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json/include/nlohmann/detail/macro_unscope.hpp
T
Niels Lohmann c5f1694b01 Add JSON_DISABLE_TUPLE_REFERENCE_CONVERSION to fix std::tuple conversions
basic_json can be constructed from std::tuple<json&>, which it turns into
a one-element array. Because of this, std::tuple picks its converting
constructor that converts the whole source tuple instead of the
element-wise one. As a result, std::tuple<const json&> built from
std::forward_as_tuple(j) binds to a temporary (a compile error with libc++,
a dangling reference with other standard libraries), and std::tuple<json>
built the same way holds [j] instead of a copy of j.

The new opt-in macro JSON_DISABLE_TUPLE_REFERENCE_CONVERSION (CMake option
JSON_DisableTupleReferenceConversion) removes the conversion from a
one-element tuple holding a reference to the same basic_json type, so
std::tuple converts element-wise. It is off by default, so existing
behavior is unchanged. It does not change any function body and therefore
is not part of the ABI tag.

Fixes #2226

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-27 17:17:51 +02:00

53 lines
1.5 KiB
C++

// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++
// | | |__ | | | | | | version 3.12.0
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT
#pragma once
// restore clang diagnostic settings
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
// clean up
#undef JSON_ASSERT
#undef JSON_INTERNAL_CATCH
#undef JSON_THROW
#undef JSON_PRIVATE_UNLESS_TESTED
#undef NLOHMANN_BASIC_JSON_TPL_DECLARATION
#undef NLOHMANN_BASIC_JSON_TPL
#undef JSON_EXPLICIT
#undef NLOHMANN_CAN_CALL_STD_FUNC_IMPL
#undef JSON_INLINE_VARIABLE
#undef JSON_NO_UNIQUE_ADDRESS
#undef JSON_DISABLE_ENUM_SERIALIZATION
#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
#undef JSON_USE_GLOBAL_UDLS
#ifndef JSON_TEST_KEEP_MACROS
#undef JSON_CATCH
#undef JSON_TRY
#undef JSON_HAS_CPP_11
#undef JSON_HAS_CPP_14
#undef JSON_HAS_CPP_17
#undef JSON_HAS_CPP_20
#undef JSON_HAS_CPP_23
#undef JSON_HAS_CPP_26
#undef JSON_HAS_FILESYSTEM
#undef JSON_HAS_EXPERIMENTAL_FILESYSTEM
#undef JSON_HAS_THREE_WAY_COMPARISON
#undef JSON_HAS_RANGES
#undef JSON_HAS_STD_FORMAT
#undef JSON_HAS_STATIC_RTTI
#undef JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
#undef JSON_BRACE_INIT_COPY_SEMANTICS
#undef JSON_PRECISE_STREAM_POSITION
#undef JSON_STRICT_NUL_HANDLING
#endif
#include <nlohmann/thirdparty/hedley/hedley_undef.hpp>