outcome/test/tests/experimental-core-result-status.cpp

/* Unit testing for outcomes
(C) 2013-2026 Niall Douglas <http://www.nedproductions.biz/> (8 commits)


Boost Software License - Version 1.0 - August 17th, 2003

Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
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Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:

The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
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a source language processor.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

#define BOOST_OUTCOME_SYSTEM_ERROR2_FATAL(msg) abort()

#include <boost/outcome/experimental/status_result.hpp>

template <class T, class S = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::system_code,
          class NoValuePolicy = BOOST_OUTCOME_V2_NAMESPACE::experimental::policy::default_status_result_policy<T, S>>
using result = BOOST_OUTCOME_V2_NAMESPACE::experimental::status_result<T, S, NoValuePolicy>;
using BOOST_OUTCOME_V2_NAMESPACE::in_place_type;

#include <boost/test/unit_test.hpp>
#include <boost/test/unit_test_monitor.hpp>

#include <exception>
#include <iostream>

#ifndef BOOST_NO_EXCEPTIONS
// Custom error type with payload
struct payload
{
  BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc ec{BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc::success};
  const char *str{nullptr};
  payload() = default;
  payload(BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc _ec, const char *_str)
      : ec(_ec)
      , str(_str)
  {
  }
};
struct payload_exception : std::exception
{
  const char *_what{nullptr};
  explicit payload_exception(const char *what)
      : _what(what)
  {
  }
  virtual const char *what() const noexcept override final { return _what; }  // NOLINT
};

class _payload_domain;
using status_code_payload = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<_payload_domain>;
class _payload_domain : public BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code_domain
{
  template <class> friend class status_code;
  using _base = BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code_domain;

public:
  using value_type = payload;
  using string_ref = _base::string_ref;

public:
  constexpr _payload_domain() noexcept
      : _base(0x7b782c8f935e34ba)
  {
  }

  static inline constexpr const _payload_domain &get();

protected:
  virtual int _do_name(_vtable_name_args &args) const noexcept override final
  {
    args.ret = string_ref("payload domain");
    return 0;
  }  // NOLINT
  virtual void _do_payload_info(_vtable_payload_info_args &args) const noexcept override final
  {
    args.ret = {sizeof(value_type), sizeof(status_code_domain *) + sizeof(value_type),
                (alignof(value_type) > alignof(status_code_domain *)) ? alignof(value_type) :
                                                                        alignof(status_code_domain *)};
  }
  virtual bool
  _do_failure(const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const noexcept override final  // NOLINT
  {
    assert(code.domain() == *this);  // NOLINT
    return static_cast<const status_code_payload &>(code).value().ec !=
           BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::errc::success;  // NOLINT
  }
  virtual bool
  _do_equivalent(const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<void> &code1,
                 const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<void> &code2) const noexcept override final  // NOLINT
  {
    assert(code1.domain() == *this);                                   // NOLINT
    const auto &c1 = static_cast<const status_code_payload &>(code1);  // NOLINT
    if(code2.domain() == *this)
    {
      const auto &c2 = static_cast<const status_code_payload &>(code2);  // NOLINT
      return c1.value().ec == c2.value().ec;
    }
    return false;
  }
  virtual void _do_generic_code(_vtable_generic_code_args &args) const noexcept override final
  {
    assert(args.code.domain() == *this);                                        // NOLINT
    args.ret = static_cast<const status_code_payload &>(args.code).value().ec;  // NOLINT
  }
  virtual int _do_message(_vtable_message_args &args) const noexcept override final
  {
    assert(args.code.domain() == *this);                                  // NOLINT
    const auto &c = static_cast<const status_code_payload &>(args.code);  // NOLINT
    args.ret = string_ref(BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::detail::generic_code_message(c.value().ec));
    return 0;
  }
  virtual void
  _do_throw_exception(const BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::status_code<void> &code) const override final  // NOLINT
  {
    assert(code.domain() == *this);                                  // NOLINT
    const auto &c = static_cast<const status_code_payload &>(code);  // NOLINT
    throw payload_exception(c.value().str);
  }
};
constexpr _payload_domain payload_domain;
inline constexpr const _payload_domain &_payload_domain::get()
{
  return payload_domain;
}
inline status_code_payload make_status_code(payload c) noexcept
{
  return status_code_payload(BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE::in_place, c);
}
#endif

