Fix stack overflow converting deep values between specializations (#5723 )

* Fix stack overflow converting deep values between specializations Constructing a basic_json from another specialization (json to ordered_json or back, also via get<ordered_json>()) converted every container with its range constructor, which calls the converting constructor for each element. The call stack therefore grew with every nesting level, and a value nested some 30,000 levels deep overflowed it. The conversion now bounds its descent the way the copy constructor does since #5387: the first 128 levels are converted exactly as before, and below that convert_iteratively() finishes the value with an explicit stack. It builds each container bottom-up from its converted elements with the container's range constructor, so member order and keys that become equal are handled as before, and it gives a value its type only once its container exists, so an exception leaves nothing behind that cannot be destroyed. Parents (JSON_DIAGNOSTICS) and positions (JSON_DIAGNOSTIC_POSITIONS) are set for every value. Converting a null value no longer resets its positions: the constructor assigned null to a value that already was null, which swapped in the positions of the temporary. Fixes #5650. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Explain why converting null keeps positions and why next is a reference Review feedback on #5723 (gregmarr): clarify in comments that the converting constructor has already copied the positions of val, which the null case keeps like every other case, and that next must be a reference into pending so that ++next advances the stored iterator. Comments only; no code change. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Refer to recursion_depth_limit() in the convert_structured() docs The comment still named nesting_depth_limit, which #5637 removed on develop in favor of detail::recursion_depth_limit(). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Advance the pending iterator through pending.back() and shorten the null comment Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Add JSON_DISABLE_TUPLE_REFERENCE_CONVERSION to fix std::tuple conversions (#5598 )
2026-09-30 19:50:34 +00:00 · 2026-09-30 21:36:04 +02:00 · 2026-09-30 20:53:56 +02:00
35 changed files with 1241 additions and 364 deletions
@@ -0,0 +1,17 @@
+arm_container:
+  image: gcc:latest
+
+check_task:
+  check_script:
+  # the gcc image ships an outdated CMake, so fetch a recent prebuilt binary
+  # instead of compiling CMake from source
+  - wget -q https://github.com/Kitware/CMake/releases/download/v4.3.4/cmake-4.3.4-linux-aarch64.tar.gz
+  - tar xfz cmake-4.3.4-linux-aarch64.tar.gz
+  - export PATH="$(pwd)/cmake-4.3.4-linux-aarch64/bin:$PATH"
+  - cmake --version
+  - mkdir build
+  - cd build
+  - cmake .. -DJSON_FastTests=ON
+  - make -j4
+  - cd tests
+  - ctest -j4
@@ -24,10 +24,6 @@ updates:
      interval: daily
    cooldown:
      default-days: 7
-    ignore:
-      # astyle is deliberately pinned (see tools/astyle/requirements.txt): newer versions
-      # reformat the code, and the pinned version defines the formatting CI enforces
-      - dependency-name: astyle

  - package-ecosystem: pip
    directory: /tools/generate_natvis
@@ -30,6 +30,14 @@ environment:
      CMAKE_OPTIONS: ""
      GENERATOR: Visual Studio 14 2015

+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      configuration: Release
+      platform: x86
+      name: with_win_header
+      CXX_FLAGS: "/W4 /WX"
+      CMAKE_OPTIONS: ""
+      GENERATOR: Visual Studio 14 2015
+
    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
      configuration: Release
      platform: x86
@@ -66,6 +74,9 @@ install:
  - if "%platform%"=="x86"    set GENERATOR_PLATFORM=Win32

 before_build:
+  # for with_win_header build, inject the inclusion of Windows.h to the single-header library
+  - ps: if ($env:name -Eq "with_win_header") { $header_path = "single_include\nlohmann\json.hpp" }
+  - ps: if ($env:name -Eq "with_win_header") { "#include <Windows.h>`n" + (Get-Content $header_path | Out-String) | Set-Content $header_path }
  - cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On "%CMAKE_OPTIONS%"

 build_script:
@@ -52,13 +52,6 @@ jobs:
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
        run: cmake --build build --target ci_infer
-      - name: Archive Infer report
-        if: always()
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
-        with:
-          name: infer-report
-          path: ${{ github.workspace }}/build/build_infer/infer-out/report.txt
-          if-no-files-found: ignore

  ci_static_analysis_ubuntu:
    runs-on: ubuntu-latest
@@ -104,13 +97,13 @@ jobs:

  ci_cmake_options:
    runs-on: ubuntu-latest
-    container: ubuntu:24.04
+    container: ubuntu:focal
    strategy:
      matrix:
-        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_disableenumserialization, ci_test_skiplibraryversioncheck, ci_test_simdutf, ci_test_strict_nul_handling, ci_test_no_thread_local]
+        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_disableenumserialization, ci_test_disabletuplereferenceconversion, ci_test_skiplibraryversioncheck, ci_test_simdutf, ci_test_strict_nul_handling, ci_test_no_thread_local]
    steps:
      - name: Install build-essential
-        run: apt-get update ; apt-get install -y build-essential unzip wget git
+        run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          persist-credentials: false
@@ -410,21 +403,3 @@ jobs:
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
        run: cmake --build build --target ${{ matrix.target }}
-
-  # Native Linux ARM64 runner with the latest GCC. The ubuntu-24.04-arm label is
-  # only available for public repositories.
-  ci_test_arm64:
-    runs-on: ubuntu-24.04-arm
-    container: gcc:latest
-    steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-        with:
-          persist-credentials: false
-      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
-      - name: Check that the job runs natively on arm64
-        run: uname -m && test "$(uname -m)" = aarch64
-      - name: Run CMake
-        run: cmake -S . -B build -DJSON_CI=On
-      - name: Build
-        run: cmake --build build --target ci_test_compiler_default
@@ -1,12 +0,0 @@
-{
-  "_comment": "Used by the ci_infer CMake target (#5715 item 4b). fail-on-issue makes CI fail on Infer findings; disable-issue-type is a type-level baseline for the ~174 pre-existing findings (all PULSE_UNNECESSARY_COPY*/PULSE_RESOURCE_LEAK/PULSE_CONST_REFABLE, mostly in test code) triaged in run https://github.com/nlohmann/json/actions/runs/35829411620 on commit 1054b2097, so CI fails only on a NEW issue type. Remove an entry here once its findings have been fixed or explicitly accepted.",
-  "fail-on-issue": true,
-  "disable-issue-type": [
-    "PULSE_UNNECESSARY_COPY_ASSIGNMENT",
-    "PULSE_UNNECESSARY_COPY",
-    "PULSE_UNNECESSARY_COPY_INTERMEDIATE",
-    "PULSE_UNNECESSARY_COPY_OPTIONAL",
-    "PULSE_RESOURCE_LEAK",
-    "PULSE_CONST_REFABLE"
-  ]
-}
@@ -55,6 +55,7 @@ option(JSON_Diagnostic_Positions           "Enable diagnostic positions." OFF)
 option(JSON_GlobalUDLs                     "Place user-defined string literals in the global namespace." ON)
 option(JSON_ImplicitConversions            "Enable implicit conversions." ON)
 option(JSON_DisableEnumSerialization       "Disable default integer enum serialization." OFF)
+option(JSON_DisableTupleReferenceConversion "Disable conversion from a one-element tuple of a JSON reference." OFF)
 option(JSON_LegacyDiscardedValueComparison "Enable legacy discarded value comparison." OFF)
 option(JSON_Install                        "Install CMake targets during install step." ${MAIN_PROJECT})
 option(JSON_MultipleHeaders                "Use non-amalgamated version of the library." ON)
@@ -101,6 +102,10 @@ if (JSON_DisableEnumSerialization)
    message(STATUS "Enum integer serialization is disabled (JSON_DISABLE_ENUM_SERIALIZATION=1)")
 endif()

+if (JSON_DisableTupleReferenceConversion)
+    message(STATUS "Tuple reference conversion is disabled (JSON_DISABLE_TUPLE_REFERENCE_CONVERSION=1)")
+endif()
+
 if (JSON_LegacyDiscardedValueComparison)
    message(STATUS "Legacy discarded value comparison enabled (JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1)")
 endif()
@@ -143,6 +148,7 @@ target_compile_definitions(
    $<$<NOT:$<BOOL:${JSON_GlobalUDLs}>>:JSON_USE_GLOBAL_UDLS=0>
    $<$<NOT:$<BOOL:${JSON_ImplicitConversions}>>:JSON_USE_IMPLICIT_CONVERSIONS=0>
    $<$<BOOL:${JSON_DisableEnumSerialization}>:JSON_DISABLE_ENUM_SERIALIZATION=1>
+    $<$<BOOL:${JSON_DisableTupleReferenceConversion}>:JSON_DISABLE_TUPLE_REFERENCE_CONVERSION=1>
    $<$<BOOL:${JSON_Diagnostics}>:JSON_DIAGNOSTICS=1>
    $<$<BOOL:${JSON_Diagnostic_Positions}>:JSON_DIAGNOSTIC_POSITIONS=1>
    $<$<BOOL:${JSON_LegacyDiscardedValueComparison}>:JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1>
@@ -33,6 +33,17 @@ Further documentation:
 > [!IMPORTANT]
 > The folder `.github/workflows` is predetermined by GitHub.

+### `.cirrus.yml`
+
+Configuration file for the pipeline at [Cirrus CI](https://cirrus-ci.com/github/nlohmann/json).
+
+Further documentation:
+
+- [Writing tasks](https://cirrus-ci.org/guide/writing-tasks/)
+
+> [!IMPORTANT]
+> The filename `.cirrus.yml` and position (root of the repository) are predetermined by Cirrus CI.
+
 ### `.github/external_ci/appveyor.yml`

 Configuration for the pipelines at [AppVeyor](https://ci.appveyor.com/project/nlohmann/json).
@@ -156,11 +156,11 @@ install_astyle:

 # call the Artistic Style pretty printer on all source files
 pretty: install_astyle
-	$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) docs/mkdocs/docs/examples/*.cpp docs/mkdocs/docs/examples/*.hpp
+	$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE) docs/mkdocs/docs/examples/*.cpp

 # call the Clang-Format on all source files
 pretty_format:
-	for FILE in $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) docs/mkdocs/docs/examples/*.cpp docs/mkdocs/docs/examples/*.hpp; do echo $$FILE; clang-format -i $$FILE; done
+	for FILE in $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) docs/mkdocs/docs/examples/*.cpp; do echo $$FILE; clang-format -i $$FILE; done

 # create single header files and pretty print
 amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_LITERALS_FILE)
@@ -179,6 +179,7 @@ $(AMALGAMATED_LITERALS_FILE): include/nlohmann/json_literals.hpp
 	cp include/nlohmann/json_literals.hpp $(AMALGAMATED_LITERALS_FILE)

 # check if file single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
+# Note: this target is called by Travis
 check-amalgamation:
 	@mv $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~
 	@mv $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~
@@ -7,6 +7,7 @@
 [![Coverage Status](https://coveralls.io/repos/github/nlohmann/json/badge.svg?branch=develop)](https://coveralls.io/github/nlohmann/json?branch=develop)
 [![Coverity Scan Build Status](https://scan.coverity.com/projects/5550/badge.svg)](https://scan.coverity.com/projects/nlohmann-json)
 [![Codacy Badge](https://app.codacy.com/project/badge/Grade/e0d1a9d5d6fd46fcb655c4cb930bb3e8)](https://app.codacy.com/gh/nlohmann/json/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade)
+[![Cirrus CI](https://api.cirrus-ci.com/github/nlohmann/json.svg)](https://cirrus-ci.com/github/nlohmann/json)
 [![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/json.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:json)
 [![Try online](https://img.shields.io/badge/try-online-blue.svg)](https://wandbox.org/permlink/1mp10JbaANo6FUc7)
 [![Documentation](https://img.shields.io/badge/docs-mkdocs-blue.svg)](https://json.nlohmann.me)
@@ -40,14 +40,6 @@ execute_process(COMMAND ${IWYU_TOOL} --version OUTPUT_VARIABLE IWYU_TOOL_VERSION
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" IWYU_TOOL_VERSION "${IWYU_TOOL_VERSION}")
 message(STATUS "🔖 include-what-you-use ${IWYU_TOOL_VERSION} (${IWYU_TOOL})")

-# CMake's CXX_INCLUDE_WHAT_YOU_USE launcher runs IWYU during the normal compile step (useful to see
-# diagnostics inline), but CMake's own __run_co_compile wrapper does not propagate the launched
-# tool's exit code to the build, so IWYU's own "-Xiwyu --error" cannot fail that step (verified: a
-# deliberately-unused #include in a header still lets `cmake --build` finish with exit code 0).
-# iwyu_tool.py, which ships with IWYU, reads compile_commands.json and does return a non-zero exit
-# code for any analyzed file with findings; ci_single_binaries uses it to actually fail on findings.
-find_program(IWYU_TOOL_PY NAMES iwyu_tool iwyu_tool.py iwyu-tool)
-
 find_program(INFER_TOOL NAMES infer)
 execute_process(COMMAND ${INFER_TOOL} --version OUTPUT_VARIABLE INFER_TOOL_VERSION ERROR_VARIABLE INFER_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" INFER_TOOL_VERSION "${INFER_TOOL_VERSION}")
@@ -63,6 +55,12 @@ execute_process(COMMAND ${NINJA_TOOL} --version OUTPUT_VARIABLE NINJA_TOOL_VERSI
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" NINJA_TOOL_VERSION "${NINJA_TOOL_VERSION}")
 message(STATUS "🔖 Ninja ${NINJA_TOOL_VERSION} (${NINJA_TOOL})")

