Reject array insert(pos, first, last) iterators not pointing into an array

The array-range insert() overload checked that pos fits the current value and that first/last share the same owning value, but never verified that value is itself an array. Passing iterators from an object, a primitive, or null handed value-initialized (singular) std::vector iterators straight to array_t::insert(), which is undefined behavior. Add the missing is_array() check, mirroring the equivalent check already present in the object-range insert() overload. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Honor allow_exceptions=false for excessive array/object size (out_of_range.408)
2026-09-05 15:57:58 +00:00 · 2026-09-05 17:05:57 +02:00 · 2026-09-05 17:05:56 +02:00 · 2026-09-05 17:05:55 +02:00 · 2026-09-05 17:05:48 +02:00 · 2026-09-05 16:54:49 +02:00
54 changed files with 1789 additions and 297 deletions
@@ -11,7 +11,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -34,7 +34,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -67,8 +67,18 @@ jobs:
          ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
            $INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp

+          # fail loudly if a directory is renamed or removed: find would only warn
+          # about the missing path and silently drop its files from the check
+          SOURCE_DIRS="docs/mkdocs/docs/examples include tests"
+          for DIR in $SOURCE_DIRS; do
+            if [ ! -d "$DIR" ]; then
+              echo "::error::source directory '$DIR' does not exist"
+              exit 1
+            fi
+          done
+
          ${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
-            $(find docs/examples include tests -type f \( -name '*.hpp' -o -name '*.cpp' -o -name '*.cu' \) -not -path 'tests/thirdparty/*' -not -path 'tests/abi/include/nlohmann/*' | sort)
+            $(find $SOURCE_DIRS -type f \( -name '*.hpp' -o -name '*.cpp' -o -name '*.cu' \) -not -path 'tests/thirdparty/*' -not -path 'tests/abi/include/nlohmann/*' | sort)

      - name: Build patch and check for differences
        id: diff
@@ -9,7 +9,7 @@ jobs:
    runs-on: ubuntu-22.04
    steps:
    - name: Harden Runner
-      uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+      uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
      with:
        egress-policy: audit

@@ -27,7 +27,7 @@ jobs:

    steps:
    - name: Harden Runner
-      uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+      uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
      with:
        egress-policy: audit

@@ -38,14 +38,14 @@ jobs:

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+      uses: github/codeql-action/init@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
      with:
        languages: c-cpp

    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
    # If this step fails, then you should remove it and run the build manually (see below)
    - name: Autobuild
-      uses: github/codeql-action/autobuild@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+      uses: github/codeql-action/autobuild@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9

    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+      uses: github/codeql-action/analyze@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
@@ -19,7 +19,7 @@ jobs:
      pull-requests: write
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -17,7 +17,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -27,7 +27,7 @@ jobs:
      security-events: write
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -43,6 +43,6 @@ jobs:
          output: 'flawfinder_results.sarif'

      - name: Upload analysis results to GitHub Security tab
-        uses: github/codeql-action/upload-sarif@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: ${{github.workspace}}/flawfinder_results.sarif
@@ -17,7 +17,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -7,7 +7,6 @@ on:
      - develop
    paths:
      - docs/mkdocs/**
-      - docs/examples/**
  workflow_dispatch:

 # we don't want to have concurrent jobs, and we don't want to cancel running jobs to avoid broken publications
@@ -27,7 +26,7 @@ jobs:
    runs-on: ubuntu-22.04
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -36,7 +36,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -76,6 +76,6 @@ jobs:

      # Upload the results to GitHub's code scanning dashboard.
      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: results.sarif
@@ -32,7 +32,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -61,7 +61,7 @@ jobs:

      # Upload SARIF file generated in previous step
      - name: Upload SARIF file
-        uses: github/codeql-action/upload-sarif@e4fba868fa4b1b91e1fdab776edc8cfbe6e9fb81 # v4.37.3
+        uses: github/codeql-action/upload-sarif@cdf488f595d80d6e07e03d4674febd5ab45fa938 # v4.37.9
        with:
          sarif_file: semgrep.sarif
        if: always()
@@ -16,7 +16,7 @@ jobs:

    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -25,7 +25,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -35,7 +35,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -47,7 +47,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -60,7 +60,7 @@ jobs:
        target: [ci_test_amalgamation, ci_test_single_header, ci_cppcheck, ci_cpplint, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_reuse_compliance, ci_test_valgrind]
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -70,7 +70,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -89,7 +89,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -108,7 +108,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -118,7 +118,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -184,7 +184,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: CXX=g++-${{ matrix.compiler }} cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -202,7 +202,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -212,14 +212,14 @@ jobs:
    runs-on: ubuntu-latest
    strategy:
      matrix:
-        compiler: ['3.4', '3.5', '3.6', '3.7', '3.8', '3.9', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15-bullseye', '16', '17', '18', '19', '20', 'latest']
+        compiler: ['3.4', '3.5', '3.6', '3.7', '3.8', '3.9', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15-bullseye', '16', '17', '18', '19', '20', '21', '22', 'latest']
    container: silkeh/clang:${{ matrix.compiler }}
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Set env FORCE_STDCPPFS_FLAG for clang 7 / 8 / 9 / 10
        run: echo "JSON_FORCED_GLOBAL_COMPILE_OPTIONS=-DJSON_HAS_FILESYSTEM=0;-DJSON_HAS_EXPERIMENTAL_FILESYSTEM=0" >> "$GITHUB_ENV"
        if: ${{ matrix.compiler == '7' || matrix.compiler == '8' || matrix.compiler == '9' || matrix.compiler == '10' }}
@@ -239,7 +239,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -259,7 +259,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build with libc++
@@ -286,7 +286,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -306,7 +306,7 @@ jobs:
      # import-std support. Its opt-in token is CMake-version-specific, so pin
      # CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
      - name: Get pinned CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
        with:
          cmakeVersion: 4.3.4
      # Clang: the std library module is provided by libc++ (the image's libstdc++
@@ -332,7 +332,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -347,7 +347,7 @@ jobs:
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -359,7 +359,7 @@ jobs:
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DJSON_CI=On
      - name: Build
@@ -369,7 +369,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -379,7 +379,7 @@ jobs:
        with:
          persist-credentials: false
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Run CMake
        run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$EMSDK/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -GNinja
      - name: Build
@@ -392,7 +392,7 @@ jobs:
        target: [ci_test_examples, ci_test_build_documentation]
    steps:
      - name: Harden Runner
-        uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
+        uses: step-security/harden-runner@05e31511f85b41b11d1cf0ef85d0992719546e2c # v2.21.0
        with:
          egress-policy: audit

@@ -88,7 +88,7 @@ jobs:
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
      - name: Get latest CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
      - name: Set extra CXX_FLAGS for latest std_version
        # /wd5285 silences C5285 emitted by the bundled third-party doctest.h, which
        # specializes std::tuple (newly diagnosed by the VS2026 v145 toolset)
@@ -153,10 +153,16 @@ jobs:
        with:
          platform: x64
          version: 12.2.0 # https://github.com/egor-tensin/setup-mingw/issues/14
+      # CMAKE_CXX_FLAGS_DEBUG is overridden to drop the default -g: linking
+      # test-regression2_cpp20 intermittently fails with "relocation truncated
+      # to fit: IMAGE_REL_AMD64_SECREL against `.debug_line'" because the
+      # MinGW linker cannot relocate the debug sections this test produces.
+      # The tests are only built and run here, so the debug info is not used.
      - name: Run CMake
        run: cmake -S . -B build ^
             -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" ^
             -DCMAKE_CXX_FLAGS="--target=x86_64-w64-mingw32 -stdlib=libstdc++ -pthread" ^
+             -DCMAKE_CXX_FLAGS_DEBUG="-g0" ^
             -DCMAKE_EXE_LINKER_FLAGS="-lwinpthread" ^
             -G"MinGW Makefiles" ^
             -DCMAKE_BUILD_TYPE=Debug ^
@@ -193,7 +199,7 @@ jobs:
      # import-std support. Its opt-in token is CMake-version-specific, so pin
      # CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
      - name: Get pinned CMake and ninja
-        uses: lukka/get-cmake@e6906078ebd1ccb8ce51ab4626ac46a1b5a517e3 # v4.4.0
+        uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
        with:
          cmakeVersion: 4.3.4
      - name: Run CMake (Debug)
@@ -42,6 +42,7 @@
  - [Specializing enum conversion](#specializing-enum-conversion)
  - [Binary formats (BSON, CBOR, MessagePack, UBJSON, and BJData)](#binary-formats-bson-cbor-messagepack-ubjson-and-bjdata)
 - [Customers](#customers)
+- [Ecosystem](#ecosystem)
 - [Supported compilers](#supported-compilers)
 - [Integration](#integration)
  - [CMake](#cmake)
@@ -1186,6 +1187,11 @@ The library is used in multiple projects, applications, operating systems, etc.

 [![logos of customers using the library](docs/mkdocs/docs/images/customers.png)](https://json.nlohmann.me/home/customers/)

+## Ecosystem
+
+Beyond projects that use the library, there are third-party projects that build on top of it - schema validators,
+language bindings, format converters, and the like. See the curated [Ecosystem](https://json.nlohmann.me/community/ecosystem/) page.
+
 ## Supported compilers

 Though it's 2026 already, the support for C++11 is still a bit sparse. Currently, the following compilers are known to work:
@@ -294,7 +294,7 @@ file(GLOB_RECURSE INDENT_FILES
        ${PROJECT_SOURCE_DIR}/tests/src/*.cpp
        ${PROJECT_SOURCE_DIR}/tests/src/*.hpp
        ${PROJECT_SOURCE_DIR}/tests/benchmarks/src/benchmarks.cpp
-    ${PROJECT_SOURCE_DIR}/docs/examples/*.cpp
+    ${PROJECT_SOURCE_DIR}/docs/mkdocs/docs/examples/*.cpp
 )

 set(include_dir ${PROJECT_SOURCE_DIR}/single_include/nlohmann)
@@ -88,6 +88,8 @@ Strong exception safety: if an exception occurs, the original value stays intact
      do not belong to the same JSON value; example: `"iterators do not fit"`
    - Throws [`invalid_iterator.211`](../../home/exceptions.md#jsonexceptioninvalid_iterator211) if `first` or `last`
      are iterators into container for which insert is called; example: `"passed iterators may not belong to container"`
+    - Throws [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) if `first` or `last`
+      do not point to an array; example: `"iterators first and last must point to arrays"`
 4. The function can throw the following exceptions:
    - Throws [`type_error.309`](../../home/exceptions.md#jsonexceptiontype_error309) if called on JSON values other than
      arrays; example: `"cannot use insert() with string"`
@@ -128,13 +128,10 @@ Strong exception safety: if an exception occurs, the original value stays intact

        When the JSON pointer traverses intermediate levels that don't exist at all yet (not just a missing
        leaf), each missing level is created as an array or an object depending on whether the corresponding
-        pointer token is a valid array index: a token that is a nonempty sequence of digits without a leading
-        `0` (or the token `-`) creates an array, and every other token creates an object. For example, on an
-        initially `#!json null` value, `/foo/0/0/0` creates nested arrays, while `/foo/one/one/one` creates
-        nested objects. Tokens such as `01` or the empty token cannot be array indices (cf. RFC 6901, Sect. 4)
-        and therefore create objects, just as they would if the level already existed as an object. This is not
-        specified by the JSON Pointer RFC; it is this library's own, intentional disambiguation rule. See also
-        [JSON Pointer](../../features/json_pointer.md).
+        pointer token parses as a non-negative integer: a numeric token creates an array, a non-numeric token
+        creates an object. For example, on an initially `#!json null` value, `/foo/0/0/0` creates nested arrays,
+        while `/foo/one/one/one` creates nested objects. This is not specified by the JSON Pointer RFC; it is
+        this library's own, intentional disambiguation rule. See also [JSON Pointer](../../features/json_pointer.md).

 ## Examples

@@ -52,6 +52,11 @@ optional, `#!cpp bjdata_version_t::draft2` by default.

 Strong guarantee: if an exception is thrown, there are no changes in the JSON value.

+## Exceptions
+
+- Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
+  is false.
+
 ## Complexity

 Linear in the size of the JSON value `j`.
@@ -46,7 +46,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va

 ## Complexity

-Linear in the size of the JSON value `j`.
+Proportional to the size of the JSON value `j` multiplied by its maximum nesting
+depth, `O(n × d)`. BSON length prefixes are computed recursively before nested
+values are written.

 ## Examples

@@ -45,6 +45,11 @@ The exact mapping and its limitations are described on a [dedicated page](../../

 Strong guarantee: if an exception is thrown, there are no changes in the JSON value.

+## Exceptions
+
+- Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
+  is false.
+
 ## Complexity

 Linear in the size of the JSON value `j`.
@@ -0,0 +1,40 @@
+# Ecosystem
+
+The projects below build on top of `nlohmann::json` rather than merely using it - schema validators, language
+bindings, format converters, and similar building blocks. The list is not exhaustive, and is curated rather than
+automatically generated. If you maintain or know of a project that belongs here,
+[please let me know](mailto:mail@nlohmann.me).
+
+For products, applications, and organizations that use the library, see [Customers](../home/customers.md) instead.
+
+## Schema validation
+
+- [**json-schema-validator**](https://github.com/pboettch/json-schema-validator), a JSON Schema (draft 7) validator
+  with human-readable error messages
+
+## Serialization and reflection
+
+- [**nlohmann_json_reflect**](https://github.com/1261385937/nlohmann_json_reflect), a reflection extension for
+  (de)serializing nested containers-in-structs-in-containers
+
+## Encodings
+
+- [**base-encode-decode**](https://github.com/saxonnicholls/base-encode-decode), a header-only Base64/32/16/8/4/2
+  (and DNA/RNA) encoding library, with an adapter that serializes binary data through `nlohmann::json`
+
+## Language bindings and interop
+
+- [**pybind11_json**](https://github.com/pybind/pybind11_json), a bidirectional type caster between
+  `nlohmann::json` and Python objects for [pybind11](https://github.com/pybind/pybind11) bindings
+- [**nanobind_json**](https://github.com/ianhbell/nanobind_json), the same idea for
+  [nanobind](https://github.com/wjakob/nanobind) bindings
+- [**nlohmann_json_qt**](https://github.com/dpurgin/nlohmann_json_qt), deserialization helpers for Qt types
+  (`QString`, `QUrl`, `QDateTime`, `QVector`, ...) from `nlohmann::json`
+- [**vulkan2json**](https://github.com/Fadis/vulkan2json), serialization and deserialization of Vulkan API structs
+
+## Format converters
+
+- [**tojson**](https://github.com/mircodz/tojson), a header-only converter between YAML/XML documents and
+  `nlohmann::json`
+- [**json2xml**](https://github.com/testillano/json2xml), a header-only converter from `nlohmann::json` to XML for
+  simple configuration documents
@@ -1,5 +1,6 @@
 # Community

+- [Ecosystem](ecosystem.md) - third-party projects built on top of this library
 - [Code of Conduct](code_of_conduct.md) - the rules and norms of this project
 - [Contribution Guidelines](contribution_guidelines.md) - guidelines how to contribute to this project
 - [Governance](governance.md) - the governance model of this project
@@ -66,6 +66,7 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
        | Clang 20.1.1                                 | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
        | Clang 20.1.8 with GNU-like command-line      | x86_64       | Windows Server 2022 (Build 20348) | GitHub    |
        | Clang 21.1.8                                 | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
+        | Clang 22.1.8                                 | x86_64       | Ubuntu 22.04.1 LTS                | GitHub    |
        | CUDA 11.8.0 (nvcc)                           | x86_64       | Ubuntu 22.04 LTS                  | GitHub    |
        | CUDA 12.1.1 (nvcc)                           | x86_64       | Ubuntu 22.04 LTS                  | GitHub    |
        | CUDA 12.6.3 (nvcc)                           | x86_64       | Ubuntu 22.04 LTS                  | GitHub    |
@@ -9,13 +9,13 @@ int main()
    auto text = R"({"IDs": [116, 943], "Width": 800})";

    // discard the array when the parser reads its opening bracket
-    json j_array_start = json::parse(text, [](int /*depth*/, json::parse_event_t event, json & /*parsed*/)
+    json j_array_start = json::parse(text, [](int /*depth*/, json::parse_event_t event, json& /*parsed*/)
    {
        return event != json::parse_event_t::array_start;
    });

    // discard the same array when the parser reads its closing bracket
-    json j_array_end = json::parse(text, [](int /*depth*/, json::parse_event_t event, json & /*parsed*/)
+    json j_array_end = json::parse(text, [](int /*depth*/, json::parse_event_t event, json& /*parsed*/)
    {
        return event != json::parse_event_t::array_end;
    });
@@ -33,7 +33,7 @@ int main()
    });

    // discard the top-level object
-    json j_root = json::parse(text, [](int /*depth*/, json::parse_event_t event, json & /*parsed*/)
+    json j_root = json::parse(text, [](int /*depth*/, json::parse_event_t event, json& /*parsed*/)
    {
        return event != json::parse_event_t::object_end;
    });
@@ -116,9 +116,19 @@ The library uses the following mapping from JSON values types to BJData types ac
    ```

    Likewise, when a JSON object in the above form is serialized using
-    [`to_bjdata`](../../api/basic_json/to_bjdata.md), it is automatically converted into a compact BJData ND-array. The
-    only exception is, that when the 1-dimensional vector stored in `"_ArraySize_"` contains a single integer or two
-    integers with one being 1, a regular 1-D optimized array is generated.
+    [`to_bjdata`](../../api/basic_json/to_bjdata.md), it is automatically converted into a compact BJData ND-array. When
+    the 1-dimensional vector stored in `"_ArraySize_"` contains a single integer or two integers with one being 1, a
+    regular 1-D optimized array is generated instead.
+
+    An object is only converted if the annotation actually describes a packed array; otherwise it is serialized as a
+    regular JSON object. This requires all of the following:
+
+    - `"_ArrayType_"` is one of `uint8`, `int8`, `uint16`, `int16`, `uint32`, `int32`, `uint64`, `int64`, `single`,
+      `double`, `char`, or `byte`,
+    - every entry of `"_ArraySize_"` is a non-negative integer, and their product is representable as a `std::size_t`,
+    - `"_ArrayData_"` holds exactly that many elements, and
+    - every element of `"_ArrayData_"` is a number of the kind named by `"_ArrayType_"` (a floating-point number for
+      `single` and `double`, an integer otherwise).

    The current version of this library does not yet support automatic detection of and conversion from a nested JSON
    array input to a BJData ND-array.
@@ -98,6 +98,17 @@ The library maps BSON record types to JSON value types as follows:
    This library deserializes BSON type `0x11` (Timestamp) as a `number_unsigned` value. The 64-bit value is preserved,
    but the Timestamp type information is not.

