Files
json/single_include/nlohmann/json_fwd.hpp
T
Niels Lohmann c093f3beb3 Fix IWYU findings for json.hpp/json_fwd.hpp/ordered_map.hpp and make CI fail on new ones (#5715 item 4c)
ci_single_binaries ran IWYU via CMake's CXX_INCLUDE_WHAT_YOU_USE launcher
property, which only printed "Warning: include-what-you-use reported
diagnostics" without failing the build: CMake's own __run_co_compile
wrapper does not propagate the launched tool's exit code, so even
`-Xiwyu --error` could never fail `cmake --build` this way. Verified
this empirically by injecting a deliberately-unused #include and
confirming the build still exited 0.

Fix the findings from the last recorded run (issue #5715 item 4, log
35829411620):
- ordered_map.hpp: add <new> (placement new) and
  nlohmann/detail/abi_macros.hpp; drop <memory> (std::allocator is
  still visible transitively via <vector>, confirmed by full local and
  containerized test suite runs).
- json_fwd.hpp: drop <memory> (same reasoning). Keep every forward
  declaration IWYU wanted removed (adl_serializer, basic_json,
  json_pointer, ordered_map): this file's only job is to forward-declare
  them for downstream users, so "nothing in this TU uses them" is
  expected, not a real finding. Mark each with `// IWYU pragma: keep`.
- json.hpp: add <cmath>, <cstdint>, <set>, <type_traits>,
  <unordered_map>, and the detail/abi_macros.hpp, detail/input/json_sax.hpp,
  detail/meta/detected.hpp, thirdparty/hedley/hedley.hpp includes IWYU
  says it needs. Do NOT remove adl_serializer.hpp,
  detail/conversions/from_json.hpp, detail/conversions/to_json.hpp,
  detail/macro_unscope.hpp, or ordered_map.hpp as IWYU suggests: nothing
  else in include/nlohmann includes adl_serializer.hpp or
  ordered_map.hpp, so basic_json<>'s own default template arguments
  (JSONSerializer = adl_serializer, and ordered_json = basic_json<ordered_map>)
  would lose their complete type; detail/macro_unscope.hpp is what
  undoes the JSON_* macros detail/macro_scope.hpp defines earlier in
  this same file, and removing it leaks those macros into every
  translation unit that includes <nlohmann/json.hpp>. Verified by
  actually removing them in a scratch test: the header still "compiles"
  stand-alone but ordered_json and every macro-using translation unit
  break. Marked each `// IWYU pragma: keep`.

Enforce it with `iwyu_tool` (ships with IWYU, e.g. as /usr/bin/iwyu_tool
on Debian/Ubuntu) instead of relying on the launcher property: it reads
compile_commands.json (now exported project-wide under JSON_CI) and
does return a real exit code for its own analysis, independent of
CMake's wrapper. ci_single_binaries now runs it over every
src_single/*.cpp with `-Xiwyu --error`, so a *new* finding fails CI.

json.hpp itself is excluded from that hard gate: even after every fix
above, IWYU's suggestion for one remaining symbol (a container
`swap, operator!=` used somewhere via a templated comparator) is not
deterministic — repeated, otherwise-identical containerized runs
reported <set>, then <unordered_map>, then <map> as "the" header to
add/remove for the exact same source. Gating a whole CI job on a
nondeterministic suggestion would make ci_single_binaries flaky rather
than informative, so json.hpp keeps the existing informational warning
(still shown during its normal compile) without failing the build on
it. Every other one of the ~50 single-header checks is included in the
hard gate.

#5715 item 4c. 4a (scan-build) and 4b (Infer) are separate commits.

Verified: full local ctest suite (129/129) and the ci_single_binaries
target itself both green in a containerized silkeh/clang:dev run
(matching the actual CI job) after this fix; a deliberately-reintroduced
unused #include in ordered_map.hpp was confirmed to fail
`cmake --build ... --target ci_single_binaries` (exit 2) with this
change, and to pass without it, on the same container/IWYU version CI
uses. `make check-amalgamation` is clean. Compiled with Clang and GCC
at -std=c++11/14/17/20 locally with no new warnings.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 20:18:19 +02:00

