Fix links to moved API pages in the API changes page

mkdocs --strict rejects links to pages that only exist as redirects. Also link operator<< to operator_ltlt.md and operator>> to operator_gtgt.md instead of the other way round. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Merge branch 'develop' into claude/todo-191-plan-508110
2026-10-10 08:27:13 +00:00 · 2026-10-10 07:42:37 +02:00 · 2026-10-10 04:01:42 +02:00 · 2026-10-04 17:35:55 +02:00 · 2026-09-30 20:36:12 +02:00 · 2026-09-28 22:22:46 +02:00
168 changed files with 74652 additions and 4093 deletions
@@ -108,16 +108,9 @@ The tests are located in [`tests/src/unit-*.cpp`](https://github.com/nlohmann/js
 are structured along the features of the library or the nature of the tests. Usually, it should be clear from the
 context which existing file needs to be extended, and only very few cases require creating new test files.

-When fixing a bug, edit `unit-regression3.cpp` and add a section referencing the fixed issue. Tests that need C++17 or
-C++20 go into `unit-regression3-cpp17.cpp` or `unit-regression3-cpp20.cpp` instead, so the large file is not rebuilt
-for every C++ standard. `unit-regression2.cpp` holds the older tests; the two files exist because a single one grew
-large enough for the MinGW linker to fail relocating it, so please keep adding to the smaller file rather than growing
-the larger one.
-
-To keep compile times down, several test files are compiled together as one translation unit. This sets a few rules
-for test files, such as giving file-scope helpers file-specific names. See the README in the
-[`tests`](https://github.com/nlohmann/json/tree/develop/tests) folder for how the tests are built and what to keep in
-mind when adding them.
+When fixing a bug, edit `unit-regression3.cpp` and add a section referencing the fixed issue.
+`unit-regression2.cpp` holds the older tests; the two files exist because a single one grew large enough for the
+MinGW linker to fail relocating it, so please keep adding to the smaller file rather than growing the larger one.

 #### Exceptions

@@ -0,0 +1,81 @@
+name: "Check API documentation"
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  check_api_docs:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        with:
+          egress-policy: audit
+
+      - name: Checkout pull request
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+
+      - name: Install clang
+        # Used only as a subprocess for `clang++ -E -v` system-include-path discovery in
+        # extract_api.py; it does not need to version-match the pinned libclang pip wheel
+        # below, which does the actual AST parsing. Do not "fix" this to be version-matched.
+        run: sudo apt-get update && sudo apt-get install -y clang
+
+      - name: Install Python dependencies
+        run: pip install -r tools/api_checker/requirements.txt
+
+      - name: Extract API and regenerate the committed surface file
+        run: |
+          python3 tools/api_checker/extract_api.py \
+            --header include/nlohmann/json.hpp \
+            --include include \
+            --output /tmp/api_snapshot.json \
+            --surface-output tools/api_checker/api_surface.json
+
+      - name: "Check API documentation (Phase 1: advisory)"
+        # Surfaces missing/broken @sa links without failing the job while the backlog from the
+        # initial AST-based rollout is burned down. See tools/api_checker/POLICY.md and the PR
+        # that introduced this workflow for the two-phase rollout plan.
+        continue-on-error: true
+        run: |
+          python3 tools/api_checker/check_docs.py \
+            --snapshot /tmp/api_snapshot.json
+
+      - name: Check macro documentation (advisory only)
+        # Cross-checks docs/mkdocs/docs/api/macros/ pages against #define sites. Only checks the
+        # documented-macro-still-exists direction; never blocks CI. See POLICY.md.
+        run: python3 tools/api_checker/check_macros.py
+
+      - name: Check for uncommitted API surface changes
+        id: diff
+        run: |
+          mkdir -p ${{ github.workspace }}/patch
+          git diff --patch --no-color -- tools/api_checker/api_surface.json > ${{ github.workspace }}/patch/api_surface.patch
+          if [ -s ${{ github.workspace }}/patch/api_surface.patch ]; then
+            echo "tools/api_checker/api_surface.json is out of date. Diff:"
+            cat ${{ github.workspace }}/patch/api_surface.patch
+            echo "has_diff=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "has_diff=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      # Uploaded so contributors can fix their PR with `git apply api_surface.patch`
+      # instead of installing libclang locally.
+      - name: Upload patch
+        if: steps.diff.outputs.has_diff == 'true'
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: api-surface-patch
+          path: patch/api_surface.patch
+
+      - name: Fail if API surface file is not up to date
+        # Unlike the doc-backlog check above, this is purely mechanical regeneration with no
+        # backlog to phase in -- blocking from the start, matching check_amalgamation.yml's
+        # precedent. Contributors who add/remove/rename public API must regenerate and commit
+        # tools/api_checker/api_surface.json as part of their PR.
+        if: steps.diff.outputs.has_diff == 'true'
+        run: exit 1
@@ -3,6 +3,7 @@
 *.gcno
 *.gcda
 .DS_Store
+__pycache__/

 /.idea
 /cmake-build-*
@@ -45,5 +46,9 @@ venv

 nlohmann_json.spdx

+# api_checker: ephemeral, location/doc-status-sensitive working file (not the committed
+# release-tracking artifact -- see tools/api_checker/api_surface.json for that)
+/tools/api_checker/api_snapshot.json
+
 # Bazel-related
 MODULE.bazel.lock
@@ -104,7 +104,7 @@ Thanks everyone!

 :books: If you want to **learn more** about how to use the library, check out the rest of the [**README**](#examples), have a look at [**code examples**](https://github.com/nlohmann/json/tree/develop/docs/mkdocs/docs/examples), or browse through the [**help pages**](https://json.nlohmann.me).

-:construction: If you want to understand the **API** better, check out the [**API Reference**](https://json.nlohmann.me/api/basic_json/) or have a look at the [quick reference](#quick-reference) below.
+:construction: If you want to understand the **API** better, check out the [**API Reference**](https://json.nlohmann.me/api/basic_json/) or have a look at the [quick reference](#quick-reference) below. The public API surface is derived mechanically and checked for documentation coverage by the tooling in [`tools/api_checker/`](tools/api_checker/), whose [POLICY.md](tools/api_checker/POLICY.md) defines what counts as public API and what stability is guaranteed.

 :bug: If you found a **bug**, please check the [**FAQ**](https://json.nlohmann.me/home/faq/) if it is a known issue or the result of a design decision. Please also have a look at the [**issue list**](https://github.com/nlohmann/json/issues) before you [**create a new issue**](https://github.com/nlohmann/json/issues/new/choose). Please provide as much information as possible to help us understand and reproduce your issue.

@@ -871,11 +871,11 @@ add_custom_target(ci_icpx
 # The following tests are excluded as they trigger known nvc++ 25.5 defects (not
 # library bugs); see https://github.com/nlohmann/json for tracking. Only the
 # affected language-standard variants are excluded so coverage is otherwise kept:
-#   - test-comparison-cpp20_cpp20, test-comparison_legacy-cpp20_cpp20
+#   - test-comparison_cpp20, test-comparison_legacy_cpp20
 #         miscompiles cross-type/<=> comparison (e.g. `-17 <= null`)
 #   - test-constructor1_cpp11
 #         std::initializer_list lifetime bug -> SIGSEGV
-#   - test-deserialization-cpp20_cpp20
+#   - test-deserialization_cpp20
 #         mangles the UTF-8 u8"" string literal in the char8_t (C++20) section
 add_custom_target(ci_nvhpc
    COMMAND ${CMAKE_COMMAND}
@@ -887,7 +887,7 @@ add_custom_target(ci_nvhpc
    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_nvhpc
    # the pipes are escaped so the surrounding shell passes them to ctest verbatim
    # instead of treating them as shell pipe operators
-    COMMAND cd ${PROJECT_BINARY_DIR}/build_nvhpc && ${CMAKE_CTEST_COMMAND} --parallel ${N} --exclude-regex "test-comparison-cpp20_cpp20\\|test-comparison_legacy-cpp20_cpp20\\|test-constructor1_cpp11\\|test-deserialization-cpp20_cpp20" --output-on-failure
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_nvhpc && ${CMAKE_CTEST_COMMAND} --parallel ${N} --exclude-regex "test-comparison_cpp20\\|test-comparison_legacy_cpp20\\|test-constructor1_cpp11\\|test-deserialization_cpp20" --output-on-failure
    COMMENT "Compile and test with NVIDIA HPC SDK (nvc++)"
 )

@@ -109,55 +109,6 @@ function(_json_test_apply_test_properties test_target properties_target)
    endif()
 endfunction()

-# for internal use by _json_test_add_test() and _json_test_add_unity_batch():
-# registers the CTest test <test_name>_cpp<cxx_standard> (plus its Valgrind
-# variant), which runs the executable target <test_target> with the arguments
-# in ARGN, and applies the test properties of the test- and standard-specific
-# interface targets
-function(_json_test_register_test test_name test_target cxx_standard)
-    set(ctest_name ${test_name}_cpp${cxx_standard})
-
-    if (JSON_FastTests)
-        add_test(NAME ${ctest_name}
-            COMMAND ${test_target} ${DOCTEST_TEST_FILTER} ${ARGN}
-            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-        )
-    else()
-        add_test(NAME ${ctest_name}
-            COMMAND ${test_target} ${DOCTEST_TEST_FILTER} ${ARGN} --no-skip
-            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-        )
-    endif()
-    set_tests_properties(${ctest_name} PROPERTIES LABELS "all" FIXTURES_REQUIRED TEST_DATA)
-
-    # apply standard-specific test properties
-    if(TARGET _json_test_interface__cpp_${cxx_standard})
-        _json_test_apply_test_properties(${ctest_name} _json_test_interface__cpp_${cxx_standard})
-    endif()
-
-    # apply test-specific test properties
-    if(TARGET _json_test_interface_${test_name})
-        _json_test_apply_test_properties(${ctest_name} _json_test_interface_${test_name})
-    endif()
-
-    # apply test- and standard-specific test properties
-    if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
-        _json_test_apply_test_properties(${ctest_name}
-            _json_test_interface_${test_name}_cpp_${cxx_standard}
-        )
-    endif()
-
-    if(JSON_Valgrind)
-        add_test(NAME ${ctest_name}_valgrind
-            COMMAND ${memcheck_command} $<TARGET_FILE:${test_target}> ${DOCTEST_TEST_FILTER} ${ARGN}
-            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-        )
-        set_tests_properties(${ctest_name}_valgrind PROPERTIES
-            LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA
-        )
-    endif()
-endfunction()
-
 # for internal use by json_test_add_test_for()
 function(_json_test_add_test test_name file main cxx_standard)
    set(test_target ${test_name}_cpp${cxx_standard})
@@ -192,7 +143,45 @@ function(_json_test_add_test test_name file main cxx_standard)
        )
    endif()

-    _json_test_register_test(${test_name} ${test_target} ${cxx_standard})
+    if (JSON_FastTests)
+        add_test(NAME ${test_target}
+            COMMAND ${test_target} ${DOCTEST_TEST_FILTER}
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        )
+    else()
+        add_test(NAME ${test_target}
+            COMMAND ${test_target} ${DOCTEST_TEST_FILTER} --no-skip
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        )
+    endif()
+    set_tests_properties(${test_target} PROPERTIES LABELS "all" FIXTURES_REQUIRED TEST_DATA)
+
+    # apply standard-specific test properties
+    if(TARGET _json_test_interface__cpp_${cxx_standard})
+        _json_test_apply_test_properties(${test_target} _json_test_interface__cpp_${cxx_standard})
+    endif()
+
+    # apply test-specific test properties
+    if(TARGET _json_test_interface_${test_name})
+        _json_test_apply_test_properties(${test_target} _json_test_interface_${test_name})
+    endif()
+
+    # apply test- and standard-specific test properties
+    if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
+        _json_test_apply_test_properties(${test_target}
+            _json_test_interface_${test_name}_cpp_${cxx_standard}
+        )
+    endif()
+
+    if(JSON_Valgrind)
+        add_test(NAME ${test_target}_valgrind
+            COMMAND ${memcheck_command} $<TARGET_FILE:${test_target}> ${DOCTEST_TEST_FILTER}
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        )
+        set_tests_properties(${test_target}_valgrind PROPERTIES
+            LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA
+        )
+    endif()
 endfunction()

 #############################################################################
@@ -211,14 +200,6 @@ endfunction()
 # Use NAME <name> to override the filename-derived test name.
 # Use FORCE to create the test regardless of the file containing
 # JSON_HAS_CPP_<version_number>.
-#
-# Tests that depend on the C++ standard (e.g., because they use the macros
-# JSON_HAS_FILESYSTEM, JSON_HAS_RANGES, or JSON_HAS_THREE_WAY_COMPARISON)
-# should not make the whole of a large unit-foo.cpp be rebuilt for every
-# standard. Put them into a separate file unit-foo-cpp<NN>.cpp (see, e.g.,
-# unit-items-cpp17.cpp) which wraps its content in #ifdef JSON_HAS_CPP_<NN>.
-# Then, unit-foo.cpp itself contains no JSON_HAS_CPP_<NN> and is only built for
-# C++11.
 # Test targets are linked against <main>.
 # CXX_STANDARDS defaults to "11".
 #############################################################################
@@ -262,314 +243,6 @@ function(json_test_add_test_for file)
    endforeach()
 endfunction()