+!!! warning "Lenient BSON input handling"
+
+    The BSON reader is lenient in a few areas where the BSON specification is more restrictive:
+
+    - array element keys are not checked against the required decimal sequence (`0`, `1`, `2`, ...),
+    - any non-zero byte is accepted as `true` for the boolean type, and
+    - the payload for binary subtype `0x02` is returned as-is, including its inner length prefix.
+
+    If BSON input must be validated for strict specification compliance, validate it separately before passing it to
+    `from_bson()`.
+
 ??? example

    ```cpp
@@ -160,14 +160,11 @@ The library maps CBOR types to JSON value types as follows:

    The mapping is **incomplete** in the sense that not all CBOR types can be converted to a JSON value. The following CBOR types are not supported and will yield parse errors:

-     - date/time (0xC0..0xC1)
-     - bignum (0xC2..0xC3)
-     - decimal fraction (0xC4)
-     - bigfloat (0xC5)
-     - expected conversions (0xD5..0xD7)
     - simple values (0xE0..0xF3, 0xF8)
     - undefined (0xF7)

+    Tagged items (0xC0..0xDB) are not interpreted either; see the note on tagged items below.
+
 !!! warning "Negative integer overflow"

    CBOR negative integers (major type 1) are decoded as `-1 - n`. If the encoded magnitude `n` is too large for the
@@ -181,7 +178,7 @@ The library maps CBOR types to JSON value types as follows:

 !!! warning "Tagged items"

-    Tagged items will throw a parse error by default. They can be ignored by passing `cbor_tag_handler_t::ignore` to function `from_cbor`. They can be stored by passing `cbor_tag_handler_t::store` to function `from_cbor`.
+    Tagged items (0xC0..0xDB) will throw a parse error by default. They can be ignored by passing `cbor_tag_handler_t::ignore` to function `from_cbor`, in which case the tag is skipped and the enclosed data item is parsed on its own. They can be stored by passing `cbor_tag_handler_t::store` to function `from_cbor`. Note that no tag is ever interpreted: for instance, a text string tagged with tag 0 (date/time) stays a string.