+find_program(OCLINT_TOOL NAMES oclint-json-compilation-database)
+find_program(OCLINT_VERSION_TOOL NAMES oclint)
+execute_process(COMMAND ${OCLINT_VERSION_TOOL} --version OUTPUT_VARIABLE OCLINT_TOOL_VERSION ERROR_VARIABLE OCLINT_TOOL_VERSION)
+string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" OCLINT_TOOL_VERSION "${OCLINT_TOOL_VERSION}")
+message(STATUS "🔖 OCLint ${OCLINT_TOOL_VERSION} (${OCLINT_TOOL})")
+
 find_program(VALGRIND_TOOL NAMES valgrind)
 execute_process(COMMAND ${VALGRIND_TOOL} --version OUTPUT_VARIABLE VALGRIND_TOOL_VERSION ERROR_VARIABLE VALGRIND_TOOL_VERSION)
 string(REGEX MATCH "[0-9]+(\\.[0-9]+)+" VALGRIND_TOOL_VERSION "${VALGRIND_TOOL_VERSION}")
@@ -130,16 +128,16 @@ foreach(CXX_STANDARD 11 14 17 20 23 26)
        COMMENT "Compile and test with Clang for C++${CXX_STANDARD}"
    )

-    # pass -stdlib=libc++ through CXXFLAGS: an explicit -DCMAKE_CXX_FLAGS would make CMake ignore CXXFLAGS
    add_custom_target(ci_test_clang_libcxx_cxx${CXX_STANDARD}
-        COMMAND CXX=${CLANG_TOOL} CXXFLAGS="${CLANG_CXXFLAGS};-stdlib=libc++" ${CMAKE_COMMAND}
+        COMMAND CXX=${CLANG_TOOL} CXXFLAGS="${CLANG_CXXFLAGS}" ${CMAKE_COMMAND}
            -DCMAKE_BUILD_TYPE=Debug -GNinja
            -DJSON_BuildTests=ON -DJSON_FastTests=ON
            -DJSON_TestStandards=${CXX_STANDARD}
+            -DCMAKE_CXX_FLAGS="-stdlib=libc++"
            -DCMAKE_EXE_LINKER_FLAGS="-lc++abi"
-            -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD}
-        COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD}
-        COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD} && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
+            -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD}
+        COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD}
+        COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD} && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
        COMMENT "Compile and test with Clang for C++${CXX_STANDARD} (libc++)"
    )
 endforeach()
@@ -278,6 +276,20 @@ add_custom_target(ci_test_disableenumserialization
    COMMENT "Compile and test with enum serialization disabled"
 )

+###############################################################################
+# Disable conversion from a one-element tuple of a JSON reference.
+###############################################################################
+
+add_custom_target(ci_test_disabletuplereferenceconversion
+    COMMAND ${CMAKE_COMMAND}
+    -DCMAKE_BUILD_TYPE=Debug -GNinja
+    -DJSON_BuildTests=ON -DJSON_FastTests=ON -DJSON_DisableTupleReferenceConversion=ON
+    -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_disabletuplereferenceconversion
+    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_disabletuplereferenceconversion
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_disabletuplereferenceconversion && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
+    COMMENT "Compile and test with tuple reference conversion disabled"
+)
+
 ###############################################################################
 # Skip the multiple-inclusion library version check.
 ###############################################################################
@@ -364,20 +376,13 @@ add_custom_target(ci_test_clang_sanitizer
 # Check if header is amalgamated and sources are properly indented.
 ###############################################################################

-# Same file set as .github/workflows/check_amalgamation.yml, so a direct push to develop/master/release/*
-# (which only this CMake target checks, not the pull_request-only workflow) is held to the same standard.
 file(GLOB_RECURSE INDENT_FILES
-    ${PROJECT_SOURCE_DIR}/docs/mkdocs/docs/examples/*.hpp
+    ${PROJECT_SOURCE_DIR}/include/nlohmann/*.hpp
+        ${PROJECT_SOURCE_DIR}/tests/src/*.cpp
+        ${PROJECT_SOURCE_DIR}/tests/src/*.hpp
+        ${PROJECT_SOURCE_DIR}/tests/benchmarks/src/benchmarks.cpp
    ${PROJECT_SOURCE_DIR}/docs/mkdocs/docs/examples/*.cpp
-    ${PROJECT_SOURCE_DIR}/docs/mkdocs/docs/examples/*.cu
-    ${PROJECT_SOURCE_DIR}/include/*.hpp
-    ${PROJECT_SOURCE_DIR}/include/*.cpp
-    ${PROJECT_SOURCE_DIR}/include/*.cu
-    ${PROJECT_SOURCE_DIR}/tests/*.hpp
-    ${PROJECT_SOURCE_DIR}/tests/*.cpp
-    ${PROJECT_SOURCE_DIR}/tests/*.cu
 )
-list(FILTER INDENT_FILES EXCLUDE REGEX "/tests/thirdparty/|/tests/abi/include/nlohmann/")

 set(include_dir ${PROJECT_SOURCE_DIR}/single_include/nlohmann)
 set(tool_dir ${PROJECT_SOURCE_DIR}/tools/amalgamate)
@@ -386,7 +391,6 @@ add_custom_target(ci_test_amalgamation
    COMMAND cp ${include_dir}/json.hpp ${include_dir}/json.hpp~
    COMMAND cp ${include_dir}/json_fwd.hpp ${include_dir}/json_fwd.hpp~
    COMMAND cp ${include_dir}/json_literals.hpp ${include_dir}/json_literals.hpp~
-    COMMAND cp ${PROJECT_SOURCE_DIR}/BUILD.bazel ${PROJECT_SOURCE_DIR}/BUILD.bazel~

    COMMAND ${Python3_EXECUTABLE} -mvenv venv_astyle
    COMMAND venv_astyle/bin/pip3 --quiet install -r ${CMAKE_SOURCE_DIR}/tools/astyle/requirements.txt
@@ -396,18 +400,16 @@ add_custom_target(ci_test_amalgamation
    COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json_fwd.json -s .
    COMMAND cp ${PROJECT_SOURCE_DIR}/include/nlohmann/json_literals.hpp ${include_dir}/json_literals.hpp
    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.hpp
-    COMMAND ${CMAKE_COMMAND} -P ${PROJECT_SOURCE_DIR}/cmake/scripts/gen_bazel_build_file.cmake

    COMMAND diff ${include_dir}/json.hpp~ ${include_dir}/json.hpp
    COMMAND diff ${include_dir}/json_fwd.hpp~ ${include_dir}/json_fwd.hpp
    COMMAND diff ${include_dir}/json_literals.hpp~ ${include_dir}/json_literals.hpp
-    COMMAND diff ${PROJECT_SOURCE_DIR}/BUILD.bazel~ ${PROJECT_SOURCE_DIR}/BUILD.bazel

    COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=orig ${INDENT_FILES}
    COMMAND for FILE in `find . -name '*.orig'`\; do false \; done

    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    COMMENT "Check amalgamation, formatting, and BUILD.bazel"
+    COMMENT "Check amalgamation and indentation"
 )

 ###############################################################################
@@ -442,14 +444,14 @@ add_custom_target(ci_test_valgrind
 # Check code with Clang Static Analyzer.
 ###############################################################################

-set(CLANG_ANALYZER_CHECKS "nullability.NullableDereferenced,nullability.NullablePassedToNonnull,nullability.NullableReturnedFromNonnull,optin.cplusplus.UninitializedObject,optin.cplusplus.VirtualCall,optin.performance.Padding,optin.portability.UnixAPI,security.FloatLoopCounter,security.insecureAPI.DeprecatedOrUnsafeBufferHandling,security.insecureAPI.bcmp,security.insecureAPI.bcopy,security.insecureAPI.bzero,security.insecureAPI.rand,security.insecureAPI.strcpy,valist.CopyToSelf,valist.Uninitialized,valist.Unterminated,core.CallAndMessage,core.DivideZero,core.NonNullParamChecker,core.NullDereference,core.StackAddressEscape,core.UndefinedBinaryOperatorResult,core.VLASize,core.uninitialized.ArraySubscript,core.uninitialized.Assign,core.uninitialized.Branch,core.uninitialized.CapturedBlockVariable,core.uninitialized.UndefReturn,cplusplus.InnerPointer,cplusplus.Move,cplusplus.NewDelete,cplusplus.NewDeleteLeaks,cplusplus.PlacementNew,cplusplus.PureVirtualCall,deadcode.DeadStores,nullability.NullPassedToNonnull,nullability.NullReturnedFromNonnull,security.insecureAPI.UncheckedReturn,security.insecureAPI.decodeValueOfObjCType,security.insecureAPI.getpw,security.insecureAPI.gets,security.insecureAPI.mkstemp,security.insecureAPI.mktemp,security.insecureAPI.vfork,unix.API,unix.Malloc,unix.MallocSizeof,unix.MismatchedDeallocator,unix.Vfork,unix.cstring.BadSizeArg,unix.cstring.NullArg")
+set(CLANG_ANALYZER_CHECKS "fuchsia.HandleChecker,nullability.NullableDereferenced,nullability.NullablePassedToNonnull,nullability.NullableReturnedFromNonnull,optin.cplusplus.UninitializedObject,optin.cplusplus.VirtualCall,optin.mpi.MPI-Checker,optin.osx.OSObjectCStyleCast,optin.osx.cocoa.localizability.EmptyLocalizationContextChecker,optin.osx.cocoa.localizability.NonLocalizedStringChecker,optin.performance.GCDAntipattern,optin.performance.Padding,optin.portability.UnixAPI,security.FloatLoopCounter,security.insecureAPI.DeprecatedOrUnsafeBufferHandling,security.insecureAPI.bcmp,security.insecureAPI.bcopy,security.insecureAPI.bzero,security.insecureAPI.rand,security.insecureAPI.strcpy,valist.CopyToSelf,valist.Uninitialized,valist.Unterminated,webkit.NoUncountedMemberChecker,webkit.RefCntblBaseVirtualDtor,core.CallAndMessage,core.DivideZero,core.NonNullParamChecker,core.NullDereference,core.StackAddressEscape,core.UndefinedBinaryOperatorResult,core.VLASize,core.uninitialized.ArraySubscript,core.uninitialized.Assign,core.uninitialized.Branch,core.uninitialized.CapturedBlockVariable,core.uninitialized.UndefReturn,cplusplus.InnerPointer,cplusplus.Move,cplusplus.NewDelete,cplusplus.NewDeleteLeaks,cplusplus.PlacementNew,cplusplus.PureVirtualCall,deadcode.DeadStores,nullability.NullPassedToNonnull,nullability.NullReturnedFromNonnull,osx.API,osx.MIG,osx.NumberObjectConversion,osx.OSObjectRetainCount,osx.ObjCProperty,osx.SecKeychainAPI,osx.cocoa.AtSync,osx.cocoa.AutoreleaseWrite,osx.cocoa.ClassRelease,osx.cocoa.Dealloc,osx.cocoa.IncompatibleMethodTypes,osx.cocoa.Loops,osx.cocoa.MissingSuperCall,osx.cocoa.NSAutoreleasePool,osx.cocoa.NSError,osx.cocoa.NilArg,osx.cocoa.NonNilReturnValue,osx.cocoa.ObjCGenerics,osx.cocoa.RetainCount,osx.cocoa.RunLoopAutoreleaseLeak,osx.cocoa.SelfInit,osx.cocoa.SuperDealloc,osx.cocoa.UnusedIvars,osx.cocoa.VariadicMethodTypes,osx.coreFoundation.CFError,osx.coreFoundation.CFNumber,osx.coreFoundation.CFRetainRelease,osx.coreFoundation.containers.OutOfBounds,osx.coreFoundation.containers.PointerSizedValues,security.insecureAPI.UncheckedReturn,security.insecureAPI.decodeValueOfObjCType,security.insecureAPI.getpw,security.insecureAPI.gets,security.insecureAPI.mkstemp,security.insecureAPI.mktemp,security.insecureAPI.vfork,unix.API,unix.Malloc,unix.MallocSizeof,unix.MismatchedDeallocator,unix.Vfork,unix.cstring.BadSizeArg,unix.cstring.NullArg")

 add_custom_target(ci_clang_analyze
    COMMAND CXX=${CLANG_TOOL} ${CMAKE_COMMAND}
        -DCMAKE_BUILD_TYPE=Debug -GNinja
        -DJSON_BuildTests=ON
        -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_clang_analyze
-    COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_analyze && ${SCAN_BUILD_TOOL} -enable-checker ${CLANG_ANALYZER_CHECKS} --use-c++=${CLANG_TOOL} --use-analyzer=${CLANG_TOOL} -analyze-headers --status-bugs -o ${PROJECT_BINARY_DIR}/report ninja
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_analyze && ${SCAN_BUILD_TOOL} -enable-checker ${CLANG_ANALYZER_CHECKS} --use-c++=${CLANG_TOOL} -analyze-headers -o ${PROJECT_BINARY_DIR}/report ninja
    COMMENT "Check code with Clang Analyzer"
 )

@@ -465,7 +467,7 @@ add_custom_target(ci_cppcheck
    COMMAND venv_cppcheck/bin/cppcheck --enable=warning --check-level=exhaustive --inline-suppr --inconclusive --force
            --std=c++11 ${PROJECT_SOURCE_DIR}/include/nlohmann/json.hpp -I ${CMAKE_SOURCE_DIR}/include
            --error-exitcode=1 --relative-paths=${PROJECT_SOURCE_DIR} -j ${N} --include=default_defines.hpp
-            --cppcheck-build-dir=cppcheck
+            --cppcheck-build-dir=cppcheck --check-level=exhaustive
            -UJSON_CATCH_USER -UJSON_TRY_USER -UJSON_ASSERT -UJSON_INTERNAL_CATCH -UJSON_THROW
            -DJSON_HAS_CPP_11 -UJSON_HAS_CPP_14 -UJSON_HAS_CPP_17 -UJSON_HAS_CPP_20 -UJSON_HAS_THREE_WAY_COMPARISON
    COMMENT "Check code with Cppcheck"
@@ -483,6 +485,34 @@ add_custom_target(ci_cpplint
    WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
 )