-# for internal use by json_test_add_unity_tests(): sets <result> to whether the
-# (absolute) <file> is built for <cxx_standard>; same rule as in
-# json_test_add_test_for(): C++11 always, others only if the file contains
-# JSON_HAS_CPP_<cxx_standard> or <force> is set
-function(_json_test_unity_applies file cxx_standard force result)
-    set(${result} TRUE PARENT_SCOPE)
-    if(NOT ("${cxx_standard}" STREQUAL 11 OR force))
-        file(READ ${file} file_content)
-        string(FIND "${file_content}" JSON_HAS_CPP_${cxx_standard} has_cpp_found)
-        if(${has_cpp_found} EQUAL -1)
-            set(${result} FALSE PARENT_SCOPE)
-        endif()
-    endif()
-endfunction()
-
-# for internal use by json_test_add_unity_tests(): creates the executable
-# test-unity-<batch_name>_cpp<cxx_standard> from the (absolute) source files
-# in ARGN, which are #include-d by a generated source file, and registers one
-# CTest test per source file that runs only the test cases of that file; if
-# <private> is true, the generated file defines JSON_TESTS_PRIVATE first
-function(_json_test_add_unity_batch batch_name cxx_standard main private)
-    set(batch_target test-unity-${batch_name}_cpp${cxx_standard})
-    set(batch_source ${PROJECT_BINARY_DIR}/tests/unity/${batch_target}.cpp)
-
-    set(batch_content "// generated by cmake/test.cmake; do not edit\n")
-    if(private)
-        string(APPEND batch_content "// at least one file of this batch needs access to private members of the library\n")
-        string(APPEND batch_content "#define JSON_TESTS_PRIVATE\n")
-        # the files define the macro again; mark this definition as used, as
-        # -Wunused-macros reports an unused definition when it is redefined
-        string(APPEND batch_content "#ifdef JSON_TESTS_PRIVATE\n#endif\n")
-    endif()
-    foreach(file ${ARGN})
-        string(APPEND batch_content "#include \"${file}\" // NOLINT(bugprone-suspicious-include)\n")
-    endforeach()
-
-    # only touch the generated file if it changed to keep incremental builds incremental
-    set(old_content "")
-    if(EXISTS ${batch_source})
-        file(READ ${batch_source} old_content)
-    endif()
-    if(NOT "${old_content}" STREQUAL "${batch_content}")
-        file(WRITE ${batch_source} "${batch_content}")
-    endif()
-
-    add_executable(${batch_target} ${batch_source})
-    target_link_libraries(${batch_target} PRIVATE ${main})
-    set_target_properties(${batch_target} PROPERTIES
-        CXX_STANDARD ${cxx_standard}
-        CXX_STANDARD_REQUIRED ON
-    )
-    if(TARGET _json_test_interface__cpp_${cxx_standard})
-        target_link_libraries(${batch_target} PRIVATE _json_test_interface__cpp_${cxx_standard})
-    endif()
-
-    # rebuild the batch when one of its files changes, and show the files in IDEs;
-    # files that are also built standalone (VARIANT_FILES) are left out, as
-    # HEADER_FILE_ONLY is a per-file property and would also affect those targets
-    set_source_files_properties(${batch_source} PROPERTIES OBJECT_DEPENDS "${ARGN}")
-    foreach(file ${ARGN})
-        if(NOT file IN_LIST _json_test_unity_variant_files)
-            set_source_files_properties(${file} PROPERTIES HEADER_FILE_ONLY ON)
-            target_sources(${batch_target} PRIVATE ${file})
-        endif()
-    endforeach()
-
-    foreach(file ${ARGN})
-        get_filename_component(file_basename ${file} NAME_WE)
-        string(REGEX REPLACE "unit-(.+)" "test-\\1" test_name ${file_basename})
-
-        # run only the test cases defined in this file (and in the shared
-        # make_test_data_available.hpp if the file uses it)
-        file(READ ${file} file_content)
-        set(source_filter "--source-file=*${file_basename}.cpp")
-        string(FIND "${file_content}" make_test_data_available.hpp uses_test_data)
-        if(NOT ${uses_test_data} EQUAL -1)
-            string(APPEND source_filter ",*make_test_data_available.hpp")
-        endif()
-
-        _json_test_register_test(${test_name} ${batch_target} ${cxx_standard} "${source_filter}")
-    endforeach()
-endfunction()
-
-#############################################################################
-# json_test_add_unity_tests(
-#     FILES <files>...
-#     MAIN <main>
-#     [CXX_STANDARDS <version_number>...] [FORCE]
-#     [BATCH_SIZE <size>]
-#     [GROUPS <group>...]
-#     [VARIANT_FILES <files>...])
-#
-# Like calling json_test_add_test_for(<file> MAIN <main> ...) for each of the
-# <files>, but compiles several files together to speed up the build: for each
-# C++ standard, the files are split into batches of <size> files (default: 8)
-# and each batch is built as a single executable
-#
-#     test-unity-<pool><index>_cpp<version_number>
-#
-# whose generated source file #include-s the files of the batch (so they share
-# the template instantiations of the library). The tests are still named
-# test-foo_cpp<version_number>, one per file, but run the batch executable with
-# a doctest filter that selects the test cases of that file only.
-#
-# Files are only batched with files that agree on the macros defined before
-# the library is included: files that define at most JSON_TESTS_PRIVATE (or
-# macros derived from global compile definitions) form the pools "plain" and
-# "private". All other files are added with json_test_add_test_for() as usual,
-# as are files with test-specific build settings (see
-# json_test_set_test_options()) and the files listed in the explicit
-# exclusion list below.
-# Each <group> names a list variable json_test_unity_group_<group> of test file
-# stems (file names without "unit-" and ".cpp"). The batchable files of a group
-# are compiled together (regardless of BATCH_SIZE) as one executable
-#
-#     test-unity-<group>_cpp<version_number>
-#
-# so that related tests, which instantiate the same templates, share one
-# translation unit. A group may mix the pools "plain" and "private"; if any of
-# its files needs JSON_TESTS_PRIVATE, the whole group is built with it. Files
-# that cannot be batched stay standalone even if they are listed in a group.
-# Files in no group are batched by BATCH_SIZE as described above.
-# <files> in VARIANT_FILES are also built standalone with other settings, so
-# they are not marked as header-only sources of the batch.
-#############################################################################
-
-function(json_test_add_unity_tests)
-    cmake_parse_arguments(args "FORCE" "MAIN;BATCH_SIZE" "FILES;CXX_STANDARDS;VARIANT_FILES;GROUPS" ${ARGN})
-
-    if("${args_MAIN}" STREQUAL "")
-        message(FATAL_ERROR "Required argument MAIN <main> missing.")
-    endif()
-
-    if("${args_BATCH_SIZE}" STREQUAL "")
-        set(args_BATCH_SIZE 8)
-    endif()
-
-    if("${args_CXX_STANDARDS}" STREQUAL "")
-        set(args_CXX_STANDARDS 11)
-    endif()
-
-    if(args_FORCE)
-        set(force FORCE)
-    else()
-        set(force "")
-    endif()
-
-    set(_json_test_unity_variant_files "")
-    foreach(file ${args_VARIANT_FILES})
-        get_filename_component(file ${file} ABSOLUTE)
-        list(APPEND _json_test_unity_variant_files ${file})
-    endforeach()
-
-    # files that must not be merged into a batch: unit-32bit.cpp is only built
-    # for 32bit targets, and unit-no-macro-leak.cpp checks that including the
-    # library defines no unprefixed macro, which any other file would disturb
-    set(standalone_files unit-32bit.cpp unit-no-macro-leak.cpp)
-
-    set(harmless_macros "^(DOCTEST_.*|SKIP_TESTS_FOR_.*|JSON_TEST_DEPRECATED_FUNCTIONS_DELETED|JSON_TEST_STRICT_NUL_HANDLING_ENABLED|JSON_TEST_STRINGIZE)$")
-
-    # classify the files
-    set(plain_files "")
-    set(private_files "")
-    set(standalone_abs_files "")
-    foreach(file ${args_FILES})
-        get_filename_component(file_name ${file} NAME)
-        get_filename_component(file_basename ${file} NAME_WE)
-        string(REGEX REPLACE "unit-(.+)" "test-\\1" test_name ${file_basename})
-
-        set(batchable TRUE)
-        if(file_name IN_LIST standalone_files)
-            set(batchable FALSE)
-        endif()
-        if(TARGET _json_test_interface_${test_name})
-            set(batchable FALSE)
-        endif()
-        foreach(cxx_standard ${args_CXX_STANDARDS})
-            if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
-                set(batchable FALSE)
-            endif()
-        endforeach()
-
-        # files that suppress GCC's -Wnoexcept around their include of the
-        # library: the suppression has no effect once another file of the
-        # batch included the library first
-        if(batchable)
-            file(READ ${file} file_content)
-            string(FIND "${file_content}" "SUPPRESS_WARNING(\"-Wnoexcept\")" suppresses_noexcept)
-            if(NOT ${suppresses_noexcept} EQUAL -1)
-                set(batchable FALSE)
-            endif()
-        endif()
-
-        set(pool plain)
-        if(batchable)
-            # collect the macros (un)defined before the library is included
-            file(READ ${file} file_content)
-            string(FIND "${file_content}" "#include <nlohmann/" include_position)
-            if(NOT ${include_position} EQUAL -1)
-                string(SUBSTRING "${file_content}" 0 ${include_position} file_content)
-            endif()
-            string(REGEX MATCHALL "(^|\n)[ \t]*#[ \t]*(define|undef)[ \t]+[A-Za-z_0-9]+" directives "${file_content}")
-            foreach(directive ${directives})
-                string(REGEX REPLACE "^.*[ \t]([A-Za-z_0-9]+)$" "\\1" macro "${directive}")
-                if(macro MATCHES "${harmless_macros}")
-                    continue()
-                elseif("${macro}" STREQUAL JSON_TESTS_PRIVATE)
-                    set(pool private)
-                else()
-                    set(batchable FALSE)
-                endif()
-            endforeach()
-        endif()
-
-        get_filename_component(file_abs ${file} ABSOLUTE)
-        if(NOT batchable)
-            list(APPEND standalone_abs_files ${file_abs})
-            json_test_add_test_for(${file} MAIN ${args_MAIN} CXX_STANDARDS ${args_CXX_STANDARDS} ${force})
-            continue()
-        endif()
-        get_filename_component(file ${file} ABSOLUTE)
-        list(APPEND ${pool}_files ${file})
-    endforeach()
-
-    # resolve the explicit groups: group_<name>_files are the (absolute) files
-    # of the group, group_<name>_private tells whether one of them is private
-    set(grouped_files "")
-    foreach(group ${args_GROUPS})
-        if(NOT DEFINED json_test_unity_group_${group})
-            message(FATAL_ERROR "Unity test group '${group}' is not defined (json_test_unity_group_${group}).")
-        endif()
-        set(group_${group}_files "")
-        set(group_${group}_private FALSE)
-        foreach(stem ${json_test_unity_group_${group}})
-            # check against the source directory, because FILES may be filtered (JSON_TestShard)
-            get_filename_component(file ${CMAKE_CURRENT_SOURCE_DIR}/src/unit-${stem}.cpp ABSOLUTE)
-            if(NOT EXISTS ${file})
-                message(FATAL_ERROR "Unity test group '${group}' lists '${stem}', but ${file} does not exist.")
-            endif()
-            if(file IN_LIST grouped_files)
-                message(FATAL_ERROR "Unity test file unit-${stem}.cpp is listed in more than one group (second: '${group}').")
-            endif()
-            list(APPEND grouped_files ${file})
-
-            if(file IN_LIST standalone_abs_files)
-                message(STATUS "Unity test group '${group}': unit-${stem}.cpp cannot be batched and stays standalone")
-            elseif(file IN_LIST plain_files)
-                list(APPEND group_${group}_files ${file})
-                list(REMOVE_ITEM plain_files ${file})
-            elseif(file IN_LIST private_files)
-                list(APPEND group_${group}_files ${file})
-                list(REMOVE_ITEM private_files ${file})
-                set(group_${group}_private TRUE)
-            endif()
-        endforeach()
-    endforeach()
-
-    foreach(cxx_standard ${args_CXX_STANDARDS})
-        if(NOT compiler_supports_cpp_${cxx_standard})
-            continue()
-        endif()
-
-        # explicit groups: one batch per group
-        foreach(group ${args_GROUPS})
-            set(batch_files "")
-            foreach(file ${group_${group}_files})
-                _json_test_unity_applies(${file} ${cxx_standard} "${force}" applies)
-                if(applies)
-                    list(APPEND batch_files ${file})
-                endif()
-            endforeach()
-            if(batch_files)
-                _json_test_add_unity_batch(${group} ${cxx_standard} ${args_MAIN} ${group_${group}_private} ${batch_files})
-            endif()
-        endforeach()
-
-        # remaining files: batches of BATCH_SIZE files per pool
-        foreach(pool plain private)
-            set(is_private FALSE)
-            if(pool STREQUAL private)
-                set(is_private TRUE)
-            endif()
-
-            set(batch_files "")
-            set(batch_count 0)
-            set(batch_index 0)
-            foreach(file ${${pool}_files})
-                _json_test_unity_applies(${file} ${cxx_standard} "${force}" applies)
-                if(NOT applies)
-                    continue()
-                endif()
-
-                list(APPEND batch_files ${file})
-                math(EXPR batch_count "${batch_count} + 1")
-                if(batch_count EQUAL args_BATCH_SIZE)
-                    _json_test_add_unity_batch(${pool}${batch_index} ${cxx_standard} ${args_MAIN} ${is_private} ${batch_files})
-                    set(batch_files "")
-                    set(batch_count 0)
-                    math(EXPR batch_index "${batch_index} + 1")
-                endif()
-            endforeach()
-            if(batch_files)
-                _json_test_add_unity_batch(${pool}${batch_index} ${cxx_standard} ${args_MAIN} ${is_private} ${batch_files})
-            endif()
-        endforeach()
-    endforeach()
-endfunction()
-
 #############################################################################
 # json_test_should_build_32bit_test(
 #     <build_32bit_var> <build_32bit_only_var> <input>)
@@ -9,11 +9,13 @@ INSERT INTO searchIndex(name, type, path) VALUES ('adl_serializer::to_json', 'Fu
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype', 'Class', 'api/byte_container_with_subtype/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::byte_container_with_subtype', 'Constructor', 'api/byte_container_with_subtype/byte_container_with_subtype/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::clear_subtype', 'Method', 'api/byte_container_with_subtype/clear_subtype/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::container_type', 'Type', 'api/byte_container_with_subtype/container_type/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::has_subtype', 'Method', 'api/byte_container_with_subtype/has_subtype/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::operator!=', 'Operator', 'api/byte_container_with_subtype/operator_ne/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::operator==', 'Operator', 'api/byte_container_with_subtype/operator_eq/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::set_subtype', 'Method', 'api/byte_container_with_subtype/set_subtype/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::subtype', 'Method', 'api/byte_container_with_subtype/subtype/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('byte_container_with_subtype::subtype_type', 'Type', 'api/byte_container_with_subtype/subtype_type/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json', 'Class', 'api/basic_json/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('format_as', 'Function', 'api/basic_json/format_as/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::accept', 'Function', 'api/basic_json/accept/index.html');
@@ -26,6 +28,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::basic_json', 'Con
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::begin', 'Method', 'api/basic_json/begin/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::binary', 'Function', 'api/basic_json/binary/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::binary_t', 'Type', 'api/basic_json/binary_t/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::bjdata_version_t', 'Enum', 'api/basic_json/bjdata_version_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::boolean_t', 'Type', 'api/basic_json/boolean_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::cbegin', 'Method', 'api/basic_json/cbegin/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::cbor_tag_handler_t', 'Enum', 'api/basic_json/cbor_tag_handler_t/index.html');
@@ -61,6 +64,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::get_binary', 'Met
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::get_ptr', 'Method', 'api/basic_json/get_ptr/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::get_ref', 'Method', 'api/basic_json/get_ref/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::get_to', 'Method', 'api/basic_json/get_to/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::initializer_list_t', 'Type', 'api/basic_json/initializer_list_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::input_format_t', 'Enum', 'api/basic_json/input_format_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::insert', 'Method', 'api/basic_json/insert/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::invalid_iterator', 'Class', 'api/basic_json/invalid_iterator/index.html');
@@ -79,6 +83,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::is_string', 'Meth
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::is_structured', 'Method', 'api/basic_json/is_structured/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::items', 'Method', 'api/basic_json/items/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::json_base_class_t', 'Type', 'api/basic_json/json_base_class_t/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::json_sax_t', 'Type', 'api/basic_json/json_sax_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::json_serializer', 'Class', 'api/basic_json/json_serializer/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::max_size', 'Method', 'api/basic_json/max_size/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::merge_patch', 'Method', 'api/basic_json/merge_patch/index.html');
@@ -154,24 +159,44 @@ INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::string_t', 'Typ
 INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::to_string', 'Method', 'api/json_pointer/to_string/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax', 'Class', 'api/json_sax/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::binary', 'Method', 'api/json_sax/binary/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::binary_t', 'Type', 'api/json_sax/binary_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::boolean', 'Method', 'api/json_sax/boolean/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::end_array', 'Method', 'api/json_sax/end_array/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::end_object', 'Method', 'api/json_sax/end_object/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::json_sax', 'Constructor', 'api/json_sax/json_sax/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::key', 'Method', 'api/json_sax/key/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::null', 'Method', 'api/json_sax/null/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_float', 'Method', 'api/json_sax/number_float/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_float_t', 'Type', 'api/json_sax/number_float_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_integer', 'Method', 'api/json_sax/number_integer/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_integer_t', 'Type', 'api/json_sax/number_integer_t/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_unsigned', 'Method', 'api/json_sax/number_unsigned/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::number_unsigned_t', 'Type', 'api/json_sax/number_unsigned_t/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::operator=', 'Operator', 'api/json_sax/operator=/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::parse_error', 'Method', 'api/json_sax/parse_error/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::start_array', 'Method', 'api/json_sax/start_array/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::start_object', 'Method', 'api/json_sax/start_object/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::string', 'Method', 'api/json_sax/string/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::string_t', 'Type', 'api/json_sax/string_t/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('json_sax::~json_sax', 'Method', 'api/json_sax/~json_sax/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('operator""_json', 'Literal', 'api/operator_literal_json/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('operator""_json_pointer', 'Literal', 'api/operator_literal_json_pointer/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('operator<<', 'Operator', 'api/operator_ltlt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('operator>>', 'Operator', 'api/operator_gtgt/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json', 'Class', 'api/ordered_json/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map', 'Class', 'api/ordered_map/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::Container', 'Type', 'api/ordered_map/Container/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::at', 'Method', 'api/ordered_map/at/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::count', 'Method', 'api/ordered_map/count/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::emplace', 'Method', 'api/ordered_map/emplace/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::erase', 'Method', 'api/ordered_map/erase/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::find', 'Method', 'api/ordered_map/find/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::insert', 'Method', 'api/ordered_map/insert/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::key_compare', 'Type', 'api/ordered_map/key_compare/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::operator=', 'Operator', 'api/ordered_map/operator=/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::operator[]', 'Operator', 'api/ordered_map/operator[]/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::ordered_map', 'Constructor', 'api/ordered_map/ordered_map/index.html');
+INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map::~ordered_map', 'Method', 'api/ordered_map/~ordered_map/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::formatter<basic_json>', 'Class', 'api/basic_json/std_formatter/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::hash<basic_json>', 'Class', 'api/basic_json/std_hash/index.html');
 INSERT INTO searchIndex(name, type, path) VALUES ('std::swap<basic_json>', 'Function', 'api/basic_json/std_swap/index.html');
@@ -475,8 +475,10 @@ basic_json(basic_json&& other) noexcept;
 1. Since version 1.0.0.
 2. Since version 1.0.0.
 3. Since version 2.1.0.
-4. Since version 3.2.0. Explicit for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since
-   version 3.13.0.
+4. Since version 3.2.0. Also initializes the position reported by
+   [`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) from `val` when
+   [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is enabled, since version 3.12.0. Explicit
+   for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since version 3.13.0.
 5. Since version 1.0.0.
 6. Since version 1.0.0.
 7. Since version 1.0.0. Fixed in version 3.13.0 to also check the iterator range for binary values; before, a range
@@ -0,0 +1,38 @@
+# <small>nlohmann::basic_json::</small>bjdata_version_t
+
+```cpp
+enum class bjdata_version_t
+{
+    draft2,
+    draft3,
+};
+```
+
+This enumeration is used in the [`to_bjdata`](to_bjdata.md) function to choose which draft version of
+the BJData specification to encode ND-array extensions for:
+
+draft2
+:   encode using the BJData Draft 2 ND-array format
+
+draft3
+:   encode using the BJData Draft 3 ND-array format
+
+## Examples
+
+??? example
+
+    The example shows how `bjdata_version_t` selects the BJData draft used by `to_bjdata`.
+
+    ```cpp
+    --8<-- "examples/bjdata_version_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/bjdata_version_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.12.0.
@@ -0,0 +1,32 @@
+# <small>nlohmann::basic_json::</small>initializer_list_t
+
+```cpp
+using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;
+```
+
+The type used for the initializer-list [constructor](basic_json.md) (overload 5) and for functions
+such as [`operator=`](operator=.md) that accept a braced-init-list of JSON values. Each element wraps a
+`basic_json` value or something convertible to one, deferring the decision of whether the list should be
+parsed as a JSON array or a JSON object to the constructor itself.
+
+See the [constructor](basic_json.md) documentation for how `initializer_list_t` values are interpreted.
+
+## Examples
+
+??? example
+
+    The example shows how an `initializer_list_t` is used to construct a JSON value.
+
+    ```cpp
+    --8<-- "examples/initializer_list_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/initializer_list_t.output"
+    ```
+
+## Version history
+
+- Since version 1.0.0.
@@ -0,0 +1,31 @@
+# <small>nlohmann::basic_json::</small>json_sax_t
+
+```cpp
+using json_sax_t = json_sax<basic_json>;
+```
+
+The [`json_sax`](../json_sax/index.md) interface bound to this `basic_json` specialization, i.e. with
+`BasicJsonType` fixed to `basic_json`. Used as the SAX interface type by [`sax_parse`](sax_parse.md) and
+other SAX-based parsing functions.
+
+See [`nlohmann::json_sax`](../json_sax/index.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `json_sax_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.2.0.
@@ -51,3 +51,5 @@ Linear.
 ## Version history

 - Added in version 1.0.0.
+- The `noexcept` specification was extended to also depend on
+  [`json_base_class_t`](json_base_class_t.md)'s move-assignment in version 3.11.3.
@@ -92,3 +92,8 @@ Linear in the size of the JSON value.
 - Since version 1.0.0.
 - Macros `JSON_EXPLICIT`/[`JSON_USE_IMPLICIT_CONVERSIONS`](../macros/json_use_implicit_conversions.md) added
  in version 3.9.0.
+- The exclusion of `std::any` from this conversion became conditional on
+  [`JSON_HAS_STATIC_RTTI`](../macros/json_has_static_rtti.md) in version 3.11.3.
+- `std::optional<T>` excluded from this conversion in version 3.13.0; use
+  [`get<std::optional<T>>()`](get.md)/[`get_to()`](get_to.md) instead (see
+  [Converting values](../../features/conversions.md)).
@@ -0,0 +1,32 @@
+# <small>nlohmann::byte_container_with_subtype::</small>container_type
+
+```cpp
+using container_type = BinaryType;
+```
+
+The type of the underlying binary container, forwarded from the `BinaryType` template parameter that
+`byte_container_with_subtype` is instantiated with. `byte_container_with_subtype` publicly inherits from
+`container_type`.
+
+See [`basic_json::binary_t`](../basic_json/binary_t.md) for the type typically used to instantiate
+`BinaryType`.
+
+## Examples
+
+??? example
+
+    The example shows the type `container_type`.
+
+    ```cpp
+    --8<-- "examples/byte_container_with_subtype__container_type.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/byte_container_with_subtype__container_type.output"
+    ```
+
+## Version history
+
+- Since version 3.8.0.
@@ -0,0 +1,28 @@
+# <small>nlohmann::byte_container_with_subtype::</small>subtype_type
+
+```cpp
+using subtype_type = std::uint64_t;
+```
+
+The type used to store the optional binary subtype tag. See [`subtype`](subtype.md) and
+[`set_subtype`](set_subtype.md).
+
+## Examples
+
+??? example
+
+    The example shows the type `subtype_type`.
+
+    ```cpp
+    --8<-- "examples/byte_container_with_subtype__subtype_type.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/byte_container_with_subtype__subtype_type.output"
+    ```
+
+## Version history
+
+- Since version 3.8.0.
@@ -0,0 +1,30 @@
+# <small>nlohmann::json_sax::</small>binary_t
+
+```cpp
+using binary_t = typename BasicJsonType::binary_t;
+```
+
+The type used by the [`binary`](binary.md) callback for JSON binary values, forwarded from the
+`BasicJsonType` template parameter.
+
+See [`basic_json::binary_t`](../basic_json/binary_t.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `binary_t` and its relation to `basic_json::binary_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax__binary_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax__binary_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.8.0.
@@ -0,0 +1,33 @@
+# <small>nlohmann::json_sax::</small>json_sax
+
+```cpp
+// (1)
+json_sax() = default;
+
+// (2)
+json_sax(const json_sax&) = default;
+
+// (3)
+json_sax(json_sax&&) noexcept = default;
+```
+
+1. Default constructor.
+2. Copy constructor.
+3. Move constructor.
+
+`json_sax` is a pure abstract base class with no data members of its own, so all three constructors are
+defaulted and only exist to make derived SAX consumers explicitly copyable/movable.
+
+## Exception safety
+
+No-throw guarantee: none of these constructors throw exceptions.
+
+## Complexity
+
+Constant.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,30 @@
+# <small>nlohmann::json_sax::</small>number_float_t
+
+```cpp
+using number_float_t = typename BasicJsonType::number_float_t;
+```
+
+The type used by the [`number_float`](number_float.md) callback for JSON floating-point numbers,
+forwarded from the `BasicJsonType` template parameter.
+
+See [`basic_json::number_float_t`](../basic_json/number_float_t.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `number_float_t` and its relation to `basic_json::number_float_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax__number_float_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax__number_float_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,30 @@
+# <small>nlohmann::json_sax::</small>number_integer_t
+
+```cpp
+using number_integer_t = typename BasicJsonType::number_integer_t;
+```
+
+The type used by the [`number_integer`](number_integer.md) callback for JSON integer numbers, forwarded
+from the `BasicJsonType` template parameter.
+
+See [`basic_json::number_integer_t`](../basic_json/number_integer_t.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `number_integer_t` and its relation to `basic_json::number_integer_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax__number_integer_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax__number_integer_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,30 @@
+# <small>nlohmann::json_sax::</small>number_unsigned_t
+
+```cpp
+using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+```
+
+The type used by the [`number_unsigned`](number_unsigned.md) callback for JSON unsigned integer numbers,
+forwarded from the `BasicJsonType` template parameter.
+
+See [`basic_json::number_unsigned_t`](../basic_json/number_unsigned_t.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `number_unsigned_t` and its relation to `basic_json::number_unsigned_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax__number_unsigned_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax__number_unsigned_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,29 @@
+# <small>nlohmann::json_sax::</small>operator=
+
+```cpp
+// (1)
+json_sax& operator=(const json_sax&) = default;
+
+// (2)
+json_sax& operator=(json_sax&&) noexcept = default;
+```
+
+1. Copy assignment operator.
+2. Move assignment operator.
+
+`json_sax` is a pure abstract base class with no data members of its own, so both assignment operators
+are defaulted and only exist to make derived SAX consumers explicitly copy-/move-assignable.
+
+## Exception safety
+
+No-throw guarantee: neither operator throws exceptions.
+
+## Complexity
+
+Constant.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,30 @@
+# <small>nlohmann::json_sax::</small>string_t
+
+```cpp
+using string_t = typename BasicJsonType::string_t;
+```
+
+The type used by the [`string`](string.md) and [`key`](key.md) callbacks for JSON strings and object
+keys, forwarded from the `BasicJsonType` template parameter.
+
+See [`basic_json::string_t`](../basic_json/string_t.md) for more information.
+
+## Examples
+
+??? example
+
+    The example shows the type `string_t` and its relation to `basic_json::string_t`.
+
+    ```cpp
+    --8<-- "examples/json_sax__string_t.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/json_sax__string_t.output"
+    ```
+
+## Version history
+
+- Added in version 3.2.0.
@@ -0,0 +1,22 @@
+# <small>nlohmann::json_sax::</small>~json_sax
+
+```cpp
+virtual ~json_sax() = default;
+```
+
+Destructor. Virtual to allow proper destruction of derived SAX consumer classes through a
+pointer/reference to `json_sax`.
+
+## Exception safety
+
+No-throw guarantee: this destructor never throws exceptions.
+
+## Complexity
+
+Constant.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.2.0.
@@ -8,16 +8,16 @@ This type preserves the insertion order of object keys.

 ## Iterator invalidation

-The type is based on [`ordered_map`](ordered_map.md) which in turn uses a `std::vector` to store object elements.
+The type is based on [`ordered_map`](ordered_map/index.md) which in turn uses a `std::vector` to store object elements.
 Therefore, adding object elements can yield a reallocation in which case all iterators (including the
 [`end()`](basic_json/end.md) iterator) and all references to the elements are invalidated. Also, any iterator or
 reference after the insertion point will point to the same index, which is now a different value.

 ## Complexity

-[`ordered_map`](ordered_map.md) has no lookup index: every key-based object operation is a linear scan, so building or
+[`ordered_map`](ordered_map/index.md) has no lookup index: every key-based object operation is a linear scan, so building or
 parsing an object of `n` keys costs O(n²) rather than O(n log n). See
-[`ordered_map` complexity](ordered_map.md#complexity) for the per-operation table and for measured numbers.
+[`ordered_map` complexity](ordered_map/index.md#complexity) for the per-operation table and for measured numbers.

 ## Examples

@@ -37,7 +37,7 @@ parsing an object of `n` keys costs O(n²) rather than O(n log n). See

 ## See also

- [ordered_map](ordered_map.md)
+- [ordered_map](ordered_map/index.md)
 - [Object Order](../features/object_order.md)

 ## Version history
@@ -0,0 +1,28 @@
+# <small>nlohmann::ordered_map::</small>Container
+
+```cpp
+using Container = std::vector<std::pair<const Key, T>, Allocator>;
+```
+
+The base container type that `ordered_map` publicly inherits from. Elements are stored in insertion
+order as `#!cpp std::pair<const Key, T>` entries in a `std::vector`.
+
+## Examples
+
+??? example
+
+    The example shows the type `Container`.
+
+    ```cpp
+    --8<-- "examples/ordered_map__Container.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__Container.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
@@ -0,0 +1,61 @@
+# <small>nlohmann::ordered_map::</small>at
+
+```cpp
+// (1)
+T& at(const key_type& key);
+const T& at(const key_type& key) const;
+
+// (2)
+template<class KeyType>
+T& at(KeyType&& key);
+template<class KeyType>
+const T& at(KeyType&& key) const;
+```
+
+1. Returns a reference to the value mapped to `key`.
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup, e.g. looking up by a `#!cpp const char*` without constructing a temporary
+   `key_type`). Only participates in overload resolution if `KeyType` is usable as a key type.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the element to find
+
+## Return value
+
+reference to the mapped value of the element with key equal to `key`
+
+## Exceptions
+
+Throws `std::out_of_range` if no element with key `key` exists.
+
+## Complexity
+
+Linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `at` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__at.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__at.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -0,0 +1,53 @@
+# <small>nlohmann::ordered_map::</small>count
+
+```cpp
+// (1)
+size_type count(const key_type& key) const;
+
+// (2)
+template<class KeyType>
+size_type count(KeyType&& key) const;
+```
+
+1. Returns the number of elements with key equal to `key` (0 or 1, since keys are unique).
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the elements to count
+
+## Return value
+
+number of elements with key equal to `key` (0 or 1)
+
+## Complexity
+
+Linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `count` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__count.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__count.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -0,0 +1,58 @@
+# <small>nlohmann::ordered_map::</small>emplace
+
+```cpp
+// (1)
+std::pair<iterator, bool> emplace(const key_type& key, T&& t);
+
+// (2)
+template<class KeyType>
+std::pair<iterator, bool> emplace(KeyType&& key, T&& t);
+```
+
+1. Inserts `#!cpp {key, t}` if no element with an equal key already exists (per [`key_compare`](key_compare.md)),
+   appending it at the end to preserve insertion order. If an equal key already exists, does nothing.
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the element to insert
+
+`t` (in)
+:   value of the element to insert
+
+## Return value
+
+pair of an iterator to the (possibly newly inserted) element, and a `bool` that is `true` if insertion
+took place and `false` if an element with an equal key already existed
+
+## Complexity
+
+Linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `emplace` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__emplace.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__emplace.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -0,0 +1,75 @@
+# <small>nlohmann::ordered_map::</small>erase
+
+```cpp
+// (1)
+size_type erase(const key_type& key);
+
+// (2)
+template<class KeyType>
+size_type erase(KeyType&& key);
+
+// (3)
+iterator erase(iterator pos);
+
+// (4)
+iterator erase(iterator first, iterator last);
+```
+
+1. Removes the element with key equal to `key`, if any, preserving the relative order of the remaining
+   elements.
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
+3. Removes the element at `pos`.
+4. Removes the elements in range `[first, last)`.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the element to remove
+
+`pos` (in)
+:   iterator to the element to remove
+
+`first` (in)
+:   iterator to the first element to remove
+
+`last` (in)
+:   iterator one past the last element to remove
+
+## Return value
+
+1. number of elements removed (0 or 1)
+2. number of elements removed (0 or 1)
+3. iterator following the removed element
+4. iterator following the last removed element
+
+## Complexity
+
+Linear in the number of elements (elements after the removed one(s) are shifted to keep storage
+contiguous).
+
+## Examples
+
+??? example
+
+    The example shows how `erase` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__erase.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__erase.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -0,0 +1,56 @@
+# <small>nlohmann::ordered_map::</small>find
+
+```cpp
+// (1)
+iterator find(const key_type& key);
+const_iterator find(const key_type& key) const;
+
+// (2)
+template<class KeyType>
+iterator find(KeyType&& key);
+template<class KeyType>
+const_iterator find(KeyType&& key) const;
+```
+
+1. Returns an iterator to the element with key equal to `key`, or `end()` if no such element exists.
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the element to find
+
+## Return value
+
+iterator to the element with key equal to `key`, or `end()` if not found
+
+## Complexity
+
+Linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `find` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__find.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__find.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -6,7 +6,7 @@ template<class Key, class T, class IgnoredLess = std::less<Key>,
 struct ordered_map : std::vector<std::pair<const Key, T>, Allocator>;
 ```

-A minimal map-like container that preserves insertion order for use within [`nlohmann::ordered_json`](ordered_json.md)
+A minimal map-like container that preserves insertion order for use within [`nlohmann::ordered_json`](../ordered_json.md)
 (`nlohmann::basic_json<ordered_map>`).

 ## Template parameters
@@ -30,19 +30,19 @@ case all iterators (including the `end()` iterator) and all references to the el

 When the storage grows, the keys are copied and the mapped values are moved to the new storage. A plain `std::vector`
 would copy the whole elements instead, because their `#!cpp const` keys make them not nothrow move constructible; for
-[`ordered_json`](ordered_json.md), this would be a deep copy of every nested value. The values are only copied if
+[`ordered_json`](../ordered_json.md), this would be a deep copy of every nested value. The values are only copied if
 `T` is not default constructible or not nothrow move assignable.

 ## Member types

 - **key_type** - key type (`Key`)
 - **mapped_type** - mapped type (`T`)
- **Container** - base container type (`#!cpp std::vector<std::pair<const Key, T>, Allocator>`)
+- [**Container**](Container.md) - base container type (`#!cpp std::vector<std::pair<const Key, T>, Allocator>`)
 - **iterator**
 - **const_iterator**
 - **size_type**
 - **value_type**
- **key_compare** - key comparison function
+- [**key_compare**](key_compare.md) - key comparison function
 ```cpp
 std::equal_to<Key>  // until C++14