 ??? example

@@ -54,6 +54,30 @@ json j = {1.0, "hello", 42};
 auto t = j.get<std::tuple<double, std::string, int>>();  // {1.0, "hello", 42}
 ```

+!!! warning "Serializing a `std::pair`/`std::tuple` whose every element is a string-keyed pair"
+
+    When *every* element of a `#!cpp std::pair` or `#!cpp std::tuple` is itself a two-element array whose first
+    element is a string (for example `#!cpp std::pair<std::string, int>`), serializing it produces a JSON **object**
+    instead of the expected array:
+
+    ```cpp
+    using kv = std::pair<std::string, int>;
+    json j = std::pair<kv, kv>{{"a", 1}, {"b", 2}};  // {"a":1,"b":2}, not [["a",1],["b",2]]
+    ```
+
+    This is a consequence of the [brace-initializer object-detection rule](creating_values.md): the same rule that
+    lets `#!cpp json{{"a", 1}, {"b", 2}}` create an object also fires here. The resulting object cannot be read back
+    into the original type (`#!cpp get<std::pair<kv, kv>>()` throws [`type_error.302`](../home/exceptions.md#jsonexceptiontype_error302)),
+    and duplicate keys collapse into one, losing elements. This only affects `#!cpp std::pair`/`#!cpp std::tuple`
+    themselves; a `#!cpp std::vector<std::pair<std::string, int>>`, or a pair/tuple with at least one element that is
+    not a string-keyed pair, serializes to an array as expected. To force an array, build one explicitly from the
+    elements with [`array`](../api/basic_json/array.md):
+
+    ```cpp
+    std::pair<kv, kv> p{{"a", 1}, {"b", 2}};
+    json a = json::array({p.first, p.second});  // [["a",1],["b",2]]
+    ```
+
 !!! info "Extracting references into a tuple"

    A tuple type may also hold references (e.g. `#!cpp std::tuple<double&, std::string&>`) to avoid copying: `get`
@@ -8,41 +8,72 @@ the result of an internet search. If you know further customers of the library,
 ## Space Exploration

 - [**Peregrine Lunar Lander Flight 01**](https://en.wikipedia.org/wiki/Peregrine_Mission_One) - The library was used for payload management in the **Peregrine Moon Lander**, developed by **Astrobotic Technology** and launched as part of NASA's **Commercial Lunar Payload Services (CLPS)** program. After six days in orbit, the spacecraft was intentionally redirected into Earth's atmosphere, where it burned up over the Pacific Ocean on **January 18, 2024**.
+- [**NASA Unsteady Pressure-Sensitive Paint Processing**](https://github.com/nasa/upsp-processing), NASA software for processing high-speed video recordings of wind tunnel tests on launch vehicle and aircraft models
+- [**Terma TEMU**](https://temu.terma.com/docs/public/temu-release-notes/latest/copying/json-for-modern-cpp.html), an emulator of spacecraft on-board computers used to develop and validate flight software for European space missions

 ## Automotive

 - [**Alexa Auto SDK**](https://github.com/alexa/alexa-auto-sdk), a software development kit enabling the integration of Alexa into automotive systems
 - [**Apollo**](https://github.com/ApolloAuto/apollo), a framework for building autonomous driving systems
 - [**Automotive Grade Linux (AGL)**](https://download.automotivelinux.org/AGL/release/jellyfish/latest/qemux86-64/deploy/licenses/nlohmann-json/), a collaborative open-source platform for automotive software development
+- [**Autoware**](https://github.com/autowarefoundation/autoware_universe), an open-source software stack for autonomous driving built on ROS 2
+- [**Eclipse S-CORE**](https://github.com/eclipse-score/nlohmann_json), an open-source software platform for the software-defined vehicle backed by major automotive manufacturers and suppliers
 - [**Genesis Motor** (infotainment)](http://webmanual.genesis.com/ccIC/AVNT/JW/KOR/English/reference010.html), a luxury automotive brand
 - [**Hyundai** (infotainment)](https://www.hyundai.com/wsvc/ww/download.file.do?id=/content/hyundai/ww/data/opensource/data/GN7-2022/licenseCode/info), a global automotive brand
 - [**Kia** (infotainment)](http://webmanual.kia.com/PREM_GEN6/AVNT/RJPE/KOR/Korean/reference010.html), a global automotive brand
 - [**Mercedes-Benz Operating System (MB.OS)**](https://group.mercedes-benz.com/careers/about-us/mercedes-benz-operating-system/), a core component of the vehicle software ecosystem from Mercedes-Benz
+- [**NVIDIA DRIVE OS**](https://developer.nvidia.com/docs/drive/drive-os/6.0.5/public/driveworks-nvcgf/dwx_open_source_attribution.html), the operating system and DriveWorks SDK powering NVIDIA's platform for autonomous vehicles
 - [**Rivian** (infotainment)](https://assets.ctfassets.net/2md5qhoeajym/3cwyo4eoufk4yingUwusFt/ded2c47da620fdfc99c88c7156d2c1d8/In-Vehicle_OSS_Attribution_2024__11-24_.pdf), an electric vehicle manufacturer
 - [**Suzuki** (infotainment)](https://www.globalsuzuki.com/motorcycle/ipc/oss/oss_48KA_00.pdf), a global automotive and motorcycle manufacturer

 ## Gaming and Entertainment

+- [**Anno 117: Pax Romana**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a city-building strategy game set in the Roman Empire
 - [**Assassin's Creed: Mirage**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a stealth-action game set in the Middle East, focusing on the journey of a young assassin with classic parkour and stealth mechanics
+- [**Battlefield 6**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a military first-person shooter known for its large-scale multiplayer battles
+- [**Battlefield: REDSEC**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a free-to-play battle royale experience set in the Battlefield universe
+- [**BioMenace: Remastered**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a remaster of the classic side-scrolling platform shooter
 - [**Chasm: The Rift**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a first-person shooter blending horror and adventure, where players navigate dark realms and battle monsters
 - [**College Football 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a college football simulation game featuring gameplay that mimics real-life college teams and competitions
+- [**College Football 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a college football simulation game featuring licensed teams and stadiums
+- [**College Football 27**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the college football simulation series
 - [**Concepts**](https://concepts.app/en/licenses), a digital sketching app designed for creative professionals, offering flexible drawing tools for illustration, design, and brainstorming
 - [**Depthkit**](https://www.depthkit.tv/third-party-licenses), a tool for creating and capturing volumetric video, enabling immersive 3D experiences and interactive content
+- [**Dune: Awakening**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an open-world survival MMO set on the desert planet Arrakis
+- [**EA Sports FC 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an association football simulation with club, career, and online modes
+- [**EA Sports FC 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the association football simulation series
+- [**EA Sports UFC 6**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a mixed martial arts fighting simulation
+- [**FiveM**](https://github.com/citizenfx/fivem), a modification framework for Grand Theft Auto V that powers custom multiplayer servers
+- [**FLUX:: Immersive**](https://doc.flux.audio/syrah/Credits.html), a suite of professional audio processing and immersive mixing plugins used in music and post-production
 - [**IMG.LY**](https://img.ly/acknowledgements), a platform offering creative tools and SDKs for integrating advanced image and video editing in applications
+- [**immersivetech**](https://immersitech.io/open-source-third-party-software/), a technology company focused on immersive experiences, providing tools and solutions for virtual and augmented reality applications
+- [**Kodi**](https://github.com/xbmc/xbmc/blob/master/xbmc/utils/JSONVariantWriter.cpp), a home theater and media center application
 - [**LOOT**](https://loot.readthedocs.io/_/downloads/en/0.13.0/pdf/), a tool for optimizing the load order of game plugins, commonly used in The Elder Scrolls and Fallout series
+- [**LunaTranslator**](https://github.com/HIllya51/LunaTranslator/blob/main/src/NativeImpl/LunaSubprocess/aspatch.cpp), a real-time translation tool for visual novels
+- [**MaaAssistantArknights**](https://github.com/MaaAssistantArknights/MaaAssistantArknights/blob/dev-v2/src/MaaCore/Vision/Roguelike/BlackFlow/BlackFlowMapAnalyzer.cpp), an automation assistant for the mobile game Arknights
 - [**Madden NFL 25**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a sports simulation game capturing the excitement of American football with realistic gameplay and team management features
+- [**Madden NFL 26**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an American football simulation with franchise and team management modes
+- [**Madden NFL 27**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), the latest installment of the American football simulation series
 - [**Marne**](https://marne.io/licenses), an unofficial private server platform for hosting custom Battlefield 1 game experiences
 - [**Minecraft**](https://www.minecraft.net/zh-hant/attribution), a popular sandbox video game
+- [**Mumble**](https://github.com/mumble-voip/mumble), a low-latency, open-source voice chat application widely used by gaming communities
 - [**NHL 22**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a hockey simulation game offering realistic gameplay, team management, and various modes to enhance the hockey experience
+- [**OBS Studio**](https://github.com/obsproject/obs-studio), a free and open-source suite for video recording and live streaming
+- [**OpenRCT2**](https://github.com/OpenRCT2/OpenRCT2/blob/develop/src/openrct2/core/JsonFwd.hpp), an open source re-implementation of RollerCoaster Tycoon 2
 - [**Pixelpart**](https://pixelpart.net/documentation/book/third-party.html), a 2D animation and video compositing software that allows users to create animated graphics and visual effects with a focus on simplicity and ease of use
 - [**Razer Cortex**](https://mysupport.razer.com/app/answers/detail/a_id/14146/~/open-source-software-for-razer-software), a gaming performance optimizer and system booster designed to enhance the gaming experience
 - [**Red Dead Redemption II**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an open-world action-adventure game following an outlaw's story in the late 1800s, emphasizing deep storytelling and immersive gameplay
+- [**RetroArch**](https://github.com/libretro/RetroArch), a frontend for emulators, game engines, and media players built on the libretro API
+- [**shadPS4**](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/user_manager.h), a PlayStation 4 emulator for Windows, Linux and macOS
+- [**skate.**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a free-to-play skateboarding game set in an open world
 - [**Snapchat**](https://www.snap.com/terms/license-android), a multimedia messaging and augmented reality app for communication and entertainment
+- [**Steel Century Groove**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), an action game released in 2026
+- [**Sunshine**](https://github.com/LizardByte/Sunshine/blob/master/src/confighttp.h), a self-hosted game streaming host compatible with Moonlight clients
 - [**Tactics Ogre: Reborn**](https://www.square-enix-games.com/en_US/documents/tactics-ogre-reborn-pc-installer-software-and-associated-plug-ins-disclosure), a tactical role-playing game featuring strategic battles and deep storytelling elements
 - [**Throne and Liberty**](https://www.amazon.com/gp/help/customer/display.html?nodeId=T7fLNw5oAevCMtJFPj&pop-up=1), an MMORPG that offers an expansive fantasy world with dynamic gameplay and immersive storytelling
 - [**Unity Vivox**](https://docs.unity3d.com/Packages/com.unity.services.vivox@15.1/license/Third%20Party%20Notices.html), a communication service that enables voice and text chat functionality in multiplayer games developed with Unity
+- [**xemu**](https://github.com/xemu-project/xemu), an emulator of the original Xbox console
 - [**Zool: Redimensioned**](https://www.mobygames.com/person/1195889/niels-lohmann/credits/), a modern reimagining of the classic platformer featuring fast-paced gameplay and vibrant environments
- [**immersivetech**](https://immersitech.io/open-source-third-party-software/), a technology company focused on immersive experiences, providing tools and solutions for virtual and augmented reality applications

 ## Consumer Electronics

@@ -50,109 +81,195 @@ the result of an internet search. If you know further customers of the library,
 - [**Canon CanoScan LIDE**](https://carolburo.com/wp-content/uploads/2024/06/LiDE400_OnlineManual_Win_FR_V02.pdf), a series of flatbed scanners offering high-resolution image scanning for home and office use
 - [**Canon PIXMA Printers**](https://www.mediaexpert.pl/products/files/73/7338196/Instrukcja-obslugi-CANON-Pixma-TS7450i.pdf), a line of all-in-one inkjet printers known for high-quality printing and wireless connectivity
 - [**Cisco Webex Desk Camera**](https://www.cisco.com/c/dam/en_us/about/doing_business/open_source/docs/CiscoWebexDeskCamera-23-1622100417.pdf), a video camera designed for professional-quality video conferencing and remote collaboration
+- [**DJI Edge SDK**](https://github.com/dji-sdk/Edge-SDK-V2-Demo), the reference applications for DJI's Edge SDK, used to build edge computing services on DJI drone docks
+- [**Elgato Stream Deck**](https://github.com/elgatosf/streamdeck-obs-plugin2), a family of programmable control surfaces for content creators and their plugin ecosystem
+- [**Instagrid**](https://instagrid.co/intellectual-property/foss), a manufacturer of portable, high-performance battery systems for professional mobile power supply
+- [**iRobot**](https://iot-content.irobot.com/iw/sfsites/c/cms/delivery/media/MCKRLTPDJSSJBNJKDA5SG5UVVIIQ), a manufacturer of autonomous home robots including the Roomba vacuum cleaner range
+- [**Logitech Logi Bolt**](https://opensource.logitech.com/wiki/Logi_BoltApp/), the management application for Logitech's secure wireless connectivity technology
+- [**Novitus**](https://novitus.pl/licencjepensource), a manufacturer of fiscal cash registers and point-of-sale devices
 - [**Philips Hue Personal Wireless Lighting**](http://2ak5ape.257.cz/), a smart lighting system for customizable and wireless home illumination
 - [**Ray-Ban Meta Smart glasses**](https://www.meta.com/de/en/legal/smart-glasses/third-party-notices-android/03/), a pair of smart glasses designed for capturing photos and videos with integrated connectivity and social features
 - [**Razer Synapse**](https://mysupport.razer.com/app/answers/detail/a_id/14146/~/open-source-software-for-razer-software), a unified configuration software enabling hardware customization for Razer devices
+- [**Sharp Professional Displays**](https://jp.sharp/restricted/business/lcd-display/cms/images/source_pnla862/PN-LA652_752_862_LicenseInformation.pdf), a range of large-format interactive displays for business and education
 - [**Siemens SINEMA Remote Connect**](https://cache.industry.siemens.com/dl/files/790/109793790/att_1054961/v2/OSS_SINEMA-RC_86.pdf), a remote connectivity solution for monitoring and managing industrial networks and devices securely
+- [**Skydio**](https://pages.skydio.com/rs/784-TUF-591/images/Open%20Source%20Software%20Notice%20v0.2.html), a manufacturer of autonomous drones for inspection, public safety, and defense applications
 - [**Sony PlayStation 4**](https://doc.dl.playstation.net/doc/ps4-oss/index.html), a gaming console developed by Sony that offers a wide range of games and multimedia entertainment features
+- [**Sony Spatial Reality Display**](https://www.sony.co.jp/en/Products/Developer-Spatial-Reality-display/download/dcc-tools/blender-plugin/SpatiaRealityDisplayPluginforPreviewBL_Manual.pdf), a glasses-free stereoscopic 3D display and its plugins for Blender, 3ds Max, and ZBrush
 - [**Sony Virtual Webcam Driver for Remote Camera**](https://helpguide.sony.net/rc/vwd/v1/zh-cn/print.pdf), a software driver that enables the use of Sony cameras as virtual webcams for video conferencing and streaming
+- [**Yamaha Clavinova**](https://usa.yamaha.com/files/download/other_assets/1/2298171/CLP-800_oss_license.pdf), a series of digital pianos combining acoustic piano feel with digital sound technology

-## Operating Systems
+## Operating Systems and Platforms

 - [**Apple iOS and macOS**](https://www.apple.com/macos), a family of operating systems developed by Apple, including iOS for mobile devices and macOS for desktop computers
+- [**Chromium**](https://chromium.googlesource.com/chromium/src/+/main/third_party/nlohmann_json/), the open-source browser project that Google Chrome, Microsoft Edge, and many other browsers are built on, where the library is used as data container for on-device model execution
 - [**Google Fuchsia**](https://fuchsia.googlesource.com/third_party/json/), an open-source operating system developed by Google, designed to be secure, updatable, and adaptable across various devices
+- [**LG webOS**](https://github.com/webosose/com.webos.service.camera), a Linux-based operating system used in LG smart TVs, signage, and embedded devices
+- [**Microsoft Azure Linux**](https://github.com/microsoft/azurelinux), a Linux distribution developed by Microsoft for Azure infrastructure and edge workloads
+- [**OpenHarmony**](https://github.com/openharmony/third_party_json), an open-source operating system for smart devices and the foundation of HarmonyOS
 - [**SerenityOS**](https://github.com/SerenityOS/serenity), an open-source operating system that aims to provide a simple and beautiful user experience with a focus on simplicity and elegance
+- [**Windows Subsystem for Linux**](https://github.com/microsoft/WSL), a compatibility layer that runs Linux environments natively on Windows
 - [**Yocto**](http://ftp.emacinc.com/openembedded-sw/kirkstone-icop-5.15-kirkstone-6.0/archive-2024-10/pn8m-090t-ppc/licenses/nlohmann-json/), a Linux-based build system for creating custom operating systems and software distributions, tailored for embedded devices and IoT applications

 ## Development Tools and IDEs

 - [**Accentize SpectralBalance**](https://www.accentize.com/products/SpectralBalanceManual.pdf), an adaptive speech analysis tool designed to enhance audio quality by optimizing frequency balance in recordings
+- [**Airbus Ghidralligator**](https://www.cyber.airbus.com/en/newsroom/stories/2025-06-ghidralligator), a Ghidra-based emulator from Airbus CyberSecurity used to fuzz and analyse embedded firmware
+- [**Apache brpc**](https://github.com/apache/brpc/blob/master/src/butil/iobuf.h), an industrial-grade remote procedure call framework for C++
 - [**Arm Compiler for Linux**](https://documentation-service.arm.com/static/66558e9d876c8d213b7843e4), a software development toolchain for compiling and optimizing applications on Arm-based Linux systems
 - [**BBEdit**](https://s3.amazonaws.com/BBSW-download/BBEdit_15.1.2_User_Manual.pdf), a professional text and code editor for macOS
 - [**CoderPad**](https://coderpad.io), a collaborative coding platform that enables real-time code interviews and assessments for developers; the library is included in every CoderPad instance and can be accessed with a simple `#include "json.hpp"`
+- [**Codon**](https://github.com/exaloop/codon/blob/develop/jupyter/jupyter.h), an ahead-of-time compiler for a Python-like language
 - [**Compiler Explorer**](https://godbolt.org), a web-based tool that allows users to write, compile, and visualize the assembly output of code in various programming languages; the library is readily available and accessible with the directive `#include <nlohmann/json.hpp>`.
- [**GitHub CodeQL**](https://github.com/github/codeql), a code analysis tool used for identifying security vulnerabilities and bugs in software through semantic queries
+- [**Flutter**](https://github.com/flutter/flutter/blob/master/engine/src/flutter/impeller/compiler/reflector.cc), a UI toolkit for building natively compiled applications for mobile, web, and desktop from a single codebase
+- [**Fraunhofer VVenC**](https://github.com/fraunhoferhhi/vvenc), a fast and efficient encoder for the Versatile Video Coding (H.266/VVC) standard
+- [**GitHub CodeQL**](https://github.com/github/codeql/blob/main/shared/cpp/Diagnostics.h), a code analysis tool used for identifying security vulnerabilities and bugs in software through semantic queries
+- [**GoPro ngfx**](https://github.com/gopro/ngfx), a low-level graphics abstraction and profiling framework developed by GoPro
+- [**gRPC**](https://github.com/grpc/grpc/blob/master/tools/artifact_gen/utils.h), a high-performance universal remote procedure call framework
 - [**Hex-Rays**](https://docs.hex-rays.com/user-guide/user-interface/licenses), a reverse engineering toolset for analyzing and decompiling binaries, primarily used for security research and vulnerability analysis
 - [**ImHex**](https://github.com/WerWolv/ImHex), a hex editor designed for reverse engineering, providing advanced features for data analysis and manipulation
+- [**Intel GITS**](https://github.com/intel/gits), a tool for capturing and replaying graphics API calls for debugging and performance analysis
 - [**Intel GPA Framework**](https://intel.github.io/gpasdk-doc/src/licenses.html), a suite of cross-platform tools for capturing, analyzing, and optimizing graphics applications across different APIs
 - [**Intopix**](https://www.intopix.com/software-licensing), a provider of advanced image processing and compression solutions used in software development and AV workflows
 - [**Java SE**](https://www.oracle.com/a/tech/docs/jdk8-lium.pdf), the core Java platform that provides the libraries and runtime needed to build and run general-purpose Java applications
- [**MKVToolNix**](https://mkvtoolnix.download/doc/README.md), a set of tools for creating, editing, and inspecting MKV (Matroska) multimedia container files
 - [**Meta Yoga**](https://github.com/facebook/yoga), a layout engine that facilitates flexible and efficient user interface design across multiple platforms
- [**NVIDIA Nsight Compute**](https://docs.nvidia.com/nsight-compute/2022.2/pdf/CopyrightAndLicenses.pdf), a performance analysis tool for CUDA applications that provides detailed insights into GPU performance metrics
+- [**MKVToolNix**](https://mkvtoolnix.download/doc/README.md), a set of tools for creating, editing, and inspecting MKV (Matroska) multimedia container files
+- [**MRTech IFF SDK**](https://mr-technologies.com/pub/iff-sdk-manual-2-0-1/iff-sdk-manual-2-0-1.pdf), an image processing SDK for machine vision applications with GPU-accelerated pipelines
+- [**Nix**](https://github.com/NixOS/nix/blob/master/src/nix/build.cc), a purely functional package manager
 - [**Notepad++**](https://github.com/notepad-plus-plus/notepad-plus-plus), a free source code editor that supports various programming languages
+- [**NVIDIA Nsight Compute**](https://docs.nvidia.com/nsight-compute/2022.2/pdf/CopyrightAndLicenses.pdf), a performance analysis tool for CUDA applications that provides detailed insights into GPU performance metrics
+- [**openFrameworks**](https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/utils/ofJson.h), a community-developed C++ toolkit for creative coding
 - [**OpenRGB**](https://gitlab.com/CalcProgrammer1/OpenRGB), an open source RGB lighting control that doesn't depend on manufacturer software
 - [**OpenTelemetry C++**](https://github.com/open-telemetry/opentelemetry-cpp), a library for collecting and exporting observability data in C++, enabling developers to implement distributed tracing and metrics in their application
+- [**Oracle GraalVM**](https://docs.oracle.com/en/graalvm/jdk/21/docs/licensing-information/), a high-performance JDK distribution with ahead-of-time compilation and polyglot runtime support
+- [**Philips amp-cucumber-cpp-runner**](https://github.com/philips-software/amp-cucumber-cpp-runner), a behaviour-driven development test runner for embedded C++ software developed at Philips
 - [**Qt Creator**](https://doc.qt.io/qtcreator/qtcreator-attribution-json-nlohmann.html), an IDE for developing applications using the Qt application framework
+- [**Qt for MCUs**](https://doc.qt.io/QtForMCUs/quickultralite-attribution-nlohmann-json.html), a graphics framework for building fluid user interfaces on microcontrollers
+- [**React Native**](https://github.com/react/react-native/blob/main/packages/react-native/ReactCxxPlatform/react/devsupport/PackagerConnection.cpp), a framework for building native mobile applications using React
 - [**Scanbot SDK**](https://docs.scanbot.io/barcode-scanner-sdk/web/third-party-libraries/), a software development kit (SDK) that provides tools for integrating advanced document scanning and barcode scanning capabilities into applications
+- [**STMicroelectronics TouchGFX**](https://www.st.com/resource/en/additional_license_terms/additional-license-terms-x-cube-touchgfx.html), a graphical user interface framework shipped with STM32 microcontrollers for building embedded HMIs
+- [**swagger-codegen**](https://github.com/swagger-api/swagger-codegen/blob/master/samples/server/petstore/pistache-server/model/Pet.h), a template-driven engine that generates API clients and server stubs from an OpenAPI specification
+- [**Swoole**](https://github.com/swoole/swoole-src/blob/master/ext-src/swoole_admin_server.cc), a coroutine-based concurrency engine for PHP
+- [**Tracy Profiler**](https://github.com/wolfpld/tracy/blob/master/profiler/src/profiler/TracyLlm.hpp), a real-time frame profiler for games and other applications
+- [**WasmEdge**](https://github.com/WasmEdge/WasmEdge/blob/master/plugins/wasi_nn/GGML/tts/tts_core.cpp), a lightweight WebAssembly runtime for edge and cloud workloads
+- [**x64dbg**](https://github.com/x64dbg/x64dbg/blob/development/src/cross/remote_table/TableRpcData.h), an open source user mode debugger for Windows, aimed at reverse engineering and malware analysis