+###############################################################################
+# Check code with OCLint.
+###############################################################################
+
+file(COPY ${PROJECT_SOURCE_DIR}/single_include/nlohmann/json.hpp DESTINATION ${PROJECT_BINARY_DIR}/src_single)
+file(RENAME ${PROJECT_BINARY_DIR}/src_single/json.hpp ${PROJECT_BINARY_DIR}/src_single/all.cpp)
+file(APPEND "${PROJECT_BINARY_DIR}/src_single/all.cpp" "\n\nint main()\n{}\n")
+
+add_executable(single_all ${PROJECT_BINARY_DIR}/src_single/all.cpp)
+target_compile_features(single_all PRIVATE cxx_std_11)
+
+add_custom_target(ci_oclint
+    COMMAND ${CMAKE_COMMAND}
+        -DCMAKE_BUILD_TYPE=Debug
+        -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+        -DJSON_BuildTests=OFF -DJSON_CI=ON
+        -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_oclint
+    COMMAND ${OCLINT_TOOL} -i ${PROJECT_BINARY_DIR}/build_oclint/src_single/all.cpp -p ${PROJECT_BINARY_DIR}/build_oclint --
+        -report-type html -enable-global-analysis --max-priority-1=0 --max-priority-2=1000 --max-priority-3=2000
+        --disable-rule=MultipleUnaryOperator
+        --disable-rule=DoubleNegative
+        --disable-rule=ShortVariableName
+        --disable-rule=GotoStatement
+        --disable-rule=LongLine
+        -o ${PROJECT_BINARY_DIR}/build_oclint/oclint_report.html
+    COMMENT "Check code with OCLint"
+)
+
 ###############################################################################
 # Check code with Clang-Tidy.
 ###############################################################################
@@ -497,16 +527,29 @@ add_custom_target(ci_clang_tidy
    COMMENT "Check code with Clang-Tidy"
 )

+###############################################################################
+# Check code with PVS-Studio Analyzer <https://www.viva64.com/en/pvs-studio/>.
+###############################################################################
+
+add_custom_target(ci_pvs_studio
+    COMMAND CXX=${CLANG_TOOL} ${CMAKE_COMMAND}
+        -DCMAKE_BUILD_TYPE=Debug
+        -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+        -DJSON_BuildTests=ON
+        -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_pvs_studio
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_pvs_studio && ${PVS_STUDIO_ANALYZER_TOOL} analyze -j 10
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_pvs_studio && ${PLOG_CONVERTER_TOOL} -a'GA:1,2;64:1;CS' -t fullhtml PVS-Studio.log -o pvs
+    COMMENT "Check code with PVS Studio"
+)
+
 ###############################################################################
 # Check code with Infer <https://fbinfer.com> static analyzer.
 ###############################################################################

-# .inferconfig (repository root) pins --fail-on-issue and the currently-triaged issue types that
-# are disabled until they are addressed separately; see #5715 item 4b.
 add_custom_target(ci_infer
    COMMAND mkdir -p ${PROJECT_BINARY_DIR}/build_infer
    COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} compile -- ${CMAKE_COMMAND} -DCMAKE_BUILD_TYPE=Debug ${PROJECT_SOURCE_DIR} -DJSON_BuildTests=ON
-    COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} run --project-root ${PROJECT_SOURCE_DIR} -- make
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_infer && ${INFER_TOOL} run -- make
    COMMENT "Check code with Infer"
 )

@@ -562,13 +605,7 @@ add_custom_target(ci_reproducible_tests
 # be compiled individually.
 ###############################################################################

-set(iwyu_options -Xiwyu --error -Xiwyu --max_line_length=300)
-set(iwyu_path_and_options ${IWYU_TOOL} ${iwyu_options})
-
-# CMake needs to know the exact flags used to compile each src_single/*.cpp below to hand them to
-# iwyu_tool.py; JSON_CI already implies a from-scratch configure, so enabling this project-wide has
-# no downside here.
-set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+set(iwyu_path_and_options ${IWYU_TOOL} -Xiwyu --max_line_length=300)

 foreach(SRC_FILE ${SRC_FILES})
    # get relative path of the header file
@@ -583,34 +620,14 @@ foreach(SRC_FILE ${SRC_FILES})
    target_include_directories(single_${RELATIVE_SRC_FILE} PRIVATE ${PROJECT_SOURCE_DIR}/include)
    target_compile_features(single_${RELATIVE_SRC_FILE} PRIVATE cxx_std_11)
    set_property(TARGET single_${RELATIVE_SRC_FILE} PROPERTY CXX_INCLUDE_WHAT_YOU_USE "${iwyu_path_and_options}")
-    # remember binary for ci_single_binaries
+    # remember binary for ci_single_binaries target
    list(APPEND single_binaries single_${RELATIVE_SRC_FILE})
-    # json.hpp pulls together the whole library behind heavily templated, SFINAE-based code, and
-    # IWYU's suggestion for its one truly ambiguous symbol (a container-comparison "swap,
-    # operator!=") is not deterministic between runs (observed <set>, <unordered_map>, and <map>
-    # for the exact same source across otherwise-identical local and containerized builds). Keep
-    # reporting its diagnostics (informational, via CXX_INCLUDE_WHAT_YOU_USE above) but exclude it
-    # from the hard gate below so a fresh IWYU/compiler combination does not fail this target on a
-    # nondeterministic suggestion for a header that already re-exports everything on purpose.
-    if(NOT RELATIVE_SRC_FILE STREQUAL "json")
-        list(APPEND single_binaries_tus src_single/${RELATIVE_SRC_FILE}.cpp)
-    endif()
 endforeach()

-if(IWYU_TOOL_PY)
-    add_custom_target(ci_single_binaries
-        DEPENDS ${single_binaries}
-        COMMAND ${IWYU_TOOL_PY} -p ${PROJECT_BINARY_DIR} ${single_binaries_tus} -- ${iwyu_options}
-        COMMENT "Check if headers are self-contained"
-    )
-else()
-    # iwyu_tool.py (ships with IWYU, e.g. as /usr/bin/iwyu_tool on Debian/Ubuntu) was not found;
-    # fall back to building the self-containment check without enforcing the IWYU findings.
-    add_custom_target(ci_single_binaries
-        DEPENDS ${single_binaries}
-        COMMENT "Check if headers are self-contained"
-    )
-endif()
+add_custom_target(ci_single_binaries
+    DEPENDS ${single_binaries}
+    COMMENT "Check if headers are self-contained"
+)

 ###############################################################################
 # Benchmarks
@@ -632,41 +649,21 @@ add_custom_target(ci_benchmarks
 # we test the project with different CMake versions:
 # - CMake 3.5 (the earliest supported)
 # - CMake 3.31.6 (the latest 3.x release)
-# - CMake 4.0.0 (the first 4.x release)
-# - the CMake version running this build (usually the latest release)
+# - CMake 4.0.0 (the latest release)

 function(ci_get_cmake version var)
    set(${var} ${PROJECT_BINARY_DIR}/cmake-${version}/bin/cmake)
-    if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Linux" AND CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "^(x86_64|amd64)$")
-        # Kitware publishes a prebuilt Linux x86_64 archive for every release; unpacking it is far
-        # cheaper than compiling all of CMake (including its own test helpers) from source.
-        add_custom_command(
-            OUTPUT ${${var}}
-            COMMAND wget -nc https://github.com/Kitware/CMake/releases/download/v${version}/cmake-${version}-linux-x86_64.tar.gz
-            COMMAND wget -nc https://github.com/Kitware/CMake/releases/download/v${version}/cmake-${version}-SHA-256.txt
-            # verify the archive against Kitware's published SHA-256 sums before unpacking it
-            COMMAND sh -c "grep ' cmake-${version}-linux-x86_64[.]tar[.]gz$' cmake-${version}-SHA-256.txt | sha256sum -c -"
-            COMMAND tar xfz cmake-${version}-linux-x86_64.tar.gz
-            COMMAND rm cmake-${version}-linux-x86_64.tar.gz cmake-${version}-SHA-256.txt
-            COMMAND ${CMAKE_COMMAND} -E rm -rf cmake-${version}
-            COMMAND ${CMAKE_COMMAND} -E rename cmake-${version}-linux-x86_64 cmake-${version}
-            WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
-            COMMENT "Download prebuilt CMake ${version}"
-        )
-    else()
-        # no prebuilt archive for this platform (e.g. macOS or Linux aarch64): build from source
-        add_custom_command(
-            OUTPUT ${${var}}
-            COMMAND wget -nc https://github.com/Kitware/CMake/releases/download/v${version}/cmake-${version}.tar.gz
-            COMMAND tar xfz cmake-${version}.tar.gz
-            COMMAND rm cmake-${version}.tar.gz
-            # -DCMAKE_POLICY_VERSION_MINIMUM=3.5 required to compile older CMake versions with CMake 4.0.0
-            COMMAND cmake -S cmake-${version} -B cmake-${version} -DCMAKE_POLICY_VERSION_MINIMUM=3.5
-            COMMAND cmake --build cmake-${version} --parallel 10
-            WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
-            COMMENT "Download and build CMake ${version} from source"
-        )
-    endif()
+    add_custom_command(
+        OUTPUT ${${var}}
+        COMMAND wget -nc https://github.com/Kitware/CMake/releases/download/v${version}/cmake-${version}.tar.gz
+        COMMAND tar xfz cmake-${version}.tar.gz
+        COMMAND rm cmake-${version}.tar.gz
+        # -DCMAKE_POLICY_VERSION_MINIMUM=3.5 required to compile older CMake versions with CMake 4.0.0
+        COMMAND cmake -S cmake-${version} -B cmake-${version} -DCMAKE_POLICY_VERSION_MINIMUM=3.5
+        COMMAND cmake --build cmake-${version} --parallel 10
+        WORKING_DIRECTORY ${PROJECT_BINARY_DIR}
+        COMMENT "Download CMake ${version}"
+    )
    set(${var} ${${var}} PARENT_SCOPE)
 endfunction()

@@ -676,24 +673,30 @@ ci_get_cmake(4.0.0  CMAKE_4_0_0_BINARY)

 # the tests require CMake 3.13 or later, so they are excluded for CMake 3.5.0
 set(JSON_CMAKE_FLAGS_3_5_0 JSON_Diagnostics JSON_Diagnostic_Positions JSON_GlobalUDLs JSON_ImplicitConversions JSON_DisableEnumSerialization
-    JSON_LegacyDiscardedValueComparison JSON_Install JSON_MultipleHeaders JSON_SystemInclude JSON_Valgrind
-    JSON_StrictNulHandling)
-set(JSON_CMAKE_FLAGS_3_31_6 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_5_0})
+    JSON_LegacyDiscardedValueComparison JSON_Install JSON_MultipleHeaders JSON_SystemInclude JSON_Valgrind)
+set(JSON_CMAKE_FLAGS_3_31_6 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_31_6})
 set(JSON_CMAKE_FLAGS_4_0_0 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_5_0})

 function(ci_add_cmake_flags_targets flag min_version)
    string(TOLOWER "ci_cmake_flag_${flag}" flag_target)
    string(REPLACE . _ min_version_var ${min_version})
    set(cmake_binary ${CMAKE_${min_version_var}_BINARY})
+    add_custom_target(${flag_target}_${min_version}_2
+        COMMENT "Check CMake flag ${flag} (CMake ${CMAKE_VERSION})"
+        COMMAND ${CMAKE_COMMAND}
+            -Werror=dev
+            -D${flag}=ON
+            -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_${flag_target}
+    )
    add_custom_target(${flag_target}_${min_version_var}
-        COMMENT "Check CMake flag ${flag} (CMake ${min_version})"
+        COMMENT "Check CMake flag ${JSON_CMAKE_FLAG} (CMake ${min_version})"
        COMMAND mkdir -pv ${PROJECT_BINARY_DIR}/build_${flag_target}_${min_version_var}
        COMMAND cd ${PROJECT_BINARY_DIR}/build_${flag_target}_${min_version_var}
            && ${cmake_binary} -Werror=dev ${PROJECT_SOURCE_DIR} -D${flag}=ON
        DEPENDS ${cmake_binary}
    )
-    list(APPEND JSON_CMAKE_FLAG_TARGETS ${flag_target}_${min_version_var})
-    list(APPEND JSON_CMAKE_FLAG_BUILD_DIRS ${PROJECT_BINARY_DIR}/build_${flag_target}_${min_version_var})
+    list(APPEND JSON_CMAKE_FLAG_TARGETS ${JSON_CMAKE_FLAG_TARGET} ${flag_target}_${min_version_var})
+    list(APPEND JSON_CMAKE_FLAG_BUILD_DIRS ${PROJECT_BINARY_DIR}/build_${flag_target} ${PROJECT_BINARY_DIR}/build_${flag_target}_${min_version_var})
    set(JSON_CMAKE_FLAG_TARGETS ${JSON_CMAKE_FLAG_TARGETS} PARENT_SCOPE)
    set(JSON_CMAKE_FLAG_BUILD_DIRS ${JSON_CMAKE_FLAG_BUILD_DIRS} PARENT_SCOPE)
 endfunction()
@@ -710,20 +713,6 @@ foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_4_0_0})
    ci_add_cmake_flags_targets(${JSON_CMAKE_FLAG} 4.0.0)
 endforeach()