@@ -51,15 +51,16 @@ std::equal_to<>     // since C++14

 ## Member functions

- (constructor)
- (destructor)
- **emplace**
- **operator\[\]**
- **at**
- **erase**
- **count**
- **find**
- **insert**
+- [(constructor)](ordered_map.md)
+- [(destructor)](~ordered_map.md)
+- [**operator=**](operator=.md)
+- [**emplace**](emplace.md)
+- [**operator\[\]**](operator[].md)
+- [**at**](at.md)
+- [**erase**](erase.md)
+- [**count**](count.md)
+- [**find**](find.md)
+- [**insert**](insert.md)

 ## Exception safety

@@ -89,7 +90,7 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).
 !!! warning "Quadratic cost of building large objects"

    Because every insertion scans all elements inserted so far, building an object of `n` distinct keys costs
-    **O(n²)** in total. This applies to filling an [`ordered_json`](ordered_json.md) object key by key as well as to
+    **O(n²)** in total. This applies to filling an [`ordered_json`](../ordered_json.md) object key by key as well as to
    parsing one, since the parser inserts each key as it is read.

    The cost is negligible for the object sizes typically found in configuration files or API payloads, but it grows
@@ -106,7 +107,7 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).
    If key order matters for objects of that size, consider a container with a lookup index, such as
    [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map)
    ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)), as the object type -- see
-    [object order](../features/object_order.md).
+    [object order](../../features/object_order.md).

 ## Examples

@@ -126,10 +127,10 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).

 ## See also

- [ordered_json](ordered_json.md)
+- [ordered_json](../ordered_json.md)

