42)");
    REQUIRE(py::globals()["var"]["number"].cast<int>() == 42);
}

TEST_CASE("Threads")
{
    // Restart interpreter to ensure threads are not initialized
    py::finalize_interpreter();
    py::initialize_interpreter();
    REQUIRE_FALSE(has_pybind11_internals_static());

    constexpr auto num_threads = 10;
    auto locals = py::dict("count"_a = 0);

    {
        py::gil_scoped_release gil_release{};

        auto threads = std::vector<std::thread>();

        for (auto i = 0; i < num_threads; ++i)
        {
            threads.emplace_back([&]()
            {
                py::gil_scoped_acquire gil{};
                locals["count"] = locals["count"].cast<int>() + 1;
            });
        }

        for (auto& thread : threads)
        {
            thread.join();
        }
    }

    REQUIRE(locals["count"].cast<int>() == num_threads);
}

// Scope exit utility https://stackoverflow.com/a/36644501/7255855
struct scope_exit
{
    std::function<void()> f_;
    explicit scope_exit(std::function<void()> f) noexcept : f_(std::move(f)) {}
    ~scope_exit()
    {
        if (f_)
        {
            f_();
        }
    }
};

TEST_CASE("Reload module from file")
{
    // Disable generation of cached bytecode (.pyc files) for this test, otherwise
    // Python might pick up an old version from the cache instead of the new versions
    // of the .py files generated below
    auto sys = py::module_::import("sys");
    bool dont_write_bytecode = sys.attr("dont_write_bytecode").cast<bool>();
    sys.attr("dont_write_bytecode") = true;
    // Reset the value at scope exit
    scope_exit reset_dont_write_bytecode(
        [&]()
    {
        sys.attr("dont_write_bytecode") = dont_write_bytecode;
    });

    std::string module_name = "test_module_reload";
    std::string module_file = module_name + ".py";

    // Create the module .py file
    std::ofstream test_module(module_file);
    test_module << "def test():\n";
    test_module << "    return 1\n";
    test_module.close();
    // Delete the file at scope exit
    scope_exit delete_module_file([&]()
    {
        std::remove(module_file.c_str());
    });

    // Import the module from file
    auto module_ = py::module_::import(module_name.c_str());
    int result = module_.attr("test")().cast<int>();
    REQUIRE(result == 1);

    // Update the module .py file with a small change
    test_module.open(module_file);
    test_module << "def test():\n";
    test_module << "    return 2\n";
    test_module.close();

    // Reload the module
    module_.reload();
    result = module_.attr("test")().cast<int>();
    REQUIRE(result == 2);
}

TEST_CASE("sys.argv gets initialized properly")
{
    py::finalize_interpreter();
    {
        py::scoped_interpreter default_scope;
        auto module = py::module::import("test_interpreter");
        auto py_widget = module.attr("DerivedWidget")("The question");
        const auto& cpp_widget = py_widget.cast<const Widget&>();
        REQUIRE(cpp_widget.argv0().empty());
    }

    {
        char* argv[] = {strdup("a.out")};
        py::scoped_interpreter argv_scope(true, 1, argv);
        std::free(argv[0]);
        auto module = py::module::import("test_interpreter");
        auto py_widget = module.attr("DerivedWidget")("The question");
        const auto& cpp_widget = py_widget.cast<const Widget&>();
        REQUIRE(cpp_widget.argv0() == "a.out");
    }
    py::initialize_interpreter();
}

TEST_CASE("make_iterator can be called before then after finalizing an interpreter")
{
    // Reproduction of issue #2101 (https://github.com/pybind/pybind11/issues/2101)
    py::finalize_interpreter();

    std::vector<int> container;
    {
        pybind11::scoped_interpreter g;
        auto iter = pybind11::make_iterator(container.begin(), container.end());
    }

    REQUIRE_NOTHROW([&]()
    {
        pybind11::scoped_interpreter g;
        auto iter = pybind11::make_iterator(container.begin(), container.end());
    }
    ());

    py::initialize_interpreter();
}