-# check the same flags with the CMake version running this build
-foreach(JSON_CMAKE_FLAG ${JSON_CMAKE_FLAGS_4_0_0})
-    string(TOLOWER "ci_cmake_flag_${JSON_CMAKE_FLAG}" flag_target)
-    add_custom_target(${flag_target}
-        COMMENT "Check CMake flag ${JSON_CMAKE_FLAG} (CMake ${CMAKE_VERSION})"
-        COMMAND ${CMAKE_COMMAND}
-            -Werror=dev
-            -D${JSON_CMAKE_FLAG}=ON
-            -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_${flag_target}
-    )
-    list(APPEND JSON_CMAKE_FLAG_TARGETS ${flag_target})
-    list(APPEND JSON_CMAKE_FLAG_BUILD_DIRS ${PROJECT_BINARY_DIR}/build_${flag_target})
-endforeach()
-
 add_custom_target(ci_cmake_flags
    DEPENDS ${JSON_CMAKE_FLAG_TARGETS}
    COMMENT "Check CMake flags"
@@ -882,6 +871,6 @@ add_custom_target(ci_test_build_documentation
 ###############################################################################

 add_custom_target(ci_clean
-    COMMAND rm -fr ${PROJECT_BINARY_DIR}/build_* ${PROJECT_BINARY_DIR}/cmake-3.5.0 ${PROJECT_BINARY_DIR}/cmake-3.31.6 ${PROJECT_BINARY_DIR}/cmake-4.0.0 ${JSON_CMAKE_FLAG_BUILD_DIRS} ${single_binaries}
+    COMMAND rm -fr ${PROJECT_BINARY_DIR}/build_* cmake-3.5.0-Darwin64 ${JSON_CMAKE_FLAG_BUILD_DIRS} ${single_binaries}
    COMMENT "Clean generated directories"
 )
@@ -210,6 +210,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('JSON_CATCH_USER', 'Macro', 'a
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DIAGNOSTICS', 'Macro', 'api/macros/json_diagnostics/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DIAGNOSTIC_POSITIONS', 'Macro', 'api/macros/json_diagnostic_positions/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DISABLE_ENUM_SERIALIZATION', 'Macro', 'api/macros/json_disable_enum_serialization/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('JSON_DISABLE_TUPLE_REFERENCE_CONVERSION', 'Macro', 'api/macros/json_disable_tuple_reference_conversion/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_11', 'Macro', 'api/macros/json_has_cpp_11/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_14', 'Macro', 'api/macros/json_has_cpp_11/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('JSON_HAS_CPP_17', 'Macro', 'api/macros/json_has_cpp_11/index.html');
@@ -159,6 +159,8 @@ basic_json(basic_json&& other) noexcept;
    - `CompatibleType` is not `basic_json` (to avoid hijacking copy/move constructors),
    - `CompatibleType` is not a different `basic_json` type (i.e. with different template arguments)
    - `CompatibleType` is not a `basic_json` nested type (e.g., `json_pointer`, `iterator`, etc.)
+    - if [`JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../macros/json_disable_tuple_reference_conversion.md) is defined
+      to `1`: `CompatibleType` is not a one-element `std::tuple` holding a reference to `basic_json`
    - `json_serializer<U>` (with `U = uncvref_t<CompatibleType>`) has a `to_json(basic_json_t&, CompatibleType&&)`
       method

@@ -53,6 +53,7 @@ header. See also the [macro overview page](../../features/macros.md).

 - [**JSON_BRACE_INIT_COPY_SEMANTICS**](json_brace_init_copy_semantics.md) - opt in to copy/move semantics for single-element brace initialization
 - [**JSON_DISABLE_ENUM_SERIALIZATION**](json_disable_enum_serialization.md) - switch off default serialization/deserialization functions for enums
+- [**JSON_DISABLE_TUPLE_REFERENCE_CONVERSION**](json_disable_tuple_reference_conversion.md) - switch off conversion from a one-element tuple of a JSON reference
 - [**JSON_USE_IMPLICIT_CONVERSIONS**](json_use_implicit_conversions.md) - control implicit conversions

 ## Comparison behavior
@@ -0,0 +1,114 @@
+# JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+
+```cpp
+#define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION /* value */
+```
+
+When defined to `1`, a `basic_json` value can no longer be constructed from a one-element `std::tuple` whose element is
+a reference to that `basic_json` type, such as `std::tuple<json&>`, `std::tuple<const json&>`, or `std::tuple<json&&>`.
+These are the tuples created by `std::forward_as_tuple(j)`.
+
+## Default definition
+
+The default value is `0` (disabled — existing behavior is preserved).
+
+```cpp
+#define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 0
+```
+
+## Notes
+
+!!! note "Background"
+
+    By default, `basic_json` can be constructed from any `std::tuple` whose elements can be converted to JSON; the result
+    is an array. This includes `std::tuple<json&>`, which becomes a one-element array.
+
+    `std::tuple` only converts another tuple element by element if its element type cannot be constructed from the whole
+    source tuple. Because `json` *can* be constructed from `std::tuple<json&>`, `std::tuple` instead converts the whole
+    tuple into a single `json` value. This has two surprising effects:
+
+    ```cpp
+    json j = true;
+
+    // rejected by some standard libraries (e.g., libc++); with others, the
+    // reference binds to a temporary that is destroyed right away
+    std::tuple<const json&> t1(std::forward_as_tuple(j));
+
+    // compiles, but std::get<0>(t2) is [true], not true
+    std::tuple<json> t2(std::forward_as_tuple(j));
+    ```
+
+    Enabling this macro removes the conversion, so both tuples are converted element by element: `std::get<0>(t1)`
+    refers to `j`, and `std::get<0>(t2)` is a copy of `j` (see [#2226](https://github.com/nlohmann/json/issues/2226)).
+
+!!! warning "Opt-in only"
+
+    This macro must be defined **before** including `<nlohmann/json.hpp>`. Defining it after the include has no effect.
+
+!!! note "Affected conversions"
+
+    Only one-element tuples holding a reference to the **same** `basic_json` type are affected. Constructing a JSON value
+    from them no longer compiles:
+
+    ```cpp
+    json j = true;
+    json a = std::forward_as_tuple(j);  // error with the macro enabled
+    json b = json::array({j});          // use this instead: [true]
+    ```
+
+    Tuples holding a JSON value (`std::make_tuple(j)`), tuples with more than one element, and tuples holding references
+    to other types (including other `basic_json` specializations) are converted to arrays as before.
+
+!!! hint "CMake option"
+
+    This behavior can also be controlled with the CMake option
+    [`JSON_DisableTupleReferenceConversion`](../../integration/cmake.md#json_disabletuplereferenceconversion)
+    (`OFF` by default) which defines `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION` accordingly.
+
+## Examples
+
+??? example "Default behavior (macro not defined)"
+
+    ```cpp
+    #include <nlohmann/json.hpp>
+
+    using json = nlohmann::json;
+
+    int main()
+    {
+        json j = true;
+
+        std::tuple<json> t(std::forward_as_tuple(j));
+        // std::get<0>(t) is [true] -- the whole tuple was converted
+    }
+    ```
+
+??? example "Conversion disabled (macro defined to 1)"
+
+    ```cpp
+    #define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 1
+    #include <nlohmann/json.hpp>
+
+    using json = nlohmann::json;
+
+    int main()
+    {
+        json j = true;
+
+        std::tuple<json> t(std::forward_as_tuple(j));
+        // std::get<0>(t) is true -- a copy of j
+
+        std::tuple<const json&> r(std::forward_as_tuple(j));
+        // std::get<0>(r) refers to j
+    }
+    ```
+
+## See also
+
+- [**basic_json(CompatibleType&&)**](../basic_json/basic_json.md) - the affected constructor
+- [:simple-cmake: JSON_DisableTupleReferenceConversion](../../integration/cmake.md#json_disabletuplereferenceconversion) -
+  CMake option to control the macro
+
+## Version history
+
+- Added in version 3.13.0.
@@ -90,7 +90,7 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
        | GNU 14.2.0                                   | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
        | GNU 15.1.0                                   | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
        | GNU 16.1.0                                   | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
-        | GNU 16.1.0                                   | arm64        | Ubuntu 24.04                      | GitHub    |
+        | GNU 16.1.0                                   | arm64        | Linux 6.1.100                     | Cirrus CI |
        | icpc (ICC) 2021.10.0 20230609                | x86_64       | Ubuntu 22.04 LTS                  | GitHub    |
        | icpx (Intel oneAPI DPC++/C++) 2025.3.2       | x86_64       | Ubuntu 24.04 LTS                  | GitHub    |
        | nvc++ (NVIDIA HPC SDK) 25.5-0                | x86_64       | Ubuntu 22.04 LTS                  | GitHub    |
@@ -132,8 +132,7 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
  [libstdc++](https://gcc.gnu.org/onlinedocs/libstdc++/) to detect subtle differences or incompatibilities.
 - [x] The code checked with [Include What You Use (IWYU)](https://include-what-you-use.org) that all required standard
  headers are included.
- [x] On Windows, the library is compiled with `<Windows.h>` being included to detect and avoid common bugs (see
-  [`unit-windows_h.cpp`](https://github.com/nlohmann/json/blob/develop/tests/src/unit-windows_h.cpp)).
+- [x] On Windows, the library is compiled with `<Windows.h>` being included to detect and avoid common bugs.
 - [x] The library is compiled with exceptions disabled to support alternative means of error handling.

 ## Stable public API
@@ -83,6 +83,13 @@ When defined, default parse and serialize functions for enums are excluded and h

 See [full documentation of `JSON_DISABLE_ENUM_SERIALIZATION`](../api/macros/json_disable_enum_serialization.md).

+## `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`
+
+When defined to `1`, a JSON value can no longer be created from a one-element `std::tuple` holding a reference to a JSON
+value, such as the result of `std::forward_as_tuple(j)`. This lets `std::tuple` convert such tuples element-wise.
+
+See [full documentation of `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../api/macros/json_disable_tuple_reference_conversion.md).
+
 ## `JSON_NO_AUTOMATIC_UDLS`

 When defined, `<nlohmann/json.hpp>` does not include `<nlohmann/json_literals.hpp>` with the user-defined string literals
@@ -169,6 +169,12 @@ Enable position diagnostics by defining macro [`JSON_DIAGNOSTIC_POSITIONS`](../a
 Disable default `enum` serialization by defining the macro
 [`JSON_DISABLE_ENUM_SERIALIZATION`](../api/macros/json_disable_enum_serialization.md). This option is `OFF` by default.

+### `JSON_DisableTupleReferenceConversion`
+
+Disable the conversion from a one-element `std::tuple` holding a reference to a JSON value by defining the macro
+[`JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../api/macros/json_disable_tuple_reference_conversion.md). This option is
+`OFF` by default.
+
 ### `JSON_FastTests`

 Skip expensive/slow test suites. This option is `OFF` by default. Depends on `JSON_BuildTests`.
@@ -287,6 +287,7 @@ nav:
          - 'JSON_DIAGNOSTICS': api/macros/json_diagnostics.md
          - 'JSON_DIAGNOSTIC_POSITIONS': api/macros/json_diagnostic_positions.md
          - 'JSON_DISABLE_ENUM_SERIALIZATION': api/macros/json_disable_enum_serialization.md
+          - 'JSON_DISABLE_TUPLE_REFERENCE_CONVERSION': api/macros/json_disable_tuple_reference_conversion.md
          - 'JSON_HAS_CPP_11, JSON_HAS_CPP_14, JSON_HAS_CPP_17, JSON_HAS_CPP_20': api/macros/json_has_cpp_11.md
          - 'JSON_HAS_EXPERIMENTAL_FILESYSTEM, JSON_HAS_FILESYSTEM': api/macros/json_has_filesystem.md
          - 'JSON_HAS_RANGES': api/macros/json_has_ranges.md
@@ -471,11 +471,13 @@ inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<
    j = { std::get<Idx>(t)... };
 }

-#if JSON_BRACE_INIT_COPY_SEMANTICS
-// JSON_BRACE_INIT_COPY_SEMANTICS makes a one-element braced list copy its
-// element instead of wrapping it, which would serialize std::tuple<int>{5} as 5
-// rather than [5]. Build what the default deduction builds instead: an object
-// if the element is a [string, value] pair, a one-element array otherwise.
+// A one-element braced list does not reliably wrap its element: with
+// JSON_BRACE_INIT_COPY_SEMANTICS it copies it, which would serialize
+// std::tuple<int>{5} as 5 rather than [5], and some compilers (e.g., Apple clang
+// 15 and 16) copy an element that is itself a basic_json even without it, so
+// std::tuple<json>{true} became true rather than [true]. Build what the default
+// deduction builds instead: an object if the element is a [string, value] pair,
+// a one-element array otherwise.
 template<typename BasicJsonType, typename Tuple>
 inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<0> /*unused*/)
 {
@@ -493,7 +495,6 @@ inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<
        j = BasicJsonType::array({std::move(element)});
    }
 }
-#endif

 template<typename BasicJsonType, typename Tuple>
 inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& /*unused*/, index_sequence<> /*unused*/)
@@ -915,3 +915,7 @@ void templated_json_throw(ExceptionType exception)
 #ifndef JSON_DISABLE_ENUM_SERIALIZATION
    #define JSON_DISABLE_ENUM_SERIALIZATION 0
 #endif
+
+#ifndef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+    #define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 0
+#endif
@@ -25,6 +25,7 @@
 #undef JSON_INLINE_VARIABLE
 #undef JSON_NO_UNIQUE_ADDRESS
 #undef JSON_DISABLE_ENUM_SERIALIZATION
+#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION

 #ifndef JSON_TEST_KEEP_MACROS
    #undef JSON_CATCH
@@ -636,6 +636,18 @@ template<typename BasicJsonType, typename CompatibleType>
 struct is_compatible_type
    : is_compatible_type_impl<BasicJsonType, CompatibleType> {};