 ## Version history

- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](ordered_json.md).
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
 - Added **key_compare** member in version 3.11.0.
 - Changed in version 3.13.0: growing the storage moves the mapped values instead of copying them.
@@ -0,0 +1,63 @@
+# <small>nlohmann::ordered_map::</small>insert
+
+```cpp
+// (1)
+std::pair<iterator, bool> insert(value_type&& value);
+std::pair<iterator, bool> insert(const value_type& value);
+
+// (2)
+template<typename InputIt>
+void insert(InputIt first, InputIt last);
+```
+
+1. Inserts `value` if no element with an equal key already exists (per [`key_compare`](key_compare.md)),
+   appending it at the end to preserve insertion order. If an equal key already exists, does nothing.
+2. Inserts the elements from range `[first, last)`, in iteration order, applying the same equal-key rule
+   as (1) to each element.
+
+## Template parameters
+
+`InputIt`
+:   an input iterator type
+
+## Parameters
+
+`value` (in)
+:   value to insert
+
+`first` (in)
+:   iterator to the first element to insert
+
+`last` (in)
+:   iterator one past the last element to insert
+
+## Return value
+
+1. pair of an iterator to the (possibly newly inserted) element, and a `bool` that is `true` if insertion
+   took place and `false` if an element with an equal key already existed
+2. (none)
+
+## Complexity
+
+1. Linear in the number of elements.
+2. Linear in the distance between `first` and `last`, times linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `insert` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__insert.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__insert.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
@@ -0,0 +1,34 @@
+# <small>nlohmann::ordered_map::</small>key_compare
+
+```cpp
+using key_compare = std::equal_to<Key>;  // until C++14
+
+using key_compare = std::equal_to<>;     // since C++14
+```
+
+The comparator used to determine key equality when looking up elements. Unlike `std::map`, `ordered_map`
+uses linear search with `key_compare` rather than an ordering relation, since element order reflects
+insertion order rather than key order.
+
+Since C++14, the transparent `#!cpp std::equal_to<>` is used, which enables heterogeneous lookup (e.g.
+looking up by a `#!cpp const char*` key without constructing a temporary `Key`).
+
+## Examples
+
+??? example
+
+    The example shows how `key_compare` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__key_compare.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__key_compare.output"
+    ```
+
+## Version history
+
+- Added in version 3.11.0.
@@ -0,0 +1,32 @@
+# <small>nlohmann::ordered_map::</small>operator=
+
+```cpp
+// (1)
+ordered_map& operator=(const ordered_map& other);
+
+// (2)
+ordered_map& operator=(ordered_map&& other) noexcept(std::is_nothrow_move_assignable<Container>::value);
+```
+
+1. Copy assignment operator.
+2. Move assignment operator.
+
+## Parameters
+
+`other` (in)
+:   value to assign from
+
+## Return value
+
+`*this`
+
+## Complexity
+
+1. Linear in the size of `other`.
+2. Constant.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
@@ -0,0 +1,62 @@
+# <small>nlohmann::ordered_map::</small>operator[]
+
+```cpp
+// (1)
+T& operator[](const key_type& key);
+const T& operator[](const key_type& key) const;
+
+// (2)
+template<class KeyType>
+T& operator[](KeyType&& key);
+template<class KeyType>
+const T& operator[](KeyType&& key) const;
+```
+
+1. Returns a reference to the value mapped to `key`, inserting a default-constructed `T` (non-`const`
+   overload only) if no such element exists yet.
+2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
+   (heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
+
+## Template parameters
+
+`KeyType`
+:   a type comparable to `key_type` via [`key_compare`](key_compare.md)
+
+## Parameters
+
+`key` (in)
+:   key of the element to find or insert
+
+## Return value
+
+reference to the mapped value of the element with key equal to `key`
+
+## Exceptions
+
+The `const` overloads throw `std::out_of_range` if no element with key `key` exists (they delegate to
+[`at`](at.md)).
+
+## Complexity
+
+Linear in the number of elements.
+
+## Examples
+
+??? example
+
+    The example shows how `operator[]` is used.
+
+    ```cpp
+    --8<-- "examples/ordered_map__operator_idx.cpp"
+    ```
+
+    Output:
+
+    ```
+    --8<-- "examples/ordered_map__operator_idx.output"
+    ```
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
+- Overload (2) added in version 3.11.0.
@@ -0,0 +1,66 @@
+# <small>nlohmann::ordered_map::</small>ordered_map
+
+```cpp
+// (1)
+ordered_map() noexcept(noexcept(Container()));
+
+// (2)
+explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc)));
+
+// (3)
+template <class It>
+ordered_map(It first, It last, const Allocator& alloc = Allocator());
+
+// (4)
+ordered_map(std::initializer_list<value_type> init, const Allocator& alloc = Allocator());
+
+// (5)
+ordered_map(const ordered_map&) = default;
+
+// (6)
+ordered_map(ordered_map&&) noexcept(std::is_nothrow_move_constructible<Container>::value) = default;
+```
+
+1. Default constructor. Creates an empty `ordered_map`.
+2. Creates an empty `ordered_map` using the given allocator.
+3. Creates an `ordered_map` from the elements in range `[first, last)`, inserted in iteration order.
+4. Creates an `ordered_map` from an initializer list of key/value pairs, inserted in list order.
+5. Copy constructor.
+6. Move constructor.
+
+These constructors are declared explicitly (rather than inherited via `#!cpp using Container::Container`)
+because older compilers (GCC <= 5.5, Xcode <= 9.4) do not handle the inherited constructors correctly.
+
+## Template parameters
+
+`It`
+:   an input iterator type
+
+## Parameters
+
+`alloc` (in)
+:   allocator to use for the underlying container
+
+`first` (in)
+:   iterator to the first element to insert
+
+`last` (in)
+:   iterator one past the last element to insert
+
+`init` (in)
+:   initializer list of key/value pairs to insert
+
+## Complexity
+
+1. Constant.
+2. Constant.
+3. Linear in the distance between `first` and `last`.
+4. Linear in the size of `init`.
+5. Linear in the size of `other`.
+6. Constant.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
@@ -0,0 +1,17 @@
+# <small>nlohmann::ordered_map::</small>~ordered_map
+
+```cpp
+~ordered_map() = default;
+```
+
+Destroys the `ordered_map` and frees all allocated memory.
+
+## Complexity
+
+Linear in the number of elements.
+
+<!-- NOLINT Examples -->
+
+## Version history
+
+- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
@@ -0,0 +1,21 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // an empty binary value is encoded differently by the two drafts:
+    // draft2 omits the optimized type marker for an empty byte array,
+    // while draft3 always writes it
+    json j = json::binary({});
+
+    // encode using BJData draft2 (the default)
+    auto v_draft2 = json::to_bjdata(j, true, true, json::bjdata_version_t::draft2);
+
+    // encode using BJData draft3
+    auto v_draft3 = json::to_bjdata(j, true, true, json::bjdata_version_t::draft3);
+
+    std::cout << "draft2 size: " << v_draft2.size() << '\n'
+              << "draft3 size: " << v_draft3.size() << std::endl;
+}
@@ -0,0 +1,2 @@
+draft2 size: 4
+draft3 size: 6
@@ -0,0 +1,11 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<byte_container_with_subtype::container_type, std::vector<std::uint8_t>>::value
+              << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<byte_container_with_subtype::subtype_type, std::uint64_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,13 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    // an initializer_list_t is what a braced-init-list of JSON values is deduced as
+    json::initializer_list_t init = {"a", 1, 2.0, false};
+
+    json j(init);
+    std::cout << j.dump() << std::endl;
+}
@@ -0,0 +1 @@
+["a",1,2.0,false]
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t::binary_t, json::binary_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t::number_float_t, json::number_float_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t::number_integer_t, json::number_integer_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t::number_unsigned_t, json::number_unsigned_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t::string_t, json::string_t>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,10 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+int main()
+{
+    std::cout << std::boolalpha
+              << std::is_same<json::json_sax_t, nlohmann::json_sax<json>>::value << std::endl;
+}
@@ -0,0 +1 @@
+true
@@ -0,0 +1,12 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    using Map = nlohmann::ordered_map<std::string, int>;
+
+    std::cout << std::boolalpha
+              << "Container is std::vector<std::pair<const Key, T>>: "
+              << std::is_same<Map::Container, std::vector<std::pair<const std::string, int>>>::value
+              << std::endl;
+}
@@ -0,0 +1 @@
+Container is std::vector<std::pair<const Key, T>>: true
@@ -0,0 +1,26 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+    m["one"] = 1;
+    m["two"] = 2;
+
+    // access an existing element
+    std::cout << "m.at(\"one\") = " << m.at("one") << std::endl;
+
+    // modify through the reference returned by at()
+    m.at("two") = 22;
+    std::cout << "m.at(\"two\") = " << m.at("two") << std::endl;
+
+    // accessing a missing key throws
+    try
+    {
+        m.at("three");
+    }
+    catch (const std::out_of_range& e)
+    {
+        std::cout << "exception: " << e.what() << std::endl;
+    }
+}
@@ -0,0 +1,3 @@
+m.at("one") = 1
+m.at("two") = 22
+exception: key not found
@@ -0,0 +1,12 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+    m["one"] = 1;
+
+    std::cout << std::boolalpha
+              << "m.count(\"one\") = " << m.count("one") << '\n'
+              << "m.count(\"two\") = " << m.count("two") << std::endl;
+}
@@ -0,0 +1,2 @@
+m.count("one") = 1
+m.count("two") = 0
@@ -0,0 +1,15 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, std::string> m;
+
+    // emplace a new element
+    auto res1 = m.emplace("one", "eins");
+    std::cout << std::boolalpha << "inserted: " << res1.second << ", value: " << res1.first->second << std::endl;
+
+    // emplace with an already-existing key: no-op, returns the existing element
+    auto res2 = m.emplace("one", "uno");
+    std::cout << std::boolalpha << "inserted: " << res2.second << ", value: " << res2.first->second << std::endl;
+}
@@ -0,0 +1,2 @@
+inserted: true, value: eins
+inserted: false, value: eins
@@ -0,0 +1,24 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+    m["one"] = 1;
+    m["two"] = 2;
+    m["three"] = 3;
+
+    // erase by key
+    std::size_t removed = m.erase("two");
+    std::cout << "removed by key: " << removed << std::endl;
+
+    // erase by iterator
+    m.erase(m.begin());
+
+    std::cout << "remaining: ";
+    for (const auto& element : m)
+    {
+        std::cout << element.first << ' ';
+    }
+    std::cout << std::endl;
+}
@@ -0,0 +1,2 @@
+removed by key: 1
+remaining: three 
@@ -0,0 +1,19 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+    m["one"] = 1;
+
+    auto it = m.find("one");
+    if (it != m.end())
+    {
+        std::cout << "found: " << it->first << " = " << it->second << std::endl;
+    }
+
+    if (m.find("two") == m.end())
+    {
+        std::cout << "\"two\" not found" << std::endl;
+    }
+}
@@ -0,0 +1,2 @@
+found: one = 1
+"two" not found
@@ -0,0 +1,21 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+
+    // insert a single value
+    auto res = m.insert({"one", 1});
+    std::cout << std::boolalpha << "inserted: " << res.second << std::endl;
+
+    // insert a range from another container
+    std::vector<std::pair<const std::string, int>> more = {{"two", 2}, {"three", 3}};
+    m.insert(more.begin(), more.end());
+
+    for (const auto& element : m)
+    {
+        std::cout << element.first << ':' << element.second << ' ';
+    }
+    std::cout << std::endl;
+}
@@ -0,0 +1,2 @@
+inserted: true
+one:1 two:2 three:3 
@@ -0,0 +1,12 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    using Map = nlohmann::ordered_map<std::string, int>;
+    Map::key_compare compare{};
+
+    std::cout << std::boolalpha
+              << "compare(\"a\", \"a\") = " << compare("a", "a") << '\n'
+              << "compare(\"a\", \"b\") = " << compare("a", "b") << std::endl;
+}
@@ -0,0 +1,2 @@
+compare("a", "a") = true
+compare("a", "b") = false
@@ -0,0 +1,14 @@
+#include <iostream>
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    nlohmann::ordered_map<std::string, int> m;
+
+    // operator[] inserts a default-constructed value if the key doesn't exist yet
+    m["one"] = 1;
+    std::cout << "m[\"one\"] = " << m["one"] << std::endl;
+
+    // accessing again just returns the existing value
+    std::cout << "m[\"one\"] = " << m["one"] << std::endl;
+}
@@ -0,0 +1,2 @@
+m["one"] = 1
+m["one"] = 1
@@ -51,16 +51,16 @@ If you do want to preserve the **insertion order**, you can use the type [`nlohm
    --8<-- "examples/ordered_json.output"
    ```

-Alternatively, [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) also preserves the insertion order and, unlike [`ordered_map`](../api/ordered_map.md), keeps a lookup index, so it does not have the quadratic cost described below. It is used through a small adapter ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
+Alternatively, [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) also preserves the insertion order and, unlike [`ordered_map`](../api/ordered_map/index.md), keeps a lookup index, so it does not have the quadratic cost described below. It is used through a small adapter ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).

 If the order does not matter and you only want faster lookup, `boost::unordered_flat_map`, `absl::flat_hash_map`, `absl::node_hash_map`, and several other hash maps work through an adapter that restores the template argument order `basic_json` expects; see [Template Parameter Requirements](types/template_parameters.md#objecttype). Note these are *unordered*, not insertion-ordered.

 [`tsl::ordered_map`](https://github.com/Tessil/ordered-map) cannot be used: its iterators expose the mapped value as `const`, while `basic_json` needs to modify it in place.

-The [`ordered_map`](../api/ordered_map.md) behind `nlohmann::ordered_json` is deliberately minimal and has no lookup
+The [`ordered_map`](../api/ordered_map/index.md) behind `nlohmann::ordered_json` is deliberately minimal and has no lookup
 index, so every key access is a linear scan and building an object of `n` keys costs O(n²). This is unnoticeable at
 typical object sizes but becomes significant for objects with many thousands of keys; see
-[`ordered_map` complexity](../api/ordered_map.md#complexity). The alternatives above keep a lookup index and do not
+[`ordered_map` complexity](../api/ordered_map/index.md#complexity). The alternatives above keep a lookup index and do not
 have this cost.

 ### Notes on parsing
@@ -88,10 +88,10 @@ whether it is worth the loss of human readability at all -- depends on the actua
 The default [`json`](../api/json.md) type stores object keys in a `#!cpp std::map`, giving logarithmic-time lookup,
 insertion, and erasure, at the cost of sorting keys alphabetically rather than preserving insertion order (see
 [Object Order](object_order.md)). [`ordered_json`](../api/ordered_json.md) uses
-[`nlohmann::ordered_map`](../api/ordered_map.md) instead, a `#!cpp std::vector`-backed container with no lookup index:
+[`nlohmann::ordered_map`](../api/ordered_map/index.md) instead, a `#!cpp std::vector`-backed container with no lookup index:
 every key-based operation is a **linear scan**, so building an object of `n` distinct keys costs **O(n²)** in total --
 this applies equally to inserting keys one by one and to parsing an object, since the parser inserts each key as it is
-read. The [measurements on the `ordered_map` page](../api/ordered_map.md#complexity) show this is
+read. The [measurements on the `ordered_map` page](../api/ordered_map/index.md#complexity) show this is
 negligible at typical object sizes (2000 keys: 0.7 ms for `json` vs. 3.6 ms for `ordered_json`, a 5x factor) but grows
 steeply for large, machine-generated objects (16 000 keys: 3.3 ms vs. 181.6 ms, a 54x factor).

@@ -42,7 +42,7 @@ Requirements are split into two groups:

 | Template parameter                                                | Default                           | Notable substitutes                                                   |
 |-------------------------------------------------------------------|-----------------------------------|-----------------------------------------------------------------------|
-| [`ObjectType`](#objecttype)                                       | `std::map`                        | [`nlohmann::ordered_map`](../../api/ordered_map.md), Abseil hash maps |
+| [`ObjectType`](#objecttype)                                       | `std::map`                        | [`nlohmann::ordered_map`](../../api/ordered_map/index.md), Abseil hash maps |
 | [`ArrayType`](#arraytype)                                         | `std::vector`                     | `#!cpp std::deque`                                                    |
 | [`StringType`](#stringtype)                                       | `std::string`                     | `std::string`-like types over `char`                                  |
 | [`BooleanType`](#booleantype)                                     | `bool`                            | none worth using                                                      |
@@ -235,7 +235,7 @@ The library does not sort or de-duplicate keys itself; the behavior described in
 | Container                                                                        | Notes                                                                         |
 |----------------------------------------------------------------------------------|-------------------------------------------------------------------------------|
 | `#!cpp std::map` (default)                                                       |                                                                               |
-| [`nlohmann::ordered_map`](../../api/ordered_map.md)                              | used by [`ordered_json`](../../api/ordered_json.md); keeps insertion order    |
+| [`nlohmann::ordered_map`](../../api/ordered_map/index.md)                              | used by [`ordered_json`](../../api/ordered_json.md); keeps insertion order    |
 | [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map)                     | keeps insertion order; adapter puts `fifo_map_compare` in the comparator slot |
 | `boost::container::map`, `boost::container::flat_map`                            | no adapter needed                                                             |
 | `#!cpp std::unordered_map`                                                       | through the adapter above; not with libstdc++ 9, see the note                 |
@@ -50,7 +50,7 @@ The public headers are in [`include/nlohmann`](https://github.com/nlohmann/json/
 - [`adl_serializer.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/adl_serializer.hpp), [`byte_container_with_subtype.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/byte_container_with_subtype.hpp), and [`ordered_map.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/ordered_map.hpp) define
  [`adl_serializer`](../api/adl_serializer/index.md),
  [`byte_container_with_subtype`](../api/byte_container_with_subtype/index.md), and
-  [`ordered_map`](../api/ordered_map.md).
+  [`ordered_map`](../api/ordered_map/index.md).

 Everything else lives in [`detail/`](https://github.com/nlohmann/json/tree/develop/include/nlohmann/detail) and namespace `nlohmann::detail`, which is not part of the public API. Paths
 below are relative to `include/nlohmann`.
@@ -97,7 +97,7 @@ is generated from these files with `make amalgamate` and must not be edited by h
 The library provides two specializations:

 - [`json`](../api/json.md) uses all default template arguments.
- [`ordered_json`](../api/ordered_json.md) uses [`ordered_map`](../api/ordered_map.md) as `ObjectType` to keep the
+- [`ordered_json`](../api/ordered_json.md) uses [`ordered_map`](../api/ordered_map/index.md) as `ObjectType` to keep the
  insertion order of object keys.

 The requirements on the template arguments are listed in
@@ -2,7 +2,8 @@

 This page summarizes the notable changes of every release and links to the relevant documentation.
 The **complete release notes** — including all changes, the download files, and their checksums — are
-published on the [GitHub releases page](https://github.com/nlohmann/json/releases).
+published on the [GitHub releases page](https://github.com/nlohmann/json/releases). For a raw,
+signature-level diff of the public API between releases, see [API Changes](api_changes.md).

 !!! info "Unreleased changes"

@@ -235,17 +235,6 @@ Build the unit tests against the [simdutf](https://github.com/simdutf/simdutf) U
 its version is set by the cache variable `JSON_SIMDUTF_VERSION`. This option is `OFF` by default. Depends on
 `JSON_BuildTests`.

-### `JSON_TestUnityBuild`
-
-Build the unit tests in batches of several test files per executable to speed up compilation: the files of a batch are
-compiled as one translation unit, so the template instantiations of the library are shared. Every test file still gets
-its own CTest test (e.g., `test-foo_cpp11`), which runs only the test cases of that file from the shared executable.
-This option is `ON` by default (and `OFF` with MinGW). Set it to `OFF` to get one executable per test file, e.g., when
-debugging a single file. The number of files per executable is set by the cache variable `JSON_TestUnityBatchSize`
-(default: `8`). Related test files (e.g., all binary formats) are grouped explicitly in `tests/CMakeLists.txt`; each
-group is compiled as one executable per C++ standard regardless of the batch size, and only the remaining files are
-batched by size. Depends on `JSON_BuildTests`.
-
 ### `JSON_Valgrind`

 Execute the test suite with [Valgrind](https://valgrind.org). This option is `OFF` by default. Depends on `JSON_BuildTests`.
@@ -52,6 +52,7 @@ nav:
      - "FAQ": home/faq.md
      - home/exceptions.md
      - home/releases.md
+      - home/api_changes.md
      - home/design_goals.md
      - home/architecture.md
      - home/customers.md
@@ -123,6 +124,7 @@ nav:
          - 'begin': api/basic_json/begin.md
          - 'binary': api/basic_json/binary.md
          - 'binary_t': api/basic_json/binary_t.md
+          - 'bjdata_version_t': api/basic_json/bjdata_version_t.md
          - 'boolean_t': api/basic_json/boolean_t.md
          - 'cbegin': api/basic_json/cbegin.md
          - 'cbor_tag_handler_t': api/basic_json/cbor_tag_handler_t.md
@@ -161,6 +163,7 @@ nav:
          - 'get_to': api/basic_json/get_to.md
          - 'std::formatter&lt;basic_json&gt;': api/basic_json/std_formatter.md
          - 'std::hash&lt;basic_json&gt;': api/basic_json/std_hash.md
+          - 'initializer_list_t': api/basic_json/initializer_list_t.md
          - 'input_format_t': api/basic_json/input_format_t.md
          - 'insert': api/basic_json/insert.md
          - 'invalid_iterator': api/basic_json/invalid_iterator.md
@@ -179,6 +182,7 @@ nav:
          - 'is_structured': api/basic_json/is_structured.md
          - 'items': api/basic_json/items.md
          - 'json_base_class_t': api/basic_json/json_base_class_t.md
+          - 'json_sax_t': api/basic_json/json_sax_t.md
          - 'json_serializer': api/basic_json/json_serializer.md
          - 'max_size': api/basic_json/max_size.md
          - 'meta': api/basic_json/meta.md
@@ -237,11 +241,13 @@ nav:
          - 'Overview': api/byte_container_with_subtype/index.md
          - '(constructor)': api/byte_container_with_subtype/byte_container_with_subtype.md
          - 'clear_subtype': api/byte_container_with_subtype/clear_subtype.md
+          - 'container_type': api/byte_container_with_subtype/container_type.md
          - 'has_subtype': api/byte_container_with_subtype/has_subtype.md
          - 'operator==': api/byte_container_with_subtype/operator_eq.md
          - 'operator!=': api/byte_container_with_subtype/operator_ne.md
          - 'set_subtype': api/byte_container_with_subtype/set_subtype.md
          - 'subtype': api/byte_container_with_subtype/subtype.md
+          - 'subtype_type': api/byte_container_with_subtype/subtype_type.md
      - adl_serializer:
          - 'Overview': api/adl_serializer/index.md
          - 'from_json': api/adl_serializer/from_json.md
@@ -268,25 +274,46 @@ nav:
          - 'to_string': api/json_pointer/to_string.md
      - json_sax:
          - 'Overview': api/json_sax/index.md
+          - '(Constructor)': api/json_sax/json_sax.md
+          - '(Destructor)': api/json_sax/~json_sax.md
+          - 'operator=': api/json_sax/operator=.md
          - 'binary': api/json_sax/binary.md
+          - 'binary_t': api/json_sax/binary_t.md
          - 'boolean': api/json_sax/boolean.md
          - 'end_array': api/json_sax/end_array.md
          - 'end_object': api/json_sax/end_object.md
          - 'key': api/json_sax/key.md
          - 'null': api/json_sax/null.md
          - 'number_float': api/json_sax/number_float.md
+          - 'number_float_t': api/json_sax/number_float_t.md
          - 'number_integer': api/json_sax/number_integer.md
+          - 'number_integer_t': api/json_sax/number_integer_t.md
          - 'number_unsigned': api/json_sax/number_unsigned.md
+          - 'number_unsigned_t': api/json_sax/number_unsigned_t.md
          - 'parse_error': api/json_sax/parse_error.md
          - 'start_array': api/json_sax/start_array.md
          - 'start_object': api/json_sax/start_object.md
          - 'string': api/json_sax/string.md
+          - 'string_t': api/json_sax/string_t.md
      - 'operator<<(basic_json), operator<<(json_pointer)': api/operator_ltlt.md
      - 'operator>>(basic_json)': api/operator_gtgt.md
      - 'operator""_json': api/operator_literal_json.md
      - 'operator""_json_pointer': api/operator_literal_json_pointer.md
      - 'ordered_json': api/ordered_json.md
-      - 'ordered_map': api/ordered_map.md
+      - ordered_map:
+          - 'Overview': api/ordered_map/index.md
+          - '(Constructor)': api/ordered_map/ordered_map.md
+          - '(Destructor)': api/ordered_map/~ordered_map.md
+          - 'operator=': api/ordered_map/operator=.md
+          - 'at': api/ordered_map/at.md
+          - 'Container': api/ordered_map/Container.md
+          - 'count': api/ordered_map/count.md
+          - 'emplace': api/ordered_map/emplace.md
+          - 'erase': api/ordered_map/erase.md
+          - 'find': api/ordered_map/find.md
+          - 'insert': api/ordered_map/insert.md
+          - 'key_compare': api/ordered_map/key_compare.md
+          - 'operator[]': api/ordered_map/operator[].md
      - macros:
          - 'Overview': api/macros/index.md
          - 'JSON_ASSERT': api/macros/json_assert.md
@@ -22,7 +22,9 @@ template<typename BinaryType>
 class byte_container_with_subtype : public BinaryType
 {
  public:
+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/container_type/
    using container_type = BinaryType;
+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/subtype_type/
    using subtype_type = std::uint64_t;

    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/byte_container_with_subtype/
@@ -54,12 +56,14 @@ class byte_container_with_subtype : public BinaryType
        , m_has_subtype(true)
    {}

+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/operator_eq/
    bool operator==(const byte_container_with_subtype& rhs) const
    {
        return std::tie(static_cast<const BinaryType&>(*this), m_subtype, m_has_subtype) ==
               std::tie(static_cast<const BinaryType&>(rhs), rhs.m_subtype, rhs.m_has_subtype);
    }

+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/operator_ne/
    bool operator!=(const byte_container_with_subtype& rhs) const
    {
        return !(rhs == *this);
@@ -34,15 +34,21 @@ input.
 template<typename BasicJsonType>
 struct json_sax
 {
+    /// @sa https://json.nlohmann.me/api/json_sax/number_integer_t/
    using number_integer_t = typename BasicJsonType::number_integer_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/number_unsigned_t/
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/number_float_t/
    using number_float_t = typename BasicJsonType::number_float_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/string_t/
    using string_t = typename BasicJsonType::string_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/binary_t/
    using binary_t = typename BasicJsonType::binary_t;

    /*!
    @brief a null value was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/null/
    */
    virtual bool null() = 0;

@@ -50,6 +56,7 @@ struct json_sax
    @brief a boolean value was read
    @param[in] val  boolean value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/boolean/
    */
    virtual bool boolean(bool val) = 0;

@@ -57,6 +64,7 @@ struct json_sax
    @brief an integer number was read
    @param[in] val  integer value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_integer/
    */
    virtual bool number_integer(number_integer_t val) = 0;

@@ -64,6 +72,7 @@ struct json_sax
    @brief an unsigned integer number was read
    @param[in] val  unsigned integer value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_unsigned/
    */
    virtual bool number_unsigned(number_unsigned_t val) = 0;

@@ -72,6 +81,7 @@ struct json_sax
    @param[in] val  floating-point value
    @param[in] s    raw token value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_float/
    */
