pybind11/tests/test_builtin_casters.cpp
Jason Rhinelander b57281bb00 Use rvalue subcasting when casting an rvalue container
This updates the std::tuple, std::pair and `stl.h` type casters to
forward their contained value according to whether the container being
cast is an lvalue or rvalue reference.  This fixes an issue where
subcaster casts were always called with a const lvalue which meant
nested type casters didn't have the desired `cast()` overload invoked.
For example, this caused Eigen values in a tuple to end up with a
readonly flag (issue #935) and made it impossible to return a container
of move-only types (issue #853).

This fixes both issues by adding templated universal reference `cast()`
methods to the various container types that forward container elements
according to the container reference type.
2017-07-05 12:27:14 -04:00

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/*
tests/test_builtin_casters.cpp -- Casters available without any additional headers
Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
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"
#include <pybind11/complex.h>
#if defined(_MSC_VER)
# pragma warning(push)
# pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
#endif
TEST_SUBMODULE(builtin_casters, m) {
// test_simple_string
m.def("string_roundtrip", [](const char *s) { return s; });
// test_unicode_conversion
// Some test characters in utf16 and utf32 encodings. The last one (the 𝐀) contains a null byte
char32_t a32 = 0x61 /*a*/, z32 = 0x7a /*z*/, ib32 = 0x203d /*‽*/, cake32 = 0x1f382 /*🎂*/, mathbfA32 = 0x1d400 /*𝐀*/;
char16_t b16 = 0x62 /*b*/, z16 = 0x7a, ib16 = 0x203d, cake16_1 = 0xd83c, cake16_2 = 0xdf82, mathbfA16_1 = 0xd835, mathbfA16_2 = 0xdc00;
std::wstring wstr;
wstr.push_back(0x61); // a
wstr.push_back(0x2e18); // ⸘
if (sizeof(wchar_t) == 2) { wstr.push_back(mathbfA16_1); wstr.push_back(mathbfA16_2); } // 𝐀, utf16
else { wstr.push_back((wchar_t) mathbfA32); } // 𝐀, utf32
wstr.push_back(0x7a); // z
m.def("good_utf8_string", []() { return std::string(u8"Say utf8\u203d \U0001f382 \U0001d400"); }); // Say utf8‽ 🎂 𝐀
m.def("good_utf16_string", [=]() { return std::u16string({ b16, ib16, cake16_1, cake16_2, mathbfA16_1, mathbfA16_2, z16 }); }); // b‽🎂𝐀z
m.def("good_utf32_string", [=]() { return std::u32string({ a32, mathbfA32, cake32, ib32, z32 }); }); // a𝐀🎂‽z
m.def("good_wchar_string", [=]() { return wstr; }); // a‽𝐀z
m.def("bad_utf8_string", []() { return std::string("abc\xd0" "def"); });
m.def("bad_utf16_string", [=]() { return std::u16string({ b16, char16_t(0xd800), z16 }); });
// Under Python 2.7, invalid unicode UTF-32 characters don't appear to trigger UnicodeDecodeError
if (PY_MAJOR_VERSION >= 3)
m.def("bad_utf32_string", [=]() { return std::u32string({ a32, char32_t(0xd800), z32 }); });
if (PY_MAJOR_VERSION >= 3 || sizeof(wchar_t) == 2)
m.def("bad_wchar_string", [=]() { return std::wstring({ wchar_t(0x61), wchar_t(0xd800) }); });
m.def("u8_Z", []() -> char { return 'Z'; });
m.def("u8_eacute", []() -> char { return '\xe9'; });
m.def("u16_ibang", [=]() -> char16_t { return ib16; });
m.def("u32_mathbfA", [=]() -> char32_t { return mathbfA32; });
m.def("wchar_heart", []() -> wchar_t { return 0x2665; });
// test_single_char_arguments
m.attr("wchar_size") = py::cast(sizeof(wchar_t));
m.def("ord_char", [](char c) -> int { return static_cast<unsigned char>(c); });
m.def("ord_char16", [](char16_t c) -> uint16_t { return c; });
m.def("ord_char32", [](char32_t c) -> uint32_t { return c; });
m.def("ord_wchar", [](wchar_t c) -> int { return c; });
// test_bytes_to_string
m.def("strlen", [](char *s) { return strlen(s); });
m.def("string_length", [](std::string s) { return s.length(); });
// test_string_view
#ifdef PYBIND11_HAS_STRING_VIEW
m.attr("has_string_view") = true;
m.def("string_view_print", [](std::string_view s) { py::print(s, s.size()); });
m.def("string_view16_print", [](std::u16string_view s) { py::print(s, s.size()); });
m.def("string_view32_print", [](std::u32string_view s) { py::print(s, s.size()); });
m.def("string_view_chars", [](std::string_view s) { py::list l; for (auto c : s) l.append((std::uint8_t) c); return l; });