+// a one-element std::tuple holding a reference to BasicJsonType, as created by
+// std::forward_as_tuple(j); see JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+template<typename BasicJsonType, typename T>
+struct is_basic_json_reference_tuple : std::false_type {};
+
+template<typename BasicJsonType, typename T>
+struct is_basic_json_reference_tuple<BasicJsonType, std::tuple<T>>
+{
+    static constexpr bool value =
+        std::is_reference<T>::value && std::is_same<uncvref_t<T>, BasicJsonType>::value;
+};
+
 template<typename BasicJsonType, typename CompatibleArrayType>
 struct is_compatible_binary_type
 {
@@ -29,9 +29,7 @@
 #endif

 #include <algorithm> // all_of, find, for_each, none_of
-#include <cmath> // isnan
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
-#include <cstdint> // uint8_t
 #include <functional> // hash, less
 #include <initializer_list> // initializer_list
 #ifndef JSON_NO_IO
@@ -40,28 +38,19 @@
 #include <iterator> // make_move_iterator, random_access_iterator_tag
 #include <limits> // numeric_limits
 #include <memory> // unique_ptr
-#include <set> // swap, operator!=
 #include <stdexcept> // length_error
 #include <string> // string, stoi, to_string
-#include <type_traits> // enable_if_t, is_same, is_scalar, ...
-#include <unordered_map> // swap (for the from_json(..., std::unordered_map&) overload)
 #include <utility> // declval, forward, move, pair, swap
 #include <vector> // vector

-// keep: json.hpp's own basic_json<> default template arguments need the complete definition of
-// each of these, not only the forward declarations from json_fwd.hpp, so IWYU's suggestion to
-// drop them (nothing in this file otherwise names the type) would break every downstream
-// translation unit that relies on basic_json<>'s defaults actually being usable.
-#include <nlohmann/adl_serializer.hpp> // IWYU pragma: keep
+#include <nlohmann/adl_serializer.hpp>
 #include <nlohmann/byte_container_with_subtype.hpp>
-#include <nlohmann/detail/abi_macros.hpp>
-#include <nlohmann/detail/conversions/from_json.hpp> // IWYU pragma: keep
-#include <nlohmann/detail/conversions/to_json.hpp> // IWYU pragma: keep
+#include <nlohmann/detail/conversions/from_json.hpp>
+#include <nlohmann/detail/conversions/to_json.hpp>
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/hash.hpp>
 #include <nlohmann/detail/input/binary_reader.hpp>
 #include <nlohmann/detail/input/input_adapters.hpp>
-#include <nlohmann/detail/input/json_sax.hpp>
 #include <nlohmann/detail/input/lexer.hpp>
 #include <nlohmann/detail/input/parser.hpp>
 #include <nlohmann/detail/iterators/internal_iterator.hpp>
@@ -73,7 +62,6 @@
 #include <nlohmann/detail/json_pointer.hpp>
 #include <nlohmann/detail/json_ref.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
-#include <nlohmann/detail/meta/detected.hpp>
 #include <nlohmann/detail/string_concat.hpp>
 #include <nlohmann/detail/string_escape.hpp>
 #include <nlohmann/detail/string_utils.hpp>
@@ -85,8 +73,7 @@
 #include <nlohmann/detail/recursion_depth_limit.hpp>
 #include <nlohmann/detail/value_t.hpp>
 #include <nlohmann/json_fwd.hpp>
-#include <nlohmann/ordered_map.hpp> // IWYU pragma: keep
-#include <nlohmann/thirdparty/hedley/hedley.hpp>
+#include <nlohmann/ordered_map.hpp>

 #if defined(JSON_HAS_CPP_17)
    #if JSON_HAS_STATIC_RTTI
@@ -919,11 +906,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /*!
    @brief how many levels the operation going on in this thread has descended into

-    Copying a value and comparing two values share this count. The library never
-    nests one inside the other - copying a value does not compare one, and
-    comparing two values does not copy them - and where user code nests them
-    anyway, sharing the count only ends a descent sooner than it had to, which
-    costs a little speed and is never wrong.
+    Copying a value, converting one from another specialization, and comparing
+    two values share this count. The library never nests one of them inside
+    another - none of them does either of the other two on the way - and where
+    user code nests them anyway, sharing the count only ends a descent sooner
+    than it had to, which costs a little speed and is never wrong.

    A byte is enough: the count never exceeds the limit by more than the single
    level that notices the limit has been reached.
@@ -1280,6 +1267,222 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        copy_iteratively(src);
    }

+    /*!
+    @brief convert the value @a val of another specialization into this null
+           value; @a val must be neither an object nor an array
+
+    Converting such a value never descends, so both ways of converting an
+    object or an array (@ref convert_structured) leave their elements of this
+    kind to the converting constructor, which leaves them to this.
+    */
+    template<typename BasicJsonType>
+    void convert_leaf(const BasicJsonType& val)
+    {
+        using other_boolean_t = typename BasicJsonType::boolean_t;
+        using other_number_float_t = typename BasicJsonType::number_float_t;
+        using other_number_integer_t = typename BasicJsonType::number_integer_t;
+        using other_number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+        using other_string_t = typename BasicJsonType::string_t;
+        using other_binary_t = typename BasicJsonType::binary_t;
+
+        switch (val.type())
+        {
+            case value_t::boolean:
+                JSONSerializer<other_boolean_t>::to_json(*this, val.template get<other_boolean_t>());
+                break;
+            case value_t::number_float:
+                JSONSerializer<other_number_float_t>::to_json(*this, val.template get<other_number_float_t>());
+                break;
+            case value_t::number_integer:
+                JSONSerializer<other_number_integer_t>::to_json(*this, val.template get<other_number_integer_t>());
+                break;
+            case value_t::number_unsigned:
+                JSONSerializer<other_number_unsigned_t>::to_json(*this, val.template get<other_number_unsigned_t>());
+                break;
+            case value_t::string:
+                JSONSerializer<other_string_t>::to_json(*this, val.template get_ref<const other_string_t&>());
+                break;
+            case value_t::binary:
+                JSONSerializer<other_binary_t>::to_json(*this, val.template get_ref<const other_binary_t&>());
+                break;
+            case value_t::null:
+                // m_data.m_type is already value_t::null
+                break;
+            case value_t::discarded:
+                m_data.m_type = value_t::discarded;
+                break;
+            case value_t::object: // LCOV_EXCL_LINE
+            case value_t::array:  // LCOV_EXCL_LINE
+            default:              // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+    }
+
+    /// scratch space for the converted elements of the arrays that
+    /// @ref convert_iteratively has yet to create
+    using convert_scratch_t = std::vector<basic_json, AllocatorType<basic_json>>;
+
+    /*!
+    @brief create the object or array @a val converted into this null value
+
+    Its converted elements are the last `val.size()` entries of @a elements (an
+    array) or of @a members (an object); they are moved into the container in
+    one go and then removed.
+    */
+    template<typename BasicJsonType>
+    void convert_level(const BasicJsonType& val, convert_scratch_t& elements, copy_scratch_t& members)
+    {
+        if (val.is_object())
+        {
+            const auto first = members.end() - static_cast<typename copy_scratch_t::difference_type>(val.size());
+            m_data.m_value.object = create<object_t>(std::make_move_iterator(first),
+                                    std::make_move_iterator(members.end()));
+            // only now that the object exists may this stop being a null value
+            m_data.m_type = value_t::object;
+            members.erase(first, members.end());
+        }
+        else
+        {
+            const auto first = elements.end() - static_cast<typename convert_scratch_t::difference_type>(val.size());
+            m_data.m_value.array = create<array_t>(std::make_move_iterator(first),
+                                                   std::make_move_iterator(elements.end()));
+            // only now that the array exists may this stop being a null value
+            m_data.m_type = value_t::array;
+            elements.erase(first, elements.end());
+        }
+
+        set_parents();
+    }
+
+    /*!
+    @brief convert the object or array @a val of another specialization into
+           this null value without recursing
+
+    The containers whose conversion has begun are kept on an explicit stack
+    rather than on the call stack. Unlike @ref copy_iteratively, this builds
+    every container from the bottom up: all its elements are converted first,
+    and the container is then created from them in one go, the way the range
+    constructor that converts the levels above the bound does. The two object
+    types need not enumerate their members in the same order, so the members
+    could not be paired up by position anyway, and building from a range keeps
+    what the range constructor does with keys that become equal on conversion.
+
+    Every value is complete before it is handed on, and a container gets its
+    type only once it exists, so whatever throws, every value left behind can
+    be destroyed.
+    */
+    template<typename BasicJsonType>
+    void convert_iteratively(const BasicJsonType& val)
+    {
+        using other_const_iterator = typename BasicJsonType::const_iterator;
+
+        // the containers whose conversion has begun, innermost last, each with
+        // its element to convert next
+        std::vector<std::pair<const BasicJsonType*, other_const_iterator>> pending;
+
+        // the converted elements of the pending arrays and the converted
+        // members of the pending objects, those of the innermost one last
+        convert_scratch_t elements;
+        copy_scratch_t members;
+
+        pending.emplace_back(&val, val.cbegin());
+
+        for (;;)
+        {
+            const BasicJsonType& container = *pending.back().first;
+            // a copy, as descending below can reallocate pending; the
+            // iterator kept in pending is only advanced through pending.back()
+            const other_const_iterator next = pending.back().second;
+
+            if (next != container.cend())
+            {
+                if (next->is_structured())
+                {
+                    // convert its elements first; next stays where it is until
+                    // the converted container is handed back to this one
+                    pending.emplace_back(&*next, next->cbegin());
+                    continue;
+                }
+
+                // the converting constructor does not descend into this value
+                if (container.is_object())
+                {
+                    members.emplace_back(next.key(), *next);
+                }
+                else
+                {
+                    elements.emplace_back(*next);
+                }
+                ++pending.back().second;
+                continue;
+            }
+
+            // all elements of the container are converted: create it
+            pending.pop_back();
+
+            if (pending.empty())
+            {
+                convert_level(container, elements, members);
+                return;
+            }
+
+            basic_json converted;
+            converted.convert_level(container, elements, members);
+#if JSON_DIAGNOSTIC_POSITIONS
+            converted.start_position = container.start_pos();
+            converted.end_position = container.end_pos();
+#endif
+
+            // hand it to the container it is an element of
+            if (pending.back().first->is_object())
+            {
+                members.emplace_back(pending.back().second.key(), std::move(converted));
+            }
+            else
+            {
+                elements.push_back(std::move(converted));
+            }
+            ++pending.back().second;
+        }
+    }
+
+    /*!
+    @brief convert the object or array @a val of another specialization into
+           this null value
+
+    Converting a container converts its elements, so a value nested deeply
+    enough used to exhaust the call stack. The descent is bounded here as in
+    @ref copy_structured: the first `detail::recursion_depth_limit()` levels
+    are converted by the containers' range constructors, just as they always were,
+    and anything below that is converted without the call stack by
+    @ref convert_iteratively.
+
+    @sa https://github.com/nlohmann/json/issues/5650
+    */
+    template<typename BasicJsonType>
+    void convert_structured(const BasicJsonType& val)
+    {
+        const nesting_depth_guard guard;
+
+        if (JSON_HEDLEY_LIKELY(guard.okay()))
+        {
+            // every element comes back to the converting constructor
+            if (val.is_object())
+            {
+                using other_object_t = typename BasicJsonType::object_t;
+                JSONSerializer<other_object_t>::to_json(*this, val.template get_ref<const other_object_t&>());
+            }
+            else
+            {
+                using other_array_t = typename BasicJsonType::array_t;
+                JSONSerializer<other_array_t>::to_json(*this, val.template get_ref<const other_array_t&>());
+            }
+            return;
+        }
+
+        convert_iteratively(val);
+    }
+

    /// the result of comparing two values, including values that cannot be
    /// ordered at all, such as a discarded value or a NaN
@@ -1609,7 +1812,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    template < typename CompatibleType,
               typename U = detail::uncvref_t<CompatibleType>,
               detail::enable_if_t <
-                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value, int > = 0 >
+                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value
+#if JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+                   // see https://github.com/nlohmann/json/issues/2226
+                   && !detail::is_basic_json_reference_tuple<basic_json_t, U>::value
+#endif
+                   , int > = 0 >
    basic_json(CompatibleType && val) noexcept(noexcept( // NOLINT(bugprone-forwarding-reference-overload,bugprone-exception-escape)
                JSONSerializer<U>::to_json(std::declval<basic_json_t&>(),
                                           std::forward<CompatibleType>(val))))
@@ -1630,49 +1838,13 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
          end_position(val.end_pos())
 #endif
    {
-        using other_boolean_t = typename BasicJsonType::boolean_t;
-        using other_number_float_t = typename BasicJsonType::number_float_t;
-        using other_number_integer_t = typename BasicJsonType::number_integer_t;
-        using other_number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-        using other_string_t = typename BasicJsonType::string_t;
-        using other_object_t = typename BasicJsonType::object_t;
-        using other_array_t = typename BasicJsonType::array_t;
-        using other_binary_t = typename BasicJsonType::binary_t;
-
-        switch (val.type())
+        if (val.is_structured())
        {
-            case value_t::boolean:
-                JSONSerializer<other_boolean_t>::to_json(*this, val.template get<other_boolean_t>());
-                break;
-            case value_t::number_float:
-                JSONSerializer<other_number_float_t>::to_json(*this, val.template get<other_number_float_t>());
-                break;
-            case value_t::number_integer:
-                JSONSerializer<other_number_integer_t>::to_json(*this, val.template get<other_number_integer_t>());
-                break;
-            case value_t::number_unsigned:
-                JSONSerializer<other_number_unsigned_t>::to_json(*this, val.template get<other_number_unsigned_t>());
-                break;
-            case value_t::string:
-                JSONSerializer<other_string_t>::to_json(*this, val.template get_ref<const other_string_t&>());
-                break;
-            case value_t::object:
-                JSONSerializer<other_object_t>::to_json(*this, val.template get_ref<const other_object_t&>());
-                break;
-            case value_t::array:
-                JSONSerializer<other_array_t>::to_json(*this, val.template get_ref<const other_array_t&>());
-                break;
-            case value_t::binary:
-                JSONSerializer<other_binary_t>::to_json(*this, val.template get_ref<const other_binary_t&>());
-                break;
-            case value_t::null:
-                *this = nullptr;
-                break;
-            case value_t::discarded:
-                m_data.m_type = value_t::discarded;
-                break;
-            default:            // LCOV_EXCL_LINE
-                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+            convert_structured(val);
+        }
+        else
+        {
+            convert_leaf(val);
        }
        JSON_ASSERT(m_data.m_type == val.type());