    virtual bool number_float(number_float_t val, const string_t& s) = 0;

@@ -80,6 +90,7 @@ struct json_sax
    @param[in] val  string value
    @return whether parsing should proceed
    @note It is safe to move the passed string value.
+    @sa https://json.nlohmann.me/api/json_sax/string/
    */
    virtual bool string(string_t& val) = 0;

@@ -88,6 +99,7 @@ struct json_sax
    @param[in] val  binary value
    @return whether parsing should proceed
    @note It is safe to move the passed binary value.
+    @sa https://json.nlohmann.me/api/json_sax/binary/
    */
    virtual bool binary(binary_t& val) = 0;

@@ -96,6 +108,7 @@ struct json_sax
    @param[in] elements  number of object elements or -1 if unknown
    @return whether parsing should proceed
    @note binary formats may report the number of elements
+    @sa https://json.nlohmann.me/api/json_sax/start_object/
    */
    virtual bool start_object(std::size_t elements) = 0;

@@ -104,12 +117,14 @@ struct json_sax
    @param[in] val  object key
    @return whether parsing should proceed
    @note It is safe to move the passed string.
+    @sa https://json.nlohmann.me/api/json_sax/key/
    */
    virtual bool key(string_t& val) = 0;

    /*!
    @brief the end of an object was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/end_object/
    */
    virtual bool end_object() = 0;

@@ -118,12 +133,14 @@ struct json_sax
    @param[in] elements  number of array elements or -1 if unknown
    @return whether parsing should proceed
    @note binary formats may report the number of elements
+    @sa https://json.nlohmann.me/api/json_sax/start_array/
    */
    virtual bool start_array(std::size_t elements) = 0;

    /*!
    @brief the end of an array was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/end_array/
    */
    virtual bool end_array() = 0;

@@ -133,16 +150,23 @@ struct json_sax
    @param[in] last_token  the last read token
    @param[in] ex          an exception object describing the error
    @return whether parsing should proceed (must return false)
+    @sa https://json.nlohmann.me/api/json_sax/parse_error/
    */
    virtual bool parse_error(std::size_t position,
                             const std::string& last_token,
                             const detail::exception& ex) = 0;

+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax() = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax(const json_sax&) = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax(json_sax&&) noexcept = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/operator=/
    json_sax& operator=(const json_sax&) = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/operator=/
    json_sax& operator=(json_sax&&) noexcept = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/~json_sax/
    virtual ~json_sax() = default;
 };

@@ -57,6 +57,7 @@ class json_pointer

  public:
    // for backwards compatibility accept BasicJsonType
+    /// @sa https://json.nlohmann.me/api/json_pointer/string_t/
    using string_t = typename string_t_helper<RefStringType>::type;

    /// @brief create JSON pointer
@@ -19,6 +19,8 @@
 #undef NLOHMANN_CAN_CALL_STD_FUNC_IMPL
 #undef JSON_INLINE_VARIABLE
 #undef JSON_NO_UNIQUE_ADDRESS
+#undef JSON_DISABLE_ENUM_SERIALIZATION
+#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION

 #ifndef JSON_TEST_KEEP_MACROS
    #undef JSON_CATCH
@@ -43,8 +45,6 @@
    #undef JSON_STRICT_BINARY_UTF8
    #undef JSON_DELETE_DEPRECATED_FUNCTIONS
    #undef JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
-    #undef JSON_DISABLE_ENUM_SERIALIZATION
-    #undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
 #endif

 #include <nlohmann/thirdparty/hedley/hedley_undef.hpp>
@@ -205,25 +205,34 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    using serializer = ::nlohmann::detail::serializer<basic_json>;

  public:
+    /// @brief the type of the JSON value
+    /// @sa https://json.nlohmann.me/api/basic_json/value_t/
    using value_t = detail::value_t;
    /// JSON Pointer, see @ref nlohmann::json_pointer
    using json_pointer = ::nlohmann::json_pointer<StringType>;
    template<typename T, typename SFINAE>
    using json_serializer = JSONSerializer<T, SFINAE>;
    /// how to treat decoding errors
+    /// @sa https://json.nlohmann.me/api/basic_json/error_handler_t/
    using error_handler_t = detail::error_handler_t;
    /// how to treat CBOR tags
+    /// @sa https://json.nlohmann.me/api/basic_json/cbor_tag_handler_t/
    using cbor_tag_handler_t = detail::cbor_tag_handler_t;
    /// how to encode BJData
+    /// @sa https://json.nlohmann.me/api/basic_json/bjdata_version_t/
    using bjdata_version_t = detail::bjdata_version_t;
    /// base class used to inject custom functionality into each instance of basic_json
    /// @sa https://json.nlohmann.me/api/basic_json/json_base_class_t/
    using json_base_class_t = ::nlohmann::detail::json_base_class<CustomBaseClass>;
    /// helper type for initializer lists of basic_json values
+    /// @sa https://json.nlohmann.me/api/basic_json/initializer_list_t/
    using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;

+    /// @brief the type of the SAX interface used to parse and serialize the JSON value
+    /// @sa https://json.nlohmann.me/api/basic_json/input_format_t/
    using input_format_t = detail::input_format_t;
    /// SAX interface type, see @ref nlohmann::json_sax
+    /// @sa https://json.nlohmann.me/api/basic_json/json_sax_t/
    using json_sax_t = json_sax<basic_json>;

    ////////////////////////////////////////////////////////////////////////////////
@@ -429,15 +438,19 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// the template arguments passed to class @ref basic_json.
    /// @{

+#if defined(JSON_HAS_CPP_14)
    /// @brief default object key comparator type
    /// The actual object key comparator type (@ref object_comparator_t) may be
    /// different.
    /// @sa https://json.nlohmann.me/api/basic_json/default_object_comparator_t/
-#if defined(JSON_HAS_CPP_14)
    // use of transparent comparator avoids unnecessary repeated construction of temporaries
    // in functions involving lookup by key with types other than object_t::key_type (aka. StringType)
    using default_object_comparator_t = std::less<>;
 #else
+    /// @brief default object key comparator type
+    /// The actual object key comparator type (@ref object_comparator_t) may be
+    /// different.
+    /// @sa https://json.nlohmann.me/api/basic_json/default_object_comparator_t/
    using default_object_comparator_t = std::less<StringType>;
 #endif

@@ -2505,6 +2518,7 @@ public:
    // other constructors and destructor //
    ///////////////////////////////////////

+    /// @sa https://json.nlohmann.me/api/basic_json/basic_json/
    template<typename JsonRef,
             detail::enable_if_t<detail::conjunction<detail::is_json_ref<JsonRef>,
                                 std::is_same<typename JsonRef::value_type, basic_json>>::value, int> = 0 >
@@ -3090,6 +3104,8 @@ public:
    @throw what @ref json_serializer<ValueType> `from_json()` method throws if conversion is required

    @since version 2.1.0
+
+    @sa https://json.nlohmann.me/api/basic_json/get/
    */
    template < typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>>
 #if defined(JSON_HAS_CPP_14)
@@ -3133,6 +3149,8 @@ public:
    @sa see @ref get_ptr() for explicit pointer-member access

    @since version 1.0.0
+
+    @sa https://json.nlohmann.me/api/basic_json/get/
    */
    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value, int>::type = 0>
@@ -3159,6 +3177,7 @@ public:

    // specialization to allow calling get_to with a basic_json value
    // see https://github.com/nlohmann/json/issues/2175
+    /// @sa https://json.nlohmann.me/api/basic_json/get_to/
    template<typename ValueType,
             detail::enable_if_t <
                 detail::is_basic_json<ValueType>::value,
@@ -3169,6 +3188,7 @@ public:
        return v;
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/get_to/
    template <
        typename T, std::size_t N,
        typename Array = T (&)[N], // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
@@ -3233,6 +3253,7 @@ public:

    @since version 1.0.0
    */
+    /// @sa https://json.nlohmann.me/api/basic_json/operator_ValueType/
    template < typename ValueType, typename std::enable_if <
                   detail::conjunction <
                       detail::negation<std::is_pointer<ValueType>>,
@@ -3541,12 +3562,14 @@ public:

    // these two functions resolve a (const) char * ambiguity affecting Clang and MSVC
    // (they seemingly cannot be constrained to resolve the ambiguity)
+    /// @sa https://json.nlohmann.me/api/basic_json/operator[]/
    template<typename T>
    reference operator[](T* key)
    {
        return operator[](typename object_t::key_type(key));
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator[]/
    template<typename T>
    const_reference operator[](T* key) const
    {
@@ -3724,6 +3747,7 @@ public:
        return found != nullptr ? found->template get<ReturnType>() : std::forward<ValueType>(default_value);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/value/
    template < class ValueType, class BasicJsonType, detail::enable_if_t <
                   detail::is_basic_json<BasicJsonType>::value
                   && detail::is_getable<basic_json_t, ValueType>::value
@@ -3738,6 +3762,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/value/
    template < class ValueType, class BasicJsonType, class ReturnType = typename value_return_type<ValueType>::type,
               detail::enable_if_t <
                   detail::is_basic_json<BasicJsonType>::value
@@ -4105,6 +4130,7 @@ public:
        return ptr.contains(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/contains/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
@@ -5621,6 +5647,7 @@ public:
        return result;
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/parse/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, parse(ptr, ptr + len))
    static basic_json parse(detail::span_input_adapter&& i,
@@ -5662,6 +5689,7 @@ public:
        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/accept/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, accept(ptr, ptr + len))
    static bool accept(detail::span_input_adapter&& i,
@@ -6108,6 +6136,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::cbor, strict, allow_exceptions, error_handler, tag_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
@@ -6123,6 +6152,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
    static basic_json from_cbor(detail::span_input_adapter&& i,
@@ -6162,6 +6192,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::msgpack, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
@@ -6176,6 +6207,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
    static basic_json from_msgpack(detail::span_input_adapter&& i,
@@ -6214,6 +6246,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::ubjson, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
@@ -6228,6 +6261,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
    static basic_json from_ubjson(detail::span_input_adapter&& i,
@@ -6342,6 +6376,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::bson, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
@@ -6356,6 +6391,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
    static basic_json from_bson(detail::span_input_adapter&& i,
@@ -6384,6 +6420,7 @@ public:
        return ptr.get_unchecked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator%5B%5D/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    reference operator[](const ::nlohmann::json_pointer<BasicJsonType>& ptr)
@@ -6402,6 +6439,7 @@ public:
        return ptr.get_unchecked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator%5B%5D/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    const_reference operator[](const ::nlohmann::json_pointer<BasicJsonType>& ptr) const
@@ -6420,6 +6458,7 @@ public:
        return ptr.get_checked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/at/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    reference at(const ::nlohmann::json_pointer<BasicJsonType>& ptr)
@@ -6438,6 +6477,7 @@ public:
        return ptr.get_checked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/at/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    const_reference at(const ::nlohmann::json_pointer<BasicJsonType>& ptr) const
@@ -34,30 +34,41 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
 {
    using key_type = Key;
    using mapped_type = T;
+    /// @sa https://json.nlohmann.me/api/ordered_map/Container/
    using Container = std::vector<std::pair<const Key, T>, Allocator>;
    using iterator = typename Container::iterator;
    using const_iterator = typename Container::const_iterator;
    using size_type = typename Container::size_type;
    using value_type = typename Container::value_type;
 #ifdef JSON_HAS_CPP_14
+    /// @sa https://json.nlohmann.me/api/ordered_map/key_compare/
    using key_compare = std::equal_to<>;
 #else
+    /// @sa https://json.nlohmann.me/api/ordered_map/key_compare/
    using key_compare = std::equal_to<Key>;
 #endif

    // Explicit constructors instead of `using Container::Container`
    // otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map() noexcept(noexcept(Container())) : Container{} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc))) : Container{alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    template <class It>
    ordered_map(It first, It last, const Allocator& alloc = Allocator())
        : Container{first, last, alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(std::initializer_list<value_type> init, const Allocator& alloc = Allocator() )
        : Container{init, alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(const ordered_map&) = default;
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(ordered_map&&) noexcept(std::is_nothrow_move_constructible<Container>::value) = default;
+    /// @sa https://json.nlohmann.me/api/ordered_map/~ordered_map/
    ~ordered_map() = default;

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator=/
    ordered_map& operator=(const ordered_map& other)
    {
        if (this != &other)
@@ -68,6 +79,7 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
        return *this;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator=/
    ordered_map& operator=(ordered_map&& other) noexcept(std::is_nothrow_move_assignable<Container>::value)
    {
        Container::operator=(std::move(static_cast<Container&>(other)));
@@ -103,6 +115,7 @@ private:
    }

 public:
+    /// @sa https://json.nlohmann.me/api/ordered_map/emplace/
    template<class V, detail::enable_if_t<
                 detail::is_constructible<T, V>::value, int> = 0>
    std::pair<iterator, bool> emplace(const key_type& key, V && t)
@@ -116,6 +129,7 @@ public:
        return {std::prev(this->end()), true};
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/emplace/
    template<class KeyType, class V, detail::enable_if_t<
                 detail::conjunction<detail::is_usable_as_key_type<key_compare, key_type, KeyType>,
                                     detail::is_constructible<T, V>>::value, int> = 0>
@@ -130,11 +144,13 @@ public:
        return {std::prev(this->end()), true};
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    T& operator[](const key_type& key)
    {
        return emplace(key, T{}).first->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    T & operator[](KeyType && key)
@@ -142,11 +158,13 @@ public:
        return emplace(std::forward<KeyType>(key), T{}).first->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    const T& operator[](const key_type& key) const
    {
        return at(key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const T & operator[](KeyType && key) const
@@ -154,6 +172,7 @@ public:
        return at(std::forward<KeyType>(key));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    T& at(const key_type& key)
    {
        const auto it = find_impl(*this, key);
@@ -164,6 +183,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    T & at(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -176,6 +196,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    const T& at(const key_type& key) const
    {
        const auto it = find_impl(*this, key);
@@ -186,6 +207,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const T & at(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -198,6 +220,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    size_type erase(const key_type& key)
    {
        const auto it = find_impl(*this, key);
@@ -209,6 +232,7 @@ public:
        return 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type erase(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -222,11 +246,13 @@ public:
        return 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    iterator erase(iterator pos)
    {
        return erase(pos, std::next(pos));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    iterator erase(iterator first, iterator last)
    {
        if (first == last)
@@ -283,11 +309,13 @@ public:
        return Container::begin() + offset;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/count/
    size_type count(const key_type& key) const
    {
        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/count/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type count(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -295,11 +323,13 @@ public:
        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    iterator find(const key_type& key)
    {
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    iterator find(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -307,11 +337,13 @@ public:
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    const_iterator find(const key_type& key) const
    {
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const_iterator find(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -319,11 +351,13 @@ public:
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    std::pair<iterator, bool> insert( value_type&& value )
    {
        return emplace(value.first, std::move(value.second));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    std::pair<iterator, bool> insert( const value_type& value )
    {
        const auto it = find_impl(*this, value.first);
@@ -339,6 +373,7 @@ public:
    using require_input_iter = typename std::enable_if<std::is_convertible<typename std::iterator_traits<InputIt>::iterator_category,
        std::input_iterator_tag>::value>::type;

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    template<typename InputIt, typename = require_input_iter<InputIt>>
    void insert(InputIt first, InputIt last)
    {
@@ -7412,7 +7412,9 @@ template<typename BinaryType>
 class byte_container_with_subtype : public BinaryType
 {
  public:
+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/container_type/
    using container_type = BinaryType;
+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/subtype_type/
    using subtype_type = std::uint64_t;

    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/byte_container_with_subtype/
@@ -7444,12 +7446,14 @@ class byte_container_with_subtype : public BinaryType
        , m_has_subtype(true)
    {}

+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/operator_eq/
    bool operator==(const byte_container_with_subtype& rhs) const
    {
        return std::tie(static_cast<const BinaryType&>(*this), m_subtype, m_has_subtype) ==
               std::tie(static_cast<const BinaryType&>(rhs), rhs.m_subtype, rhs.m_has_subtype);
    }

+    /// @sa https://json.nlohmann.me/api/byte_container_with_subtype/operator_ne/
    bool operator!=(const byte_container_with_subtype& rhs) const
    {
        return !(rhs == *this);
@@ -12461,15 +12465,21 @@ input.
 template<typename BasicJsonType>
 struct json_sax
 {
+    /// @sa https://json.nlohmann.me/api/json_sax/number_integer_t/
    using number_integer_t = typename BasicJsonType::number_integer_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/number_unsigned_t/
    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/number_float_t/
    using number_float_t = typename BasicJsonType::number_float_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/string_t/
    using string_t = typename BasicJsonType::string_t;
+    /// @sa https://json.nlohmann.me/api/json_sax/binary_t/
    using binary_t = typename BasicJsonType::binary_t;

    /*!
    @brief a null value was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/null/
    */
    virtual bool null() = 0;

@@ -12477,6 +12487,7 @@ struct json_sax
    @brief a boolean value was read
    @param[in] val  boolean value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/boolean/
    */
    virtual bool boolean(bool val) = 0;

@@ -12484,6 +12495,7 @@ struct json_sax
    @brief an integer number was read
    @param[in] val  integer value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_integer/
    */
    virtual bool number_integer(number_integer_t val) = 0;

@@ -12491,6 +12503,7 @@ struct json_sax
    @brief an unsigned integer number was read
    @param[in] val  unsigned integer value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_unsigned/
    */
    virtual bool number_unsigned(number_unsigned_t val) = 0;

@@ -12499,6 +12512,7 @@ struct json_sax
    @param[in] val  floating-point value
    @param[in] s    raw token value
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/number_float/
    */
    virtual bool number_float(number_float_t val, const string_t& s) = 0;

@@ -12507,6 +12521,7 @@ struct json_sax
    @param[in] val  string value
    @return whether parsing should proceed
    @note It is safe to move the passed string value.
+    @sa https://json.nlohmann.me/api/json_sax/string/
    */
    virtual bool string(string_t& val) = 0;

@@ -12515,6 +12530,7 @@ struct json_sax
    @param[in] val  binary value
    @return whether parsing should proceed
    @note It is safe to move the passed binary value.
+    @sa https://json.nlohmann.me/api/json_sax/binary/
    */
    virtual bool binary(binary_t& val) = 0;

@@ -12523,6 +12539,7 @@ struct json_sax
    @param[in] elements  number of object elements or -1 if unknown
    @return whether parsing should proceed
    @note binary formats may report the number of elements
+    @sa https://json.nlohmann.me/api/json_sax/start_object/
    */
    virtual bool start_object(std::size_t elements) = 0;

@@ -12531,12 +12548,14 @@ struct json_sax
    @param[in] val  object key
    @return whether parsing should proceed
    @note It is safe to move the passed string.
+    @sa https://json.nlohmann.me/api/json_sax/key/
    */
    virtual bool key(string_t& val) = 0;

    /*!
    @brief the end of an object was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/end_object/
    */
    virtual bool end_object() = 0;

@@ -12545,12 +12564,14 @@ struct json_sax
    @param[in] elements  number of array elements or -1 if unknown
    @return whether parsing should proceed
    @note binary formats may report the number of elements
+    @sa https://json.nlohmann.me/api/json_sax/start_array/
    */
    virtual bool start_array(std::size_t elements) = 0;

    /*!
    @brief the end of an array was read
    @return whether parsing should proceed
+    @sa https://json.nlohmann.me/api/json_sax/end_array/
    */
    virtual bool end_array() = 0;

@@ -12560,16 +12581,23 @@ struct json_sax
    @param[in] last_token  the last read token
    @param[in] ex          an exception object describing the error
    @return whether parsing should proceed (must return false)
+    @sa https://json.nlohmann.me/api/json_sax/parse_error/
    */
    virtual bool parse_error(std::size_t position,
                             const std::string& last_token,
                             const detail::exception& ex) = 0;

+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax() = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax(const json_sax&) = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/json_sax/
    json_sax(json_sax&&) noexcept = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/operator=/
    json_sax& operator=(const json_sax&) = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/operator=/
    json_sax& operator=(json_sax&&) noexcept = default;
+    /// @sa https://json.nlohmann.me/api/json_sax/~json_sax/
    virtual ~json_sax() = default;
 };

@@ -19975,6 +20003,7 @@ class json_pointer

  public:
    // for backwards compatibility accept BasicJsonType
+    /// @sa https://json.nlohmann.me/api/json_pointer/string_t/
    using string_t = typename string_t_helper<RefStringType>::type;

    /// @brief create JSON pointer
@@ -27567,30 +27596,41 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
 {
    using key_type = Key;
    using mapped_type = T;
+    /// @sa https://json.nlohmann.me/api/ordered_map/Container/
    using Container = std::vector<std::pair<const Key, T>, Allocator>;
    using iterator = typename Container::iterator;
    using const_iterator = typename Container::const_iterator;
    using size_type = typename Container::size_type;
    using value_type = typename Container::value_type;
 #ifdef JSON_HAS_CPP_14
+    /// @sa https://json.nlohmann.me/api/ordered_map/key_compare/
    using key_compare = std::equal_to<>;
 #else
+    /// @sa https://json.nlohmann.me/api/ordered_map/key_compare/
    using key_compare = std::equal_to<Key>;
 #endif

    // Explicit constructors instead of `using Container::Container`
    // otherwise older compilers choke on it (GCC <= 5.5, xcode <= 9.4)
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map() noexcept(noexcept(Container())) : Container{} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc))) : Container{alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    template <class It>
    ordered_map(It first, It last, const Allocator& alloc = Allocator())
        : Container{first, last, alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(std::initializer_list<value_type> init, const Allocator& alloc = Allocator() )
        : Container{init, alloc} {}
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(const ordered_map&) = default;
+    /// @sa https://json.nlohmann.me/api/ordered_map/ordered_map/
    ordered_map(ordered_map&&) noexcept(std::is_nothrow_move_constructible<Container>::value) = default;
+    /// @sa https://json.nlohmann.me/api/ordered_map/~ordered_map/
    ~ordered_map() = default;

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator=/
    ordered_map& operator=(const ordered_map& other)
    {
        if (this != &other)
@@ -27601,6 +27641,7 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
        return *this;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator=/
    ordered_map& operator=(ordered_map&& other) noexcept(std::is_nothrow_move_assignable<Container>::value)
    {
        Container::operator=(std::move(static_cast<Container&>(other)));
@@ -27636,6 +27677,7 @@ private:
    }

 public:
+    /// @sa https://json.nlohmann.me/api/ordered_map/emplace/
    template<class V, detail::enable_if_t<
                 detail::is_constructible<T, V>::value, int> = 0>
    std::pair<iterator, bool> emplace(const key_type& key, V && t)
@@ -27649,6 +27691,7 @@ public:
        return {std::prev(this->end()), true};
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/emplace/
    template<class KeyType, class V, detail::enable_if_t<
                 detail::conjunction<detail::is_usable_as_key_type<key_compare, key_type, KeyType>,
                                     detail::is_constructible<T, V>>::value, int> = 0>
@@ -27663,11 +27706,13 @@ public:
        return {std::prev(this->end()), true};
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    T& operator[](const key_type& key)
    {
        return emplace(key, T{}).first->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    T & operator[](KeyType && key)
@@ -27675,11 +27720,13 @@ public:
        return emplace(std::forward<KeyType>(key), T{}).first->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    const T& operator[](const key_type& key) const
    {
        return at(key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/operator[]/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const T & operator[](KeyType && key) const
@@ -27687,6 +27734,7 @@ public:
        return at(std::forward<KeyType>(key));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    T& at(const key_type& key)
    {
        const auto it = find_impl(*this, key);
@@ -27697,6 +27745,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    T & at(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27709,6 +27758,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    const T& at(const key_type& key) const
    {
        const auto it = find_impl(*this, key);
@@ -27719,6 +27769,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/at/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const T & at(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27731,6 +27782,7 @@ public:
        return it->second;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    size_type erase(const key_type& key)
    {
        const auto it = find_impl(*this, key);
@@ -27742,6 +27794,7 @@ public:
        return 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type erase(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27755,11 +27808,13 @@ public:
        return 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    iterator erase(iterator pos)
    {
        return erase(pos, std::next(pos));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/erase/
    iterator erase(iterator first, iterator last)
    {
        if (first == last)
@@ -27816,11 +27871,13 @@ public:
        return Container::begin() + offset;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/count/
    size_type count(const key_type& key) const
    {