 ## Machine Learning and AI

+- [**Alibaba MNN**](https://github.com/alibaba/MNN), a lightweight deep learning inference engine for mobile and embedded devices
+- [**AMD Gaia**](https://github.com/amd/gaia), an open-source framework for running generative AI applications locally on AMD hardware
+- [**AMD Vitis AI (VAIP)**](https://github.com/amd/vaip), the execution provider stack that runs AI models on AMD Ryzen AI and adaptive computing devices
 - [**Apple Core ML Tools**](https://github.com/apple/coremltools), a set of tools for converting and configuring machine learning models for deployment in Apple's Core ML framework
 - [**Avular Mobile Robotics**](https://www.avular.com/licenses/nlohmann-json-3.9.1.txt), a platform for developing and deploying mobile robotics solutions
+- [**FunASR**](https://github.com/modelscope/FunASR/blob/main/runtime/http/bin/asr_sessions.h), a speech recognition toolkit for training and deploying end-to-end models
 - [**Google gemma.cpp**](https://github.com/google/gemma.cpp), a lightweight C++ inference engine designed for running AI models from the Gemma family
+- [**Google Magenta The Infinite Crate**](https://github.com/magenta/the-infinite-crate), an open-source generative AI plugin for digital audio workstations from Google's Magenta research team
+- [**GPT4All**](https://github.com/nomic-ai/gpt4all/blob/main/gpt4all-chat/src/tool.h), a desktop application for running local large language models on consumer hardware
+- [**Huawei MindSpore**](https://github.com/mindspore-ai/mindspore/blob/master/Third_Party_Open_Source_Software_Notice), a deep learning framework for training and inference across device, edge, and cloud
+- [**KTransformers**](https://github.com/kvcache-ai/ktransformers/blob/main/archive/csrc/balance_serve/sched/model_config.h), a framework for heterogeneous large language model inference
 - [**llama.cpp**](https://github.com/ggerganov/llama.cpp), a C++ library designed for efficient inference of large language models (LLMs), enabling streamlined integration into applications
+- [**LocalAI**](https://github.com/mudler/LocalAI/blob/master/backend/cpp/ds4/dsml_renderer.cpp), a self-hosted inference engine that exposes local models through an OpenAI-compatible API
 - [**MLX**](https://github.com/ml-explore/mlx), an array framework for machine learning on Apple Silicon
 - [**Mozilla llamafile**](https://github.com/Mozilla-Ocho/llamafile), a tool designed for distributing and executing large language models (LLMs) efficiently using a single file format
 - [**NVIDIA ACE**](https://docs.nvidia.com/ace/latest/index.html), a suite of real-time AI solutions designed for the development of interactive avatars and digital human applications, enabling scalable and sophisticated user interactions
+- [**NVIDIA Instant NGP**](https://github.com/NVlabs/instant-ngp/blob/master/src/nerf_loader.cu), an implementation of instant neural graphics primitives for rapid scene reconstruction
+- [**NVIDIA TensorRT**](https://github.com/NVIDIA/TensorRT), an SDK for high-performance deep learning inference, including its TensorRT-LLM extension for large language models
+- [**NVIDIA TensorRT-LLM**](https://github.com/NVIDIA/TensorRT-LLM/blob/main/cpp/tensorrt_llm/common/safetensors.cpp), a toolkit for optimizing and serving large language model inference on GPUs
+- [**ONNX Runtime**](https://github.com/microsoft/onnxruntime), a cross-platform inference and training accelerator for machine learning models
+- [**OpenVINO**](https://github.com/openvinotoolkit/openvino), Intel's toolkit for optimizing and deploying deep learning inference across CPUs, GPUs, and NPUs
+- [**PaddleOCR**](https://github.com/PaddlePaddle/PaddleOCR/blob/main/deploy/cpp_infer/src/modules/text_detection/result.cc), an optical character recognition toolkit that turns documents and images into structured data
+- [**PaddlePaddle**](https://github.com/PaddlePaddle/Paddle/blob/develop/paddle/ap/src/axpr/anf_expr.cc), a deep learning framework for distributed training and inference
 - [**Peer**](https://support.peer.inc/hc/en-us/articles/17261335054235-Licenses), a platform offering personalized AI assistants for interactive learning and creative collaboration
+- [**PyTorch**](https://github.com/pytorch/pytorch), a machine learning framework for building and training neural networks, widely used in research and production
+- [**Qualcomm AI Engine Direct**](https://github.com/qualcomm/qai-appbuilder), a toolchain for building and running generative AI applications on Snapdragon devices
+- [**sherpa-onnx**](https://github.com/k2-fsa/sherpa-onnx/blob/master/sherpa-onnx/csrc/sentence-piece-tokenizer.cc), a speech toolkit for on-device recognition, synthesis and speaker diarization
 - [**stable-diffusion.cpp**](https://github.com/leejet/stable-diffusion.cpp), a C++ implementation of the Stable Diffusion image generation model
 - [**TanvasTouch**](https://tanvas.co/tanvastouch-sdk-third-party-acknowledgments), a software development kit (SDK) that enables developers to create tactile experiences on touchscreens, allowing users to feel textures and physical sensations in a digital environment
 - [**TensorFlow**](https://github.com/tensorflow/tensorflow), a machine learning framework that facilitates the development and training of models, supporting data serialization and efficient data exchange between components
+- [**whisper.cpp**](https://github.com/ggml-org/whisper.cpp), a C++ implementation of OpenAI's Whisper automatic speech recognition model

 ## Scientific Research and Analysis

 - [**BLACK**](https://www.black-sat.org/en/stable/installation/linux.html), a bounded linear temporal logic (LTL) satisfiability checker
+- [**CERN ALICE O2**](https://github.com/AliceO2Group/AliceO2), the online-offline computing framework of the ALICE heavy-ion experiment at the Large Hadron Collider
 - [**CERN Atlas Athena**](https://gitlab.cern.ch/atlas/athena/-/blob/main/Control/PerformanceMonitoring/PerfMonComps/src/PerfMonMTSvc.h), a software framework used in the ATLAS experiment at the Large Hadron Collider (LHC) for performance monitoring
+- [**CERN CMSSW**](https://github.com/cms-sw/cmssw), the offline software framework of the CMS experiment at the Large Hadron Collider
+- [**CERN Gaudi**](https://gitlab.cern.ch/gaudi/Gaudi), the event-processing framework used by the LHCb and ATLAS experiments at the Large Hadron Collider
 - [**ICU**](https://github.com/unicode-org/icu), the International Components for Unicode, a mature library for software globalization and multilingual support
 - [**KAMERA**](https://github.com/Kitware/kamera), a platform for synchronized data collection and real-time deep learning to map marine species like polar bears and seals, aiding Arctic ecosystem research
 - [**KiCad**](https://gitlab.com/kicad/code/kicad/-/tree/master/thirdparty/nlohmann_json), a free and open-source software suite for electronic design automation
+- [**LLNL ROSE**](https://github.com/llnl/rose), a compiler infrastructure from Lawrence Livermore National Laboratory for building source-to-source program analysis and transformation tools
 - [**Maple**](https://www.maplesoft.com/support/help/Maple/view.aspx?path=copyright), a symbolic and numeric computing environment for advanced mathematical modeling and analysis
 - [**MeVisLab**](https://mevislabdownloads.mevis.de/docs/current/MeVis/ThirdParty/Documentation/Publish/ThirdPartyReference/index.html), a software framework for medical image processing and visualization.
+- [**MITK**](https://github.com/MITK/MITK), the Medical Imaging Interaction Toolkit, a framework for developing interactive medical image processing software
 - [**OpenPMD API**](https://openpmd-api.readthedocs.io/en/0.8.0-alpha/backends/json.html), a versatile programming interface for accessing and managing scientific data, designed to facilitate the efficient storage, retrieval, and sharing of simulation data across various applications and platforms
+- [**ORNL DataFed**](https://github.com/ORNL/DataFed), a federated scientific data management system developed at Oak Ridge National Laboratory
 - [**ParaView**](https://github.com/Kitware/ParaView), an open-source tool for large-scale data visualization and analysis across various scientific domains
 - [**QGIS**](https://gitlab.b-data.ch/qgis/qgis/-/blob/backport-57658-to-release-3_34/external/nlohmann/json.hpp), a free and open-source geographic information system (GIS) application that allows users to create, edit, visualize, and analyze geospatial data across a variety of formats
- [**VTK**](https://github.com/Kitware/VTK), a software library for 3D computer graphics, image processing, and visualization
+- [**Sandia InterSpec**](https://github.com/sandialabs/InterSpec), spectral radiation analysis software from Sandia National Laboratories for identifying radioactive isotopes
 - [**VolView**](https://github.com/Kitware/VolView), a lightweight application for interactive visualization and analysis of 3D medical imaging data.
+- [**VTK**](https://github.com/Kitware/VTK), a software library for 3D computer graphics, image processing, and visualization

 ## Business and Productivity Software

 - [**ArcGIS PRO**](https://www.esri.com/content/dam/esrisites/en-us/media/legal/open-source-acknowledgements/arcgis-pro-2-8-attribution-report.html), a desktop geographic information system (GIS) application developed by Esri for mapping and spatial analysis
 - [**Autodesk Desktop**](https://damassets.autodesk.net/content/dam/autodesk/www/Company/legal-notices-trademarks/autodesk-desktop-platform-components/internal-autodesk-components-web-page-2023.pdf), a software platform developed by Autodesk for creating and managing desktop applications and services
 - [**Check Point**](https://www.checkpoint.com/about-us/copyright-and-trademarks/), a cybersecurity company specializing in threat prevention and network security solutions, offering a range of products designed to protect enterprises from cyber threats and ensure data integrity
+- [**EasyEffects**](https://github.com/wwmm/easyeffects/blob/master/src/presets_manager.hpp), an audio effects processor for PipeWire offering limiting, compression and equalization
+- [**espanso**](https://github.com/espanso/espanso/blob/dev/espanso-ui/src/win32/native.cpp), a cross-platform text expander
+- [**Karabiner-Elements**](https://github.com/pqrs-org/Karabiner-Elements/blob/main/src/share/app_icon.hpp), a keyboard customizer for macOS
+- [**MacType**](https://github.com/snowie2000/mactype/blob/directwrite/settings.h), a font rendering engine for Windows
+- [**magicplan**](https://help.magicplan.app/acknowledgments), a mobile application for creating floor plans and interior designs using augmented reality
 - [**Microsoft Office for Mac**](https://officecdnmac.microsoft.com/pr/legal/mac/OfficeforMacAttributions.html), a suite of productivity applications developed by Microsoft for macOS, including tools for word processing, spreadsheets, and presentations
 - [**Microsoft Teams**](https://www.microsoft.com/microsoft-teams/), a team collaboration application offering workspace chat and video conferencing, file storage, and integration of proprietary and third-party applications and services
+- [**MuseScore**](https://github.com/musescore/MuseScore), a free and open-source music notation and composition application
+- [**NanaZip**](https://github.com/M2Team/NanaZip/blob/main/NanaZip.Codecs/NanaZip.Codecs.Archive.ElectronAsar.cpp), a 7-Zip derivative built for modern Windows
 - [**Nexthink Infinity**](https://docs.nexthink.com/legal/services-terms/experience-open-source-software-licenses/infinity-2022.8-software-licenses), a digital employee experience management platform for monitoring and improving IT performance
 - [**Sophos Connect Client**](https://docs.sophos.com/nsg/licenses/SophosConnect/SophosConnectAttribution.html), a secure VPN client from Sophos that allows remote users to connect to their corporate network, ensuring secure access to resources and data
 - [**Stonebranch**](https://stonebranchdocs.atlassian.net/wiki/spaces/UA77/pages/799545647/Licenses+for+Third-Party+Libraries), a cloud-based cybersecurity solution that integrates backup, disaster recovery, and cybersecurity features to protect data and ensure business continuity for organizations
 - [**Tablecruncher**](https://tablecruncher.com/), a data analysis tool that allows users to import, analyze, and visualize spreadsheet data, offering interactive features for better insights and decision-making
- [**magicplan**](https://help.magicplan.app/acknowledgments), a mobile application for creating floor plans and interior designs using augmented reality
+- [**VNote**](https://github.com/vnotex/vnote/blob/master/src/core/services/notebookcoreservice.cpp), a Markdown-based note-taking application written in C++

 ## Databases and Big Data

 - [**ADIOS2**](https://code.ornl.gov/ecpcitest/adios2/-/tree/pr4285_FFSUpstream/thirdparty/nlohmann_json?ref_type=heads), a data management framework designed for high-performance input and output operations
+- [**Apache Doris**](https://github.com/apache/doris/blob/master/be/src/runtime/be_proc_monitor.cpp), a real-time analytical database for high-concurrency queries
+- [**Claris FileMaker Server**](https://www.claris.com/company/legal/docs/acknowledgements/filemaker-server-macwin/claris_fms2025_acknowledgements_en.pdf), the server platform hosting FileMaker custom apps and databases, developed by Apple subsidiary Claris
+- [**ClickHouse**](https://github.com/ClickHouse/ClickHouse), a column-oriented database management system for real-time analytical queries
 - [**Cribl Stream**](https://docs.cribl.io/stream/third-party-current-list/), a real-time data processing platform that enables organizations to collect, route, and transform observability data, enhancing visibility and insights into their systems
 - [**DB Browser for SQLite**](https://github.com/sqlitebrowser/sqlitebrowser), a visual open-source tool for creating, designing, and editing SQLite database files
+- [**Manticore Search**](https://github.com/manticoresoftware/manticoresearch/blob/main/src/searchdhttpcompat.cpp), a database for search, offering full-text and vector queries
+- [**Milvus**](https://github.com/milvus-io/milvus/blob/master/internal/core/src/query/PlanImpl.h), a cloud-native vector database built for embedding similarity search
+- [**MongoDB**](https://github.com/mongodb/mongo/blob/master/src/mongo/replay/config_handler.cpp), a general-purpose document database
 - [**MySQL Connector/C++**](https://docs.oracle.com/cd/E17952_01/connector-cpp-9.1-license-com-en/license-opentelemetry-cpp-com.html), a C++ library for connecting and interacting with MySQL databases
 - [**MySQL NDB Cluster**](https://downloads.mysql.com/docs/licenses/cluster-9.0-com-en.pdf), a distributed database system that provides high availability and scalability for MySQL databases
 - [**MySQL Shell**](https://downloads.mysql.com/docs/licenses/mysql-shell-8.0-gpl-en.pdf), an advanced client and code editor for interacting with MySQL servers, supporting SQL, Python, and JavaScript
- [**PrestoDB**](https://github.com/prestodb/presto), a distributed SQL query engine designed for large-scale data analytics, originally developed by Facebook
+- [**PrestoDB**](https://github.com/prestodb/presto/blob/master/presto-native-execution/presto_cpp/main/Announcer.cpp), a distributed SQL query engine designed for large-scale data analytics, originally developed by Facebook
 - [**ROOT Data Analysis Framework**](https://root.cern/doc/v614/classnlohmann_1_1basic__json.html), an open-source data analysis framework widely used in high-energy physics and other fields for data processing and visualization
+- [**Typesense**](https://github.com/typesense/typesense/blob/v31/include/join.h), an open source typo-tolerant search engine
+- [**Vearch**](https://github.com/jd-opensource/vearch), a distributed vector database developed at JD.com for similarity search and retrieval-augmented generation
 - [**WiredTiger**](https://github.com/wiredtiger/wiredtiger), a high-performance storage engine for databases, offering support for compression, concurrency, and checkpointing

 ## Simulation and Modeling

+- [**Adobe Lagrange**](https://github.com/adobe/lagrange), a geometry processing library developed by Adobe for mesh manipulation and analysis
 - [**Arcturus HoloSuite**](https://www.datocms-assets.com/104353/1698904597-holosuite-third-party-software-credits-and-attributions-2.pdf), a software toolset for capturing, editing, and streaming volumetric video, featuring advanced compression technologies for high-quality 3D content creation
 - [**azul**](https://pure.tudelft.nl/ws/files/85338589/tgis.12673.pdf), a fast and efficient 3D city model viewer designed for visualizing urban environments and spatial data
+- [**Bambu Studio**](https://github.com/bambulab/BambuStudio), a slicing and print management application for Bambu Lab 3D printers
 - [**Blender**](https://projects.blender.org/blender/blender/search?q=nlohmann), a free and open-source 3D creation suite for modeling, animation, rendering, and more
 - [**cpplot**](https://cpplot.readthedocs.io/en/latest/library_api/function_eigen_8h_1ac080eac0541014c5892a55e41bf785e6.html), a library for creating interactive graphs and charts in C++, which can be viewed in web browsers
 - [**Foundry Nuke**](https://learn.foundry.com/nuke/content/misc/studio_third_party_libraries.html), a powerful node-based digital compositing and visual effects application used in film and television post-production
+- [**FreeCAD**](https://github.com/FreeCAD/FreeCAD), a free and open-source parametric 3D CAD modeler for product design and engineering
 - [**GAMS**](https://www.gams.com/47/docs/THIRDPARTY.html), a high-performance mathematical modeling system for optimization and decision support
+- [**Keysight WirelessPro**](https://docs.keysight.com/display/engdocwirelesspro/WirelessPro+2026+Release+Notes), a simulation platform for 5G, 5G-Advanced, and 6G cellular network research
 - [**Kitware SMTK**](https://github.com/Kitware/SMTK), a software toolkit for managing simulation models and workflows in scientific and engineering applications
 - [**M-Star**](https://docs.mstarcfd.com/3_Licensing/thirdparty-licenses.html), a computational fluid dynamics software for simulating and analyzing fluid flow
 - [**MapleSim CAD Toolbox**](https://www.maplesoft.com/support/help/MapleSim/view.aspx?path=CADToolbox/copyright), a software extension for MapleSim that integrates CAD models, allowing users to import, manipulate, and analyze 3D CAD data within the MapleSim environment for enhanced modeling and simulation
+- [**Microsoft AirSim**](https://github.com/microsoft/AirSim/blob/main/AirLib/include/common/Settings.hpp), a simulator for autonomous vehicles and drones built on Unreal Engine
 - [**NVIDIA Omniverse**](https://docs.omniverse.nvidia.com/composer/latest/common/product-licenses/usd-explorer/usd-explorer-2023.2.0-licenses-manifest.html), a platform for 3D content creation and collaboration that enables real-time simulations and interactive experiences across various industries
+- [**OpenSCAD**](https://github.com/openscad/openscad/blob/master/src/core/AIClient.cc), a script-driven solid 3D CAD modeller
+- [**OrcaSlicer**](https://github.com/SoftFever/OrcaSlicer), an open-source slicer supporting a wide range of consumer 3D printers
 - [**Pixar Renderman**](https://rmanwiki-26.pixar.com/space/REN26/19662083/Legal+Notice), a photorealistic 3D rendering software developed by Pixar, widely used in the film industry for creating high-quality visual effects and animations
+- [**PrusaSlicer**](https://github.com/prusa3d/PrusaSlicer), the slicing software developed by Prusa Research for its 3D printers
 - [**ROS - Robot Operating System**](http://docs.ros.org/en/noetic/api/behaviortree_cpp/html/json_8hpp_source.html), a set of software libraries and tools that assist in developing robot applications
 - [**UBS**](https://www.ubs.com/), a multinational financial services and banking company

@@ -161,18 +278,31 @@ the result of an internet search. If you know further customers of the library,
 - [**Acronis Cyber Protect Cloud**](https://care.acronis.com/s/article/59533-Third-party-software-used-in-Acronis-Cyber-Protect-Cloud?language=en_US), an all-in-one data protection solution that combines backup, disaster recovery, and cybersecurity to safeguard business data from threats like ransomware
 - [**Baereos**](https://gitlab.tiger-computing.co.uk/packages/bareos/-/blob/tiger/bullseye/third-party/CLI11/examples/json.cpp), a backup solution that provides data protection and recovery options for various environments, including physical and virtual systems
 - [**Bitdefender Home Scanner**](https://www.bitdefender.de/site/Main/view/home-scanner-open-source.html), a tool from Bitdefender that scans devices for malware and security threats, providing a safeguard against potential online dangers
+- [**Cisco MLS++**](https://github.com/cisco/mlspp), an implementation of the Messaging Layer Security protocol for end-to-end encrypted group messaging
 - [**Citrix Provisioning**](https://docs.citrix.com/en-us/provisioning/2203-ltsr/downloads/pvs-third-party-notices-2203.pdf), a solution that streamlines the delivery of virtual desktops and applications by allowing administrators to manage and provision resources efficiently across multiple environments
 - [**Citrix Virtual Apps and Desktops**](https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/2305/downloads/third-party-notices-apps-and-desktops.pdf), a solution from Citrix that delivers virtual apps and desktops
 - [**Cyberarc**](https://docs.cyberark.com/Downloads/Legal/Privileged%20Session%20Manager%20for%20SSH%20Third-Party%20Notices.pdf), a security solution that specializes in privileged access management, enabling organizations to control and monitor access to critical systems and data, thereby enhancing overall cybersecurity posture
+- [**Deutsche Telekom sysrepo-plugins**](https://github.com/telekom/sysrepo-plugins), a collection of YANG datastore plugins used to manage network devices
 - [**Egnyte Desktop**](https://helpdesk.egnyte.com/hc/en-us/articles/360007071732-Third-Party-Software-Acknowledgements), a secure cloud storage solution designed for businesses, enabling file sharing, collaboration, and data management across teams while ensuring compliance and data protection
 - [**Elster**](https://www.secunet.com/en/about-us/press/article/elstersecure-bietet-komfortablen-login-ohne-passwort-dank-secunet-protect4use), a digital platform developed by German tax authorities for secure and efficient electronic tax filing and management using secunet protect4use
+- [**Envoy**](https://github.com/envoyproxy/envoy), a cloud-native edge and service proxy that forms the data plane of many service meshes
 - [**Ethereum Solidity**](https://github.com/ethereum/solidity), a high-level, object-oriented programming language designed for implementing smart contracts on the Ethereum platform
+- [**gVisor**](https://github.com/google/gvisor), an application kernel that provides a secure sandbox for running untrusted containers
+- [**IBM Storage Virtualize**](https://public.dhe.ibm.com/systems/support/warranty/pdfs/stgoilc/SV_for_FS_7300_v8_7_0_Base_OILC.pdf), the software powering IBM FlashSystem enterprise storage arrays
 - [**Inciga**](https://fossies.org/linux/icinga2/third-party/nlohmann_json/json.hpp), a monitoring tool for IT infrastructure, designed to provide insights into system performance and availability through customizable dashboards and alerts
 - [**Intel Accelerator Management Daemon for VMware ESXi**](https://downloadmirror.intel.com/772507/THIRD-PARTY.txt), a management tool designed for monitoring and controlling Intel hardware accelerators within VMware ESXi environments, optimizing performance and resource allocation
 - [**Juniper Identity Management Service**](https://www.juniper.net/documentation/us/en/software/jims/jims-guide/jims-guide.pdf)
+- [**Meta FBOSS**](https://github.com/facebook/fboss), the software stack that controls the network switches in Meta's data centers
 - [**Microsoft Azure IoT SDK**](https://library.e.abb.com/public/2779c5f85f30484192eb3cb3f666a201/IP%20Gateway%20Open%20License%20Declaration_9AKK108467A4095_Rev_C.pdf), a collection of tools and libraries to help developers connect, build, and deploy Internet of Things (IoT) solutions on the Azure cloud platform
+- [**Microsoft Confidential Consortium Framework**](https://github.com/microsoft/CCF), a framework for building secure, highly available applications on trusted execution environments
 - [**Microsoft WinGet**](https://github.com/microsoft/winget-cli), a command-line utility included in the Windows Package Manager
+- [**Mitsubishi Electric SECS/GEM**](https://dl.mitsubishielectric.com/dl/fa/document/manual/plc/sh082483eng/sh082483engi.pdf), the semiconductor equipment communication software running on Mitsubishi Electric C Controller and C intelligent function modules
+- [**Moxa**](https://www.moxa.com/getmedia/fbe2a0c7-8dda-4b5b-a501-15e45adebb1f/moxa-foss-statement-for-da-720-series-win-10-ltsc-21h2-declaration-v1.0.pdf), a provider of industrial networking, computing, and automation infrastructure
 - [**plexusAV**](https://www.sisme.com/media/10994/manual_plexusav-p-avn-4-form8244-c.pdf), a high-performance AV-over-IP transceiver device capable of video encoding and decoding using the IPMX standard
 - [**Pointr**](https://docs-dev.pointr.tech/docs/8.x/Developer%20Portal/Open%20Source%20Licenses/), a platform for indoor positioning and navigation solutions, offering tools and SDKs for developers to create location-based applications
 - [**secunet protect4use**](https://www.secunet.com/en/about-us/press/article/elstersecure-bietet-komfortablen-login-ohne-passwort-dank-secunet-protect4use), a secure, passwordless multifactor authentication solution that transforms smartphones into digital keyrings, ensuring high security for online services and digital identities