@@ -6630,10 +6802,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c

 }  // namespace std

-// keep: undoes the macros defined via detail/macro_scope.hpp at the top of this file; removing it
-// (nothing in this file *uses* a symbol from it) would leak JSON_* macros into every translation
-// unit that includes this header.
-#include <nlohmann/detail/macro_unscope.hpp> // IWYU pragma: keep
+#include <nlohmann/detail/macro_unscope.hpp>

 // End of GCC diagnostic pragmas for C++ modules support
 #if defined(__GNUC__) && !defined(__clang__) && __cplusplus >= 202002L
@@ -11,7 +11,8 @@

 #include <cstdint> // int64_t, uint64_t
 #include <map> // map
-#include <string> // allocator, string
+#include <memory> // allocator
+#include <string> // string
 #include <vector> // vector

 #include <nlohmann/detail/abi_macros.hpp>
@@ -31,7 +32,7 @@ This serializer ignores the template arguments and uses ADL
 for serialization.
 */
 template<typename T = void, typename SFINAE = void>
-struct adl_serializer; // IWYU pragma: keep
+struct adl_serializer;

 /// a class to store JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/
@@ -47,12 +48,12 @@ template<template<typename U, typename V, typename... Args> class ObjectType =
         adl_serializer,
         class BinaryType = std::vector<std::uint8_t>, // cppcheck-suppress syntaxError
         class CustomBaseClass = void>
-class basic_json; // IWYU pragma: keep
+class basic_json;

 /// @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
+class json_pointer;

 /*!
@brief default specialization
@@ -63,7 +64,7 @@ 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
+struct ordered_map;

 /// @brief specialization that maintains the insertion order of object keys
 /// @sa https://json.nlohmann.me/api/ordered_json/
@@ -12,14 +12,13 @@
 #include <functional> // equal_to, less
 #include <initializer_list> // initializer_list
 #include <iterator> // input_iterator_tag, iterator_traits
-#include <new> // for operator new (placement new)
+#include <memory> // allocator
 #include <stdexcept> // for out_of_range
 #include <tuple> // forward_as_tuple
 #include <type_traits> // enable_if, integral_constant, is_convertible, is_nothrow_move_constructible
 #include <utility> // forward, move, pair, piecewise_construct
-#include <vector> // vector, allocator
+#include <vector> // vector

-#include <nlohmann/detail/abi_macros.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>

@@ -29,9 +29,7 @@
 #endif

 #include <algorithm> // all_of, find, for_each, none_of
-#include <cmath> // isnan
 #include <cstddef> // nullptr_t, ptrdiff_t, size_t
-#include <cstdint> // uint8_t
 #include <functional> // hash, less
 #include <initializer_list> // initializer_list
 #ifndef JSON_NO_IO
@@ -40,18 +38,11 @@
 #include <iterator> // make_move_iterator, random_access_iterator_tag
 #include <limits> // numeric_limits
 #include <memory> // unique_ptr
-#include <set> // swap, operator!=
 #include <stdexcept> // length_error
 #include <string> // string, stoi, to_string
-#include <type_traits> // enable_if_t, is_same, is_scalar, ...
-#include <unordered_map> // swap (for the from_json(..., std::unordered_map&) overload)
 #include <utility> // declval, forward, move, pair, swap
 #include <vector> // vector

-// keep: json.hpp's own basic_json<> default template arguments need the complete definition of
-// each of these, not only the forward declarations from json_fwd.hpp, so IWYU's suggestion to
-// drop them (nothing in this file otherwise names the type) would break every downstream
-// translation unit that relies on basic_json<>'s defaults actually being usable.
 // #include <nlohmann/adl_serializer.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -3338,6 +3329,10 @@ void templated_json_throw(ExceptionType exception)
    #define JSON_DISABLE_ENUM_SERIALIZATION 0
 #endif

+#ifndef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+    #define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 0
+#endif
+
 #if JSON_HAS_THREE_WAY_COMPARISON
    #include <compare> // partial_ordering
 #endif
@@ -3980,7 +3975,8 @@ NLOHMANN_JSON_NAMESPACE_END

    #include <cstdint> // int64_t, uint64_t
    #include <map> // map
-    #include <string> // allocator, string
+    #include <memory> // allocator
+    #include <string> // string
    #include <vector> // vector

    // #include <nlohmann/detail/abi_macros.hpp>
@@ -4001,7 +3997,7 @@ NLOHMANN_JSON_NAMESPACE_END
    for serialization.
    */
    template<typename T = void, typename SFINAE = void>
-    struct adl_serializer; // IWYU pragma: keep
+    struct adl_serializer;

    /// a class to store JSON values
    /// @sa https://json.nlohmann.me/api/basic_json/
@@ -4017,12 +4013,12 @@ NLOHMANN_JSON_NAMESPACE_END
    adl_serializer,
    class BinaryType = std::vector<std::uint8_t>, // cppcheck-suppress syntaxError
    class CustomBaseClass = void>
-    class basic_json; // IWYU pragma: keep
+    class basic_json;

    /// @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
+    class json_pointer;

    /*!
    @brief default specialization
@@ -4033,7 +4029,7 @@ NLOHMANN_JSON_NAMESPACE_END
    /// @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
+    struct ordered_map;

    /// @brief specialization that maintains the insertion order of object keys
    /// @sa https://json.nlohmann.me/api/ordered_json/
@@ -4652,6 +4648,18 @@ template<typename BasicJsonType, typename CompatibleType>
 struct is_compatible_type
    : is_compatible_type_impl<BasicJsonType, CompatibleType> {};

+// a one-element std::tuple holding a reference to BasicJsonType, as created by
+// std::forward_as_tuple(j); see JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+template<typename BasicJsonType, typename T>
+struct is_basic_json_reference_tuple : std::false_type {};
+
+template<typename BasicJsonType, typename T>
+struct is_basic_json_reference_tuple<BasicJsonType, std::tuple<T>>
+{
+    static constexpr bool value =
+        std::is_reference<T>::value && std::is_same<uncvref_t<T>, BasicJsonType>::value;
+};
+
 template<typename BasicJsonType, typename CompatibleArrayType>
 struct is_compatible_binary_type
 {
@@ -7010,11 +7018,13 @@ inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<
    j = { std::get<Idx>(t)... };
 }

-#if JSON_BRACE_INIT_COPY_SEMANTICS
-// JSON_BRACE_INIT_COPY_SEMANTICS makes a one-element braced list copy its
-// element instead of wrapping it, which would serialize std::tuple<int>{5} as 5
-// rather than [5]. Build what the default deduction builds instead: an object
-// if the element is a [string, value] pair, a one-element array otherwise.
+// A one-element braced list does not reliably wrap its element: with
+// JSON_BRACE_INIT_COPY_SEMANTICS it copies it, which would serialize
+// std::tuple<int>{5} as 5 rather than [5], and some compilers (e.g., Apple clang
+// 15 and 16) copy an element that is itself a basic_json even without it, so
+// std::tuple<json>{true} became true rather than [true]. Build what the default
+// deduction builds instead: an object if the element is a [string, value] pair,
+// a one-element array otherwise.
 template<typename BasicJsonType, typename Tuple>
 inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<0> /*unused*/)
 {
@@ -7032,7 +7042,6 @@ inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& t, index_sequence<
        j = BasicJsonType::array({std::move(element)});
    }
 }
-#endif

 template<typename BasicJsonType, typename Tuple>
 inline void to_json_tuple_impl(BasicJsonType& j, const Tuple& /*unused*/, index_sequence<> /*unused*/)
@@ -7137,7 +7146,7 @@ struct adl_serializer
 };

 NLOHMANN_JSON_NAMESPACE_END
-// IWYU pragma: keep
+
 // #include <nlohmann/byte_container_with_subtype.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -7244,12 +7253,10 @@ class byte_container_with_subtype : public BinaryType

 NLOHMANN_JSON_NAMESPACE_END

-// #include <nlohmann/detail/abi_macros.hpp>
-
 // #include <nlohmann/detail/conversions/from_json.hpp>
-// IWYU pragma: keep
+
 // #include <nlohmann/detail/conversions/to_json.hpp>
-// IWYU pragma: keep
+
 // #include <nlohmann/detail/exceptions.hpp>

 // #include <nlohmann/detail/hash.hpp>
@@ -17898,8 +17905,6 @@ NLOHMANN_JSON_NAMESPACE_END

 // #include <nlohmann/detail/input/input_adapters.hpp>

-// #include <nlohmann/detail/input/json_sax.hpp>
-
 // #include <nlohmann/detail/input/lexer.hpp>

 // #include <nlohmann/detail/input/parser.hpp>
@@ -20881,8 +20886,6 @@ NLOHMANN_JSON_NAMESPACE_END

 // #include <nlohmann/detail/macro_scope.hpp>

-// #include <nlohmann/detail/meta/detected.hpp>
-
 // #include <nlohmann/detail/string_concat.hpp>

 // #include <nlohmann/detail/string_escape.hpp>
@@ -26574,14 +26577,12 @@ NLOHMANN_JSON_NAMESPACE_END
 #include <functional> // equal_to, less
 #include <initializer_list> // initializer_list
 #include <iterator> // input_iterator_tag, iterator_traits
-#include <new> // for operator new (placement new)
+#include <memory> // allocator
 #include <stdexcept> // for out_of_range
 #include <tuple> // forward_as_tuple
 #include <type_traits> // enable_if, integral_constant, is_convertible, is_nothrow_move_constructible
 #include <utility> // forward, move, pair, piecewise_construct
-#include <vector> // vector, allocator
-
-// #include <nlohmann/detail/abi_macros.hpp>
+#include <vector> // vector

 // #include <nlohmann/detail/macro_scope.hpp>

@@ -27016,8 +27017,6 @@ private:
 };

 NLOHMANN_JSON_NAMESPACE_END
-// IWYU pragma: keep
-// #include <nlohmann/thirdparty/hedley/hedley.hpp>


 #if defined(JSON_HAS_CPP_17)
@@ -27851,11 +27850,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /*!
    @brief how many levels the operation going on in this thread has descended into

-    Copying a value and comparing two values share this count. The library never
-    nests one inside the other - copying a value does not compare one, and
-    comparing two values does not copy them - and where user code nests them
-    anyway, sharing the count only ends a descent sooner than it had to, which
-    costs a little speed and is never wrong.
+    Copying a value, converting one from another specialization, and comparing
+    two values share this count. The library never nests one of them inside
+    another - none of them does either of the other two on the way - and where
+    user code nests them anyway, sharing the count only ends a descent sooner
+    than it had to, which costs a little speed and is never wrong.

    A byte is enough: the count never exceeds the limit by more than the single
    level that notices the limit has been reached.
@@ -28212,6 +28211,222 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        copy_iteratively(src);
    }