        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/count/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type count(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27828,11 +27885,13 @@ public:
        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    iterator find(const key_type& key)
    {
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    iterator find(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27840,11 +27899,13 @@ public:
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    const_iterator find(const key_type& key) const
    {
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/find/
    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const_iterator find(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
@@ -27852,11 +27913,13 @@ public:
        return find_impl(*this, key);
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    std::pair<iterator, bool> insert( value_type&& value )
    {
        return emplace(value.first, std::move(value.second));
    }

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    std::pair<iterator, bool> insert( const value_type& value )
    {
        const auto it = find_impl(*this, value.first);
@@ -27872,6 +27935,7 @@ public:
    using require_input_iter = typename std::enable_if<std::is_convertible<typename std::iterator_traits<InputIt>::iterator_category,
        std::input_iterator_tag>::value>::type;

+    /// @sa https://json.nlohmann.me/api/ordered_map/insert/
    template<typename InputIt, typename = require_input_iter<InputIt>>
    void insert(InputIt first, InputIt last)
    {
@@ -28075,25 +28139,34 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    using serializer = ::nlohmann::detail::serializer<basic_json>;

  public:
+    /// @brief the type of the JSON value
+    /// @sa https://json.nlohmann.me/api/basic_json/value_t/
    using value_t = detail::value_t;
    /// JSON Pointer, see @ref nlohmann::json_pointer
    using json_pointer = ::nlohmann::json_pointer<StringType>;
    template<typename T, typename SFINAE>
    using json_serializer = JSONSerializer<T, SFINAE>;
    /// how to treat decoding errors
+    /// @sa https://json.nlohmann.me/api/basic_json/error_handler_t/
    using error_handler_t = detail::error_handler_t;
    /// how to treat CBOR tags
+    /// @sa https://json.nlohmann.me/api/basic_json/cbor_tag_handler_t/
    using cbor_tag_handler_t = detail::cbor_tag_handler_t;
    /// how to encode BJData
+    /// @sa https://json.nlohmann.me/api/basic_json/bjdata_version_t/
    using bjdata_version_t = detail::bjdata_version_t;
    /// base class used to inject custom functionality into each instance of basic_json
    /// @sa https://json.nlohmann.me/api/basic_json/json_base_class_t/
    using json_base_class_t = ::nlohmann::detail::json_base_class<CustomBaseClass>;
    /// helper type for initializer lists of basic_json values
+    /// @sa https://json.nlohmann.me/api/basic_json/initializer_list_t/
    using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;

+    /// @brief the type of the SAX interface used to parse and serialize the JSON value
+    /// @sa https://json.nlohmann.me/api/basic_json/input_format_t/
    using input_format_t = detail::input_format_t;
    /// SAX interface type, see @ref nlohmann::json_sax
+    /// @sa https://json.nlohmann.me/api/basic_json/json_sax_t/
    using json_sax_t = json_sax<basic_json>;

    ////////////////////////////////////////////////////////////////////////////////
@@ -28299,15 +28372,19 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    /// the template arguments passed to class @ref basic_json.
    /// @{

+#if defined(JSON_HAS_CPP_14)
    /// @brief default object key comparator type
    /// The actual object key comparator type (@ref object_comparator_t) may be
    /// different.
    /// @sa https://json.nlohmann.me/api/basic_json/default_object_comparator_t/
-#if defined(JSON_HAS_CPP_14)
    // use of transparent comparator avoids unnecessary repeated construction of temporaries
    // in functions involving lookup by key with types other than object_t::key_type (aka. StringType)
    using default_object_comparator_t = std::less<>;
 #else
+    /// @brief default object key comparator type
+    /// The actual object key comparator type (@ref object_comparator_t) may be
+    /// different.
+    /// @sa https://json.nlohmann.me/api/basic_json/default_object_comparator_t/
    using default_object_comparator_t = std::less<StringType>;
 #endif

@@ -30375,6 +30452,7 @@ public:
    // other constructors and destructor //
    ///////////////////////////////////////

+    /// @sa https://json.nlohmann.me/api/basic_json/basic_json/
    template<typename JsonRef,
             detail::enable_if_t<detail::conjunction<detail::is_json_ref<JsonRef>,
                                 std::is_same<typename JsonRef::value_type, basic_json>>::value, int> = 0 >
@@ -30960,6 +31038,8 @@ public:
    @throw what @ref json_serializer<ValueType> `from_json()` method throws if conversion is required

    @since version 2.1.0
+
+    @sa https://json.nlohmann.me/api/basic_json/get/
    */
    template < typename ValueTypeCV, typename ValueType = detail::uncvref_t<ValueTypeCV>>
 #if defined(JSON_HAS_CPP_14)
@@ -31003,6 +31083,8 @@ public:
    @sa see @ref get_ptr() for explicit pointer-member access

    @since version 1.0.0
+
+    @sa https://json.nlohmann.me/api/basic_json/get/
    */
    template<typename PointerType, typename std::enable_if<
                 std::is_pointer<PointerType>::value, int>::type = 0>
@@ -31029,6 +31111,7 @@ public:

    // specialization to allow calling get_to with a basic_json value
    // see https://github.com/nlohmann/json/issues/2175
+    /// @sa https://json.nlohmann.me/api/basic_json/get_to/
    template<typename ValueType,
             detail::enable_if_t <
                 detail::is_basic_json<ValueType>::value,
@@ -31039,6 +31122,7 @@ public:
        return v;
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/get_to/
    template <
        typename T, std::size_t N,
        typename Array = T (&)[N], // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
@@ -31103,6 +31187,7 @@ public:

    @since version 1.0.0
    */
+    /// @sa https://json.nlohmann.me/api/basic_json/operator_ValueType/
    template < typename ValueType, typename std::enable_if <
                   detail::conjunction <
                       detail::negation<std::is_pointer<ValueType>>,
@@ -31411,12 +31496,14 @@ public:

    // these two functions resolve a (const) char * ambiguity affecting Clang and MSVC
    // (they seemingly cannot be constrained to resolve the ambiguity)
+    /// @sa https://json.nlohmann.me/api/basic_json/operator[]/
    template<typename T>
    reference operator[](T* key)
    {
        return operator[](typename object_t::key_type(key));
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator[]/
    template<typename T>
    const_reference operator[](T* key) const
    {
@@ -31594,6 +31681,7 @@ public:
        return found != nullptr ? found->template get<ReturnType>() : std::forward<ValueType>(default_value);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/value/
    template < class ValueType, class BasicJsonType, detail::enable_if_t <
                   detail::is_basic_json<BasicJsonType>::value
                   && detail::is_getable<basic_json_t, ValueType>::value
@@ -31608,6 +31696,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/value/
    template < class ValueType, class BasicJsonType, class ReturnType = typename value_return_type<ValueType>::type,
               detail::enable_if_t <
                   detail::is_basic_json<BasicJsonType>::value
@@ -31975,6 +32064,7 @@ public:
        return ptr.contains(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/contains/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
@@ -33491,6 +33581,7 @@ public:
        return result;
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/parse/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, parse(ptr, ptr + len))
    static basic_json parse(detail::span_input_adapter&& i,
@@ -33532,6 +33623,7 @@ public:
        return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/accept/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, accept(ptr, ptr + len))
    static bool accept(detail::span_input_adapter&& i,
@@ -33978,6 +34070,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::cbor, strict, allow_exceptions, error_handler, tag_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
@@ -33993,6 +34086,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_cbor/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_cbor(ptr, ptr + len))
    static basic_json from_cbor(detail::span_input_adapter&& i,
@@ -34032,6 +34126,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::msgpack, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
@@ -34046,6 +34141,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_msgpack/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_msgpack(ptr, ptr + len))
    static basic_json from_msgpack(detail::span_input_adapter&& i,
@@ -34084,6 +34180,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::ubjson, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
@@ -34098,6 +34195,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_ubjson/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_ubjson(ptr, ptr + len))
    static basic_json from_ubjson(detail::span_input_adapter&& i,
@@ -34212,6 +34310,7 @@ public:
        return from_binary_impl(detail::input_adapter(std::move(first), std::move(last)), input_format_t::bson, strict, allow_exceptions, error_handler);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
    template<typename T>
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
@@ -34226,6 +34325,7 @@ public:
    }
 #endif

+    /// @sa https://json.nlohmann.me/api/basic_json/from_bson/
    JSON_HEDLEY_WARN_UNUSED_RESULT
    JSON_HEDLEY_DEPRECATED_FOR(3.8.0, from_bson(ptr, ptr + len))
    static basic_json from_bson(detail::span_input_adapter&& i,
@@ -34254,6 +34354,7 @@ public:
        return ptr.get_unchecked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator%5B%5D/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    reference operator[](const ::nlohmann::json_pointer<BasicJsonType>& ptr)
@@ -34272,6 +34373,7 @@ public:
        return ptr.get_unchecked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/operator%5B%5D/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    const_reference operator[](const ::nlohmann::json_pointer<BasicJsonType>& ptr) const
@@ -34290,6 +34392,7 @@ public:
        return ptr.get_checked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/at/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    reference at(const ::nlohmann::json_pointer<BasicJsonType>& ptr)
@@ -34308,6 +34411,7 @@ public:
        return ptr.get_checked(this);
    }

+    /// @sa https://json.nlohmann.me/api/basic_json/at/
    template<typename BasicJsonType, detail::enable_if_t<detail::is_basic_json<BasicJsonType>::value, int> = 0>
    JSON_HEDLEY_DEPRECATED_FOR(3.11.0, basic_json::json_pointer or nlohmann::json_pointer<basic_json::string_t>) // NOLINT(readability/alt_tokens)
    const_reference at(const ::nlohmann::json_pointer<BasicJsonType>& ptr) const
@@ -35465,6 +35569,8 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
 #undef NLOHMANN_CAN_CALL_STD_FUNC_IMPL
 #undef JSON_INLINE_VARIABLE
 #undef JSON_NO_UNIQUE_ADDRESS
+#undef JSON_DISABLE_ENUM_SERIALIZATION
+#undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION

 #ifndef JSON_TEST_KEEP_MACROS
    #undef JSON_CATCH
@@ -35489,8 +35595,6 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
    #undef JSON_STRICT_BINARY_UTF8
    #undef JSON_DELETE_DEPRECATED_FUNCTIONS
    #undef JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
-    #undef JSON_DISABLE_ENUM_SERIALIZATION
-    #undef JSON_DISABLE_TUPLE_REFERENCE_CONVERSION
 #endif

 // #include <nlohmann/thirdparty/hedley/hedley_undef.hpp>
@@ -2,14 +2,12 @@ cmake_minimum_required(VERSION 3.13...4.0)

 option(JSON_Valgrind    "Execute test suite with Valgrind." OFF)
 option(JSON_FastTests   "Skip expensive/slow tests." OFF)
-option(JSON_TestUnityBuild "Build the unit tests in batches of several files per executable to speed up compilation." ON)
 option(JSON_TestSimdutf "Build the unit tests against the simdutf UTF-8 validation backend." OFF)

 set(JSON_SIMDUTF_VERSION 9.1.0 CACHE STRING "The simdutf version used by JSON_TestSimdutf.")

 set(JSON_32bitTest     AUTO CACHE STRING "Enable the 32bit unit test (ON/OFF/AUTO/ONLY).")
 set(JSON_TestStandards "" CACHE STRING "The list of standards to test explicitly.")
-set(JSON_TestUnityBatchSize 8 CACHE STRING "The number of unit test files compiled into one executable with JSON_TestUnityBuild.")
 set(JSON_TestShard     "" CACHE STRING "Build only a part of the unit tests, given as <index>/<count> (e.g. 0/2), to split them across CI jobs with a time limit.")

 # using an env var, since this will also affect targets executing cmake (such as "ci_test_compiler_default")
@@ -22,11 +20,6 @@ endif()

 include(test)

-# MinGW's GNU ld hits section and relocation limits with the large merged translation units
-if(MINGW)
-    set(JSON_TestUnityBuild OFF)
-endif()
-
 #############################################################################
 # override standard support
 #############################################################################
@@ -329,28 +322,9 @@ if(NOT "${JSON_TestShard}" STREQUAL "")
    message(STATUS "Test shard ${JSON_TestShard}: ${shard_file_count} of ${test_file_count} unit test files")
 endif()

-# Explicit groups of test files (file names without "unit-" and ".cpp") for
-# JSON_TestUnityBuild: all files of a group are compiled into one translation
-# unit per C++ standard, so that related tests share their template
-# instantiations (all binary formats instantiate the same readers and
-# writers). Only add a group where this was measured to pay off: grouping
-# files that share little just creates one slow translation unit. Files in no
-# group are batched alphabetically by JSON_TestUnityBatchSize.
-set(json_test_unity_groups binary)
-set(json_test_unity_group_binary binary_formats binary_utf8_error_handler binary_writer_sinks bjdata bon8 bon8-cpp17 bson byte_container_with_subtype cbor msgpack msgpack-cpp17 ubjson)
-
-if(JSON_TestUnityBuild)
-    message(STATUS "Building the unit tests in batches of ${JSON_TestUnityBatchSize} files (JSON_TestUnityBuild)")
-    json_test_add_unity_tests(FILES ${files} MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
-        BATCH_SIZE ${JSON_TestUnityBatchSize}
-        GROUPS ${json_test_unity_groups}
-        VARIANT_FILES src/unit-comparison.cpp src/unit-comparison-cpp20.cpp src/unit-class_parser.cpp src/unit-diagnostic-positions.cpp
-    )
-else()
-    foreach(file ${files})
-        json_test_add_test_for(${file} MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force})
-    endforeach()
-endif()
+foreach(file ${files})
+    json_test_add_test_for(${file} MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force})
+endforeach()

 # tests/src/unit-no-macro-leak.cpp #include-s the generated leak-check file,
 # so its test targets must be built after generate_hedley_undef_checks.
@@ -376,13 +350,6 @@ json_test_add_test_for(src/unit-comparison.cpp
    NAME test-comparison_legacy
    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
 )
-json_test_set_test_options(test-comparison_legacy-cpp20
-    COMPILE_DEFINITIONS JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1
-)
-json_test_add_test_for(src/unit-comparison-cpp20.cpp
-    NAME test-comparison_legacy-cpp20
-    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
-)

 # test the parser again with JSON_DIAGNOSTIC_POSITIONS enabled
 json_test_set_test_options(test-class_parser_diagnostic_positions
@@ -1,92 +0,0 @@
-# Unit tests
-
-The unit tests are in [`src/unit-*.cpp`](src) and use [doctest](https://github.com/doctest/doctest). Each file becomes
-one CTest test per C++ standard it is built for, named after the file: `src/unit-foo.cpp` becomes `test-foo_cpp11`.
-
-## Build and run
-
-```sh
-cmake -S . -B build -DJSON_BuildTests=ON
-cmake --build build -j 10
-ctest --test-dir build -j 10
-```
-
-The [CMake options](../docs/mkdocs/docs/integration/cmake.md) starting with `JSON_Test` (and `JSON_FastTests`,
-`JSON_Valgrind`) control the test build. The most relevant ones:
-
- `JSON_TestStandards`: build every test file for the given standards, e.g., `-DJSON_TestStandards=17`. By default,
-  a file is built for C++11 and for each standard whose `JSON_HAS_CPP_<N>` macro it mentions (see below).
- `JSON_TestUnityBuild`: compile several test files together (see below). Set it to `OFF` to get one executable per
-  test file, e.g., to debug a single test in a debugger.
- `JSON_TestShard`: build only a part of the test files, e.g., `-DJSON_TestShard=0/2`.
-
-To run the tests of one file only, run its CTest test, e.g., `ctest --test-dir build -R test-foo_cpp11`.
-
-## How test files are built
-
-Two mechanisms keep the compile time down. Both are automatic, but they set a few rules for test files.
-
-### C++ standards
-
-A test file is built for a C++ standard beyond C++11 if its text contains `JSON_HAS_CPP_<N>`, for instance in
-`#ifdef JSON_HAS_CPP_17`, or in a comment `// JSON_HAS_CPP_17` next to code that needs a macro only defined for that
-standard, such as `JSON_HAS_FILESYSTEM`. Then the *whole file* is compiled again for that standard.
-
-So that this does not happen for the large files, tests that need C++14, C++17, or C++20 go into a separate file
-`src/unit-<name>-cpp<N>.cpp` (e.g., [`src/unit-regression3-cpp17.cpp`](src/unit-regression3-cpp17.cpp)), whose body
-is wrapped in `#ifdef JSON_HAS_CPP_<N>`. The main file `src/unit-<name>.cpp` must not mention `JSON_HAS_CPP_<N>` at
-all, not even in a comment, so it is built for C++11 only. The CI jobs `ci_test_*_cxx<N>` still build every test file
-for every standard.
-
-### Unity build
-
-With `JSON_TestUnityBuild` (`ON` by default, `OFF` with MinGW), CMake compiles several test files as one translation
-unit, so they share the template instantiations of the library. CMake generates `build/tests/unity/test-unity-*.cpp`,
-which `#include` the test files of a batch. Every test file still gets its own CTest test, which runs the batch
-executable with `--source-file=*unit-foo.cpp`, so only the test cases of that file run.
-
-CMake decides from the macros a file defines *before* including `<nlohmann/json.hpp>`:
-
-| Macros defined before the include                                                         | Built as                          |
-|-------------------------------------------------------------------------------------------|-----------------------------------|
-| none (or only `SKIP_TESTS_FOR_*` and similar macros derived from global definitions)      | batch with the other plain files  |
-| only `JSON_TESTS_PRIVATE`                                                                 | batch with the other such files   |
-| any library configuration macro (`JSON_DIAGNOSTICS`, `JSON_NO_IO`, `JSON_ASSERT`, ...)    | its own executable                |
-
-Files with test-specific build options (`json_test_set_test_options(test-foo ...)` in
-[`CMakeLists.txt`](CMakeLists.txt)) also get their own executable. The batchable files are split alphabetically into
-batches of `JSON_TestUnityBatchSize` files, except for explicit groups of related files: `json_test_unity_group_binary`
-compiles all binary-format tests together, because they share the binary readers and writers. Only add a group if it
-measurably pays off; files that share little just make one slow translation unit.
-
-## Rules for test files
-
-Because the files of a batch share one translation unit, a test file must not affect the files that follow it:
-
-1. **Give file-scope helpers file-specific names.** An anonymous namespace does not help, as the batch is one
-   translation unit. Use a name such as `my_allocator_2982`, or wrap the helpers in a namespace named after the file
-   (e.g., `namespace unit_comparison_detail`). Clashes show up as compile errors.
-2. **Do not `#undef` library macros**, such as `JSON_HAS_CPP_17`, at the end of a file: this silently disables the tests
-   that depend on them in the later files of the batch. `#undef` macros you define yourself after including the library.
-3. **Put version-dependent tests into `unit-<name>-cpp<N>.cpp`** (see [C++ standards](#c-standards)).
-4. **Define test cases in the `.cpp` file itself.** The batch executable selects the tests of a file by its name, so a
-   `TEST_CASE` in a shared header is not run. The only exception is the test case in
-   [`src/make_test_data_available.hpp`](src/make_test_data_available.hpp), which CMake handles explicitly.
-
-To check a new file for clashes with all others at once, build with `-DJSON_TestUnityBatchSize=1000`, which puts all
-batchable files of a kind into one translation unit.
-
-## Where to add tests
-
-Tests are structured along the features of the library. Usually, an existing file is the right place:
-
- For a bug fix, add a section referencing the issue to [`src/unit-regression3.cpp`](src/unit-regression3.cpp), or to
-  [`src/unit-regression3-cpp17.cpp`](src/unit-regression3-cpp17.cpp) /
-  [`src/unit-regression3-cpp20.cpp`](src/unit-regression3-cpp20.cpp) if the test needs C++17 / C++20.
-  [`src/unit-regression2.cpp`](src/unit-regression2.cpp) holds older tests and should not grow further.
- When testing exceptions, use `CHECK_THROWS_WITH_AS`, which also checks the `what()` message.
-
-A new file `src/unit-<name>.cpp` is picked up automatically when CMake runs again; no change to `CMakeLists.txt` is
-needed.
-
-See also [`fuzzing.md`](fuzzing.md) for fuzz testing.
@@ -1,98 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  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
-
-// This file contains the C++17-only part of unit-allocator.cpp (std::string_view key
-// lookup with a failing allocator). It is kept in a separate translation unit so the (much
-// larger) unit-allocator.cpp is built for C++11 only and not rebuilt for every C++
-// standard.
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-
-#ifdef JSON_HAS_CPP_17
-#include <memory>
-#include <new>
-#include <string_view>
-#include <utility>
-
-namespace
-{
-bool next_construct_fails_cpp17 = false;
-bool next_destroy_fails_cpp17 = false;
-bool next_deallocate_fails_cpp17 = false;
-
-template<class T>
-struct my_allocator_cpp17 : std::allocator<T>
-{
-    using std::allocator<T>::allocator;
-
-    template<class... Args>
-    void construct(T* p, Args&& ... args)
-    {
-        if (next_construct_fails_cpp17)
-        {
-            next_construct_fails_cpp17 = false;
-            throw std::bad_alloc();
-        }
-
-        ::new (reinterpret_cast<void*>(p)) T(std::forward<Args>(args)...);
-    }
-
-    void deallocate(T* p, std::size_t n)
-    {
-        if (next_deallocate_fails_cpp17)
-        {
-            next_deallocate_fails_cpp17 = false;
-            throw std::bad_alloc();
-        }
-
-        std::allocator<T>::deallocate(p, n);
-    }
-
-    void destroy(T* p)
-    {
-        if (next_destroy_fails_cpp17)
-        {
-            next_destroy_fails_cpp17 = false;
-            throw std::bad_alloc();
-        }
-
-        static_cast<void>(p); // fix MSVC's C4100 warning
-        p->~T();
-    }
-
-    template <class U>
-    struct rebind
-    {
-        using other = my_allocator_cpp17<U>;
-    };
-};
-} // namespace
-
-// the no-exceptions CI job skips every CHECK_THROWS_AS, which would leave
-// next_construct_fails_cpp17 set for the next allocation outside a check
-#if !defined(JSON_NOEXCEPTION)
-TEST_CASE("a failed allocation leaves the value unchanged (C++17)")
-{
-    // create JSON type using the throwing allocator
-    using my_json = nlohmann::json::with_allocator_t<my_allocator_cpp17>;
-
-    SECTION("turning a null value into an array or object")
-    {
-        my_json j;
-
-        next_construct_fails_cpp17 = true;
-        CHECK_THROWS_AS(j[std::string_view("key")], std::bad_alloc&);
-        CHECK(j.is_null());
-
-        next_construct_fails_cpp17 = false;
-    }
-}
-#endif
-#endif
@@ -1,115 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  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
-
-// This file contains the C++20-only part of unit-allocator.cpp (creating a value from a
-// std::ranges view with a failing allocator). It is kept in a separate translation unit so
-// the (much larger) unit-allocator.cpp is built for C++11 only and not rebuilt for every
-// C++ standard.
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-
-#ifdef JSON_HAS_CPP_20
-#if JSON_HAS_RANGES
-    #include <ranges>
-#endif
-
-#include <memory>
-#include <new>
-#include <utility>
-#include <vector>
-
-namespace
-{
-bool next_construct_fails_cpp20 = false;
-bool next_destroy_fails_cpp20 = false;
-bool next_deallocate_fails_cpp20 = false;
-
-template<class T>
-struct my_allocator_cpp20 : std::allocator<T>
-{
-    using std::allocator<T>::allocator;
-
-    template<class... Args>
-    void construct(T* p, Args&& ... args)
-    {
-        if (next_construct_fails_cpp20)
-        {
-            next_construct_fails_cpp20 = false;
-            throw std::bad_alloc();
-        }
-
-        ::new (reinterpret_cast<void*>(p)) T(std::forward<Args>(args)...);
-    }
-
-    void deallocate(T* p, std::size_t n)
-    {
-        if (next_deallocate_fails_cpp20)
-        {
-            next_deallocate_fails_cpp20 = false;
-            throw std::bad_alloc();
-        }
-
-        std::allocator<T>::deallocate(p, n);
-    }
-
-    void destroy(T* p)
-    {
-        if (next_destroy_fails_cpp20)
-        {
-            next_destroy_fails_cpp20 = false;
-            throw std::bad_alloc();
-        }
-
-        static_cast<void>(p); // fix MSVC's C4100 warning
-        p->~T();
-    }
-
-    template <class U>
-    struct rebind
-    {
-        using other = my_allocator_cpp20<U>;
-    };
-};
-} // namespace
-
-// the no-exceptions CI job skips every CHECK_THROWS_AS, which would leave
-// next_construct_fails_cpp20 set for the next allocation outside a check
-#if !defined(JSON_NOEXCEPTION)
-TEST_CASE("a failed allocation leaves the value unchanged (C++20)")
-{
-    // create JSON type using the throwing allocator
-    using my_json = nlohmann::json::with_allocator_t<my_allocator_cpp20>;
-
-    // With iterator debugging, VS 2015's containers construct a proxy with the
-    // allocator in constructors that cannot report its failure, so a failing
-    // allocator crashes this section there (SIGSEGV with VS 2015 Debug x86).
-#if !(defined(_MSC_VER) && _MSC_VER < 1910 && defined(_ITERATOR_DEBUG_LEVEL) && _ITERATOR_DEBUG_LEVEL > 0)
-    SECTION("converting into an existing value")
-    {
-        // to_json replaces the value it is given; the old one must survive a
-        // failed creation of the new one
-        my_json j = "old";
-
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
-        const std::vector<int> numbers = {1, 2};
-        next_construct_fails_cpp20 = true;
-        CHECK_THROWS_AS(nlohmann::to_json(j, numbers | std::views::filter([](int /*unused*/)
-        {
-            return true;
-        })), std::bad_alloc&);
-        CHECK(j == "old");
-#endif
-
-        next_construct_fails_cpp20 = false;
-    }
-#endif
-}
-#endif
-#endif
@@ -13,6 +13,9 @@
 using nlohmann::json;

 #include <valarray>
+#if JSON_HAS_RANGES
+    #include <ranges>
+#endif

 namespace
 {
@@ -681,6 +684,12 @@ TEST_CASE("a failed allocation leaves the value unchanged")
        CHECK_THROWS_AS(j["key"], std::bad_alloc&);
        CHECK(j.is_null());

+#ifdef JSON_HAS_CPP_17
+        next_construct_fails = true;
+        CHECK_THROWS_AS(j[std::string_view("key")], std::bad_alloc&);
+        CHECK(j.is_null());
+#endif
+
        next_construct_fails = true;
        CHECK_THROWS_AS(j.push_back(my_json(1)), std::bad_alloc&);
        CHECK(j.is_null());
@@ -778,6 +787,16 @@ TEST_CASE("a failed allocation leaves the value unchanged")
        CHECK_THROWS_AS(nlohmann::to_json(j, std::valarray<int> {1, 2}), std::bad_alloc&);
        CHECK(j == "old");

+#if JSON_HAS_RANGES && !defined(__MINGW32__)
+        const std::vector<int> numbers = {1, 2};
+        next_construct_fails = true;
+        CHECK_THROWS_AS(nlohmann::to_json(j, numbers | std::views::filter([](int /*unused*/)
+        {
+            return true;
+        })), std::bad_alloc&);
+        CHECK(j == "old");
+#endif
+
        next_construct_fails = false;
        nlohmann::to_json(j, std::vector<int> {1, 2});
        CHECK(j == my_json({1, 2}));
@@ -1,60 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  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
-
-// This file contains the C++17-only part of unit-bon8.cpp (BON8 with std::byte
-// containers). It is kept in a separate translation unit so the (much larger) unit-
-// bon8.cpp is built for C++11 only and not rebuilt for every C++ standard.
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-using nlohmann::json;
-
-#ifdef JSON_HAS_CPP_17
-#include <cstddef>
-#include <cstdint>
-#include <vector>
-
-TEST_CASE("BON8 with std::byte")
-{
-    SECTION("vector roundtrip")
-    {
-        const json original =
-        {
-            {"name", "test"},
-            {"value", 42},
-            {"array", {1, 2, 3}}
-        };
-
-        const std::vector<uint8_t> temp = json::to_bon8(original);
-        std::vector<std::byte> bon8_data(temp.size());
-        for (size_t i = 0; i < temp.size(); ++i)
-        {
-            bon8_data[i] = std::byte(temp[i]);
-        }
-
-        json from_bytes;
-        CHECK_NOTHROW(from_bytes = json::from_bon8(bon8_data));
-        CHECK(from_bytes == original);
-    }
-
-    SECTION("empty vector")
-    {
-        const std::vector<std::byte> empty_data;