 - [**Sencore MRD 7000**](https://www.foccusdigital.com/wp-content/uploads/2025/03/MRD-7000-Manual-8175V.pdf), a professional multi-channel receiver and decoder supporting UHD and HD stream decoding
+- [**Siemens SINEC**](https://cache.industry.siemens.com/dl/files/917/109974917/att_1298783/v2/OSS_SINEC-NMS_99.pdf), a family of network management and infrastructure services for industrial networks
+- [**Toshiba Industrial Servers**](https://www.global.toshiba/content/dam/toshiba/jp/products-solutions/industrial/computer/product/server/fs20000r/pdf/FS20000R_OSS_License_6E8C5817_rev0.pdf), the FS20000R series of industrial servers for factory automation and control systems
+- [**Wazuh**](https://github.com/wazuh/wazuh/blob/main/src/data_provider/src/sysInfo.cpp), a security platform for threat detection, integrity monitoring and incident response
+- [**ZeroTier**](https://github.com/zerotier/ZeroTierOne/blob/dev/osdep/OSUtils.hpp), a software-defined networking service that creates virtual Ethernet networks
@@ -965,3 +965,19 @@ A JSON Patch operation 'test' failed. The unsuccessful operation is also printed
    ```
    [json.exception.other_error.501] unsuccessful: {"op":"test","path":"/baz","value":"bar"}
    ```
+
+### json.exception.other_error.502
+
+[`to_ubjson`](../api/basic_json/to_ubjson.md) and [`to_bjdata`](../api/basic_json/to_bjdata.md) were called with
+`use_type = true` but `use_size = false`. UBJSON requires a size marker (`#`) after a type marker (`$`).
+
+!!! failure "Example message"
+
+    ```
+    [json.exception.other_error.502] use_type requires use_size = true
+    ```
+
+!!! note
+
+    This exception was added in version 3.13.0. Before that, debug builds aborted on an assertion and release builds
+    wrote a `$` marker without `#`, which [`from_ubjson`](../api/basic_json/from_ubjson.md) then rejected.
@@ -308,6 +308,7 @@ nav:
          - 'NLOHMANN_JSON_VERSION_MAJOR, NLOHMANN_JSON_VERSION_MINOR, NLOHMANN_JSON_VERSION_PATCH': api/macros/nlohmann_json_version_major.md
  - Community:
      - community/index.md
+      - community/ecosystem.md
      - "Code of Conduct": community/code_of_conduct.md
      - community/contribution_guidelines.md
      - community/quality_assurance.md
@@ -1,7 +1,7 @@
-wheel==0.47.0
+wheel==0.48.0

 mkdocs==1.6.1                                       # documentation framework
-mkdocs-git-revision-date-localized-plugin==1.5.3    # plugin "git-revision-date-localized"
+mkdocs-git-revision-date-localized-plugin==1.5.4    # plugin "git-revision-date-localized"
 mkdocs-material==9.7.7                             # theme for mkdocs
 mkdocs-material-extensions==1.3.1                   # extensions
 mkdocs-minify-plugin==0.8.0                         # plugin "minify"
@@ -465,15 +465,6 @@ class binary_reader
    // CBOR //
    //////////

-    /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true) or whether the last read character should
-                         be considered instead (false)
-    @param[in] tag_handler how CBOR tags should be treated
-
-    @return whether a valid CBOR value was passed to the SAX parser
-    */
-
    template<typename NumberType>
    bool get_cbor_negative_integer()
    {
@@ -492,6 +483,14 @@ class binary_reader
        return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
    }

+    /*!
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true) or whether the last read character should
+                         be considered instead (false)
+    @param[in] tag_handler how CBOR tags should be treated
+
+    @return whether a valid CBOR value was passed to the SAX parser
+    */
    bool parse_cbor_internal(const bool get_char,
                             const cbor_tag_handler_t tag_handler)
    {
@@ -774,7 +773,13 @@ class binary_reader
            case 0xBF: // map (indefinite length)
                return get_cbor_object(detail::unknown_size(), tag_handler);

-            case 0xC6: // tagged item
+            case 0xC0: // tagged item
+            case 0xC1:
+            case 0xC2:
+            case 0xC3:
+            case 0xC4:
+            case 0xC5:
+            case 0xC6:
            case 0xC7:
            case 0xC8:
            case 0xC9:
@@ -789,6 +794,9 @@ class binary_reader
            case 0xD2:
            case 0xD3:
            case 0xD4:
+            case 0xD5:
+            case 0xD6:
+            case 0xD7:
            case 0xD8: // tagged item (1 byte follows)
            case 0xD9: // tagged item (2 bytes follow)
            case 0xDA: // tagged item (4 bytes follow)
@@ -1988,7 +1996,11 @@ class binary_reader
    {
        if (get_char)
        {
-            get();  // TODO(niels): may we ignore N here?
+            // no get_ignore_noop() here: the byte read next must be a string
+            // length type specification, and a no-op ('N') is not valid in
+            // that position. No-ops at positions where a value may appear are
+            // already consumed by the callers via get_ignore_noop().
+            get();
        }

        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format, "value")))
@@ -345,8 +345,12 @@ struct wide_string_input_helper<BaseInputAdapter, 4>
            }
            else
            {
-                // unknown character
-                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                // A code point above U+10FFFF has no UTF-8 encoding. Passing the
+                // unit through would narrow it to int, where 0xFFFFFFFF becomes
+                // char_traits<char>::eof() and would end the input silently, so
+                // emit a byte that is never valid UTF-8 and let the decoder
+                // reject it.
+                utf8_bytes[0] = 0xFF;
                utf8_bytes_filled = 1;
            }
        }
@@ -8,10 +8,11 @@

 #pragma once

+#include <algorithm> // find_if
 #include <cstddef>
 #include <string> // string
 #include <type_traits> // enable_if_t
-#include <utility> // move
+#include <utility> // move, pair
 #include <vector> // vector

 #include <nlohmann/detail/exceptions.hpp>
@@ -249,7 +250,7 @@ class json_sax_dom_parser

        if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
        {
-            JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
+            return parse_error(0, "", out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
        }

        return true;
@@ -298,7 +299,7 @@ class json_sax_dom_parser

        if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
        {
-            JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
+            return parse_error(0, "", out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
        }

        return true;
@@ -370,8 +371,10 @@ class json_sax_dom_parser

                case value_t::string:
                {
-                    // include the length of the quotes, which is 2
-                    v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
+                    // escape sequences make the token longer than the value it
+                    // parses to, so the start position cannot be derived from
+                    // the value; use the offset the lexer recorded instead
+                    v.start_position = m_lexer_ref->get_token_start_position();
                    break;
                }

@@ -566,7 +569,7 @@ class json_sax_dom_callback_parser
            // check object limit
            if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
            {
-                JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
+                return parse_error(0, "", out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
            }
        }
        return true;
@@ -583,7 +586,17 @@ class json_sax_dom_callback_parser
        // add discarded value at the given key and store the reference for later
        if (keep && ref_stack.back())
        {
-            object_element = &(ref_stack.back()->m_data.m_value.object->operator[](val) = discarded);
+            auto& obj = *ref_stack.back()->m_data.m_value.object;
+            const auto it = obj.find(val);
+            if (it != obj.end())
+            {
+                // this is a duplicate key (legal in JSON); remember its
+                // current value so it can be restored later if the new
+                // value is rejected by the callback, instead of being
+                // erased together with the discarded placeholder
+                duplicate_key_stash.emplace_back(&(it->second), it->second);
+            }
+            object_element = &(obj[val] = discarded);
        }

        return true;
@@ -595,13 +608,18 @@ class json_sax_dom_callback_parser
        {
            if (!callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::object_end, *ref_stack.back()))
            {
-                // discard object
-                *ref_stack.back() = discarded;
+                // discard object, unless this slot holds a duplicate key's
+                // previous value pending restoration, in which case that
+                // value is restored instead of being discarded
+                if (!resolve_duplicate_key_stash(ref_stack.back(), true))
+                {
+                    *ref_stack.back() = discarded;

 #if JSON_DIAGNOSTIC_POSITIONS
-                // Set start/end positions for discarded object.
-                handle_diagnostic_positions_for_json_value(*ref_stack.back());
+                    // Set start/end positions for discarded object.
+                    handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
+                }
            }
            else
            {
@@ -615,6 +633,10 @@ class json_sax_dom_callback_parser
 #endif

                ref_stack.back()->set_parents();
+                // this object is finally, definitively kept; drop any
+                // pending duplicate-key stash entry for its slot since it
+                // can no longer be restored
+                resolve_duplicate_key_stash(ref_stack.back(), false);
            }
        }

@@ -657,7 +679,7 @@ class json_sax_dom_callback_parser
            // check array limit
            if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
            {
-                JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
+                return parse_error(0, "", out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
            }
        }

@@ -684,16 +706,25 @@ class json_sax_dom_callback_parser
 #endif

                ref_stack.back()->set_parents();
+                // this array is finally, definitively kept; drop any
+                // pending duplicate-key stash entry for its slot since it
+                // can no longer be restored
+                resolve_duplicate_key_stash(ref_stack.back(), false);
            }
            else
            {
-                // discard array
-                *ref_stack.back() = discarded;
+                // discard array, unless this slot holds a duplicate key's
+                // previous value pending restoration, in which case that
+                // value is restored instead of being discarded
+                if (!resolve_duplicate_key_stash(ref_stack.back(), true))
+                {
+                    *ref_stack.back() = discarded;

 #if JSON_DIAGNOSTIC_POSITIONS
-                // Set start/end positions for discarded array.
-                handle_diagnostic_positions_for_json_value(*ref_stack.back());
+                    // Set start/end positions for discarded array.
+                    handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
+                }
            }
        }

@@ -769,8 +800,10 @@ class json_sax_dom_callback_parser

                case value_t::string:
                {
-                    // include the length of the quotes, which is 2
-                    v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
+                    // escape sequences make the token longer than the value it
+                    // parses to, so the start position cannot be derived from
+                    // the value; use the offset the lexer recorded instead
+                    v.start_position = m_lexer_ref->get_token_start_position();
                    break;
                }

@@ -805,14 +838,48 @@ class json_sax_dom_callback_parser
    }
 #endif

-    /// remove the discarded value the callback rejected from its parent
-    static void remove_discarded_value(BasicJsonType& parent)
+    /// if there is a pending duplicate-key stash entry for this exact slot,
+    /// remove it from the stash; if restore_value is true, the stashed
+    /// previous value is moved back into the slot first (use this when the
+    /// new value at that slot was rejected); otherwise the stash entry is
+    /// simply dropped (use this when the new value was accepted, so it
+    /// correctly supersedes the old one and no restore should ever happen
+    /// for this slot again)
+    /// @return whether a matching stash entry was found (and processed)
+    bool resolve_duplicate_key_stash(BasicJsonType* slot, bool restore_value)
+    {
+        const auto it = std::find_if(duplicate_key_stash.begin(), duplicate_key_stash.end(),
+                                     [slot](const std::pair<BasicJsonType*, BasicJsonType>& entry)
+        {
+            return entry.first == slot;
+        });
+
+        if (it == duplicate_key_stash.end())
+        {
+            return false;
+        }
+
+        if (restore_value)
+        {
+            *slot = std::move(it->second);
+        }
+        duplicate_key_stash.erase(it);
+        return true;
+    }
+
+    /// remove the discarded value the callback rejected from its parent,
+    /// unless it is a duplicate key's slot with a stashed previous value,
+    /// in which case that previous value is restored instead
+    void remove_discarded_value(BasicJsonType& parent)
    {
        for (auto it = parent.begin(); it != parent.end(); ++it)
        {
            if (it->is_discarded())
            {
-                parent.erase(it);
+                if (!resolve_duplicate_key_stash(&(*it), true))
+                {
+                    parent.erase(it);
+                }
                break;
            }
        }
@@ -910,6 +977,16 @@ class json_sax_dom_callback_parser

        JSON_ASSERT(object_element);
        *object_element = std::move(value);
+        if (!skip_callback)
+        {
+            // this scalar value finally, definitively replaces whatever was
+            // at this slot; drop any pending duplicate-key stash entry for
+            // it since it can no longer be restored (a container value at
+            // this slot is resolved later, in end_object()/end_array(),
+            // since skip_callback is true for the placeholder handling that
+            // happens here for those)
+            resolve_duplicate_key_stash(object_element, false);
+        }
        return {true, object_element};
    }

@@ -923,6 +1000,12 @@ class json_sax_dom_callback_parser
    std::vector<bool> key_keep_stack {}; // NOLINT(readability-redundant-member-init)
    /// helper to hold the reference for the next object element
    BasicJsonType* object_element = nullptr;
+    /// stash of (slot pointer, previous value) for object members that
+    /// already existed when key() was called again for the same key
+    /// (duplicate keys); used to restore the previous value if the new
+    /// value is later rejected by the callback, instead of erasing the
+    /// member entirely
+    std::vector<std::pair<BasicJsonType*, BasicJsonType>> duplicate_key_stash {};
    /// whether a syntax error occurred
    bool errored = false;
    /// callback function
@@ -1357,6 +1357,11 @@ scan_number_done:
        token_buffer.clear();
        decimal_point_position = std::string::npos;

+#if JSON_DIAGNOSTIC_POSITIONS
+        // the first character of the token has already been read, hence the -1
+        token_start_position = position.chars_read_total - 1;
+#endif
+
        note_token_start(std::integral_constant<bool, lazy_token_string> {});
    }

@@ -1519,6 +1524,15 @@ scan_number_done:
        return position;
    }

+#if JSON_DIAGNOSTIC_POSITIONS
+    /// return the offset of the first character of the last read token; unlike
+    /// the token's parsed value, this accounts for escape sequences
+    constexpr std::size_t get_token_start_position() const noexcept
+    {
+        return token_start_position;
+    }
+#endif
+
    /// seekable adapter: rebuild the last read token from the input on demand
    const std::vector<char_type>& collect_token_chars(std::vector<char_type>& out, std::true_type /*lazy*/) const
    {
@@ -1719,6 +1733,12 @@ scan_number_done:
    /// the last read token on error for seekable adapters (see collect_token_chars)
    std::size_t token_string_start = 0;

+#if JSON_DIAGNOSTIC_POSITIONS
+    /// start offset of the current token within the input, used to report
+    /// diagnostic positions (see reset())
+    std::size_t token_start_position = 0;
+#endif
+
    /// buffer for variable-length tokens (numbers, strings)
    string_t token_buffer {};

@@ -396,19 +396,15 @@ class json_pointer
            // convert null values to arrays or objects before continuing
            if (ptr->is_null())
            {
-                // check if the reference token is a valid array index, that is
-                // a nonempty sequence of digits without a leading '0'
-                // (cf. RFC 6901, Sect. 4); tokens that could never be a valid
-                // array index (such as "01" or "") are treated as object keys
-                const bool nums = !reference_token.empty()
-                                  && (reference_token.size() == 1 || reference_token[0] != '0')
-                                  && std::all_of(reference_token.begin(), reference_token.end(),
-                                                 [](const unsigned char x)
+                // check if the reference token is a number
+                const bool nums =
+                    std::all_of(reference_token.begin(), reference_token.end(),
+                                [](const unsigned char x)
                {
                    return std::isdigit(x);
                });

-                // change value to an array for array indices or "-" or to object otherwise
+                // change value to an array for numbers or "-" or to object otherwise
                *ptr = (nums || reference_token == "-")
                       ? detail::value_t::array
                       : detail::value_t::object;
@@ -813,7 +813,10 @@ class binary_writer
                bool prefix_required = true;
                if (use_type && !j.m_data.m_value.array->empty())
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
@@ -859,7 +862,10 @@ class binary_writer

                if (use_type && (bjdata_draft3 || !j.m_data.m_value.binary->empty()))
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    oa->write_character(to_char_type('$'));
                    oa->write_character(bjdata_draft3 ? 'B' : 'U');
                }
@@ -911,7 +917,10 @@ class binary_writer
                bool prefix_required = true;
                if (use_type && !j.m_data.m_value.object->empty())
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin(), j.end(),
                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
@@ -1670,7 +1679,23 @@ class binary_writer
            {
                return true;
            }
-            len *= static_cast<std::size_t>(el.template get<std::uint64_t>());
+
+            // a dimension that does not fit into std::size_t, or a product that
+            // overflows it, would wrap around and could match the size of
+            // _ArrayData_ by accident; the resulting header announces an
+            // element count that no reader can honor (the binary reader rejects
+            // it with out_of_range.408), so encode as a plain object instead
+            const auto dim = el.template get<std::uint64_t>();
+            if (!value_in_range_of<std::size_t>(dim))
+            {
+                return true;
+            }
+            const auto dim_size = static_cast<std::size_t>(dim);
+            if (dim_size != 0 && len > (std::numeric_limits<std::size_t>::max)() / dim_size)
+            {
+                return true;
+            }
+            len *= dim_size;
        }

        key = "_ArrayData_";
@@ -9,9 +9,12 @@
 #pragma once

 #include <array> // array
+#include <cmath> // isnan, ldexp, trunc
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t
+#include <limits> // numeric_limits
 #include <string> // string
+#include <type_traits> // is_signed

 #include <nlohmann/detail/macro_scope.hpp>
 #if JSON_HAS_THREE_WAY_COMPARISON
@@ -114,5 +117,67 @@ inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 }
 #endif

+
+/*!
+@brief compare an integer with a floating point number without precision loss
+
+Widening the integer to the floating point type loses precision beyond the
+float's mantissa, which makes equality intransitive: both 2^63-2 and 2^63-1
+round to 2^63, so each compares equal to that float while differing from each
+other. Ordering built on that is not a strict weak ordering, so sorting such
+values, or using them as keys in an ordered container, is undefined behavior.
+
+Returns a value to be compared against zero with the original operator, which
+reproduces the exact ordering. A NaN operand is returned as is, so comparing it
+against zero keeps NaN's semantics: false for the relational operators and
+unordered for `<=>`.
+*/
+template<typename IntegerType, typename FloatType>
+FloatType compare_integer_with_float(const IntegerType i, const FloatType f) noexcept
+{
+    const auto ordered = [](int c) noexcept
+    {
+        return static_cast<FloatType>(c);
+    };
+
+    if (std::isnan(f))
+    {
+        return f;
+    }
+
+    // values of IntegerType lie in [-bound, bound) when signed and in
+    // [0, bound) when unsigned; digits excludes the sign bit, so bound is a
+    // power of two that the float represents exactly
+    const FloatType bound = std::ldexp(static_cast<FloatType>(1), std::numeric_limits<IntegerType>::digits);
+    if (f >= bound)
+    {
+        return ordered(-1);
+    }
+    if (std::is_signed<IntegerType>::value ? (f < -bound) : (f < static_cast<FloatType>(0)))
+    {
+        return ordered(1);
+    }
+
+    // f is now within the integer's range, so truncating it is exact
+    const FloatType truncated = std::trunc(f);
+    const auto as_integer = static_cast<IntegerType>(truncated);
+    if (i != as_integer)
+    {
+        return ordered(i < as_integer ? -1 : 1);
+    }
+
+    // the integer parts agree, so any fractional part decides
+    const FloatType fraction = f - truncated;
+    if (fraction > static_cast<FloatType>(0))
+    {
+        return ordered(-1);
+    }
+    if (fraction < static_cast<FloatType>(0))
+    {
+        return ordered(1);
+    }
+    return ordered(0);
+}
+
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END
@@ -3425,6 +3425,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container", this));
        }

+        // passed iterators must belong to arrays
+        if (JSON_HEDLEY_UNLIKELY(!first.m_object->is_array()))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to arrays", this));
+        }
+
        // insert to array and return iterator
        return insert_iterator(pos, first.m_it.array_iterator, last.m_it.array_iterator);
    }
@@ -3516,7 +3522,10 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
            if (merge_objects && it.value().is_object())
            {
                auto it2 = m_data.m_value.object->find(it.key());
-                if (it2 != m_data.m_value.object->end())
+                // Only recurse when the existing value is itself an object.
+                // Otherwise overwrite, matching the documented "all other values
+                // are overwritten as usual" behavior (see #5402).
+                if (it2 != m_data.m_value.object->end() && it2->second.is_object())
                {
                    it2->second.update(it.value(), true);
 #if JSON_DIAGNOSTICS
@@ -3570,6 +3579,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        {
            using std::swap;
            swap(*(m_data.m_value.array), other);
+            set_parents();
        }
        else
        {
@@ -3586,6 +3596,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        {
            using std::swap;
            swap(*(m_data.m_value.object), other);
+            set_parents();
        }
        else
        {
@@ -3652,6 +3663,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    // note parentheses around operands are necessary; see
    // https://github.com/nlohmann/json/issues/1530
+    // Mixed signed/unsigned integer comparisons check whether the signed value
+    // is negative before casting. If it is, the comparison is performed with
+    // the fixed values -1 and 1, which preserves the ordering relationship
+    // because any negative signed value is smaller than any unsigned value.
+    // Otherwise, the non-negative signed value is cast to unsigned before the
+    // comparison to avoid wraparound.
 #define JSON_IMPLEMENT_OPERATOR(op, null_result, unordered_result, default_result)                       \
    const auto lhs_type = lhs.type();                                                                    \
    const auto rhs_type = rhs.type();                                                                    \
@@ -3694,28 +3711,32 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    }                                                                                                    \