BOOST_OUTCOME_AUTO_TEST_CASE(works_status_code_result, "Tests that the result with status_code works as intended")
{
  using namespace BOOST_OUTCOME_SYSTEM_ERROR2_NAMESPACE;

  {  // errored int
    result<int> m(generic_code{errc::bad_address});
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(m.value(), generic_error);
    BOOST_CHECK_NO_THROW(m.error());
  }
  {  // errored void
    result<void> m(generic_code{errc::bad_address});
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(([&m]() -> void { return m.value(); }()), generic_error);
    BOOST_CHECK_NO_THROW(m.error());
  }
  {  // valued int
    result<int> m(5);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == 5);
    m.value() = 6;
    BOOST_CHECK(m.value() == 6);
  }
  {  // valued bool
    result<bool> m(false);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == false);
    m.value() = true;
    BOOST_CHECK(m.value() == true);
  }
  {  // moves do not clear state
    result<std::string> m("niall");
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK(m.value() == "niall");
    m.value() = "NIALL";
    BOOST_CHECK(m.value() == "NIALL");
    auto temp(std::move(m).value());
    BOOST_CHECK(temp == "NIALL");
    BOOST_CHECK(m.value().empty());  // NOLINT
  }
  {  // valued void
    result<void> m(in_place_type<void>);
    BOOST_CHECK(m);
    BOOST_CHECK(m.has_value());
    BOOST_CHECK(!m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_NO_THROW(m.value());  // works, but type returned is unusable
  }
  {  // errored
    error ec(errc::no_link);
    result<int> m(ec.clone());
    BOOST_CHECK(!m);
    BOOST_CHECK(!m.has_value());
    BOOST_CHECK(m.has_error());
    // BOOST_CHECK(!m.has_exception());
    BOOST_CHECK_THROW(m.value(), generic_error);
    BOOST_CHECK(m.error() == ec);
  }
  if(false)  // NOLINT
  {          // void, void is permitted, but is not constructible
    result<void, void> *m = nullptr;
    m->value();
    m->error();
  }

  {
    // Deliberately define non-trivial operations
    struct udt
    {
      int _v{0};
      udt() = default;
      udt(udt &&o) noexcept
          : _v(o._v)
      {
      }
      udt(const udt &o)  // NOLINT
          : _v(o._v)
      {
      }
      udt &operator=(udt &&o) noexcept
      {
        _v = o._v;
        return *this;
      }
      udt &operator=(const udt &o)  // NOLINT
      {
        _v = o._v;
        return *this;
      }
      ~udt() { _v = 0; }
    };
    // No default construction, no copy nor move
    struct udt2
    {
      udt2() = delete;
      udt2(udt2 &&) = delete;
      udt2(const udt2 &) = delete;
      udt2 &operator=(udt2 &&) = delete;
      udt2 &operator=(const udt2 &) = delete;
      explicit udt2(int /*unused*/) {}
      ~udt2() = default;
    };
    // Can only be constructed via multiple args
    struct udt3
    {
      udt3() = delete;
      udt3(udt3 &&) = delete;
      udt3(const udt3 &) = delete;
      udt3 &operator=(udt3 &&) = delete;
      udt3 &operator=(const udt3 &) = delete;
      explicit udt3(int /*unused*/, const char * /*unused*/, std::nullptr_t /*unused*/) {}
      ~udt3() = default;
    };