-        CHECK_THROWS_WITH_AS([&]()
-        {
-            [[maybe_unused]] auto result = json::from_bon8(empty_data);
-            return true;
-        }
-        (),
-        "[json.exception.parse_error.110] parse error at byte 1: syntax error while parsing BON8 value: unexpected end of input",
-        json::parse_error&);
-    }
-}
-
-#endif
@@ -1052,3 +1052,41 @@ TEST_CASE("issue #5648 - from_bon8(ptr, len) must read len bytes, not treat ptr
 #endif
 }

+#ifdef JSON_HAS_CPP_17
+TEST_CASE("BON8 with std::byte")
+{
+    SECTION("vector roundtrip")
+    {
+        const json original =
+        {
+            {"name", "test"},
+            {"value", 42},
+            {"array", {1, 2, 3}}
+        };
+
+        const std::vector<uint8_t> temp = json::to_bon8(original);
+        std::vector<std::byte> bon8_data(temp.size());
+        for (size_t i = 0; i < temp.size(); ++i)
+        {
+            bon8_data[i] = std::byte(temp[i]);
+        }
+
+        json from_bytes;
+        CHECK_NOTHROW(from_bytes = json::from_bon8(bon8_data));
+        CHECK(from_bytes == original);
+    }
+
+    SECTION("empty vector")
+    {
+        const std::vector<std::byte> empty_data;
+        CHECK_THROWS_WITH_AS([&]()
+        {
+            [[maybe_unused]] auto result = json::from_bon8(empty_data);
+            return true;
+        }
+        (),
+        "[json.exception.parse_error.110] parse error at byte 1: syntax error while parsing BON8 value: unexpected end of input",
+        json::parse_error&);
+    }
+}
+#endif
@@ -1,496 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  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
-
-// This file contains the C++20-only part of unit-comparison.cpp (tests of operator<=> and
-// other three-way comparison specific behavior). It is kept in a separate translation unit
-// so the (much larger) unit-comparison.cpp is built for C++11 only and not rebuilt for
-// every C++ standard.
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-using nlohmann::json;
-
-#ifdef JSON_HAS_CPP_20
-#if JSON_HAS_THREE_WAY_COMPARISON
-#include <cmath>
-#include <compare>
-#include <cstddef>
-#include <limits>
-#include <string>
-#include <utility>
-#include <vector>
-
-// this can be replaced with the doctest stl extension header in version 2.5
-namespace doctest
-{
-template<> struct StringMaker<std::partial_ordering>
-{
-    static String convert(const std::partial_ordering& order)
-    {
-        if (order == std::partial_ordering::less)
-        {
-            return "std::partial_ordering::less";
-        }
-        if (order == std::partial_ordering::equivalent)
-        {
-            return "std::partial_ordering::equivalent";
-        }
-        if (order == std::partial_ordering::greater)
-        {
-            return "std::partial_ordering::greater";
-        }
-        if (order == std::partial_ordering::unordered)
-        {
-            return "std::partial_ordering::unordered";
-        }
-        return "{?}";
-    }
-};
-} // namespace doctest
-
-TEST_CASE("lexicographical comparison operators (C++20)")
-{
-    constexpr auto f_ = false;
-    constexpr auto _t = true;
-    constexpr auto nan = std::numeric_limits<json::number_float_t>::quiet_NaN();
-    constexpr auto lt = std::partial_ordering::less;
-    constexpr auto gt = std::partial_ordering::greater;
-    constexpr auto eq = std::partial_ordering::equivalent;
-    constexpr auto un = std::partial_ordering::unordered;
-
-    INFO("using 3-way comparison");
-
-#if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
-    INFO("using legacy comparison");
-#endif
-
-    SECTION("types")
-    {
-        std::vector<json::value_t> j_types =
-        {
-            json::value_t::null,
-            json::value_t::boolean,
-            json::value_t::number_integer,
-            json::value_t::number_unsigned,
-            json::value_t::number_float,
-            json::value_t::object,
-            json::value_t::array,
-            json::value_t::string,
-            json::value_t::binary,
-            json::value_t::discarded
-        };
-
-        std::vector<std::vector<bool>> expected_lt =
-        {
-            //0   1   2   3   4   5   6   7   8   9
-            {f_, _t, _t, _t, _t, _t, _t, _t, _t, f_}, //  0
-            {f_, f_, _t, _t, _t, _t, _t, _t, _t, f_}, //  1
-            {f_, f_, f_, f_, f_, _t, _t, _t, _t, f_}, //  2
-            {f_, f_, f_, f_, f_, _t, _t, _t, _t, f_}, //  3
-            {f_, f_, f_, f_, f_, _t, _t, _t, _t, f_}, //  4
-            {f_, f_, f_, f_, f_, f_, _t, _t, _t, f_}, //  5
-            {f_, f_, f_, f_, f_, f_, f_, _t, _t, f_}, //  6
-            {f_, f_, f_, f_, f_, f_, f_, f_, _t, f_}, //  7
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  8
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  9
-        };
-
-        SECTION("comparison: less")
-        {
-            for (size_t i = 0; i < j_types.size(); ++i)
-            {
-                for (size_t j = 0; j < j_types.size(); ++j)
-                {
-                    CAPTURE(i)
-                    CAPTURE(j)
-                    // check precomputed values
-                    CHECK((j_types[i] < j_types[j]) == expected_lt[i][j]);
-                }
-            }
-        }
-
-        SECTION("comparison: 3-way")
-        {
-            // doctest runs the REQUIRE in the test case body once per leaf section; keep it
-            // here to run it as often as before the 3-way sections moved from unit-comparison.cpp
-            REQUIRE(std::isnan(nan));
-
-            std::vector<std::vector<std::partial_ordering>> expected =
-            {
-                //0   1   2   3   4   5   6   7   8   9
-                {eq, lt, lt, lt, lt, lt, lt, lt, lt, un}, //  0
-                {gt, eq, lt, lt, lt, lt, lt, lt, lt, un}, //  1
-                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  2
-                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  3
-                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  4
-                {gt, gt, gt, gt, gt, eq, lt, lt, lt, un}, //  5
-                {gt, gt, gt, gt, gt, gt, eq, lt, lt, un}, //  6
-                {gt, gt, gt, gt, gt, gt, gt, eq, lt, un}, //  7
-                {gt, gt, gt, gt, gt, gt, gt, gt, eq, un}, //  8
-                {un, un, un, un, un, un, un, un, un, un}, //  9
-            };
-
-            // check expected partial_ordering against expected boolean
-            REQUIRE(expected.size() == expected_lt.size());
-            for (size_t i = 0; i < expected.size(); ++i)
-            {
-                REQUIRE(expected[i].size() == expected_lt[i].size());
-                for (size_t j = 0; j < expected[i].size(); ++j)
-                {
-                    CAPTURE(i)
-                    CAPTURE(j)
-                    CHECK(std::is_lt(expected[i][j]) == expected_lt[i][j]);
-                }
-            }
-
-            // check 3-way comparison against expected partial_ordering
-            REQUIRE(expected.size() == j_types.size());
-            for (size_t i = 0; i < j_types.size(); ++i)
-            {
-                REQUIRE(expected[i].size() == j_types.size());
-                for (size_t j = 0; j < j_types.size(); ++j)
-                {
-                    CAPTURE(i)
-                    CAPTURE(j)
-                    CHECK((j_types[i] <=> j_types[j]) == expected[i][j]); // *NOPAD*
-                }
-            }
-        }
-    }
-
-    SECTION("values")
-    {
-        json j_values =
-        {
-            nullptr, nullptr,                                              // 0 1
-            -17, 42,                                                       // 2 3
-            8u, 13u,                                                       // 4 5
-            3.14159, 23.42,                                                // 6 7
-            nan, nan,                                                      // 8 9
-            "foo", "bar",                                                  // 10 11
-            true, false,                                                   // 12 13
-            {1, 2, 3}, {"one", "two", "three"},                            // 14 15
-            {{"first", 1}, {"second", 2}}, {{"a", "A"}, {"b", {"B"}}},     // 16 17
-            json::binary({1, 2, 3}), json::binary({1, 2, 4}),              // 18 19
-            json(json::value_t::discarded), json(json::value_t::discarded) // 20 21
-        };
-
-        std::vector<std::vector<bool>> expected_eq =
-        {
-            //0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21
-            {_t, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  0
-            {_t, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  1
-            {f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  2
-            {f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  3
-            {f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  4
-            {f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  5
-            {f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  6
-            {f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  7
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  8
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, //  9
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 10
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 11
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 12
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, f_}, // 13
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_}, // 14
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_}, // 15
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_}, // 16
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_}, // 17
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_}, // 18
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_}, // 19
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 20
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 21
-        };
-
-        std::vector<std::vector<bool>> expected_lt =
-        {
-            //0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21
-            {f_, f_, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, f_, f_}, //  0
-            {f_, f_, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, f_, f_}, //  1
-            {f_, f_, f_, _t, _t, _t, _t, _t, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  2
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  3
-            {f_, f_, f_, _t, f_, _t, f_, _t, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  4
-            {f_, f_, f_, _t, f_, f_, f_, _t, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  5
-            {f_, f_, f_, _t, _t, _t, f_, _t, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  6
-            {f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  7
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  8
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, //  9
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_}, // 10
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_}, // 11
-            {f_, f_, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, f_, f_, _t, _t, _t, _t, _t, _t, f_, f_}, // 12
-            {f_, f_, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, _t, f_, _t, _t, _t, _t, _t, _t, f_, f_}, // 13
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, f_, _t, f_, f_, _t, _t, f_, f_}, // 14
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_}, // 15
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, f_, f_, _t, _t, f_, f_}, // 16
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, _t, f_, f_, _t, _t, _t, f_, _t, _t, f_, f_}, // 17
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, _t, f_, f_}, // 18
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 19
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 20
-            {f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_, f_}, // 21
-        };
-
-        SECTION("signed/unsigned mixed comparison above INT64_MAX")
-        {
-            const json above_int64_max = static_cast<std::uint64_t>((std::numeric_limits<std::int64_t>::max)()) + 1ULL;
-            const json max_uint64 = (std::numeric_limits<std::uint64_t>::max)();
-            const json negative_one = -1;
-            const json one = 1;
-            const json max_int64 = (std::numeric_limits<std::int64_t>::max)();
-
-            CHECK((negative_one <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
-            CHECK((above_int64_max <=> negative_one) == std::partial_ordering::greater); // *NOPAD*
-            CHECK((negative_one <=> max_uint64) == std::partial_ordering::less); // *NOPAD*
-            CHECK((max_uint64 <=> negative_one) == std::partial_ordering::greater); // *NOPAD*
-            CHECK((one <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
-            CHECK((above_int64_max <=> one) == std::partial_ordering::greater); // *NOPAD*
-            CHECK((max_int64 <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
-            CHECK((above_int64_max <=> max_int64) == std::partial_ordering::greater); // *NOPAD*
-        }
-
-        SECTION("integer/float mixed comparison is exact")
-        {
-            // Widening the integer to a double loses precision past the
-            // mantissa, so 2^63-2 and 2^63-1 both used to compare equal to the
-            // double 2^63 while differing from each other. That makes equality
-            // intransitive and the ordering not a strict weak ordering.
-            const json below_two_63 = static_cast<std::int64_t>(9223372036854775806LL);
-            const json max_int64 = (std::numeric_limits<std::int64_t>::max)();
-            const json two_63 = 9223372036854775808.0;
-
-            // the same past the unsigned range
-            const json max_uint64 = (std::numeric_limits<std::uint64_t>::max)();
-            const json two_64 = 18446744073709551616.0;
-
-            CHECK((max_int64 <=> two_63) == std::partial_ordering::less); // *NOPAD*
-            CHECK((two_63 <=> max_int64) == std::partial_ordering::greater); // *NOPAD*
-            CHECK((below_two_63 <=> max_int64) == std::partial_ordering::less); // *NOPAD*
-            CHECK((max_uint64 <=> two_64) == std::partial_ordering::less); // *NOPAD*
-            CHECK((json(1) <=> json(1.0)) == std::partial_ordering::equivalent); // *NOPAD*
-            CHECK((json(1) <=> json(nan)) == std::partial_ordering::unordered); // *NOPAD*
-        }
-
-        SECTION("comparison: 3-way")
-        {
-            // doctest runs the REQUIRE in the test case body once per leaf section; keep it
-            // here to run it as often as before the 3-way sections moved from unit-comparison.cpp
-            REQUIRE(std::isnan(nan));
-
-            std::vector<std::vector<std::partial_ordering>> expected =
-            {
-                //0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21
-                {eq, eq, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, un, un}, //  0
-                {eq, eq, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, un, un}, //  1
-                {gt, gt, eq, lt, lt, lt, lt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  2
-                {gt, gt, gt, eq, gt, gt, gt, gt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  3
-                {gt, gt, gt, lt, eq, lt, gt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  4
-                {gt, gt, gt, lt, gt, eq, gt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  5
-                {gt, gt, gt, lt, lt, lt, eq, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  6
-                {gt, gt, gt, lt, gt, gt, gt, eq, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  7
-                {gt, gt, un, un, un, un, un, un, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  8
-                {gt, gt, un, un, un, un, un, un, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  9
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, gt, gt, gt, gt, gt, gt, gt, lt, lt, un, un}, // 10
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, eq, gt, gt, gt, gt, gt, gt, lt, lt, un, un}, // 11
-                {gt, gt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, eq, gt, lt, lt, lt, lt, lt, lt, un, un}, // 12
-                {gt, gt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, eq, lt, lt, lt, lt, lt, lt, un, un}, // 13
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, eq, lt, gt, gt, lt, lt, un, un}, // 14
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, gt, eq, gt, gt, lt, lt, un, un}, // 15
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, lt, lt, eq, gt, lt, lt, un, un}, // 16
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, lt, lt, lt, eq, lt, lt, un, un}, // 17
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, lt, un, un}, // 18
-                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, un, un}, // 19
-                {un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un}, // 20
-                {un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un}, // 21
-            };
-
-            // check expected partial_ordering against expected booleans
-            REQUIRE(expected.size() == expected_eq.size());
-            REQUIRE(expected.size() == expected_lt.size());
-            for (size_t i = 0; i < expected.size(); ++i)
-            {
-                REQUIRE(expected[i].size() == expected_eq[i].size());
-                REQUIRE(expected[i].size() == expected_lt[i].size());
-                for (size_t j = 0; j < expected[i].size(); ++j)
-                {
-                    CAPTURE(i)
-                    CAPTURE(j)
-                    CHECK(std::is_eq(expected[i][j]) == expected_eq[i][j]);
-                    CHECK(std::is_lt(expected[i][j]) == expected_lt[i][j]);
-                    if (std::is_gt(expected[i][j]))
-                    {
-                        CHECK((!expected_eq[i][j] && !expected_lt[i][j]));
-                    }
-                }
-            }
-
-            // check that two values compare according to their expected ordering
-            REQUIRE(expected.size() == j_values.size());
-            for (size_t i = 0; i < j_values.size(); ++i)
-            {
-                REQUIRE(expected[i].size() == j_values.size());
-                for (size_t j = 0; j < j_values.size(); ++j)
-                {
-                    CAPTURE(i)
-                    CAPTURE(j)
-                    CHECK((j_values[i] <=> j_values[j]) == expected[i][j]); // *NOPAD*
-                }
-            }
-        }
-    }
-
-}
-
-TEST_CASE("regression #3868 - heterogeneous comparisons compile under C++20 (P2468R2)")
-{
-    // Issue #3868: operator!= was preventing compiler from synthesizing reversed
-    // operator== candidates under C++20's P2468R2 rewritten candidate rules.
-    // Verify that heterogeneous comparisons now work.
-
-    SECTION("string vs json")
-    {
-        std::string s = "string";
-        json j = "string";
-        CHECK(s == j);
-        CHECK(j == s);
-        CHECK_FALSE(s != j);
-        CHECK_FALSE(j != s);
-    }
-
-    SECTION("other heterogeneous types")
-    {
-        int i = 42;
-        json j = 42;
-        CHECK(i == j);
-        CHECK(j == i);
-        CHECK_FALSE(i != j);
-        CHECK_FALSE(j != i);
-    }
-}
-
-#if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
-TEST_CASE("regression #5665 - scalar <= discarded and scalar >= discarded in C++20 legacy mode")
-{
-    // Issue #5665: with a scalar on the left-hand side, <= and >= only had the
-    // candidate rewritten from operator<=>, which does not emulate the legacy
-    // discarded-value behavior. Check that scalar-on-the-left now matches the
-    // other three operand orders.
-    const json discarded(json::value_t::discarded);
-    const json one = 1;
-
-    CHECK(discarded <= 1);
-    CHECK(discarded >= 1);
-    CHECK(one <= discarded);
-    CHECK(one >= discarded);
-    CHECK(1 <= discarded);
-    CHECK(1 >= discarded);
-    CHECK(1.5 <= discarded);
-    CHECK(1.5 >= discarded);
-}
-
-#endif
-
-TEST_CASE("containers are compared element by element (C++20)")
-{
-    // Containers nested deeper than a bound are compared without the call
-    // stack, by code of their own; every relation is checked both at the top
-    // level and below that bound.
-    const auto deep = [](const json & j, const std::size_t depth)
-    {
-        json result = j;
-        for (std::size_t i = 0; i < depth; ++i)
-        {
-            result = json::array({std::move(result)});
-        }
-        return result;
-    };
-
-    for (const std::size_t depth : std::vector<std::size_t> {0, 200})
-    {
-        CAPTURE(depth)
-
-        // objects with different keys
-        {
-            const json a = deep({{"a", 1}}, depth);
-            const json b = deep({{"b", 1}}, depth);
-            CHECK((a <=> b) == std::partial_ordering::less); // *NOPAD*
-            CHECK((b <=> a) == std::partial_ordering::greater); // *NOPAD*
-            CHECK((a <=> a) == std::partial_ordering::equivalent); // *NOPAD*
-        }
-
-        // a container that is a prefix of the other one
-        {
-            // the one that runs out of elements first is the smaller one
-            const json shorter = deep({1}, depth);
-            const json longer = deep({1, 2}, depth);
-
-            const json smaller_object = deep({{"a", 1}}, depth);
-            const json larger_object = deep({{"a", 1}, {"b", 2}}, depth);
-            CHECK((shorter <=> longer) == std::partial_ordering::less); // *NOPAD*
-            CHECK((longer <=> shorter) == std::partial_ordering::greater); // *NOPAD*
-        }
-
-        // elements that cannot be ordered
-        {
-            const double nan = std::numeric_limits<double>::quiet_NaN();
-            const json lhs = deep({nan, 1}, depth);
-            const json rhs = deep({nan, 2}, depth);
-            // operator<=> stops there, as std::lexicographical_compare_three_way
-            // does, and operator< is derived from it
-            CHECK((lhs <=> rhs) == std::partial_ordering::unordered); // *NOPAD*
-            CHECK_FALSE(lhs < rhs);
-        }
-    }
-}
-
-TEST_CASE("operator<=> of binary values with a different subtype does not depend on nesting depth")
-{
-    // #5654: std::vector<std::uint8_t>::operator<=>, which the binary type's
-    // own operator<=> uses, ignores the subtype that operator== checks. So a
-    // pair of binary values with the same bytes but a different subtype is
-    // unequal, yet <=>-equivalent - the same inconsistency between == and <=>
-    // that a NaN has. Within the nesting bound, an array compares itself
-    // with std::vector's own operator<=>, which treats an equivalent pair as
-    // undecided and lets the next element decide, same as
-    // std::lexicographical_compare_three_way does. Past the bound,
-    // compare_iteratively<true>() takes over and must classify the pair the
-    // same way, or the result of operator<=> - and of <, which C++20 derives
-    // from it - depends on how deeply the values are nested.
-    const json a = json::array({json::binary({1}, 1), 1});
-    const json b = json::array({json::binary({1}, 2), 2});
-
-    // the root inconsistency: unequal, yet <=>-equivalent
-    CHECK_FALSE(a[0] == b[0]);
-    CHECK((a[0] <=> b[0]) == std::partial_ordering::equivalent); // *NOPAD*
-
-    const auto deep = [](const json & j, const std::size_t depth)
-    {
-        json result = j;
-        for (std::size_t i = 0; i < depth; ++i)
-        {
-            result = json::array({std::move(result)});
-        }
-        return result;
-    };
-
-    // 127 levels stay within nesting_depth_limit() (128); 128 and 200 do not,
-    // and must still agree with the levels that do
-    for (const std::size_t depth : std::vector<std::size_t> {0, 127, 128, 200})
-    {
-        CAPTURE(depth)
-        const json x = deep(a, depth);
-        const json y = deep(b, depth);
-        CHECK((x <=> y) == std::partial_ordering::less); // *NOPAD*
-        CHECK((y <=> x) == std::partial_ordering::greater); // *NOPAD*
-        CHECK(x < y);
-        CHECK(y > x);
-        CHECK_FALSE(y < x);
-    }
-}
-
-#endif // JSON_HAS_THREE_WAY_COMPARISON
-#endif
@@ -6,11 +6,12 @@
 // SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
 // SPDX-License-Identifier: MIT

-// cmake/test.cmake builds a unit test with C++ standards beyond C++11 only if the
-// source file mentions the corresponding version macro. To avoid rebuilding this
-// large file for every standard, tests that depend on the standard version (e.g.,
-// those using JSON_HAS_FILESYSTEM, JSON_HAS_RANGES, or JSON_HAS_THREE_WAY_COMPARISON)
-// go into a separate file unit-comparison-cpp<NN>.cpp. This file stays C++11-only.
+// cmake/test.cmake selects the C++ standard versions with which to build a
+// unit test based on the presence of JSON_HAS_CPP_<VERSION> macros.
+// When using macros that are only defined for particular versions of the standard
+// (e.g., JSON_HAS_FILESYSTEM for C++17 and up), please mention the corresponding
+// version macro in a comment close by, like this:
+// JSON_HAS_CPP_<VERSION> (do not remove; see note at top of file)

 #include "doctest_compatibility.h"

@@ -27,6 +28,37 @@
 #include <nlohmann/json.hpp>
 using nlohmann::json;

+#if JSON_HAS_THREE_WAY_COMPARISON
+// this can be replaced with the doctest stl extension header in version 2.5
+namespace doctest
+{
+template<> struct StringMaker<std::partial_ordering>
+{
+    static String convert(const std::partial_ordering& order)
+    {
+        if (order == std::partial_ordering::less)
+        {
+            return "std::partial_ordering::less";
+        }
+        if (order == std::partial_ordering::equivalent)
+        {
+            return "std::partial_ordering::equivalent";
+        }
+        if (order == std::partial_ordering::greater)
+        {
+            return "std::partial_ordering::greater";
+        }
+        if (order == std::partial_ordering::unordered)
+        {
+            return "std::partial_ordering::unordered";
+        }
+        return "{?}";
+    }
+};
+} // namespace doctest
+
+#endif
+
 namespace
 {
 // helper function to check std::less<json::value_t>
@@ -43,6 +75,16 @@ TEST_CASE("lexicographical comparison operators")
    constexpr auto f_ = false;
    constexpr auto _t = true;
    constexpr auto nan = std::numeric_limits<json::number_float_t>::quiet_NaN();
+#if JSON_HAS_THREE_WAY_COMPARISON
+    constexpr auto lt = std::partial_ordering::less;
+    constexpr auto gt = std::partial_ordering::greater;
+    constexpr auto eq = std::partial_ordering::equivalent;
+    constexpr auto un = std::partial_ordering::unordered;
+#endif
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+    INFO("using 3-way comparison");
+#endif

 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
    INFO("using legacy comparison");
@@ -93,13 +135,62 @@ TEST_CASE("lexicographical comparison operators")
                    CAPTURE(i)
                    CAPTURE(j)
                    // check precomputed values
-#if !JSON_HAS_THREE_WAY_COMPARISON
+#if JSON_HAS_THREE_WAY_COMPARISON
+                    // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+                    CHECK((j_types[i] < j_types[j]) == expected_lt[i][j]);
+#else
                    CHECK(operator<(j_types[i], j_types[j]) == expected_lt[i][j]);
 #endif
                    CHECK(f(j_types[i], j_types[j]) == expected_lt[i][j]);
                }
            }
        }
+#if JSON_HAS_THREE_WAY_COMPARISON
+        // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+        SECTION("comparison: 3-way")
+        {
+            std::vector<std::vector<std::partial_ordering>> expected =
+            {
+                //0   1   2   3   4   5   6   7   8   9
+                {eq, lt, lt, lt, lt, lt, lt, lt, lt, un}, //  0
+                {gt, eq, lt, lt, lt, lt, lt, lt, lt, un}, //  1
+                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  2
+                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  3
+                {gt, gt, eq, eq, eq, lt, lt, lt, lt, un}, //  4
+                {gt, gt, gt, gt, gt, eq, lt, lt, lt, un}, //  5
+                {gt, gt, gt, gt, gt, gt, eq, lt, lt, un}, //  6
+                {gt, gt, gt, gt, gt, gt, gt, eq, lt, un}, //  7
+                {gt, gt, gt, gt, gt, gt, gt, gt, eq, un}, //  8
+                {un, un, un, un, un, un, un, un, un, un}, //  9
+            };
+
+            // check expected partial_ordering against expected boolean
+            REQUIRE(expected.size() == expected_lt.size());
+            for (size_t i = 0; i < expected.size(); ++i)
+            {
+                REQUIRE(expected[i].size() == expected_lt[i].size());
+                for (size_t j = 0; j < expected[i].size(); ++j)
+                {
+                    CAPTURE(i)
+                    CAPTURE(j)
+                    CHECK(std::is_lt(expected[i][j]) == expected_lt[i][j]);
+                }
+            }
+
+            // check 3-way comparison against expected partial_ordering
+            REQUIRE(expected.size() == j_types.size());
+            for (size_t i = 0; i < j_types.size(); ++i)
+            {
+                REQUIRE(expected[i].size() == j_types.size());
+                for (size_t j = 0; j < j_types.size(); ++j)
+                {
+                    CAPTURE(i)
+                    CAPTURE(j)
+                    CHECK((j_types[i] <=> j_types[j]) == expected[i][j]); // *NOPAD*
+                }
+            }
+        }
+#endif
    }

    SECTION("values")
@@ -228,6 +319,18 @@ TEST_CASE("lexicographical comparison operators")
            CHECK_FALSE(above_int64_max <= max_int64);
            CHECK(above_int64_max > max_int64);
            CHECK(above_int64_max >= max_int64);