220 lines
7.5 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
#ifndef INCLUDE_NLOHMANN_JSON_FWD_HPP_
#define INCLUDE_NLOHMANN_JSON_FWD_HPP_
#include <cstdint> // int64_t, uint64_t
#include <map> // map
#include <string> // allocator, string
#include <vector> // vector
// #include <nlohmann/detail/abi_macros.hpp>
// __ _____ _____ _____
// __| | __| | | | 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
// This file contains all macro definitions affecting or depending on the ABI
#ifndef JSON_SKIP_LIBRARY_VERSION_CHECK
#if defined(NLOHMANN_JSON_VERSION_MAJOR) && defined(NLOHMANN_JSON_VERSION_MINOR) && defined(NLOHMANN_JSON_VERSION_PATCH)
#if NLOHMANN_JSON_VERSION_MAJOR != 3 || NLOHMANN_JSON_VERSION_MINOR != 12 || NLOHMANN_JSON_VERSION_PATCH != 0
#warning "Already included a different version of the library!"
#endif
#endif
#endif
#define NLOHMANN_JSON_VERSION_MAJOR 3 // NOLINT(modernize-macro-to-enum)
#define NLOHMANN_JSON_VERSION_MINOR 12 // NOLINT(modernize-macro-to-enum)
#define NLOHMANN_JSON_VERSION_PATCH 0 // NOLINT(modernize-macro-to-enum)
#ifndef JSON_DIAGNOSTICS
#define JSON_DIAGNOSTICS 0
#endif
#ifndef JSON_DIAGNOSTIC_POSITIONS
#define JSON_DIAGNOSTIC_POSITIONS 0
#endif
#ifndef JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
#define JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON 0
#endif
#ifndef JSON_BRACE_INIT_COPY_SEMANTICS
#define JSON_BRACE_INIT_COPY_SEMANTICS 0
#endif
#ifndef JSON_PRECISE_STREAM_POSITION
#define JSON_PRECISE_STREAM_POSITION 0
#endif
#ifndef JSON_STRICT_NUL_HANDLING
#define JSON_STRICT_NUL_HANDLING 0
#endif
#if JSON_DIAGNOSTICS
#define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
#else
#define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS
#endif
#if JSON_DIAGNOSTIC_POSITIONS
#define NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS _dp
#else
#define NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS
#endif
#if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
#define NLOHMANN_JSON_ABI_TAG_LEGACY_DISCARDED_VALUE_COMPARISON _ldvcmp
#else
#define NLOHMANN_JSON_ABI_TAG_LEGACY_DISCARDED_VALUE_COMPARISON
#endif
#if JSON_BRACE_INIT_COPY_SEMANTICS
#define NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS _bics
#else
#define NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS
#endif
#if JSON_PRECISE_STREAM_POSITION
#define NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION _psp
#else
#define NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION
#endif
#if JSON_STRICT_NUL_HANDLING
#define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING _snul
#else
#define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING
#endif
#ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
#define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
#endif
// Construct the namespace ABI tags component
#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f) json_abi ## a ## b ## c ## d ## e ## f
#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f) \
NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f)
#define NLOHMANN_JSON_ABI_TAGS \
NLOHMANN_JSON_ABI_TAGS_CONCAT( \
NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS, \
NLOHMANN_JSON_ABI_TAG_LEGACY_DISCARDED_VALUE_COMPARISON, \
NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS, \
NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS, \
NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION, \
NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING)
// Construct the namespace version component
#define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \
_v ## major ## _ ## minor ## _ ## patch
#define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT(major, minor, patch) \
NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch)
#if NLOHMANN_JSON_NAMESPACE_NO_VERSION
#define NLOHMANN_JSON_NAMESPACE_VERSION
#else
#define NLOHMANN_JSON_NAMESPACE_VERSION \
NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT(NLOHMANN_JSON_VERSION_MAJOR, \
NLOHMANN_JSON_VERSION_MINOR, \
NLOHMANN_JSON_VERSION_PATCH)
#endif
// Combine namespace components
#define NLOHMANN_JSON_NAMESPACE_CONCAT_EX(a, b) a ## b
#define NLOHMANN_JSON_NAMESPACE_CONCAT(a, b) \
NLOHMANN_JSON_NAMESPACE_CONCAT_EX(a, b)
#ifndef NLOHMANN_JSON_NAMESPACE
#define NLOHMANN_JSON_NAMESPACE \
nlohmann::NLOHMANN_JSON_NAMESPACE_CONCAT( \
NLOHMANN_JSON_ABI_TAGS, \
NLOHMANN_JSON_NAMESPACE_VERSION)
#endif
#ifndef NLOHMANN_JSON_NAMESPACE_BEGIN
#define NLOHMANN_JSON_NAMESPACE_BEGIN \
namespace nlohmann \
{ \
inline namespace NLOHMANN_JSON_NAMESPACE_CONCAT( \
NLOHMANN_JSON_ABI_TAGS, \
NLOHMANN_JSON_NAMESPACE_VERSION) \
{
#endif
#ifndef NLOHMANN_JSON_NAMESPACE_END
#define NLOHMANN_JSON_NAMESPACE_END \
} /* namespace (inline namespace) NOLINT(readability/namespace) */ \
} // namespace nlohmann
#endif
/*!
@brief namespace for Niels Lohmann
@see https://github.com/nlohmann
@since version 1.0.0
*/
NLOHMANN_JSON_NAMESPACE_BEGIN
/*!
@brief default JSONSerializer template argument
This serializer ignores the template arguments and uses ADL
([argument-dependent lookup](https://en.cppreference.com/w/cpp/language/adl))
for serialization.
*/
template<typename T = void, typename SFINAE = void>
struct adl_serializer; // IWYU pragma: keep
/// a class to store JSON values
/// @sa https://json.nlohmann.me/api/basic_json/
template<template<typename U, typename V, typename... Args> class ObjectType =
std::map,
template<typename U, typename... Args> class ArrayType = std::vector,
class StringType = std::string, class BooleanType = bool,
class NumberIntegerType = std::int64_t,
class NumberUnsignedType = std::uint64_t,
class NumberFloatType = double,
template<typename U> class AllocatorType = std::allocator,
template<typename T, typename SFINAE = void> class JSONSerializer =
adl_serializer,
class BinaryType = std::vector<std::uint8_t>, // cppcheck-suppress syntaxError
class CustomBaseClass = void>
class basic_json; // IWYU pragma: keep
/// @brief JSON Pointer defines a string syntax for identifying a specific value within a JSON document
/// @sa https://json.nlohmann.me/api/json_pointer/
template<typename RefStringType>
class json_pointer; // IWYU pragma: keep
/*!
@brief default specialization
@sa https://json.nlohmann.me/api/json/
*/
using json = basic_json<>;
/// @brief a minimal map-like container that preserves insertion order
/// @sa https://json.nlohmann.me/api/ordered_map/
template<class Key, class T, class IgnoredLess, class Allocator>
struct ordered_map; // IWYU pragma: keep
/// @brief specialization that maintains the insertion order of object keys
/// @sa https://json.nlohmann.me/api/ordered_json/
using ordered_json = basic_json<nlohmann::ordered_map>;
NLOHMANN_JSON_NAMESPACE_END
#endif // INCLUDE_NLOHMANN_JSON_FWD_HPP_