    result<int> a(5);
    result<int> b(generic_code{errc::invalid_argument});
    std::cout << sizeof(a) << std::endl;  // 32 bytes
    if(false)                             // NOLINT
    {
      b.assume_value();
      a.assume_error();
    }
#ifndef BOOST_NO_EXCEPTIONS
    try
    {
      b.value();
      std::cerr << "fail" << std::endl;
      std::terminate();
    }
    catch(const generic_error &e)
    {
      BOOST_CHECK(!strcmp(e.what(), b.error().message().c_str()));
    }
#endif
    static_assert(!std::is_default_constructible<decltype(a)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(a)>::value, "");
    static_assert(!std::is_copy_constructible<decltype(a)>::value, "");
// Quality of implementation of std::optional is poor :(
#ifndef TESTING_WG21_EXPERIMENTAL_RESULT
    static_assert(!std::is_trivially_copy_constructible<decltype(a)>::value, "");
    static_assert(!std::is_nothrow_copy_constructible<decltype(a)>::value, "");
    static_assert(!std::is_copy_assignable<decltype(a)>::value, "");
    static_assert(!std::is_trivially_copy_assignable<decltype(a)>::value, "");
    static_assert(!std::is_nothrow_copy_assignable<decltype(a)>::value, "");
#endif
    static_assert(!std::is_trivially_destructible<decltype(a)>::value, "");
    static_assert(std::is_nothrow_destructible<decltype(a)>::value, "");

    // Test void compiles
    result<void> c(in_place_type<void>);

    // Test a standard udt compiles
    result<udt> d(in_place_type<udt>);
    static_assert(!std::is_default_constructible<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(d)>::value, "");
    static_assert(!std::is_copy_constructible<decltype(d)>::value, "");
    static_assert(!std::is_trivially_copy_constructible<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_copy_constructible<decltype(d)>::value, "");
    static_assert(!std::is_copy_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_copy_assignable<decltype(d)>::value, "");
    static_assert(!std::is_nothrow_copy_assignable<decltype(d)>::value, "");
    static_assert(std::is_move_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_move_assignable<decltype(d)>::value, "");
    static_assert(std::is_nothrow_move_assignable<decltype(d)>::value, "");
    static_assert(!std::is_trivially_destructible<decltype(d)>::value, "");
    static_assert(std::is_nothrow_destructible<decltype(d)>::value, "");

    // Test a highly pathological udt compiles
    result<udt2> e(in_place_type<udt2>, 5);
    // result<udt2> e2(e);
    static_assert(!std::is_default_constructible<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_default_constructible<decltype(e)>::value, "");
    static_assert(!std::is_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_trivially_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_copy_constructible<decltype(e)>::value, "");
    static_assert(!std::is_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_trivially_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_copy_assignable<decltype(e)>::value, "");
    static_assert(!std::is_move_assignable<decltype(e)>::value, "");
    static_assert(!std::is_trivially_move_assignable<decltype(e)>::value, "");
    static_assert(!std::is_nothrow_move_assignable<decltype(e)>::value, "");

    // Test a udt which can only be constructed in place compiles
    result<udt3> g(in_place_type<udt3>, 5, static_cast<const char *>("niall"), nullptr);
    // Does converting inplace construction also work?
    result<udt3> h(5, static_cast<const char *>("niall"), nullptr);
    result<udt3> i(generic_code{errc::not_enough_memory});
    BOOST_CHECK(h.has_value());
    BOOST_CHECK(i.has_error());
  }

  // Test direct use of error code enum works
  {
    constexpr result<int, errc, BOOST_OUTCOME_V2_NAMESPACE::policy::all_narrow> a(5), b(errc::invalid_argument);
    static_assert(a.value() == 5, "a is not 5");
    static_assert(b.error() == errc::invalid_argument, "b is not errored");
  }

#ifndef BOOST_NO_EXCEPTIONS
  // Test payload facility
  {
    const char *niall = "niall";
    result<int, status_code_payload> b{payload{errc::invalid_argument, niall}};
    try
    {
      b.value();
      BOOST_CHECK(false);
    }
    catch(const payload_exception &e)
    {
      BOOST_CHECK(!strcmp(e.what(), niall));
    }
    catch(...)
    {
      BOOST_CHECK(false);
    }
  }
#endif
}