    else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)                   \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_integer) op rhs.m_data.m_value.number_float;      \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_integer, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)                   \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_integer);      \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_integer, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)                  \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_unsigned) op rhs.m_data.m_value.number_float;     \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_unsigned, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)                  \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_unsigned);     \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_unsigned, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_integer)                \
    {                                                                                                    \
-        return static_cast<number_integer_t>(lhs.m_data.m_value.number_unsigned) op rhs.m_data.m_value.number_integer; \
+        return (rhs.m_data.m_value.number_integer < 0)                                                   \
+               ? (number_integer_t(1) op number_integer_t(-1))                                           \
+               : (lhs.m_data.m_value.number_unsigned op static_cast<number_unsigned_t>(rhs.m_data.m_value.number_integer)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_unsigned)                \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_integer op static_cast<number_integer_t>(rhs.m_data.m_value.number_unsigned); \
-    }                                                                                                    \
+        return (lhs.m_data.m_value.number_integer < 0)                                                   \
+               ? (number_integer_t(-1) op number_integer_t(1))                                           \
+               : (static_cast<number_unsigned_t>(lhs.m_data.m_value.number_integer) op rhs.m_data.m_value.number_unsigned); \
+    }                                                                                             \
    else if(compares_unordered(lhs, rhs))\
    {\
        return (unordered_result);\
@@ -5115,19 +5136,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                // We now reached the end of at least one array
                // in a second pass, traverse the remaining elements

-                // remove my remaining elements
-                const auto end_index = static_cast<difference_type>(result.size());
-                while (i < source.size())
+                // remove my remaining elements, highest index first; appending
+                // in that order avoids the quadratic reinsertion done before
+                for (std::size_t j = source.size(); j > i; --j)
                {
-                    // add operations in reverse order to avoid invalid
-                    // indices
-                    result.insert(result.begin() + end_index, object(
+                    result.push_back(object(
                    {
                        {"op", "remove"},
-                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(i))}
+                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(j - 1))}
                    }));
-                    ++i;
                }
+                i = source.size();

                // add other remaining elements
                while (i < target.size())
@@ -5146,34 +5165,130 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

            case value_t::object:
            {
-                // first pass: traverse this object's elements
+                // first pass: find keys that were deleted (i.e., in source but
+                // not in target), and record the keys common to both, in
+                // source's iteration order -- this is a by-product of the
+                // target.find() call already needed to detect removed keys,
+                // so it adds no extra lookups.
+                std::vector<typename object_t::key_type> common_keys_source_order;
                for (auto it = source.cbegin(); it != source.cend(); ++it)
                {
-                    // escape the key name to be used in a JSON patch
-                    const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
-
-                    if (target.find(it.key()) != target.end())
+                    if (target.find(it.key()) == target.end())
                    {
-                        // recursive call to compare object values at key it
-                        auto temp_diff = diff(it.value(), target[it.key()], path_key);
-                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                    }
-                    else
-                    {
-                        // found a key that is not in o -> remove it
+                        // found a key that is not in target -> remove it
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
                        result.push_back(object(
                        {
                            {"op", "remove"}, {"path", path_key}
                        }));
                    }
+                    else
+                    {
+                        common_keys_source_order.push_back(it.key());
+                    }
                }

-                // second pass: traverse other object's elements
+                // second pass: find keys that were added (i.e., in target but
+                // not in source), and record the keys common to both, in
+                // target's iteration order -- again a by-product of the
+                // source.find() call already needed to detect added keys. At
+                // the same time, determine whether every added key comes
+                // after every common key in target's order (a precondition
+                // for the fast path below, which only ever appends new keys
+                // at the very end): for an object_t whose iteration order is
+                // a pure function of the key set (e.g. the default std::map,
+                // which always iterates in sorted key order), the order
+                // check further below is always true and this whole
+                // mechanism is effectively a no-op; it only matters for a
+                // reorderable object_t such as the one backing `ordered_json`.
+                // patch ops for keys that were added (i.e., in target but not
+                // in source); built here so the fast path below can reuse
+                // them without a second source.find() per target key. Only
+                // used by the fast path -- the slow (reordering) path
+                // rebuilds "add" ops for every key itself.
+                std::vector<typename object_t::key_type> common_keys_target_order;
+                basic_json added_ops(value_t::array);
+                bool new_keys_form_suffix = true;
+                bool seen_new_key = false;
                for (auto it = target.cbegin(); it != target.cend(); ++it)
                {
                    if (source.find(it.key()) == source.end())
                    {
-                        // found a key that is not in this -> add it
+                        seen_new_key = true;
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
+                        added_ops.push_back(
+                        {
+                            {"op", "add"}, {"path", path_key},
+                            {"value", it.value()}
+                        });
+                    }
+                    else
+                    {
+                        common_keys_target_order.push_back(it.key());
+                        if (seen_new_key)
+                        {
+                            new_keys_form_suffix = false;
+                        }
+                    }
+                }
+
+                if (common_keys_source_order == common_keys_target_order && new_keys_form_suffix)
+                {
+                    // fast path: order of common keys already matches (or the
+                    // object_t's iteration order does not depend on
+                    // insertion history), so a plain per-key recursive diff
+                    // is correct and minimal, as before. common_keys_source_order
+                    // is, by construction, the subsequence of source's keys
+                    // that are common to both objects, in source's iteration
+                    // order -- so it can be walked in lockstep with `source`
+                    // using a cheap key comparison instead of another lookup.
+                    auto common_it = common_keys_source_order.cbegin();
+                    for (auto it = source.cbegin(); it != source.cend() && common_it != common_keys_source_order.cend(); ++it)
+                    {
+                        if (it.key() == *common_it)
+                        {
+                            const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
+                            auto temp_diff = diff(it.value(), target[it.key()], path_key);
+                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                            ++common_it;
+                        }
+                    }
+
+                    // append the "add" ops for brand-new keys collected above
+                    // during the pass over target -- no second source.find()
+                    // per target key needed
+                    result.insert(result.end(), added_ops.begin(), added_ops.end());
+                }
+                else
+                {
+                    // slow path: the common keys are in a different relative
+                    // order in source and target (only possible for a
+                    // reorderable object_t like ordered_map). Building a
+                    // minimal reordering patch is a nontrivial (LCS-like)
+                    // problem; instead, remove every common key and re-add it
+                    // (with its final target value) in target's order, which
+                    // is enough to guarantee source.patch(diff(source,
+                    // target)) == target. basic_json::patch()'s "add"
+                    // operation on an object uses operator[], which appends
+                    // at the end for a vector-backed insertion-ordered map
+                    // when the key does not already exist -- so removing a
+                    // key and then adding it moves it to the end, fixing its
+                    // position.
+                    for (const auto& key : common_keys_source_order)
+                    {
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(key));
+                        result.push_back(object(
+                        {
+                            {"op", "remove"}, {"path", path_key}
+                        }));
+                    }
+
+                    // add every key that is either common (just removed
+                    // above) or brand new, in target's iteration order, so
+                    // that the final order after applying the patch matches
+                    // target exactly
+                    for (auto it = target.cbegin(); it != target.cend(); ++it)
+                    {
                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
                        result.push_back(
                        {
@@ -223,9 +223,12 @@


 #include <array> // array
+#include <cmath> // isnan, ldexp, trunc
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t
+#include <limits> // numeric_limits
 #include <string> // string
+#include <type_traits> // is_signed

 // #include <nlohmann/detail/macro_scope.hpp>
 //     __ _____ _____ _____
@@ -3283,6 +3286,68 @@ inline bool operator<(const value_t lhs, const value_t rhs) noexcept
 }
 #endif

+
+/*!
+@brief compare an integer with a floating point number without precision loss
+
+Widening the integer to the floating point type loses precision beyond the
+float's mantissa, which makes equality intransitive: both 2^63-2 and 2^63-1
+round to 2^63, so each compares equal to that float while differing from each
+other. Ordering built on that is not a strict weak ordering, so sorting such
+values, or using them as keys in an ordered container, is undefined behavior.
+
+Returns a value to be compared against zero with the original operator, which
+reproduces the exact ordering. A NaN operand is returned as is, so comparing it
+against zero keeps NaN's semantics: false for the relational operators and
+unordered for `<=>`.
+*/
+template<typename IntegerType, typename FloatType>
+FloatType compare_integer_with_float(const IntegerType i, const FloatType f) noexcept
+{
+    const auto ordered = [](int c) noexcept
+    {
+        return static_cast<FloatType>(c);
+    };
+
+    if (std::isnan(f))
+    {
+        return f;
+    }
+
+    // values of IntegerType lie in [-bound, bound) when signed and in
+    // [0, bound) when unsigned; digits excludes the sign bit, so bound is a
+    // power of two that the float represents exactly
+    const FloatType bound = std::ldexp(static_cast<FloatType>(1), std::numeric_limits<IntegerType>::digits);
+    if (f >= bound)
+    {
+        return ordered(-1);
+    }
+    if (std::is_signed<IntegerType>::value ? (f < -bound) : (f < static_cast<FloatType>(0)))
+    {
+        return ordered(1);
+    }
+
+    // f is now within the integer's range, so truncating it is exact
+    const FloatType truncated = std::trunc(f);
+    const auto as_integer = static_cast<IntegerType>(truncated);
+    if (i != as_integer)
+    {
+        return ordered(i < as_integer ? -1 : 1);
+    }
+
+    // the integer parts agree, so any fractional part decides
+    const FloatType fraction = f - truncated;
+    if (fraction > static_cast<FloatType>(0))
+    {
+        return ordered(-1);
+    }
+    if (fraction < static_cast<FloatType>(0))
+    {
+        return ordered(1);
+    }
+    return ordered(0);
+}
+
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

@@ -7348,8 +7413,12 @@ struct wide_string_input_helper<BaseInputAdapter, 4>
            }
            else
            {
-                // unknown character
-                utf8_bytes[0] = static_cast<std::char_traits<char>::int_type>(wc);
+                // A code point above U+10FFFF has no UTF-8 encoding. Passing the
+                // unit through would narrow it to int, where 0xFFFFFFFF becomes
+                // char_traits<char>::eof() and would end the input silently, so
+                // emit a byte that is never valid UTF-8 and let the decoder
+                // reject it.
+                utf8_bytes[0] = 0xFF;
                utf8_bytes_filled = 1;
            }
        }
@@ -7699,10 +7768,11 @@ NLOHMANN_JSON_NAMESPACE_END



+#include <algorithm> // find_if
 #include <cstddef>
 #include <string> // string
 #include <type_traits> // enable_if_t
-#include <utility> // move
+#include <utility> // move, pair
 #include <vector> // vector

 // #include <nlohmann/detail/exceptions.hpp>
@@ -9071,6 +9141,11 @@ scan_number_done:
        token_buffer.clear();
        decimal_point_position = std::string::npos;

+#if JSON_DIAGNOSTIC_POSITIONS
+        // the first character of the token has already been read, hence the -1
+        token_start_position = position.chars_read_total - 1;
+#endif
+
        note_token_start(std::integral_constant<bool, lazy_token_string> {});
    }

@@ -9233,6 +9308,15 @@ scan_number_done:
        return position;
    }

+#if JSON_DIAGNOSTIC_POSITIONS
+    /// return the offset of the first character of the last read token; unlike
+    /// the token's parsed value, this accounts for escape sequences
+    constexpr std::size_t get_token_start_position() const noexcept
+    {
+        return token_start_position;
+    }
+#endif
+
    /// seekable adapter: rebuild the last read token from the input on demand
    const std::vector<char_type>& collect_token_chars(std::vector<char_type>& out, std::true_type /*lazy*/) const
    {
@@ -9433,6 +9517,12 @@ scan_number_done:
    /// the last read token on error for seekable adapters (see collect_token_chars)
    std::size_t token_string_start = 0;

+#if JSON_DIAGNOSTIC_POSITIONS
+    /// start offset of the current token within the input, used to report
+    /// diagnostic positions (see reset())
+    std::size_t token_start_position = 0;
+#endif
+
    /// buffer for variable-length tokens (numbers, strings)
    string_t token_buffer {};

@@ -9688,7 +9778,7 @@ class json_sax_dom_parser

        if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
        {
-            JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
+            return parse_error(0, "", out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
        }

        return true;
@@ -9737,7 +9827,7 @@ class json_sax_dom_parser

        if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
        {
-            JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
+            return parse_error(0, "", out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
        }

        return true;
@@ -9809,8 +9899,10 @@ class json_sax_dom_parser

                case value_t::string:
                {
-                    // include the length of the quotes, which is 2
-                    v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
+                    // escape sequences make the token longer than the value it
+                    // parses to, so the start position cannot be derived from
+                    // the value; use the offset the lexer recorded instead
+                    v.start_position = m_lexer_ref->get_token_start_position();
                    break;
                }

@@ -10005,7 +10097,7 @@ class json_sax_dom_callback_parser
            // check object limit
            if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
            {
-                JSON_THROW(out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
+                return parse_error(0, "", out_of_range::create(408, concat("excessive object size: ", std::to_string(len)), ref_stack.back()));
            }
        }
        return true;
@@ -10022,7 +10114,17 @@ class json_sax_dom_callback_parser
        // add discarded value at the given key and store the reference for later
        if (keep && ref_stack.back())
        {
-            object_element = &(ref_stack.back()->m_data.m_value.object->operator[](val) = discarded);
+            auto& obj = *ref_stack.back()->m_data.m_value.object;
+            const auto it = obj.find(val);
+            if (it != obj.end())
+            {
+                // this is a duplicate key (legal in JSON); remember its
+                // current value so it can be restored later if the new
+                // value is rejected by the callback, instead of being
+                // erased together with the discarded placeholder
+                duplicate_key_stash.emplace_back(&(it->second), it->second);
+            }
+            object_element = &(obj[val] = discarded);
        }

        return true;
@@ -10034,13 +10136,18 @@ class json_sax_dom_callback_parser
        {
            if (!callback(static_cast<int>(ref_stack.size()) - 1, parse_event_t::object_end, *ref_stack.back()))
            {
-                // discard object
-                *ref_stack.back() = discarded;
+                // discard object, unless this slot holds a duplicate key's
+                // previous value pending restoration, in which case that
+                // value is restored instead of being discarded
+                if (!resolve_duplicate_key_stash(ref_stack.back(), true))
+                {
+                    *ref_stack.back() = discarded;

 #if JSON_DIAGNOSTIC_POSITIONS
-                // Set start/end positions for discarded object.
-                handle_diagnostic_positions_for_json_value(*ref_stack.back());
+                    // Set start/end positions for discarded object.
+                    handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
+                }
            }
            else
            {
@@ -10054,6 +10161,10 @@ class json_sax_dom_callback_parser
 #endif

                ref_stack.back()->set_parents();
+                // this object is finally, definitively kept; drop any
+                // pending duplicate-key stash entry for its slot since it
+                // can no longer be restored
+                resolve_duplicate_key_stash(ref_stack.back(), false);
            }
        }

@@ -10096,7 +10207,7 @@ class json_sax_dom_callback_parser
            // check array limit
            if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref_stack.back()->max_size()))
            {
-                JSON_THROW(out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
+                return parse_error(0, "", out_of_range::create(408, concat("excessive array size: ", std::to_string(len)), ref_stack.back()));
            }
        }

@@ -10123,16 +10234,25 @@ class json_sax_dom_callback_parser
 #endif

                ref_stack.back()->set_parents();
+                // this array is finally, definitively kept; drop any
+                // pending duplicate-key stash entry for its slot since it
+                // can no longer be restored
+                resolve_duplicate_key_stash(ref_stack.back(), false);
            }
            else
            {
-                // discard array
-                *ref_stack.back() = discarded;
+                // discard array, unless this slot holds a duplicate key's
+                // previous value pending restoration, in which case that
+                // value is restored instead of being discarded
+                if (!resolve_duplicate_key_stash(ref_stack.back(), true))
+                {
+                    *ref_stack.back() = discarded;

 #if JSON_DIAGNOSTIC_POSITIONS
-                // Set start/end positions for discarded array.
-                handle_diagnostic_positions_for_json_value(*ref_stack.back());
+                    // Set start/end positions for discarded array.
+                    handle_diagnostic_positions_for_json_value(*ref_stack.back());
 #endif
+                }
            }
        }

@@ -10208,8 +10328,10 @@ class json_sax_dom_callback_parser

                case value_t::string:
                {
-                    // include the length of the quotes, which is 2
-                    v.start_position = v.end_position - v.m_data.m_value.string->size() - 2;
+                    // escape sequences make the token longer than the value it
+                    // parses to, so the start position cannot be derived from
+                    // the value; use the offset the lexer recorded instead
+                    v.start_position = m_lexer_ref->get_token_start_position();
                    break;
                }

@@ -10244,14 +10366,48 @@ class json_sax_dom_callback_parser
    }
 #endif

-    /// remove the discarded value the callback rejected from its parent
-    static void remove_discarded_value(BasicJsonType& parent)
+    /// if there is a pending duplicate-key stash entry for this exact slot,
+    /// remove it from the stash; if restore_value is true, the stashed
+    /// previous value is moved back into the slot first (use this when the
+    /// new value at that slot was rejected); otherwise the stash entry is
+    /// simply dropped (use this when the new value was accepted, so it
+    /// correctly supersedes the old one and no restore should ever happen
+    /// for this slot again)
+    /// @return whether a matching stash entry was found (and processed)
+    bool resolve_duplicate_key_stash(BasicJsonType* slot, bool restore_value)
+    {
+        const auto it = std::find_if(duplicate_key_stash.begin(), duplicate_key_stash.end(),
+                                     [slot](const std::pair<BasicJsonType*, BasicJsonType>& entry)
+        {
+            return entry.first == slot;
+        });
+
+        if (it == duplicate_key_stash.end())
+        {
+            return false;
+        }
+
+        if (restore_value)
+        {
+            *slot = std::move(it->second);
+        }
+        duplicate_key_stash.erase(it);
+        return true;
+    }
+
+    /// remove the discarded value the callback rejected from its parent,
+    /// unless it is a duplicate key's slot with a stashed previous value,
+    /// in which case that previous value is restored instead
+    void remove_discarded_value(BasicJsonType& parent)
    {
        for (auto it = parent.begin(); it != parent.end(); ++it)
        {
            if (it->is_discarded())
            {
-                parent.erase(it);
+                if (!resolve_duplicate_key_stash(&(*it), true))
+                {
+                    parent.erase(it);
+                }
                break;
            }
        }
@@ -10349,6 +10505,16 @@ class json_sax_dom_callback_parser

        JSON_ASSERT(object_element);
        *object_element = std::move(value);
+        if (!skip_callback)
+        {
+            // this scalar value finally, definitively replaces whatever was
+            // at this slot; drop any pending duplicate-key stash entry for
+            // it since it can no longer be restored (a container value at
+            // this slot is resolved later, in end_object()/end_array(),
+            // since skip_callback is true for the placeholder handling that
+            // happens here for those)
+            resolve_duplicate_key_stash(object_element, false);
+        }
        return {true, object_element};
    }

@@ -10362,6 +10528,12 @@ class json_sax_dom_callback_parser
    std::vector<bool> key_keep_stack {}; // NOLINT(readability-redundant-member-init)
    /// helper to hold the reference for the next object element
    BasicJsonType* object_element = nullptr;
+    /// stash of (slot pointer, previous value) for object members that
+    /// already existed when key() was called again for the same key
+    /// (duplicate keys); used to restore the previous value if the new
+    /// value is later rejected by the callback, instead of erasing the
+    /// member entirely
+    std::vector<std::pair<BasicJsonType*, BasicJsonType>> duplicate_key_stash {};