m.def("string_view16_chars", [](std::u16string_view s) { py::list l; for (auto c : s) l.append((int) c); return l; });
m.def("string_view32_chars", [](std::u32string_view s) { py::list l; for (auto c : s) l.append((int) c); return l; });
m.def("string_view_return", []() { return std::string_view(u8"utf8 secret \U0001f382"); });
m.def("string_view16_return", []() { return std::u16string_view(u"utf16 secret \U0001f382"); });
m.def("string_view32_return", []() { return std::u32string_view(U"utf32 secret \U0001f382"); });
#endif
// test_integer_casting
m.def("i32_str", [](std::int32_t v) { return std::to_string(v); });
m.def("u32_str", [](std::uint32_t v) { return std::to_string(v); });
m.def("i64_str", [](std::int64_t v) { return std::to_string(v); });
m.def("u64_str", [](std::uint64_t v) { return std::to_string(v); });
// test_tuple
m.def("pair_passthrough", [](std::pair<bool, std::string> input) {
return std::make_pair(input.second, input.first);
}, "Return a pair in reversed order");
m.def("tuple_passthrough", [](std::tuple<bool, std::string, int> input) {
return std::make_tuple(std::get<2>(input), std::get<1>(input), std::get<0>(input));
}, "Return a triple in reversed order");
m.def("empty_tuple", []() { return std::tuple<>(); });
static std::pair<RValueCaster, RValueCaster> lvpair;
static std::tuple<RValueCaster, RValueCaster, RValueCaster> lvtuple;
static std::pair<RValueCaster, std::tuple<RValueCaster, std::pair<RValueCaster, RValueCaster>>> lvnested;
m.def("rvalue_pair", []() { return std::make_pair(RValueCaster{}, RValueCaster{}); });
m.def("lvalue_pair", []() -> const decltype(lvpair) & { return lvpair; });
m.def("rvalue_tuple", []() { return std::make_tuple(RValueCaster{}, RValueCaster{}, RValueCaster{}); });
m.def("lvalue_tuple", []() -> const decltype(lvtuple) & { return lvtuple; });
m.def("rvalue_nested", []() {
return std::make_pair(RValueCaster{}, std::make_tuple(RValueCaster{}, std::make_pair(RValueCaster{}, RValueCaster{}))); });
m.def("lvalue_nested", []() -> const decltype(lvnested) & { return lvnested; });
// test_builtins_cast_return_none
m.def("return_none_string", []() -> std::string * { return nullptr; });
m.def("return_none_char", []() -> const char * { return nullptr; });
m.def("return_none_bool", []() -> bool * { return nullptr; });
m.def("return_none_int", []() -> int * { return nullptr; });
m.def("return_none_float", []() -> float * { return nullptr; });
// test_none_deferred
m.def("defer_none_cstring", [](char *) { return false; });
m.def("defer_none_cstring", [](py::none) { return true; });
m.def("defer_none_custom", [](UserType *) { return false; });
m.def("defer_none_custom", [](py::none) { return true; });
m.def("nodefer_none_void", [](void *) { return true; });
m.def("nodefer_none_void", [](py::none) { return false; });
// test_void_caster
m.def("load_nullptr_t", [](std::nullptr_t) {}); // not useful, but it should still compile
m.def("cast_nullptr_t", []() { return std::nullptr_t{}; });
// test_reference_wrapper
m.def("refwrap_builtin", [](std::reference_wrapper<int> p) { return 10 * p.get(); });
m.def("refwrap_usertype", [](std::reference_wrapper<UserType> p) { return p.get().value(); });
// Not currently supported (std::pair caster has return-by-value cast operator);
// triggers static_assert failure.
//m.def("refwrap_pair", [](std::reference_wrapper<std::pair<int, int>>) { });
m.def("refwrap_list", [](bool copy) {
static IncType x1(1), x2(2);
py::list l;
for (auto &f : {std::ref(x1), std::ref(x2)}) {
l.append(py::cast(f, copy ? py::return_value_policy::copy
: py::return_value_policy::reference));
}
return l;
}, "copy"_a);
m.def("refwrap_iiw", [](const IncType &w) { return w.value(); });
m.def("refwrap_call_iiw", [](IncType &w, py::function f) {
py::list l;
l.append(f(std::ref(w)));
l.append(f(std::cref(w)));
IncType x(w.value());
l.append(f(std::ref(x)));
IncType y(w.value());
auto r3 = std::ref(y);
l.append(f(r3));
return l;
});
// test_complex
m.def("complex_cast", [](float x) { return "{}"_s.format(x); });
m.def("complex_cast", [](std::complex<float> x) { return "({}, {})"_s.format(x.real(), x.imag()); });
}