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            CHECK((negative_one <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
+            CHECK((above_int64_max <=> negative_one) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((negative_one <=> max_uint64) == std::partial_ordering::less); // *NOPAD*
+            CHECK((max_uint64 <=> negative_one) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((one <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
+            CHECK((above_int64_max <=> one) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((max_int64 <=> above_int64_max) == std::partial_ordering::less); // *NOPAD*
+            CHECK((above_int64_max <=> max_int64) == std::partial_ordering::greater); // *NOPAD*
+#endif
        }

        SECTION("integer/float mixed comparison is exact")
@@ -278,6 +381,16 @@ TEST_CASE("lexicographical comparison operators")
            CHECK_FALSE(json(1) < json(nan));
            CHECK_FALSE(json(nan) < json(1));
            CHECK_FALSE(json(1u) == json(nan));
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            CHECK((max_int64 <=> two_63) == std::partial_ordering::less); // *NOPAD*
+            CHECK((two_63 <=> max_int64) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((below_two_63 <=> max_int64) == std::partial_ordering::less); // *NOPAD*
+            CHECK((max_uint64 <=> two_64) == std::partial_ordering::less); // *NOPAD*
+            CHECK((json(1) <=> json(1.0)) == std::partial_ordering::equivalent); // *NOPAD*
+            CHECK((json(1) <=> json(nan)) == std::partial_ordering::unordered); // *NOPAD*
+#endif
        }

        SECTION("compares unordered")
@@ -504,6 +617,72 @@ TEST_CASE("lexicographical comparison operators")
                }
            }
        }
+
+#if JSON_HAS_THREE_WAY_COMPARISON
+        // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+        SECTION("comparison: 3-way")
+        {
+            std::vector<std::vector<std::partial_ordering>> expected =
+            {
+                //0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21
+                {eq, eq, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, un, un}, //  0
+                {eq, eq, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, un, un}, //  1
+                {gt, gt, eq, lt, lt, lt, lt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  2
+                {gt, gt, gt, eq, gt, gt, gt, gt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  3
+                {gt, gt, gt, lt, eq, lt, gt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  4
+                {gt, gt, gt, lt, gt, eq, gt, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  5
+                {gt, gt, gt, lt, lt, lt, eq, lt, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  6
+                {gt, gt, gt, lt, gt, gt, gt, eq, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  7
+                {gt, gt, un, un, un, un, un, un, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  8
+                {gt, gt, un, un, un, un, un, un, un, un, lt, lt, gt, gt, lt, lt, lt, lt, lt, lt, un, un}, //  9
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, gt, gt, gt, gt, gt, gt, gt, lt, lt, un, un}, // 10
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, eq, gt, gt, gt, gt, gt, gt, lt, lt, un, un}, // 11
+                {gt, gt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, eq, gt, lt, lt, lt, lt, lt, lt, un, un}, // 12
+                {gt, gt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, lt, eq, lt, lt, lt, lt, lt, lt, un, un}, // 13
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, eq, lt, gt, gt, lt, lt, un, un}, // 14
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, gt, eq, gt, gt, lt, lt, un, un}, // 15
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, lt, lt, eq, gt, lt, lt, un, un}, // 16
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, lt, lt, gt, gt, lt, lt, lt, eq, lt, lt, un, un}, // 17
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, lt, un, un}, // 18
+                {gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, gt, eq, un, un}, // 19
+                {un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un}, // 20
+                {un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un, un}, // 21
+            };
+
+            // check expected partial_ordering against expected booleans
+            REQUIRE(expected.size() == expected_eq.size());
+            REQUIRE(expected.size() == expected_lt.size());
+            for (size_t i = 0; i < expected.size(); ++i)
+            {
+                REQUIRE(expected[i].size() == expected_eq[i].size());
+                REQUIRE(expected[i].size() == expected_lt[i].size());
+                for (size_t j = 0; j < expected[i].size(); ++j)
+                {
+                    CAPTURE(i)
+                    CAPTURE(j)
+                    CHECK(std::is_eq(expected[i][j]) == expected_eq[i][j]);
+                    CHECK(std::is_lt(expected[i][j]) == expected_lt[i][j]);
+                    if (std::is_gt(expected[i][j]))
+                    {
+                        CHECK((!expected_eq[i][j] && !expected_lt[i][j]));
+                    }
+                }
+            }
+
+            // check that two values compare according to their expected ordering
+            REQUIRE(expected.size() == j_values.size());
+            for (size_t i = 0; i < j_values.size(); ++i)
+            {
+                REQUIRE(expected[i].size() == j_values.size());
+                for (size_t j = 0; j < j_values.size(); ++j)
+                {
+                    CAPTURE(i)
+                    CAPTURE(j)
+                    CHECK((j_values[i] <=> j_values[j]) == expected[i][j]); // *NOPAD*
+                }
+            }
+        }
+#endif
    }

 #if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
@@ -542,7 +721,60 @@ TEST_CASE("lexicographical comparison operators")
 #endif
 }

-namespace unit_comparison_detail
+#if JSON_HAS_THREE_WAY_COMPARISON
+// JSON_HAS_CPP_20 (do not remove; see note at top of file)
+
+TEST_CASE("regression #3868 - heterogeneous comparisons compile under C++20 (P2468R2)")
+{
+    // Issue #3868: operator!= was preventing compiler from synthesizing reversed
+    // operator== candidates under C++20's P2468R2 rewritten candidate rules.
+    // Verify that heterogeneous comparisons now work.
+
+    SECTION("string vs json")
+    {
+        std::string s = "string";
+        json j = "string";
+        CHECK(s == j);
+        CHECK(j == s);
+        CHECK_FALSE(s != j);
+        CHECK_FALSE(j != s);
+    }
+
+    SECTION("other heterogeneous types")
+    {
+        int i = 42;
+        json j = 42;
+        CHECK(i == j);
+        CHECK(j == i);
+        CHECK_FALSE(i != j);
+        CHECK_FALSE(j != i);
+    }
+}
+
+#if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
+TEST_CASE("regression #5665 - scalar <= discarded and scalar >= discarded in C++20 legacy mode")
+{
+    // Issue #5665: with a scalar on the left-hand side, <= and >= only had the
+    // candidate rewritten from operator<=>, which does not emulate the legacy
+    // discarded-value behavior. Check that scalar-on-the-left now matches the
+    // other three operand orders.
+    const json discarded(json::value_t::discarded);
+    const json one = 1;
+
+    CHECK(discarded <= 1);
+    CHECK(discarded >= 1);
+    CHECK(one <= discarded);
+    CHECK(one >= discarded);
+    CHECK(1 <= discarded);
+    CHECK(1 >= discarded);
+    CHECK(1.5 <= discarded);
+    CHECK(1.5 >= discarded);
+}
+#endif
+
+#endif
+
+namespace
 {
 // orders keys ascending or descending, as chosen when a map is created
 template<class Key>
@@ -594,6 +826,29 @@ struct unordered_object_t : std::map<Key, Value, directed_less<Key>, Allocator>
 };
 using unordered_json = nlohmann::json::with_object_t<unordered_object_t>;

+// the entries "0" to "9", enumerated in ascending or in descending order
+unordered_json make_unordered_object(const bool descending)
+{
+    unordered_json j = unordered_json::object_t(directed_less<std::string>(descending));
+    for (int i = 0; i < 10; ++i)
+    {
+        j[std::to_string(i)] = i;
+    }
+    return j;
+}
+
+template<typename Json>
+Json nest(Json j, const std::size_t depth)
+{
+    for (std::size_t i = 0; i < depth; ++i)
+    {
+        Json outer = Json::object();
+        outer["x"] = std::move(j);
+        j = std::move(outer);
+    }
+    return j;
+}
+
 // a std::map comparator with state: case-insensitive, unless constructed
 // case-sensitive. Used to check that copying an object copies the original's
 // comparator rather than default-constructing a new one (see #5649).
@@ -622,6 +877,18 @@ template<class Key, class Value, class /*Compare*/, class Allocator>
 using key_case_map = std::map<Key, Value, key_case_less, Allocator>;
 using key_case_json = nlohmann::json::with_object_t<key_case_map>;

+// the innermost value of a chain of single-element arrays
+template<typename Json>
+const Json& innermost(const Json& j)
+{
+    const Json* p = &j;
+    while (p->is_array())
+    {
+        p = &(*p)[0];
+    }
+    return *p;
+}
+
 // orders keys case-insensitively, so "key" and "KEY" compare equivalent
 // (neither less than the other) although they are not equal
 struct case_insensitive_less
@@ -639,58 +906,7 @@ struct case_insensitive_less
 template<class Key, class Value, class /*Compare*/, class Allocator>
 using case_insensitive_map = std::map<Key, Value, case_insensitive_less, Allocator>;
 using ci_json = nlohmann::json::with_object_t<case_insensitive_map>;
-
-// the types above keep external linkage: a basic_json specialized with a type
-// of an anonymous namespace has internal linkage, which GCC reports in a file
-// #include-d into a batch (-Wsubobject-linkage); the functions need none
-namespace
-{
-// the entries "0" to "9", enumerated in ascending or in descending order
-unordered_json make_unordered_object(const bool descending)
-{
-    unordered_json j = unordered_json::object_t(directed_less<std::string>(descending));
-    for (int i = 0; i < 10; ++i)
-    {
-        j[std::to_string(i)] = i;
-    }
-    return j;
-}
-
-template<typename Json>
-Json nest(Json j, const std::size_t depth)
-{
-    for (std::size_t i = 0; i < depth; ++i)
-    {
-        Json outer = Json::object();
-        outer["x"] = std::move(j);
-        j = std::move(outer);
-    }
-    return j;
-}
-
-// the innermost value of a chain of single-element arrays
-template<typename Json>
-const Json& innermost(const Json& j)
-{
-    const Json* p = &j;
-    while (p->is_array())
-    {
-        p = &(*p)[0];
-    }
-    return *p;
-}
 } // namespace
-} // namespace unit_comparison_detail
-
-// using-declarations rather than a using-directive, as this file may be
-// #include-d into a batch with other test files (JSON_TestUnityBuild)
-using unit_comparison_detail::ci_json;
-using unit_comparison_detail::innermost;
-using unit_comparison_detail::key_case_json;
-using unit_comparison_detail::key_case_less;
-using unit_comparison_detail::make_unordered_object;
-using unit_comparison_detail::nest;
-using unit_comparison_detail::unordered_json;

 TEST_CASE("equality of objects whose entries have no fixed order")
 {
@@ -833,6 +1049,12 @@ TEST_CASE("containers are compared element by element")
            CHECK(a < b);
            CHECK(b > a);
            CHECK_FALSE(b < a);
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            CHECK((a <=> b) == std::partial_ordering::less); // *NOPAD*
+            CHECK((b <=> a) == std::partial_ordering::greater); // *NOPAD*
+            CHECK((a <=> a) == std::partial_ordering::equivalent); // *NOPAD*
+#endif
        }

        // a container that is a prefix of the other one
@@ -850,6 +1072,11 @@ TEST_CASE("containers are compared element by element")
            CHECK(smaller_object < larger_object);
            CHECK(larger_object > smaller_object);
            CHECK_FALSE(smaller_object == larger_object);
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            CHECK((shorter <=> longer) == std::partial_ordering::less); // *NOPAD*
+            CHECK((longer <=> shorter) == std::partial_ordering::greater); // *NOPAD*
+#endif
        }

        // elements that cannot be ordered
@@ -860,7 +1087,13 @@ TEST_CASE("containers are compared element by element")

            CHECK_FALSE(lhs == lhs);
            CHECK_FALSE(rhs < lhs);
-#if !JSON_HAS_THREE_WAY_COMPARISON
+#if JSON_HAS_THREE_WAY_COMPARISON
+            // JSON_HAS_CPP_20 (do not remove; see note at top of file)
+            // operator<=> stops there, as std::lexicographical_compare_three_way
+            // does, and operator< is derived from it
+            CHECK((lhs <=> rhs) == std::partial_ordering::unordered); // *NOPAD*
+            CHECK_FALSE(lhs < rhs);
+#else
            // operator< skips a pair of elements that cannot be ordered, as
            // std::lexicographical_compare does, and the next pair decides
            CHECK(lhs < rhs);
@@ -869,3 +1102,50 @@ TEST_CASE("containers are compared element by element")
    }
 }

+#if JSON_HAS_THREE_WAY_COMPARISON
+// JSON_HAS_CPP_20 (do not remove; see note at top of file)
+TEST_CASE("operator<=> of binary values with a different subtype does not depend on nesting depth")
+{
+    // #5654: std::vector<std::uint8_t>::operator<=>, which the binary type's
+    // own operator<=> uses, ignores the subtype that operator== checks. So a
+    // pair of binary values with the same bytes but a different subtype is
+    // unequal, yet <=>-equivalent - the same inconsistency between == and <=>
+    // that a NaN has. Within the nesting bound, an array compares itself
+    // with std::vector's own operator<=>, which treats an equivalent pair as
+    // undecided and lets the next element decide, same as
+    // std::lexicographical_compare_three_way does. Past the bound,
+    // compare_iteratively<true>() takes over and must classify the pair the
+    // same way, or the result of operator<=> - and of <, which C++20 derives
+    // from it - depends on how deeply the values are nested.
+    const json a = json::array({json::binary({1}, 1), 1});
+    const json b = json::array({json::binary({1}, 2), 2});
+
+    // the root inconsistency: unequal, yet <=>-equivalent
+    CHECK_FALSE(a[0] == b[0]);
+    CHECK((a[0] <=> b[0]) == std::partial_ordering::equivalent); // *NOPAD*
+
+    const auto deep = [](const json & j, const std::size_t depth)
+    {
+        json result = j;
+        for (std::size_t i = 0; i < depth; ++i)
+        {
+            result = json::array({std::move(result)});
+        }
+        return result;
+    };
+
+    // 127 levels stay within nesting_depth_limit() (128); 128 and 200 do not,
+    // and must still agree with the levels that do
+    for (const std::size_t depth : std::vector<std::size_t> {0, 127, 128, 200})
+    {
+        CAPTURE(depth)
+        const json x = deep(a, depth);
+        const json y = deep(b, depth);
+        CHECK((x <=> y) == std::partial_ordering::less); // *NOPAD*
+        CHECK((y <=> x) == std::partial_ordering::greater); // *NOPAD*
+        CHECK(x < y);
+        CHECK(y > x);
+        CHECK_FALSE(y < x);
+    }
+}
+#endif
@@ -1,95 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  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
-
-// This file contains the C++17-only part of unit-conversions1.cpp (conversions to and from
-// std::string_view). It is kept in a separate translation unit so the (much larger) unit-
-// conversions1.cpp is built for C++11 only and not rebuilt for every C++ standard.
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-using nlohmann::json;
-
-// workaround for MSVC, which does not set __cplusplus to the language version (#464)
-#if (defined(__cplusplus) && __cplusplus >= 201703L) || (defined(_HAS_CXX17) && _HAS_CXX17 == 1) // fix for issue #464
-    #define JSON_HAS_CPP_17
-#endif
-
-#ifdef JSON_HAS_CPP_17
-#include <string>
-#include <string_view>
-
-#if __has_include(<optional>)
-    #include <optional>
-#elif __has_include(<experimental/optional>)
-    #include <experimental/optional>
-#endif
-
-TEST_CASE("value conversion (C++17)")
-{
-    SECTION("get a string (explicit)")
-    {
-        const json::string_t s_reference{"Hello world"};
-        json j(s_reference);
-
-        SECTION("std::string_view")
-        {
-            std::string_view const s = j.get<std::string_view>();
-            CHECK(json(s) == j);
-        }
-
-        SECTION("exception in case of a non-string type using string_view")
-        {
-            CHECK_THROWS_WITH_AS(json(json::value_t::null).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is null", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::object).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is object", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::array).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is array", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::boolean).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is boolean", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::number_integer).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is number", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::number_unsigned).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is number", json::type_error&);
-            CHECK_THROWS_WITH_AS(json(json::value_t::number_float).get<std::string_view>(),
-                                 "[json.exception.type_error.302] type must be string, but is number", json::type_error&);
-        }
-    }
-
-    SECTION("get a string (explicit, get_to)")
-    {
-        const json::string_t s_reference{"Hello world"};
-        json j(s_reference);
-
-        SECTION("std::string_view")
-        {
-            std::string const s = "previous value";
-            std::string_view sv = s;
-            j.get_to(sv);
-            CHECK(json(sv) == j);
-        }
-    }
-
-#if JSON_USE_IMPLICIT_CONVERSIONS
-    SECTION("get a string (implicit)")
-    {
-        const json::string_t s_reference{"Hello world"};
-        json j(s_reference);
-
-        SECTION("std::string_view")
-        {
-            std::string_view const s = j.get<std::string_view>();
-            CHECK(json(s) == j);
-        }
-    }
-#endif
-
-}
-
-#endif
Author	SHA1	Message	Date
Niels Lohmann	d13c9e7212	Fix links to moved API pages in the API changes page mkdocs --strict rejects links to pages that only exist as redirects. Also link operator<< to operator_ltlt.md and operator>> to operator_gtgt.md instead of the other way round. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-10 07:42:37 +02:00
Niels Lohmann	522e7465b0	Merge branch 'develop' into claude/todo-191-plan-508110 Regenerate tools/api_checker/api_surface.json with the CI libclang (18.1.1 on Linux) and point the new ordered_map links in features/performance.md to api/ordered_map/index.md. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-10 04:01:42 +02:00
Niels Lohmann	fe4e78e867	Merge branch 'develop' into claude/todo-191-plan-508110 - ordered_map.hpp: develop's refactored members, with this branch's @sa links on every public member - byte_container_with_subtype operator==/!= and ordered_map docs: develop's reviewed text (#5638); drop the now unreferenced examples - basic_json.md: keep both version-history additions - add the docset entries that develop's style check now requires for the 25 API pages this branch adds - regenerate tools/api_checker/api_surface.json for develop's API Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-04 17:35:55 +02:00
Niels Lohmann	9196e92520	Merge branch 'develop' into claude/todo-191-plan-508110 Conflicts: none textual. Follow-up fixes for develop's changes: - docs/mkdocs/docs/api/ordered_map/index.md: develop's new paragraph (#5609) was written for api/ordered_map.md; fixed its relative ordered_json.md link for the page's new location, plus two pre-existing links from an earlier merge (ordered_json.md, features/object_order.md) - tools/api_checker/api_surface.json: regenerated with libclang 18.1.1 on Linux (swap() noexcept now includes json_base_class_t; new integral-key contains/count/find/value overloads) Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 20:36:12 +02:00
Niels Lohmann	7d22d865dd	Merge branch 'develop' into claude/todo-191-plan-508110 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-28 22:22:46 +02:00
Niels Lohmann	4c73319d3b	Use one-line module docstrings in the API checker scripts Codacy runs two docstring checkers with opposite rules for module docstrings: with the summary on the first line it reported D213, with the summary on the second line it reports D212. A one-line docstring satisfies both. Keep the summary as the docstring and move the details into a comment below it; nothing reads the module docstrings. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-28 18:42:34 +02:00
Niels Lohmann	da5097abcd	Restore the CI spelling of json_pointer's operator string_t in the API surface The develop merge regenerated api_surface.json on macOS, whose libclang spells the name of the deprecated conversion operator as "operator nlohmann::json_pointer::string_t_helper<...>::type". CI's pinned libclang 18.1.1 on Linux spells it "operator typename string_t_helper<...>::type", so check_api_docs reported the file as out of date. This restores CI's spelling, which is byte-identical to the file CI regenerated. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-27 21:37:14 +02:00
Niels Lohmann	2319f6e6f9	Address Codacy findings in the API checker scripts Put multi-line docstring summaries on their own line, as a single sentence followed by a blank line (pydocstyle D205, D209, D213, D415). Annotate the subprocess import and calls with nosec: they only run fixed argument lists, never through a shell (Bandit B404, B603, B607). Do the same for the three broad except clauses in extract_api.py, which deliberately fall through to the next libclang candidate or skip an unresolvable alias (Bandit B110, B112). Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-27 18:09:03 +02:00
Niels Lohmann	9a0d1c0c47	Merge branch 'develop' into claude/todo-191-plan-508110 Resolve the conflict in docs/mkdocs/docs/home/architecture.md by taking develop's rewritten page and pointing its ordered_map links at the moved api/ordered_map/index.md. Also update the ordered_map.md links develop added in ordered_json.md, object_order.md, and template_parameters.md. Regenerate api_surface.json for the new BON8 functions and the changed comparison operator. Restrict the documented_non_public leak check to @sa URLs into json.nlohmann.me: develop now uses @sa to link GitHub issues from private members such as copy_structured, which is not a documentation leak. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-27 18:07:00 +02:00
Niels Lohmann	1bbb5d400a	Regenerate api_surface.json after merging develop develop added JSON_HEDLEY_WARN_UNUSED_RESULT to a number of basic_json members (#5520) and reworked operator<<'s output adapter, so the committed API surface no longer matched what extract_api.py produces and the "Check for uncommitted API surface changes" step failed. This is the patch the workflow itself uploads for that purpose; the changes are limited to recorded signatures plus the way libclang spells json_pointer's conversion operator. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-15 10:06:55 +02:00
Niels Lohmann	08d18d5a82	Merge remote-tracking branch 'origin/develop' into HEAD	2026-09-14 21:26:29 +02:00
Niels LohmannandClaude Sonnet 5	a27065bd12	Regenerate api_surface.json after merging develop develop gained iterator+sentinel support for accept()/parse()/sax_parse()/ from_cbor()/from_msgpack()/from_ubjson()/from_bjdata()/from_bson() (#5205) since this branch was created, which check_api_docs.yml's drift check caught immediately: GitHub's pull_request trigger checks out the PR-vs-base merge commit, not the PR branch in isolation, so CI was comparing the committed api_surface.json (generated before that upstream change existed) against a fresh extraction of a json.hpp that already had it. This superseded an earlier, incorrect diagnosis of the same symptom (a JSON_HAS_RANGES cross-environment pin) -- that fix remains in place since it's still a real, independent determinism improvement for three other JSON_HAS_RANGES-gated locations in type_traits.hpp, but it wasn't the actual cause of this particular mismatch: these new overloads turned out to be unconditional (SFINAE-gated via can_compare_ne, not preprocessor-gated), so no environment-detection difference was involved here at all. Signed-off-by: Niels Lohmann <mail@nlohmann.me> Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-07-11 23:45:46 +02:00
Niels Lohmann	3940f4b730	Merge remote-tracking branch 'origin/develop' into claude/todo-191-plan-508110	2026-07-11 23:43:30 +02:00
Niels LohmannandClaude Sonnet 5	0663907b68	Fix cross-environment API-surface drift and lint findings from CI extract_api.py's own extraction wasn't deterministic across machines, which CI's drift check caught immediately: JSON_HAS_RANGES auto-detects via the standard library's __cpp_lib_ranges feature-test macro, which isn't reliably gated to C++20 mode by every stdlib -- undefined under -std=c++17 with macOS's libc++, but defined under the identical flag with the Ubuntu stdlib CI uses, so parse()/accept()/from_*() extracted different signatures purely depending on which machine ran the extraction. Pinned to -DJSON_HAS_RANGES=0: the deterministic and safe choice, since pinning to 1 was tried first and found to fail to parse on a stdlib without full <ranges> support even when the macro claims otherwise. Also found and fixed a second, independent source of the same class of drift: get_identity_name() used cursor.spelling verbatim for CONVERSION_FUNCTION cursors, which libclang renders as its own internally-canonicalized form of the return type rather than what's literally written. Confirmed for json_pointer::operator string_t() spelling differently on two machines pinned to the identical libclang==18.1.1 wheel, with the JSON_HAS_RANGES fix above ruled out as the cause. Now derived from the cursor's own raw source text instead, immune to libclang's dependent-type resolution differences and incidentally more readable than the libclang-internal forms it replaces. Bumped SURFACE_FORMAT_VERSION to 3 and regenerated all 27 history snapshots and the committed api_surface.json; both fixes are documented in tools/api_checker/history/README.md's format-history log. Also fixes diff_api.py's format_version guard, which only compared the two loaded surfaces against each other and never against SURFACE_FORMAT_VERSION (what this build actually understands) -- two surfaces on the same, newer-than-expected format_version would have silently passed the guard. Remaining fixes are the concretely actionable findings from Codacy's review of the new tools/api_checker/ files: unused imports/variables, a stray f-string with no placeholders. Left the docstring-formatting nitpicks (pydocstyle D2xx/D4xx) and generic subprocess-usage notices alone -- the former has no established convention elsewhere in this codebase's Python tooling to conform to, and the latter are inherent to a dev tool that shells out to git/clang with developer-controlled arguments, not user input. Signed-off-by: Niels Lohmann <mail@nlohmann.me> Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-07-11 18:59:19 +02:00
Niels LohmannandClaude Sonnet 5	f23b3c63a2	Add AST-based public API checker and fix documentation gaps it found (#3691 ) Adds tools/api_checker/: extract_api.py derives the public API surface directly from the libclang AST (independent of documentation status), check_docs.py flags public entries missing @sa links (and @sa on non-public ones), diff_api.py does an overload-aware breaking/feature diff between two refs, check_macros.py cross- checks documented macros against #define sites, and snapshot_release.py backfills immutable per-release surface snapshots into tools/api_checker/history/ (v3.1.0 through v3.12.0) so diff_api.py can compare releases without live extraction. POLICY.md documents what counts as public API and what stability is guaranteed. Running this tooling against the current tree found and fixed a real documentation backlog: ~25 new API doc pages (ordered_map's methods, json_sax's ctor/dtor/ operator=, byte_container_with_subtype's comparison operators, several orphaned type aliases), each with a compiled and output-verified example, plus missing @sa comments and stale/incorrect Version History entries on several existing pages (found by diffing consecutive release pairs and checking whether the resulting change was actually reflected in the target page's history section). Also adds docs/home/api_changes.md, a per-release, per-function reference of public API changes (v3.1.0 through v3.12.0) generated from the history/ snapshots, complementing (not replacing) the existing release notes. Along the way, found and fixed several extractor bugs by testing against real release tags rather than trusting the algorithm in isolation -- most notably an identity-key scheme based on libclang's USR that encoded the enclosing class template's own arity, and a since-renamed ABI inline-namespace pattern (json_v3_11_0 vs. today's json_abi_v3_11_2) that neither of two earlier regex attempts stripped correctly. Both are documented in extract_api.py's docstrings and tools/api_checker/history/README.md so the failure mode doesn't recur silently. .github/workflows/check_api_docs.yml runs extract_api.py + check_docs.py in CI, advisory-only for now (documented backlog may not be at zero for entities this PR didn't touch), plus a blocking drift check on the committed tools/api_checker/api_surface.json. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-07-11 18:59:00 +02:00
				`@@ -0,0 +1 @@`
				`Container is std::vector<std::pair<const Key, T>>: true`