+    /*!
+    @brief convert the value @a val of another specialization into this null
+           value; @a val must be neither an object nor an array
+
+    Converting such a value never descends, so both ways of converting an
+    object or an array (@ref convert_structured) leave their elements of this
+    kind to the converting constructor, which leaves them to this.
+    */
+    template<typename BasicJsonType>
+    void convert_leaf(const BasicJsonType& val)
+    {
+        using other_boolean_t = typename BasicJsonType::boolean_t;
+        using other_number_float_t = typename BasicJsonType::number_float_t;
+        using other_number_integer_t = typename BasicJsonType::number_integer_t;
+        using other_number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+        using other_string_t = typename BasicJsonType::string_t;
+        using other_binary_t = typename BasicJsonType::binary_t;
+
+        switch (val.type())
+        {
+            case value_t::boolean:
+                JSONSerializer<other_boolean_t>::to_json(*this, val.template get<other_boolean_t>());
+                break;
+            case value_t::number_float:
+                JSONSerializer<other_number_float_t>::to_json(*this, val.template get<other_number_float_t>());
+                break;
+            case value_t::number_integer:
+                JSONSerializer<other_number_integer_t>::to_json(*this, val.template get<other_number_integer_t>());
+                break;
+            case value_t::number_unsigned:
+                JSONSerializer<other_number_unsigned_t>::to_json(*this, val.template get<other_number_unsigned_t>());
+                break;
+            case value_t::string:
+                JSONSerializer<other_string_t>::to_json(*this, val.template get_ref<const other_string_t&>());
+                break;
+            case value_t::binary:
+                JSONSerializer<other_binary_t>::to_json(*this, val.template get_ref<const other_binary_t&>());
+                break;
+            case value_t::null:
+                // m_data.m_type is already value_t::null
+                break;
+            case value_t::discarded:
+                m_data.m_type = value_t::discarded;
+                break;
+            case value_t::object: // LCOV_EXCL_LINE
+            case value_t::array:  // LCOV_EXCL_LINE
+            default:              // LCOV_EXCL_LINE
+                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+        }
+    }
+
+    /// scratch space for the converted elements of the arrays that
+    /// @ref convert_iteratively has yet to create
+    using convert_scratch_t = std::vector<basic_json, AllocatorType<basic_json>>;
+
+    /*!
+    @brief create the object or array @a val converted into this null value
+
+    Its converted elements are the last `val.size()` entries of @a elements (an
+    array) or of @a members (an object); they are moved into the container in
+    one go and then removed.
+    */
+    template<typename BasicJsonType>
+    void convert_level(const BasicJsonType& val, convert_scratch_t& elements, copy_scratch_t& members)
+    {
+        if (val.is_object())
+        {
+            const auto first = members.end() - static_cast<typename copy_scratch_t::difference_type>(val.size());
+            m_data.m_value.object = create<object_t>(std::make_move_iterator(first),
+                                    std::make_move_iterator(members.end()));
+            // only now that the object exists may this stop being a null value
+            m_data.m_type = value_t::object;
+            members.erase(first, members.end());
+        }
+        else
+        {
+            const auto first = elements.end() - static_cast<typename convert_scratch_t::difference_type>(val.size());
+            m_data.m_value.array = create<array_t>(std::make_move_iterator(first),
+                                                   std::make_move_iterator(elements.end()));
+            // only now that the array exists may this stop being a null value
+            m_data.m_type = value_t::array;
+            elements.erase(first, elements.end());
+        }
+
+        set_parents();
+    }
+
+    /*!
+    @brief convert the object or array @a val of another specialization into
+           this null value without recursing
+
+    The containers whose conversion has begun are kept on an explicit stack
+    rather than on the call stack. Unlike @ref copy_iteratively, this builds
+    every container from the bottom up: all its elements are converted first,
+    and the container is then created from them in one go, the way the range
+    constructor that converts the levels above the bound does. The two object
+    types need not enumerate their members in the same order, so the members
+    could not be paired up by position anyway, and building from a range keeps
+    what the range constructor does with keys that become equal on conversion.
+
+    Every value is complete before it is handed on, and a container gets its
+    type only once it exists, so whatever throws, every value left behind can
+    be destroyed.
+    */
+    template<typename BasicJsonType>
+    void convert_iteratively(const BasicJsonType& val)
+    {
+        using other_const_iterator = typename BasicJsonType::const_iterator;
+
+        // the containers whose conversion has begun, innermost last, each with
+        // its element to convert next
+        std::vector<std::pair<const BasicJsonType*, other_const_iterator>> pending;
+
+        // the converted elements of the pending arrays and the converted
+        // members of the pending objects, those of the innermost one last
+        convert_scratch_t elements;
+        copy_scratch_t members;
+
+        pending.emplace_back(&val, val.cbegin());
+
+        for (;;)
+        {
+            const BasicJsonType& container = *pending.back().first;
+            // a copy, as descending below can reallocate pending; the
+            // iterator kept in pending is only advanced through pending.back()
+            const other_const_iterator next = pending.back().second;
+
+            if (next != container.cend())
+            {
+                if (next->is_structured())
+                {
+                    // convert its elements first; next stays where it is until
+                    // the converted container is handed back to this one
+                    pending.emplace_back(&*next, next->cbegin());
+                    continue;
+                }
+
+                // the converting constructor does not descend into this value
+                if (container.is_object())
+                {
+                    members.emplace_back(next.key(), *next);
+                }
+                else
+                {
+                    elements.emplace_back(*next);
+                }
+                ++pending.back().second;
+                continue;
+            }
+
+            // all elements of the container are converted: create it
+            pending.pop_back();
+
+            if (pending.empty())
+            {
+                convert_level(container, elements, members);
+                return;
+            }
+
+            basic_json converted;
+            converted.convert_level(container, elements, members);
+#if JSON_DIAGNOSTIC_POSITIONS
+            converted.start_position = container.start_pos();
+            converted.end_position = container.end_pos();
+#endif
+
+            // hand it to the container it is an element of
+            if (pending.back().first->is_object())
+            {
+                members.emplace_back(pending.back().second.key(), std::move(converted));
+            }
+            else
+            {
+                elements.push_back(std::move(converted));
+            }
+            ++pending.back().second;
+        }
+    }
+
+    /*!
+    @brief convert the object or array @a val of another specialization into
+           this null value
+
+    Converting a container converts its elements, so a value nested deeply
+    enough used to exhaust the call stack. The descent is bounded here as in
+    @ref copy_structured: the first `detail::recursion_depth_limit()` levels
+    are converted by the containers' range constructors, just as they always were,
+    and anything below that is converted without the call stack by
+    @ref convert_iteratively.
+
+    @sa https://github.com/nlohmann/json/issues/5650
+    */
+    template<typename BasicJsonType>
+    void convert_structured(const BasicJsonType& val)
+    {
+        const nesting_depth_guard guard;
+
+        if (JSON_HEDLEY_LIKELY(guard.okay()))
+        {
+            // every element comes back to the converting constructor
+            if (val.is_object())
+            {
+                using other_object_t = typename BasicJsonType::object_t;
+                JSONSerializer<other_object_t>::to_json(*this, val.template get_ref<const other_object_t&>());
+            }
+            else
+            {
+                using other_array_t = typename BasicJsonType::array_t;
+                JSONSerializer<other_array_t>::to_json(*this, val.template get_ref<const other_array_t&>());
+            }
+            return;
+        }
+
+        convert_iteratively(val);
+    }
+

    /// the result of comparing two values, including values that cannot be
    /// ordered at all, such as a discarded value or a NaN
@@ -28541,7 +28756,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    template < typename CompatibleType,
               typename U = detail::uncvref_t<CompatibleType>,
               detail::enable_if_t <
-                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value, int > = 0 >
+                   !detail::is_basic_json<U>::value && detail::is_compatible_type<basic_json_t, U>::value
+#if JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+                   // see https://github.com/nlohmann/json/issues/2226
+                   && !detail::is_basic_json_reference_tuple<basic_json_t, U>::value
+#endif
+                   , int > = 0 >
    basic_json(CompatibleType && val) noexcept(noexcept( // NOLINT(bugprone-forwarding-reference-overload,bugprone-exception-escape)
            JSONSerializer<U>::to_json(std::declval<basic_json_t&>(),
                                       std::forward<CompatibleType>(val))))
@@ -28562,49 +28782,13 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
          end_position(val.end_pos())
 #endif
    {
-        using other_boolean_t = typename BasicJsonType::boolean_t;
-        using other_number_float_t = typename BasicJsonType::number_float_t;
-        using other_number_integer_t = typename BasicJsonType::number_integer_t;
-        using other_number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-        using other_string_t = typename BasicJsonType::string_t;
-        using other_object_t = typename BasicJsonType::object_t;
-        using other_array_t = typename BasicJsonType::array_t;
-        using other_binary_t = typename BasicJsonType::binary_t;
-
-        switch (val.type())
+        if (val.is_structured())
        {
-            case value_t::boolean:
-                JSONSerializer<other_boolean_t>::to_json(*this, val.template get<other_boolean_t>());
-                break;
-            case value_t::number_float:
-                JSONSerializer<other_number_float_t>::to_json(*this, val.template get<other_number_float_t>());
-                break;
-            case value_t::number_integer:
-                JSONSerializer<other_number_integer_t>::to_json(*this, val.template get<other_number_integer_t>());
-                break;
-            case value_t::number_unsigned:
-                JSONSerializer<other_number_unsigned_t>::to_json(*this, val.template get<other_number_unsigned_t>());
-                break;
-            case value_t::string:
-                JSONSerializer<other_string_t>::to_json(*this, val.template get_ref<const other_string_t&>());
-                break;
-            case value_t::object:
-                JSONSerializer<other_object_t>::to_json(*this, val.template get_ref<const other_object_t&>());
-                break;
-            case value_t::array:
-                JSONSerializer<other_array_t>::to_json(*this, val.template get_ref<const other_array_t&>());
-                break;
-            case value_t::binary:
-                JSONSerializer<other_binary_t>::to_json(*this, val.template get_ref<const other_binary_t&>());
-                break;
-            case value_t::null:
-                *this = nullptr;
-                break;
-            case value_t::discarded:
-                m_data.m_type = value_t::discarded;
-                break;
-            default:            // LCOV_EXCL_LINE
-                JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
+            convert_structured(val);
+        }
+        else
+        {
+            convert_leaf(val);
        }
        JSON_ASSERT(m_data.m_type == val.type());

@@ -33562,9 +33746,6 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c

 }  // namespace std

-// keep: undoes the macros defined via detail/macro_scope.hpp at the top of this file; removing it
-// (nothing in this file *uses* a symbol from it) would leak JSON_* macros into every translation
-// unit that includes this header.
 // #include <nlohmann/detail/macro_unscope.hpp>
 //     __ _____ _____ _____
 //  __|  |   __|     |   | |  JSON for Modern C++
@@ -33593,6 +33774,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
 #undef JSON_INLINE_VARIABLE
 #undef JSON_NO_UNIQUE_ADDRESS
 #undef JSON_DISABLE_ENUM_SERIALIZATION
+#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION

 #ifndef JSON_TEST_KEEP_MACROS
    #undef JSON_CATCH
@@ -33778,7 +33960,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
 #undef JSON_HEDLEY_WARN_UNUSED_RESULT_MSG
 #undef JSON_HEDLEY_FALL_THROUGH

-// IWYU pragma: keep
+

 // End of GCC diagnostic pragmas for C++ modules support
 #if defined(__GNUC__) && !defined(__clang__) && __cplusplus >= 202002L
@@ -11,7 +11,8 @@

 #include <cstdint> // int64_t, uint64_t
 #include <map> // map
-#include <string> // allocator, string
+#include <memory> // allocator
+#include <string> // string
 #include <vector> // vector

 // #include <nlohmann/detail/abi_macros.hpp>
@@ -176,7 +177,7 @@ This serializer ignores the template arguments and uses ADL
 for serialization.
 */
 template<typename T = void, typename SFINAE = void>
-struct adl_serializer; // IWYU pragma: keep
+struct adl_serializer;

 /// a class to store JSON values
 /// @sa https://json.nlohmann.me/api/basic_json/
@@ -192,12 +193,12 @@ template<template<typename U, typename V, typename... Args> class ObjectType =
         adl_serializer,
         class BinaryType = std::vector<std::uint8_t>, // cppcheck-suppress syntaxError
         class CustomBaseClass = void>
-class basic_json; // IWYU pragma: keep
+class basic_json;

 /// @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
+class json_pointer;

 /*!
@brief default specialization
@@ -208,7 +209,7 @@ 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
+struct ordered_map;

 /// @brief specialization that maintains the insertion order of object keys
 /// @sa https://json.nlohmann.me/api/ordered_json/
@@ -479,6 +479,77 @@ TEST_CASE("deep copy uses the provided allocator")
    CHECK(copy == j);
 }

+namespace
+{
+// the number of constructions countdown_allocator lets happen, including the
+// one that fails; 0 means none ever fails
+std::size_t constructions_until_failure = 0;
+
+template<class T>
+struct countdown_allocator : std::allocator<T>
+{
+    using std::allocator<T>::allocator;
+
+    template<class U, class... Args>
+    void construct(U* p, Args&& ... args)
+    {
+        if (constructions_until_failure != 0 && --constructions_until_failure == 0)
+        {
+            throw std::bad_alloc();
+        }
+
+        ::new (static_cast<void*>(p)) U(std::forward<Args>(args)...);
+    }
+
+    template <class U>
+    struct rebind
+    {
+        using other = countdown_allocator<U>;
+    };
+};
+} // namespace
+
+TEST_CASE("converting a deeply nested value from another specialization fails cleanly (#5650)")
+{
+    using countdown_json = nlohmann::basic_json<std::map,
+          std::vector,
+          std::string,
+          bool,
+          std::int64_t,
+          std::uint64_t,
+          double,
+          countdown_allocator>;
+
+    // deeper than the 128 levels the converting constructor descends into, so
+    // that failures land on both sides of the bound - or, built with
+    // JSON_NO_THREAD_LOCAL, all in the iterative conversion
+    json j = {1, "two", {{"three", 3}}};
+    for (std::size_t i = 0; i < 150; ++i)
+    {
+        j = json{{"a", json::array({j, "sibling"})}};
+    }
+
+    // Fail every construction in turn. Each failure has to reach the caller,
+    // and everything built until then has to be destroyed cleanly.
+    std::size_t failures = 0;
+    for (std::size_t n = 1;; ++n)
+    {
+        constructions_until_failure = n;
+        try
+        {
+            const countdown_json converted = j;
+            constructions_until_failure = 0;
+            CHECK(converted.dump() == j.dump());
+            break;
+        }
+        catch (const std::bad_alloc&)
+        {
+            ++failures;
+        }
+    }
+    CHECK(failures > 0);
+}
+
 namespace
 {
 template<class T>
@@ -141,6 +141,58 @@ TEST_CASE("Better diagnostics with positions")
        check_objects(300);
    }

+    SECTION("converting keeps the positions of nested values (#5650)")
+    {
+        // Values nested deeper than the converting constructor's descent bound
+        // are converted without the call stack, on a path that has to carry the
+        // positions of every value over itself. Objects and arrays take turns,
+        // and the innermost value is null, which used to lose its positions.
+        const auto check_conversion = [](std::size_t depth)
+        {
+            CAPTURE(depth)
+
+            std::string text;
+            std::string closing;
+            for (std::size_t i = 0; i < depth; ++i)
+            {
+                text += (i % 2 == 0) ? "[12, " : R"({"b":1, "a":)";
+                closing += (i % 2 == 0) ? ']' : '}';
+            }
+            text += "null";
+            text.append(closing.rbegin(), closing.rend());
+
+            const json original = json::parse(text);
+            const nlohmann::ordered_json converted = original;
+
+            const json* o = &original;
+            const nlohmann::ordered_json* c = &converted;
+            for (std::size_t level = 0; level <= depth; ++level)
+            {
+                CAPTURE(level)
+                REQUIRE(c->start_pos() == o->start_pos());
+                REQUIRE(c->end_pos() == o->end_pos());
+
+                if (level < depth)
+                {
+                    // the number beside the value nested next
+                    const json& o_number = o->is_object() ? o->at("b") : o->at(0);
+                    const nlohmann::ordered_json& c_number = c->is_object() ? c->at("b") : c->at(0);
+                    REQUIRE(c_number.start_pos() == o_number.start_pos());
+                    REQUIRE(c_number.end_pos() == o_number.end_pos());
+
+                    o = o->is_object() ? &o->at("a") : &o->at(1);
+                    c = c->is_object() ? &c->at("a") : &c->at(1);
+                }
+            }
+        };
+
+        check_conversion(1);
+        check_conversion(127);
+        check_conversion(128);
+        check_conversion(129);
+        check_conversion(300);
+    }
+
    SECTION("JSON patch add to primitive parent (#4292)")
    {
        // the JSON Patch "add" target /foo/bar/baz has a string parent
@@ -341,6 +341,36 @@ TEST_CASE("Regression tests for extended diagnostics")
        }
    }