    /// whether a syntax error occurred
    bool errored = false;
    /// callback function
@@ -11059,15 +11231,6 @@ class binary_reader
    // CBOR //
    //////////

-    /*!
-    @param[in] get_char  whether a new character should be retrieved from the
-                         input (true) or whether the last read character should
-                         be considered instead (false)
-    @param[in] tag_handler how CBOR tags should be treated
-
-    @return whether a valid CBOR value was passed to the SAX parser
-    */
-
    template<typename NumberType>
    bool get_cbor_negative_integer()
    {
@@ -11086,6 +11249,14 @@ class binary_reader
        return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
    }

+    /*!
+    @param[in] get_char  whether a new character should be retrieved from the
+                         input (true) or whether the last read character should
+                         be considered instead (false)
+    @param[in] tag_handler how CBOR tags should be treated
+
+    @return whether a valid CBOR value was passed to the SAX parser
+    */
    bool parse_cbor_internal(const bool get_char,
                             const cbor_tag_handler_t tag_handler)
    {
@@ -11368,7 +11539,13 @@ class binary_reader
            case 0xBF: // map (indefinite length)
                return get_cbor_object(detail::unknown_size(), tag_handler);

-            case 0xC6: // tagged item
+            case 0xC0: // tagged item
+            case 0xC1:
+            case 0xC2:
+            case 0xC3:
+            case 0xC4:
+            case 0xC5:
+            case 0xC6:
            case 0xC7:
            case 0xC8:
            case 0xC9:
@@ -11383,6 +11560,9 @@ class binary_reader
            case 0xD2:
            case 0xD3:
            case 0xD4:
+            case 0xD5:
+            case 0xD6:
+            case 0xD7:
            case 0xD8: // tagged item (1 byte follows)
            case 0xD9: // tagged item (2 bytes follow)
            case 0xDA: // tagged item (4 bytes follow)
@@ -12582,7 +12762,11 @@ class binary_reader
    {
        if (get_char)
        {
-            get();  // TODO(niels): may we ignore N here?
+            // no get_ignore_noop() here: the byte read next must be a string
+            // length type specification, and a no-op ('N') is not valid in
+            // that position. No-ops at positions where a value may appear are
+            // already consumed by the callers via get_ignore_noop().
+            get();
        }

        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format, "value")))
@@ -15937,19 +16121,15 @@ class json_pointer
            // convert null values to arrays or objects before continuing
            if (ptr->is_null())
            {
-                // check if the reference token is a valid array index, that is
-                // a nonempty sequence of digits without a leading '0'
-                // (cf. RFC 6901, Sect. 4); tokens that could never be a valid
-                // array index (such as "01" or "") are treated as object keys
-                const bool nums = !reference_token.empty()
-                                  && (reference_token.size() == 1 || reference_token[0] != '0')
-                                  && std::all_of(reference_token.begin(), reference_token.end(),
-                                                 [](const unsigned char x)
+                // check if the reference token is a number
+                const bool nums =
+                    std::all_of(reference_token.begin(), reference_token.end(),
+                                [](const unsigned char x)
                {
                    return std::isdigit(x);
                });

-                // change value to an array for array indices or "-" or to object otherwise
+                // change value to an array for numbers or "-" or to object otherwise
                *ptr = (nums || reference_token == "-")
                       ? detail::value_t::array
                       : detail::value_t::object;
@@ -17720,7 +17900,10 @@ class binary_writer
                bool prefix_required = true;
                if (use_type && !j.m_data.m_value.array->empty())
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin() + 1, j.end(),
                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
@@ -17766,7 +17949,10 @@ class binary_writer

                if (use_type && (bjdata_draft3 || !j.m_data.m_value.binary->empty()))
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    oa->write_character(to_char_type('$'));
                    oa->write_character(bjdata_draft3 ? 'B' : 'U');
                }
@@ -17818,7 +18004,10 @@ class binary_writer
                bool prefix_required = true;
                if (use_type && !j.m_data.m_value.object->empty())
                {
-                    JSON_ASSERT(use_count);
+                    if (!use_count)
+                    {
+                        JSON_THROW(other_error::create(502, "use_type requires use_size = true", &j));
+                    }
                    const CharType first_prefix = ubjson_prefix(j.front(), use_bjdata);
                    const bool same_prefix = std::all_of(j.begin(), j.end(),
                                                         [this, first_prefix, use_bjdata](const BasicJsonType & v)
@@ -18577,7 +18766,23 @@ class binary_writer
            {
                return true;
            }
-            len *= static_cast<std::size_t>(el.template get<std::uint64_t>());
+
+            // a dimension that does not fit into std::size_t, or a product that
+            // overflows it, would wrap around and could match the size of
+            // _ArrayData_ by accident; the resulting header announces an
+            // element count that no reader can honor (the binary reader rejects
+            // it with out_of_range.408), so encode as a plain object instead
+            const auto dim = el.template get<std::uint64_t>();
+            if (!value_in_range_of<std::size_t>(dim))
+            {
+                return true;
+            }
+            const auto dim_size = static_cast<std::size_t>(dim);
+            if (dim_size != 0 && len > (std::numeric_limits<std::size_t>::max)() / dim_size)
+            {
+                return true;
+            }
+            len *= dim_size;
        }

        key = "_ArrayData_";
@@ -24718,6 +24923,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
            JSON_THROW(invalid_iterator::create(211, "passed iterators may not belong to container", this));
        }

+        // passed iterators must belong to arrays
+        if (JSON_HEDLEY_UNLIKELY(!first.m_object->is_array()))
+        {
+            JSON_THROW(invalid_iterator::create(202, "iterators first and last must point to arrays", this));
+        }
+
        // insert to array and return iterator
        return insert_iterator(pos, first.m_it.array_iterator, last.m_it.array_iterator);
    }
@@ -24809,7 +25020,10 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
            if (merge_objects && it.value().is_object())
            {
                auto it2 = m_data.m_value.object->find(it.key());
-                if (it2 != m_data.m_value.object->end())
+                // Only recurse when the existing value is itself an object.
+                // Otherwise overwrite, matching the documented "all other values
+                // are overwritten as usual" behavior (see #5402).
+                if (it2 != m_data.m_value.object->end() && it2->second.is_object())
                {
                    it2->second.update(it.value(), true);
 #if JSON_DIAGNOSTICS
@@ -24863,6 +25077,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        {
            using std::swap;
            swap(*(m_data.m_value.array), other);
+            set_parents();
        }
        else
        {
@@ -24879,6 +25094,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
        {
            using std::swap;
            swap(*(m_data.m_value.object), other);
+            set_parents();
        }
        else
        {
@@ -24945,6 +25161,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

    // note parentheses around operands are necessary; see
    // https://github.com/nlohmann/json/issues/1530
+    // Mixed signed/unsigned integer comparisons check whether the signed value
+    // is negative before casting. If it is, the comparison is performed with
+    // the fixed values -1 and 1, which preserves the ordering relationship
+    // because any negative signed value is smaller than any unsigned value.
+    // Otherwise, the non-negative signed value is cast to unsigned before the
+    // comparison to avoid wraparound.
 #define JSON_IMPLEMENT_OPERATOR(op, null_result, unordered_result, default_result)                       \
    const auto lhs_type = lhs.type();                                                                    \
    const auto rhs_type = rhs.type();                                                                    \
@@ -24987,28 +25209,32 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    }                                                                                                    \
    else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_float)                   \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_integer) op rhs.m_data.m_value.number_float;      \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_integer, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_integer)                   \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_integer);      \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_integer, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_float)                  \
    {                                                                                                    \
-        return static_cast<number_float_t>(lhs.m_data.m_value.number_unsigned) op rhs.m_data.m_value.number_float;     \
+        return (detail::compare_integer_with_float(lhs.m_data.m_value.number_unsigned, rhs.m_data.m_value.number_float)) op (static_cast<number_float_t>(0)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_float && rhs_type == value_t::number_unsigned)                  \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_float op static_cast<number_float_t>(rhs.m_data.m_value.number_unsigned);     \
+        return (static_cast<number_float_t>(0)) op (detail::compare_integer_with_float(rhs.m_data.m_value.number_unsigned, lhs.m_data.m_value.number_float)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_unsigned && rhs_type == value_t::number_integer)                \
    {                                                                                                    \
-        return static_cast<number_integer_t>(lhs.m_data.m_value.number_unsigned) op rhs.m_data.m_value.number_integer; \
+        return (rhs.m_data.m_value.number_integer < 0)                                                   \
+               ? (number_integer_t(1) op number_integer_t(-1))                                           \
+               : (lhs.m_data.m_value.number_unsigned op static_cast<number_unsigned_t>(rhs.m_data.m_value.number_integer)); \
    }                                                                                                    \
    else if (lhs_type == value_t::number_integer && rhs_type == value_t::number_unsigned)                \
    {                                                                                                    \
-        return lhs.m_data.m_value.number_integer op static_cast<number_integer_t>(rhs.m_data.m_value.number_unsigned); \
-    }                                                                                                    \
+        return (lhs.m_data.m_value.number_integer < 0)                                                   \
+               ? (number_integer_t(-1) op number_integer_t(1))                                           \
+               : (static_cast<number_unsigned_t>(lhs.m_data.m_value.number_integer) op rhs.m_data.m_value.number_unsigned); \
+    }                                                                                             \
    else if(compares_unordered(lhs, rhs))\
    {\
        return (unordered_result);\
@@ -26408,19 +26634,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                // We now reached the end of at least one array
                // in a second pass, traverse the remaining elements

-                // remove my remaining elements
-                const auto end_index = static_cast<difference_type>(result.size());
-                while (i < source.size())
+                // remove my remaining elements, highest index first; appending
+                // in that order avoids the quadratic reinsertion done before
+                for (std::size_t j = source.size(); j > i; --j)
                {
-                    // add operations in reverse order to avoid invalid
-                    // indices
-                    result.insert(result.begin() + end_index, object(
+                    result.push_back(object(
                    {
                        {"op", "remove"},
-                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(i))}
+                        {"path", detail::concat<string_t>(path, '/', detail::to_string<string_t>(j - 1))}
                    }));
-                    ++i;
                }
+                i = source.size();

                // add other remaining elements
                while (i < target.size())
@@ -26439,34 +26663,130 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec

            case value_t::object:
            {
-                // first pass: traverse this object's elements
+                // first pass: find keys that were deleted (i.e., in source but
+                // not in target), and record the keys common to both, in
+                // source's iteration order -- this is a by-product of the
+                // target.find() call already needed to detect removed keys,
+                // so it adds no extra lookups.
+                std::vector<typename object_t::key_type> common_keys_source_order;
                for (auto it = source.cbegin(); it != source.cend(); ++it)
                {
-                    // escape the key name to be used in a JSON patch
-                    const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
-
-                    if (target.find(it.key()) != target.end())
+                    if (target.find(it.key()) == target.end())
                    {
-                        // recursive call to compare object values at key it
-                        auto temp_diff = diff(it.value(), target[it.key()], path_key);
-                        result.insert(result.end(), temp_diff.begin(), temp_diff.end());
-                    }
-                    else
-                    {
-                        // found a key that is not in o -> remove it
+                        // found a key that is not in target -> remove it
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
                        result.push_back(object(
                        {
                            {"op", "remove"}, {"path", path_key}
                        }));
                    }
+                    else
+                    {
+                        common_keys_source_order.push_back(it.key());
+                    }
                }

-                // second pass: traverse other object's elements
+                // second pass: find keys that were added (i.e., in target but
+                // not in source), and record the keys common to both, in
+                // target's iteration order -- again a by-product of the
+                // source.find() call already needed to detect added keys. At
+                // the same time, determine whether every added key comes
+                // after every common key in target's order (a precondition
+                // for the fast path below, which only ever appends new keys
+                // at the very end): for an object_t whose iteration order is
+                // a pure function of the key set (e.g. the default std::map,
+                // which always iterates in sorted key order), the order
+                // check further below is always true and this whole
+                // mechanism is effectively a no-op; it only matters for a
+                // reorderable object_t such as the one backing `ordered_json`.
+                // patch ops for keys that were added (i.e., in target but not
+                // in source); built here so the fast path below can reuse
+                // them without a second source.find() per target key. Only
+                // used by the fast path -- the slow (reordering) path
+                // rebuilds "add" ops for every key itself.
+                std::vector<typename object_t::key_type> common_keys_target_order;
+                basic_json added_ops(value_t::array);
+                bool new_keys_form_suffix = true;
+                bool seen_new_key = false;
                for (auto it = target.cbegin(); it != target.cend(); ++it)
                {
                    if (source.find(it.key()) == source.end())
                    {
-                        // found a key that is not in this -> add it
+                        seen_new_key = true;
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
+                        added_ops.push_back(
+                        {
+                            {"op", "add"}, {"path", path_key},
+                            {"value", it.value()}
+                        });
+                    }
+                    else
+                    {
+                        common_keys_target_order.push_back(it.key());
+                        if (seen_new_key)
+                        {
+                            new_keys_form_suffix = false;
+                        }
+                    }
+                }
+
+                if (common_keys_source_order == common_keys_target_order && new_keys_form_suffix)
+                {
+                    // fast path: order of common keys already matches (or the
+                    // object_t's iteration order does not depend on
+                    // insertion history), so a plain per-key recursive diff
+                    // is correct and minimal, as before. common_keys_source_order
+                    // is, by construction, the subsequence of source's keys
+                    // that are common to both objects, in source's iteration
+                    // order -- so it can be walked in lockstep with `source`
+                    // using a cheap key comparison instead of another lookup.
+                    auto common_it = common_keys_source_order.cbegin();
+                    for (auto it = source.cbegin(); it != source.cend() && common_it != common_keys_source_order.cend(); ++it)
+                    {
+                        if (it.key() == *common_it)
+                        {
+                            const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
+                            auto temp_diff = diff(it.value(), target[it.key()], path_key);
+                            result.insert(result.end(), temp_diff.begin(), temp_diff.end());
+                            ++common_it;
+                        }
+                    }
+
+                    // append the "add" ops for brand-new keys collected above
+                    // during the pass over target -- no second source.find()
+                    // per target key needed
+                    result.insert(result.end(), added_ops.begin(), added_ops.end());
+                }
+                else
+                {
+                    // slow path: the common keys are in a different relative
+                    // order in source and target (only possible for a
+                    // reorderable object_t like ordered_map). Building a
+                    // minimal reordering patch is a nontrivial (LCS-like)
+                    // problem; instead, remove every common key and re-add it
+                    // (with its final target value) in target's order, which
+                    // is enough to guarantee source.patch(diff(source,
+                    // target)) == target. basic_json::patch()'s "add"
+                    // operation on an object uses operator[], which appends
+                    // at the end for a vector-backed insertion-ordered map
+                    // when the key does not already exist -- so removing a
+                    // key and then adding it moves it to the end, fixing its
+                    // position.
+                    for (const auto& key : common_keys_source_order)
+                    {
+                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(key));
+                        result.push_back(object(
+                        {
+                            {"op", "remove"}, {"path", path_key}
+                        }));
+                    }
+
+                    // add every key that is either common (just removed
+                    // above) or brand new, in target's iteration order, so
+                    // that the final order after applying the patch matches
+                    // target exactly
+                    for (auto it = target.cbegin(); it != target.cend(); ++it)
+                    {
                        const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
                        result.push_back(
                        {
@@ -2730,6 +2730,27 @@ TEST_CASE("BJData")
                CHECK(json::from_bjdata(json::to_bjdata(j_type), true, true) == j_type);
                CHECK(json::from_bjdata(json::to_bjdata(j_size), true, true) == j_size);
            }
+
+            SECTION("ndarray whose dimensions overflow stays as object")
+            {
+                // the product of the dimensions wraps around std::size_t to 0
+                // and so matches the size of the empty _ArrayData_; writing this
+                // as an ndarray would announce an element count no reader can
+                // honor, so it has to stay a plain object
+                json j_overflow = json({{"_ArrayData_", json::array()}, {"_ArraySize_", {9223372036854775808ull, 2}}, {"_ArrayType_", "uint8"}});
+                CHECK(json::from_bjdata(json::to_bjdata(j_overflow), true, true) == j_overflow);
+
+                // a single dimension that does not fit into std::size_t is
+                // rejected for the same reason (only observable where
+                // std::size_t is narrower than 64 bit)
+                json j_huge = json({{"_ArrayData_", json::array()}, {"_ArraySize_", {18446744073709551615ull}}, {"_ArrayType_", "uint8"}});
+                CHECK(json::from_bjdata(json::to_bjdata(j_huge), true, true) == j_huge);
+
+                // a well-formed ndarray is still encoded as one
+                json j_ok = json({{"_ArrayData_", {1, 2, 3, 4, 5, 6}}, {"_ArraySize_", {2, 3}}, {"_ArrayType_", "uint8"}});
+                CHECK(json::to_bjdata(j_ok) == std::vector<uint8_t>({'[', '$', 'U', '#', '[', 'i', 2, 'i', 3, ']', 1, 2, 3, 4, 5, 6}));
+                CHECK(json::from_bjdata(json::to_bjdata(j_ok), true, true) == j_ok);
+            }
        }
    }

@@ -3822,6 +3843,48 @@ TEST_CASE("all BJData first bytes")
 }
 #endif

+TEST_CASE("BJData use_type requires use_size")
+{
+    SECTION("non-empty object throws other_error.502")
+    {
+        const json j = {{"a", 1}, {"b", 2}};
+        CHECK_THROWS_WITH_AS(json::to_bjdata(j, false, true),
+                             "[json.exception.other_error.502] use_type requires use_size = true",
+                             json::other_error&);
+    }
+
+    SECTION("non-empty array throws other_error.502")
+    {
+        const json j = {1, 2, 3};
+        CHECK_THROWS_WITH_AS(json::to_bjdata(j, false, true),
+                             "[json.exception.other_error.502] use_type requires use_size = true",
+                             json::other_error&);
+    }
+
+    SECTION("scalars do not throw with use_type=true, use_count=false")
+    {
+        CHECK_NOTHROW(json::to_bjdata(42, false, true));
+        CHECK_NOTHROW(json::to_bjdata(3.14, false, true));
+        CHECK_NOTHROW(json::to_bjdata("hello", false, true));
+        CHECK_NOTHROW(json::to_bjdata(true, false, true));
+        CHECK_NOTHROW(json::to_bjdata(nullptr, false, true));
+    }
+
+    SECTION("empty containers do not throw with use_type=true, use_count=false")
+    {
+        CHECK_NOTHROW(json::to_bjdata(json::array(), false, true));
+        CHECK_NOTHROW(json::to_bjdata(json::object(), false, true));
+    }
+
+    SECTION("valid combinations on non-empty containers")
+    {
+        const json j = {{"a", 1}, {"b", 2}};
+        CHECK_NOTHROW(json::to_bjdata(j, false, false));
+        CHECK_NOTHROW(json::to_bjdata(j, true, false));
+        CHECK_NOTHROW(json::to_bjdata(j, true, true));
+    }
+}
+
 TEST_CASE("BJData roundtrips" * doctest::skip())
 {
    SECTION("input from self-generated BJData files")
@@ -2565,11 +2565,16 @@ TEST_CASE("Tagged values")
    const json j = "s";
    auto v = json::to_cbor(j);

-    SECTION("0xC6..0xD4")
+    const json j_bin_payload = json::binary(std::vector<std::uint8_t> {0x01, 0x02, 0x03});
+    auto v_bin_payload = json::to_cbor(j_bin_payload);
+
+    SECTION("0xC0..0xD7")
    {
        for (const auto b : std::vector<std::uint8_t>
    {
-        0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4
+        0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5,
+        0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
+        0xD5, 0xD6, 0xD7
    })
        {
            CAPTURE(b);
@@ -2589,6 +2594,12 @@ TEST_CASE("Tagged values")

            auto j_tagged_stored = json::from_cbor(v_tagged, true, true, json::cbor_tag_handler_t::store);
            CHECK(j_tagged_stored == j);
+
+            auto v_binary_tagged = v_bin_payload;
+            v_binary_tagged.insert(v_binary_tagged.begin(), b);