+    SECTION("Regression test for issue #5650 - converting keeps the parents of nested values")
+    {
+        // A value nested deeper than the converting constructor's descent bound
+        // is converted without the call stack. Every container that path creates
+        // has to have the parents of its children set, or the JSON Pointer in the
+        // diagnostic is cut short. Objects and arrays take turns.
+        const std::size_t pairs = 150;
+
+        json j = "not a number";
+        std::string pointer;
+        for (std::size_t i = 0; i < pairs; ++i)
+        {
+            j = json{{"a", json::array({j})}};
+            pointer += "/a/0";
+        }
+
+        const nlohmann::ordered_json converted = j;
+
+        const nlohmann::ordered_json* inner = &converted;
+        for (std::size_t i = 0; i < pairs; ++i)
+        {
+            inner = &inner->at("a").at(0);
+        }
+
+        std::string const expected = "[json.exception.type_error.302] (" + pointer + ") type must be number, but is string";
+        int i = 0;
+        CHECK_THROWS_WITH_AS(i = inner->get<int>(), expected.c_str(), nlohmann::ordered_json::type_error);
+        CHECK(i == 0);
+    }
+
    SECTION("Regression test for issue #5668 - wrong path for std::map/unordered_map with non-string keys")
    {
        // a map with non-string keys is read from an array of [key, value] arrays;
@@ -0,0 +1,93 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#include "doctest_compatibility.h"
+
+// This file tests the opt-in JSON_DISABLE_TUPLE_REFERENCE_CONVERSION, so it
+// defines the macro itself rather than relying on a -D flag, and runs in every
+// build.
+#ifdef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+    #undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
+#endif
+
+#define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 1
+
+#include <nlohmann/json.hpp>
+using nlohmann::json;
+using nlohmann::ordered_json;
+
+#include <string>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+// clang before 4 and GCC before 5 cannot create a std::tuple of basic_json
+// references at all, with or without JSON_DISABLE_TUPLE_REFERENCE_CONVERSION:
+// the tuple constructors make them instantiate basic_json's conversion operator
+// for libstdc++'s internal tuple bases, which fails hard
+#if (defined(__clang__) && __clang_major__ < 4) || (!defined(__clang__) && defined(__GNUC__) && __GNUC__ < 5)
+    #define SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+#endif
+
+TEST_CASE("JSON_DISABLE_TUPLE_REFERENCE_CONVERSION")
+{
+    SECTION("json is not constructible from a one-element tuple of a json reference")
+    {
+        CHECK_FALSE(std::is_constructible<json, std::tuple<json&>>::value);
+        CHECK_FALSE(std::is_constructible<json, std::tuple<const json&>>::value);
+        CHECK_FALSE(std::is_constructible < json, std::tuple < json && >>::value);
+        CHECK_FALSE(std::is_constructible<json, const std::tuple<json&>&>::value);
+        CHECK_FALSE(std::is_constructible<ordered_json, std::tuple<ordered_json&>>::value);
+    }
+
+#ifndef SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+    SECTION("issue #2226 - tuple<const json&> from tuple<json&> keeps the reference")
+    {
+        json j = true;
+        const std::tuple<const json&> tup(std::forward_as_tuple(j));
+        CHECK(&std::get<0>(tup) == &j);
+    }
+
+    SECTION("tuple<json> from tuple<json&> copies the element")
+    {
+        const json j = {{"key", "value"}};
+        const std::tuple<json> t1(std::forward_as_tuple(j));
+        CHECK(std::get<0>(t1) == j);
+
+        json j2 = "text";
+        const std::tuple<json> t2(std::forward_as_tuple(std::move(j2)));
+        CHECK(std::get<0>(t2) == "text");
+    }
+#endif
+
+    SECTION("other tuple conversions are not affected")
+    {
+        const json j = true;
+
+        // one-element tuple holding a json value
+        CHECK(json(std::make_tuple(j)) == json::array({true}));
+
+        // tuples with more than one element, even when holding references
+        int i = 1;
+#ifndef SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+        CHECK(json(std::forward_as_tuple(i, j)) == json::array({1, true}));
+        CHECK(json(std::forward_as_tuple(j, j)) == json::array({true, true}));
+#endif
+
+        // one-element tuples holding references to other types
+        std::string s = "text";
+        CHECK(json(std::forward_as_tuple(s)) == json::array({"text"}));
+        CHECK(json(std::forward_as_tuple(i)) == json::array({1}));
+
+#ifndef SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+        // a reference to a different basic_json specialization
+        ordered_json oj = true;
+        CHECK(json(std::forward_as_tuple(oj)) == json::array({true}));
+#endif
+    }
+}
@@ -13,6 +13,7 @@ using nlohmann::json;

 #include <algorithm>
 #include <string>
+#include <vector>

 TEST_CASE("tests on very large JSONs")
 {
@@ -53,6 +54,24 @@ const json* innermost_value(const json& j, std::size_t& depth)
    return current;
 }

+// The text of a value nested depth levels deep around the number 0. Level i is
+// an array if pattern[i % pattern.size()] is '[', and otherwise an object with
+// the single member "a", which every object type enumerates in the same order.
+std::string nested_text(std::size_t depth, const std::string& pattern)
+{
+    std::string text;
+    std::string closing;
+    for (std::size_t i = 0; i < depth; ++i)
+    {
+        const bool array = pattern[i % pattern.size()] == '[';
+        text += array ? "[" : "{\"a\":";
+        closing += array ? ']' : '}';
+    }
+    text += '0';
+    text.append(closing.rbegin(), closing.rend());
+    return text;
+}
+
 } // namespace

 TEST_CASE("tests on deeply nested JSONs")
@@ -224,5 +243,114 @@ TEST_CASE("tests on deeply nested JSONs")
            CHECK(*innermost_value(j, unused) == 0);
        }
    }
+
+    SECTION("issue #5650 - stack overflow converting between specializations")
+    {
+        const std::vector<std::string> patterns = {"[", "{", "[{"};
+
+        SECTION("json to ordered_json")
+        {
+            for (const auto& pattern : patterns)
+            {
+                CAPTURE(pattern);
+                const std::string text = nested_text(depth, pattern);
+                const json j = json::parse(text);
+
+                const nlohmann::ordered_json converted = j;
+                CHECK(converted.dump() == text);
+            }
+        }
+
+        SECTION("ordered_json to json")
+        {
+            for (const auto& pattern : patterns)
+            {
+                CAPTURE(pattern);
+                const std::string text = nested_text(depth, pattern);
+                const nlohmann::ordered_json o = nlohmann::ordered_json::parse(text);
+
+                const json converted = o;
+                CHECK(converted.dump() == text);
+            }
+        }
+
+        SECTION("get<ordered_json>()")
+        {
+            for (const auto& pattern : patterns)
+            {
+                CAPTURE(pattern);
+                const std::string text = nested_text(depth, pattern);
+                const json j = json::parse(text);
+
+                CHECK(j.get<nlohmann::ordered_json>().dump() == text);
+            }
+        }
+
+        SECTION("depths around the bound of the recursive descent")
+        {
+            for (std::size_t d = 1; d <= 300; ++d)
+            {
+                CAPTURE(d);
+                for (const auto& pattern : patterns)
+                {
+                    CAPTURE(pattern);
+                    const std::string text = nested_text(d, pattern);
+                    const json j = json::parse(text);
+
+                    const nlohmann::ordered_json converted = j;
+                    CHECK(converted.dump() == text);
+                    const json back = converted;
+                    CHECK(back.dump() == text);
+                }
+            }
+        }
+
+        SECTION("values below the bound are converted as values above it")
+        {
+            // Bury a value below the bound, where it is converted without the
+            // call stack, and compare it with the same value converted on its
+            // own by the containers' range constructors. Its objects have
+            // members that the two object types enumerate in different orders.
+            const auto bury = [](nlohmann::ordered_json value)
+            {
+                for (std::size_t i = 0; i < 200; ++i)
+                {
+                    value = nlohmann::ordered_json::array({std::move(value)});
+                }
+                return value;
+            };
+            const auto dig = [](const json & value)
+            {
+                const json* current = &value;
+                for (std::size_t i = 0; i < 200; ++i)
+                {
+                    current = &current->at(0);
+                }
+                return current;
+            };
+
+            nlohmann::ordered_json value = nlohmann::ordered_json::object();
+            value["z"] = {1, -2, 3U, 4.5, true, nullptr, "six", nlohmann::ordered_json::binary({7, 8}, 9),
+                          nlohmann::ordered_json::binary({10}), nlohmann::ordered_json::array(), nlohmann::ordered_json::object()
+                         };
+            value["y"] = {{"x", {{"w", 1}, {"v", 2}}}, {"u", {3, {{"t", 4}, {"s", 5}}}}};
+            value["r"] = nlohmann::ordered_json::array({nlohmann::ordered_json(nlohmann::ordered_json::value_t::discarded)});
+
+            const json converted_above = value;
+            const json buried = bury(value);
+            const json& converted_below = *dig(buried);
+
+            CHECK(converted_below.dump() == converted_above.dump());
+            CHECK(converted_below.at("z").at(7).get_binary().subtype() == 9);
+            CHECK_FALSE(converted_below.at("z").at(8).get_binary().has_subtype());
+            CHECK(converted_below.at("r").at(0).is_discarded());
+
+            // a discarded value is never equal to anything, so compare the rest
+            value.erase("r");
+            const json without_discarded_above = value;
+            const json without_discarded_buried = bury(value);
+            CHECK(*dig(without_discarded_buried) == without_discarded_above);
+        }
+    }
 }

@@ -18,6 +18,19 @@
 // for some reason including this after the json header leads to linker errors with VS 2017...
 #include <locale>

+// skip tests if JSON_DISABLE_TUPLE_REFERENCE_CONVERSION=1 (#2226)
+#if defined(JSON_DISABLE_TUPLE_REFERENCE_CONVERSION) && (JSON_DISABLE_TUPLE_REFERENCE_CONVERSION == 1)
+    #define SKIP_TESTS_FOR_TUPLE_REFERENCE_CONVERSION
+#endif
+
+// clang before 4 and GCC before 5 cannot create a std::tuple of basic_json
+// references at all, with or without JSON_DISABLE_TUPLE_REFERENCE_CONVERSION:
+// the tuple constructors make them instantiate basic_json's conversion operator
+// for libstdc++'s internal tuple bases, which fails hard
+#if (defined(__clang__) && __clang_major__ < 4) || (!defined(__clang__) && defined(__GNUC__) && __GNUC__ < 5)
+    #define SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+#endif
+
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using json = nlohmann::json;
@@ -28,6 +41,7 @@ using ordered_json = nlohmann::ordered_json;

 #include <cstdio>
 #include <list>
+#include <tuple>
 #include <type_traits>
 #include <utility>

@@ -542,6 +556,20 @@ TEST_CASE("regression tests 2")
                      )));
    }

+#ifndef SKIP_TESTS_FOR_TUPLE_REFERENCE_CONVERSION
+    SECTION("issue #2226 - std::tuple dangling reference - implicit conversion")
+    {
+        // by default, a one-element tuple holding a json reference converts to
+        // a one-element array; JSON_DISABLE_TUPLE_REFERENCE_CONVERSION removes
+        // this conversion (see unit-disable-tuple-reference-conversion.cpp)
+        const json j = true;
+        CHECK(std::is_constructible<json, std::tuple<const json&>>::value);
+#ifndef SKIP_TESTS_FOR_JSON_REFERENCE_TUPLES
+        CHECK(json(std::forward_as_tuple(j)) == json::array({true}));
+#endif
+    }
+#endif
+
    SECTION("PR #2181 - regression bug with lvalue")
    {
        // see https://github.com/nlohmann/json/pull/2181#issuecomment-653326060
@@ -7,22 +7,4 @@
 // SPDX-License-Identifier: MIT

 #define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
-
-// libc++ annotates std::mutex for Clang's thread safety analysis, so -Weverything
-// reports -Wthread-safety-negative for the locks in doctest's reporters, which are
-// only compiled in this file. __has_warning keeps older Clang versions from
-// reporting an unknown warning group.
-#if defined(__clang__) && defined(__has_warning)
-    #if __has_warning("-Wthread-safety-negative")
-        #pragma clang diagnostic push
-        #pragma clang diagnostic ignored "-Wthread-safety-negative"
-    #endif
-#endif
-
 #include "doctest_compatibility.h"
-
-#if defined(__clang__) && defined(__has_warning)
-    #if __has_warning("-Wthread-safety-negative")
-        #pragma clang diagnostic pop
-    #endif
-#endif
@@ -1,4 +1 @@
-# astyle is deliberately pinned: newer versions reformat the code, and this version
-# defines the formatting that `make amalgamate` produces and check_amalgamation.yml enforces.
-# Dependabot is told to ignore it in .github/dependabot.yml.
 astyle==3.4.13