+            auto j_binary_tagged_stored = json::from_cbor(v_binary_tagged, true, true, json::cbor_tag_handler_t::store);
+            CHECK(j_binary_tagged_stored == j_bin_payload);
+            CHECK(!j_binary_tagged_stored.get_binary().has_subtype());
        }
    }

@@ -15,6 +15,8 @@

 #include "doctest_compatibility.h"

+#include <cstdint>
+
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using nlohmann::json;
@@ -255,6 +257,126 @@ TEST_CASE("lexicographical comparison operators")
            {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_FALSE(above_int64_max == negative_one);
+            CHECK(above_int64_max != negative_one);
+            CHECK(negative_one < above_int64_max);
+            CHECK(negative_one <= above_int64_max);
+            CHECK_FALSE(negative_one > above_int64_max);
+            CHECK_FALSE(negative_one >= above_int64_max);
+            CHECK_FALSE(above_int64_max < negative_one);
+            CHECK_FALSE(above_int64_max <= negative_one);
+            CHECK(above_int64_max > negative_one);
+            CHECK(above_int64_max >= negative_one);
+            CHECK(negative_one != above_int64_max);
+            CHECK_FALSE(negative_one == above_int64_max);
+
+            CHECK_FALSE(max_uint64 == negative_one);
+            CHECK(max_uint64 != negative_one);
+            CHECK(negative_one < max_uint64);
+            CHECK(negative_one <= max_uint64);
+            CHECK_FALSE(negative_one > max_uint64);
+            CHECK_FALSE(negative_one >= max_uint64);
+            CHECK_FALSE(max_uint64 < negative_one);
+            CHECK_FALSE(max_uint64 <= negative_one);
+            CHECK(max_uint64 > negative_one);
+            CHECK(max_uint64 >= negative_one);
+            CHECK(negative_one != max_uint64);
+            CHECK_FALSE(negative_one == max_uint64);
+
+            CHECK_FALSE(one == above_int64_max);
+            CHECK(one != above_int64_max);
+            CHECK(one < above_int64_max);
+            CHECK(one <= above_int64_max);
+            CHECK_FALSE(one > above_int64_max);
+            CHECK_FALSE(one >= above_int64_max);
+            CHECK_FALSE(above_int64_max < one);
+            CHECK_FALSE(above_int64_max <= one);
+            CHECK(above_int64_max > one);
+            CHECK(above_int64_max >= one);
+
+            CHECK_FALSE(max_int64 == above_int64_max);
+            CHECK(max_int64 != above_int64_max);
+            CHECK(max_int64 < above_int64_max);
+            CHECK(max_int64 <= above_int64_max);
+            CHECK_FALSE(max_int64 > above_int64_max);
+            CHECK_FALSE(max_int64 >= above_int64_max);
+            CHECK_FALSE(above_int64_max < max_int64);
+            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")
+        {
+            // 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;
+
+            CHECK_FALSE(below_two_63 == two_63);
+            CHECK_FALSE(max_int64 == two_63);
+            CHECK(below_two_63 != max_int64);
+            CHECK(below_two_63 < max_int64);
+            CHECK(below_two_63 < two_63);
+            CHECK(max_int64 < two_63);
+            CHECK(two_63 > max_int64);
+            CHECK_FALSE(two_63 < max_int64);
+
+            // the same past the unsigned range
+            const json max_uint64 = (std::numeric_limits<std::uint64_t>::max)();
+            const json two_64 = 18446744073709551616.0;
+            CHECK_FALSE(max_uint64 == two_64);
+            CHECK(max_uint64 < two_64);
+            CHECK(two_64 > max_uint64);
+
+            // values a double represents exactly still compare equal
+            CHECK(json(1) == json(1.0));
+            CHECK(json(1u) == json(1.0));
+            CHECK(json(-3) == json(-3.0));
+            CHECK(json(1) < json(1.5));
+            CHECK(json(1.5) < json(2));
+            CHECK(json(2) > json(1.5));
+
+            // a NaN operand stays unordered against either integer kind
+            CHECK_FALSE(json(1) == json(nan));
+            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")
        {
            std::vector<std::vector<bool>> expected =
@@ -38,6 +38,36 @@ TEST_CASE("Better diagnostics with positions")
                             "[json.exception.type_error.302] type must be number, but is string", json::type_error);
    }

+    SECTION("positions of strings containing escape sequences")
+    {
+        // escape sequences make the token longer than the string it parses to,
+        // so the positions must not be derived from the parsed value's length
+        const auto check = [](const std::string & text, const std::string & token)
+        {
+            CAPTURE(text)
+            CAPTURE(token)
+            const json j = json::parse(text);
+            const json& v = j.at("a");
+            CHECK(text.substr(v.start_pos(), v.end_pos() - v.start_pos()) == token);
+        };
+
+        check(R"({"a":"plain"})", R"("plain")");
+        check(R"({"a":"tab\there"})", R"("tab\there")");
+        check(R"({"a":"\n\n\n\n\n\n"})", R"("\n\n\n\n\n\n")");
+        check(R"({"a":"\""})", R"("\"")");
+        check(R"({"a":"\\"})", R"("\\")");
+        check(R"({"a":"é"})", R"("é")");
+        check(R"({"a":"🌞"})", R"("🌞")");
+        check("{\"a\":\"\xc3\xa9\"}", "\"\xc3\xa9\"");  // multi-byte UTF-8, no escapes
+
+        // a string at the root, where an escape would otherwise push the
+        // reported start position past the opening quote
+        const std::string root = R"("a\tb")";
+        const json j = json::parse(root);
+        CHECK(j.start_pos() == 0);
+        CHECK(j.end_pos() == root.size());
+    }
+
    SECTION("JSON patch add to primitive parent (#4292)")
    {
        // the JSON Patch "add" target /foo/bar/baz has a string parent
@@ -273,5 +273,36 @@ TEST_CASE("Regression tests for extended diagnostics")
        CHECK(j1["numbers"]["two"] == 2);
        CHECK(j1["string"] == "t");
    }
+
+    SECTION("Regression test - swap(array_t&)/swap(object_t&) must update JSON_DIAGNOSTICS parent pointers")
+    {
+        // swap(array_t&)
+        {
+            json j = json::array();
+            json::array_t arr = {json::array({1})};
+            j.swap(arr);
+
+            // parent pointers of the moved-in elements must point into j, not
+            // into the now-defunct free-standing array_t
+            CHECK_THROWS_WITH_AS(j[0][0].get<std::string>(), "[json.exception.type_error.302] (/0/0) type must be string, but is number", json::type_error);
+
+            // must not trigger assert_invariant() in a debug/assert-enabled build
+            json const k = j;
+            CHECK(k == j);
+        }
+
+        // swap(object_t&)
+        {
+            json o = json::object();
+            json::object_t obj = {{"a", json::array({1})}};
+            o.swap(obj);
+
+            CHECK_THROWS_WITH_AS(o["a"][0].get<std::string>(), "[json.exception.type_error.302] (/a/0) type must be string, but is number", json::type_error);
+
+            // must not trigger assert_invariant() in a debug/assert-enabled build
+            json const p = o;
+            CHECK(p == o);
+        }
+    }
 }

@@ -1388,3 +1388,84 @@ TEST_CASE("JSON patch - add to a primitive parent (regression #4292)")
        CHECK_THROWS_AS(doc.patch(patch), json::out_of_range&);
    }
 }
+
+TEST_CASE("JSON patch - diff emits array removals in descending index order")
+{
+    SECTION("array shrunk to empty")
+    {
+        json const source = {0, 1, 2, 3, 4};
+        json const target = json::array();
+
+        json const patch = json::diff(source, target);
+
+        json const expected = R"(
+            [
+                {"op": "remove", "path": "/4"},
+                {"op": "remove", "path": "/3"},
+                {"op": "remove", "path": "/2"},
+                {"op": "remove", "path": "/1"},
+                {"op": "remove", "path": "/0"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("array partially shrunk, after a replacement at a common index")
+    {
+        json const source = {0, 1, 2, 3, 4};
+        json const target = {0, 9};
+
+        json const patch = json::diff(source, target);
+
+        // the replacement comes first, then the removals, highest index first
+        json const expected = R"(
+            [
+                {"op": "replace", "path": "/1", "value": 9},
+                {"op": "remove", "path": "/4"},
+                {"op": "remove", "path": "/3"},
+                {"op": "remove", "path": "/2"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("nested array shrunk")
+    {
+        json const source = {{"a", {0, 1, 2}}};
+        json const target = {{"a", json::array()}};
+
+        json const patch = json::diff(source, target);
+
+        json const expected = R"(
+            [
+                {"op": "remove", "path": "/a/2"},
+                {"op": "remove", "path": "/a/1"},
+                {"op": "remove", "path": "/a/0"}
+            ]
+        )"_json;
+
+        CHECK(patch == expected);
+        CHECK(source.patch(patch) == target);
+    }
+
+    SECTION("many removals still round-trip")
+    {
+        json source = json::array();
+        for (int i = 0; i < 1000; ++i)
+        {
+            source.push_back(i);
+        }
+        json const target = json::array();
+
+        json const patch = json::diff(source, target);
+
+        CHECK(patch.size() == 1000);
+        CHECK(patch.front().at("path") == "/999");
+        CHECK(patch.back().at("path") == "/0");
+        CHECK(source.patch(patch) == target);
+    }
+}
@@ -396,72 +396,6 @@ TEST_CASE("JSON pointers")
        }
    }

-    SECTION("creating intermediate levels")
-    {
-        SECTION("tokens that are valid array indices create arrays")
-        {
-            json j;
-            j["/0"_json_pointer] = 1;
-            CHECK(j == json({1}));
-
-            json j2;
-            j2["/2"_json_pointer] = 1;
-            CHECK(j2 == json({nullptr, nullptr, 1}));
-
-            json j3;
-            j3["/-"_json_pointer] = 1;
-            CHECK(j3 == json({1}));
-
-            json j4;
-            j4["/foo/0/0"_json_pointer] = 1;
-            CHECK(j4 == json({{"foo", {{1}}}}));
-        }
-
-        SECTION("tokens that are no valid array indices create objects")
-        {
-            json j;
-            j["/one"_json_pointer] = 1;
-            CHECK(j == json({{"one", 1}}));
-
-            // leading '0' can never be a valid array index (RFC 6901, Sect. 4)
-            json j2;
-            j2["/01"_json_pointer] = 1;
-            CHECK(j2 == json({{"01", 1}}));
-
-            // the empty token is a valid object key, but no valid array index
-            json j3;
-            j3["/"_json_pointer] = 1;
-            CHECK(j3 == json({{"", 1}}));
-        }
-
-        SECTION("creating a level yields the same result as reusing it (#5357)")
-        {
-            json j;
-            j["/a/b/01/d"_json_pointer] = "value";
-
-            json j_init = json::object();
-            j_init["/a/b"_json_pointer] = json::object();
-            j_init["/a/b/01/d"_json_pointer] = "value";
-
-            const json expected = json::parse(R"({"a":{"b":{"01":{"d":"value"}}}})");
-            CHECK(j == expected);
-            CHECK(j_init == expected);
-
-            // unflatten uses the same key
-            const json flat = {{"/a/b/01/d", "value"}};
-            CHECK(flat.unflatten() == expected);
-        }
-
-        SECTION("existing arrays still reject invalid indices")
-        {
-            json j = {1, 2, 3};
-            CHECK_THROWS_WITH_AS(j["/01"_json_pointer],
-                                 "[json.exception.parse_error.106] parse error: array index '01' must not begin with '0'", json::parse_error&);
-            CHECK_THROWS_WITH_AS(j.at("/01"_json_pointer),
-                                 "[json.exception.parse_error.106] parse error: array index '01' must not begin with '0'", json::parse_error&);
-        }
-    }
-
    SECTION("flatten")
    {
        json j =
@@ -641,6 +641,20 @@ TEST_CASE("modifiers")
                CHECK_THROWS_WITH_AS(j_array.insert(j_array.end(), j_other_array.begin(), j_other_array2.end()), "[json.exception.invalid_iterator.210] iterators do not fit",
                                     json::invalid_iterator&);
            }
+
+            SECTION("iterators not pointing into an array")
+            {
+                json j_object2 = {{"k", 1}, {"l", 2}};
+                json j_primitive = 5;
+                json j_null;
+
+                CHECK_THROWS_WITH_AS(j_array.insert(j_array.begin(), j_object2.begin(), j_object2.end()), "[json.exception.invalid_iterator.202] iterators first and last must point to arrays",
+                                     json::invalid_iterator&);
+                CHECK_THROWS_WITH_AS(j_array.insert(j_array.begin(), j_primitive.begin(), j_primitive.end()), "[json.exception.invalid_iterator.202] iterators first and last must point to arrays",
+                                     json::invalid_iterator&);
+                CHECK_THROWS_WITH_AS(j_array.insert(j_array.begin(), j_null.begin(), j_null.end()), "[json.exception.invalid_iterator.202] iterators first and last must point to arrays",
+                                     json::invalid_iterator&);
+            }
        }

        SECTION("range for object")
@@ -801,6 +815,30 @@ TEST_CASE("modifiers")
                    j1.update(j2, true);
                    CHECK(j1 == json({{"string", "t"}, {"numbers", 1}}));
                }
+
+                SECTION("overwrite primitive with object")
+                {
+                    json j1 = {{"k", 1}};
+                    json const j2 = {{"k", {{"x", 2}}}};
+                    j1.update(j2, true);
+                    CHECK(j1 == json({{"k", {{"x", 2}}}}));
+                }
+
+                SECTION("overwrite array with object")
+                {
+                    json j1 = {{"k", {1, 2}}};
+                    json const j2 = {{"k", {{"x", 2}}}};
+                    j1.update(j2, true);
+                    CHECK(j1 == json({{"k", {{"x", 2}}}}));
+                }
+
+                SECTION("overwrite nested primitive with object")
+                {
+                    json j1 = {{"k", {{"inner", 1}}}};
+                    json const j2 = {{"k", {{"inner", {{"x", 2}}}}}};
+                    j1.update(j2, true);
+                    CHECK(j1 == json({{"k", {{"inner", {{"x", 2}}}}}}));
+                }
            }
        }
    }
@@ -81,3 +81,84 @@ TEST_CASE("regression test for issue #3732 - iteration_proxy_value<iter_impl<ord
    };
    static_cast<void>(fn);
 }
+
+TEST_CASE("regression test - diff() must account for ordered_json member order")
+{
+    SECTION("pure reorder, no value changes")
+    {
+        ordered_json a = {{"a", 1}, {"b", 2}};
+        ordered_json b = {{"b", 2}, {"a", 1}};
+        CHECK(a != b); // order-sensitive equality
+        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+    }
+
+    SECTION("new key must land at the front")
+    {
+        ordered_json c = {{"b", 2}};
+        ordered_json e = {{"a", 1}, {"b", 2}};
+        CHECK(c.patch(ordered_json::diff(c, e)) == e);
+    }
+
+    SECTION("reorder plus a value change on one of the reordered keys")
+    {
+        ordered_json a = {{"a", 1}, {"b", 2}};
+        ordered_json b = {{"b", 20}, {"a", 1}};
+        CHECK(a != b);
+        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+    }
+
+    SECTION("reorder plus a deleted key")
+    {
+        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}};
+        ordered_json b = {{"b", 2}, {"a", 1}};
+        CHECK(a != b);
+        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+    }
+
+    SECTION("reorder plus a nested value that itself needs a recursive diff")
+    {
+        ordered_json a = {{"a", {{"x", 1}, {"y", 2}}}, {"b", 2}};
+        ordered_json b = {{"b", 2}, {"a", {{"x", 1}, {"y", 99}}}};
+        CHECK(a != b);
+        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+    }
+
+    SECTION("three or more keys shuffled into a different order")
+    {
+        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}, {"d", 4}};
+        ordered_json b = {{"d", 4}, {"b", 2}, {"a", 1}, {"c", 3}};
+        CHECK(a != b);
+        CHECK(a.patch(ordered_json::diff(a, b)) == b);
+    }
+
+    SECTION("matching order still produces a minimal patch (fast path unaffected)")
+    {
+        ordered_json a = {{"a", 1}, {"b", 2}, {"c", 3}};
+        ordered_json b = {{"a", 1}, {"b", 20}, {"c", 3}};
+        auto p = ordered_json::diff(a, b);
+        // only the changed value should be touched, not a wholesale remove+add
+        CHECK(p.size() == 1);
+        CHECK(p[0]["op"] == "replace");
+        CHECK(p[0]["path"] == "/b");
+        CHECK(a.patch(p) == b);
+    }
+
+    SECTION("plain json (std::map-backed) is unaffected by same-key-different-insertion-order")
+    {
+        json a;
+        a["b"] = 2;
+        a["a"] = 1;
+
+        json b;
+        b["a"] = 1;
+        b["b"] = 2;
+
+        // std::map iteration is always sorted by key, so a == b regardless of
+        // insertion order, and diff() must still produce the same minimal
+        // (empty) result as before this fix
+        CHECK(a == b);
+        auto p = json::diff(a, b);
+        CHECK(p.empty());
+        CHECK(a.patch(p) == b);
+    }
+}
@@ -1555,4 +1555,112 @@ TEST_CASE("issue #5338 - truncated CBOR tagged binary subtype is rejected")
    }
 }

+TEST_CASE("issue #5402 - update(merge_objects=true) overwrites a primitive with an object")
+{
+    json t = {{"k", 1}};
+    t.update(json{{"k", {{"x", 2}}}}, true);
+    CHECK(t == json({{"k", {{"x", 2}}}}));
+
+    json mixed = {{"keep", {{"a", 1}}}, {"replace", 1}};
+    mixed.update(json{{"keep", {{"b", 2}}}, {"replace", {{"x", 2}}}}, true);
+    CHECK(mixed == json({{"keep", {{"a", 1}, {"b", 2}}}, {"replace", {{"x", 2}}}}));
+}
+
+TEST_CASE("regression test - parser callback must not lose a duplicate key's prior value")
+{
+    // a callback that rejects only the scalar value 2
+    const json::parser_callback_t drop_value_2 = [](int /*depth*/, json::parse_event_t ev, json & v)
+    {
+        return !(ev == json::parse_event_t::value && v == 2);
+    };
+
+    SECTION("duplicate key, second (scalar) value rejected - prior value is restored")
+    {
+        const json j = json::parse(R"({"a":1,"a":2})", drop_value_2);
+        CHECK(j.dump() == "{\"a\":1}");
+    }
+
+    SECTION("duplicate key, second value is an object rejected at object_end - prior value is restored")
+    {
+        const json j = json::parse(R"({"a":1,"a":{"x":2}})",
+                                   [](int depth, json::parse_event_t ev, json& /*parsed*/)
+        {
+            return !(ev == json::parse_event_t::object_end && depth == 1);
+        });
+        CHECK(j.dump() == "{\"a\":1}");
+    }
+
+    SECTION("duplicate key, second value is an array rejected at array_end - prior value is restored")
+    {
+        const json j = json::parse(R"({"a":1,"a":[9,9]})",
+                                   [](int depth, json::parse_event_t ev, json& /*parsed*/)
+        {
+            return !(ev == json::parse_event_t::array_end && depth == 1);
+        });
+        CHECK(j.dump() == "{\"a\":1}");
+    }
+
+    SECTION("duplicate key, second value accepted (scalar) - last value wins")
+    {
+        const json j = json::parse(R"({"a":1,"a":2})", [](int, json::parse_event_t, json&) noexcept
+        {
+            return true;
+        });
+        CHECK(j.dump() == "{\"a\":2}");
+    }
+
+    SECTION("duplicate key, second value accepted (object) - last value wins")
+    {
+        const json j = json::parse(R"({"a":1,"a":{"x":2}})", [](int, json::parse_event_t, json&) noexcept
+        {
+            return true;
+        });
+        CHECK(j.dump() == "{\"a\":{\"x\":2}}");
+    }
+
+    SECTION("brand new (non-duplicate) key, value rejected - member is fully absent")
+    {
+        const json j = json::parse(R"({"a":1,"b":2})", drop_value_2);
+        CHECK(j.dump() == "{\"a\":1}");
+    }
+
+    SECTION("duplicate key nested two levels deep")
+    {
+        const json j = json::parse(R"({"outer":{"a":1,"a":2}})", drop_value_2);
+        CHECK(j.dump() == "{\"outer\":{\"a\":1}}");
+    }
+
+    SECTION("three occurrences of the same key - middle rejected, last accepted")
+    {
+        const json j = json::parse(R"({"k":1,"k":2,"k":3})", drop_value_2);
+        CHECK(j.dump() == "{\"k\":3}");
+    }
+}
+
+TEST_CASE("regression test - excessive binary container size honors allow_exceptions=false")
+{
+    // CBOR array with declared length 2^63
+    const std::vector<std::uint8_t> cbor = {0x9b, 0x80, 0, 0, 0, 0, 0, 0, 0};
+    // CBOR map with declared length 2^63
+    const std::vector<std::uint8_t> cbor_m = {0xbb, 0x80, 0, 0, 0, 0, 0, 0, 0};
+    // UBJSON array with declared length 2^63-1
+    const std::vector<std::uint8_t> ubj = {'[', '#', 'L', 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+    // BJData array with declared length 2^63-1 (little endian)
+    const std::vector<std::uint8_t> bjd = {'[', '#', 'L', 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f};
+
+    // allow_exceptions=false must report failure instead of throwing/aborting
+    CHECK(json::from_cbor(cbor, true, false).is_discarded());
+    CHECK(json::from_cbor(cbor_m, true, false).is_discarded());
+    CHECK(json::from_ubjson(ubj, true, false).is_discarded());
+    CHECK(json::from_bjdata(bjd, true, false).is_discarded());
+
+    // allow_exceptions=true (the default) must still throw exactly as before
+    CHECK_THROWS_AS(json::from_cbor(cbor), json::out_of_range);
+    CHECK_THROWS_WITH(json::from_cbor(cbor),
+                      "[json.exception.out_of_range.408] excessive array size: 9223372036854775808");
+
+    // regression guard: a genuinely truncated CBOR input must remain discarded
+    CHECK(json::from_cbor(std::vector<std::uint8_t> {0x9b, 0, 0, 0, 0, 0, 0, 0, 0x02}, true, false).is_discarded());
+}
+
 DOCTEST_CLANG_SUPPRESS_WARNING_POP
@@ -1713,6 +1713,44 @@ TEST_CASE("UBJSON")
            CHECK(json::to_ubjson(json::from_ubjson(s_L)) == s_i);
        }

+        SECTION("no-op markers")
+        {
+            // A no-op ('N') is valid wherever a value may start; it is consumed
+            // by get_ignore_noop() before the value is read. It is not valid
+            // where a string length type specification is expected.
+
+            SECTION("accepted where a value may start")
+            {
+                // at top level, also repeated
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'N', 'i', 1})) == json(1));
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'N', 'N', 'N', 'i', 1})) == json(1));
+
+                // inside an array of unknown size, before and after an element
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'[', 'N', 'i', 1, ']'})) == json({1}));
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'[', 'i', 1, 'N', ']'})) == json({1}));
+
+                // inside an object of unknown size: before a key, between key
+                // and value, and before the closing '}'
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'{', 'N', 'U', 1, 'a', 'i', 1, '}'})) == json({{"a", 1}}));
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'{', 'U', 1, 'a', 'N', 'i', 1, '}'})) == json({{"a", 1}}));
+                CHECK(json::from_ubjson(std::vector<uint8_t>({'{', 'U', 1, 'a', 'i', 1, 'N', '}'})) == json({{"a", 1}}));
+            }
+
+            SECTION("rejected where a length type specification is expected")
+            {
+                json _;
+
+                // after the 'S' marker of a string value
+                std::vector<uint8_t> const v_S = {'S', 'N', 'U', 1, 'a'};
+                CHECK_THROWS_WITH_AS(_ = json::from_ubjson(v_S), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing UBJSON string: expected length type specification (U, i, I, l, L); last byte: 0x4E", json::parse_error&);
+
+                // as the key length of an object with a known size, where
+                // no-ops are not permitted in the first place
+                std::vector<uint8_t> const v_key = {'{', '#', 'i', 1, 'N', 'U', 1, 'a', 'i', 1};
+                CHECK_THROWS_WITH_AS(_ = json::from_ubjson(v_key), "[json.exception.parse_error.113] parse error at byte 5: syntax error while parsing UBJSON string: expected length type specification (U, i, I, l, L); last byte: 0x4E", json::parse_error&);
+            }
+        }
+
        SECTION("number")
        {
            SECTION("float")
@@ -2465,6 +2503,48 @@ TEST_CASE("all UBJSON first bytes")
 }
 #endif

+TEST_CASE("UBJSON use_type requires use_size")
+{
+    SECTION("non-empty array throws other_error.502")
+    {
+        const json j = {1, 2, 3};
+        CHECK_THROWS_WITH_AS(json::to_ubjson(j, false, true),
+                             "[json.exception.other_error.502] use_type requires use_size = true",
+                             json::other_error&);
+    }
+
+    SECTION("non-empty object throws other_error.502")
+    {
+        const json j = {{"a", 1}, {"b", 2}};
+        CHECK_THROWS_WITH_AS(json::to_ubjson(j, false, true),
+                             "[json.exception.other_error.502] use_type requires use_size = true",
+                             json::other_error&);
+    }
+
+    SECTION("scalars do not throw with use_type=true, use_count=false")
+    {
+        CHECK_NOTHROW(json::to_ubjson(42, false, true));
+        CHECK_NOTHROW(json::to_ubjson(3.14, false, true));
+        CHECK_NOTHROW(json::to_ubjson("hello", false, true));
+        CHECK_NOTHROW(json::to_ubjson(true, false, true));
+        CHECK_NOTHROW(json::to_ubjson(nullptr, false, true));
+    }
+
+    SECTION("empty containers do not throw with use_type=true, use_count=false")
+    {
+        CHECK_NOTHROW(json::to_ubjson(json::array(), false, true));
+        CHECK_NOTHROW(json::to_ubjson(json::object(), false, true));
+    }
+
+    SECTION("valid combinations on non-empty containers")
+    {
+        const json j = {1, 2, 3};
+        CHECK_NOTHROW(json::to_ubjson(j, false, false));
+        CHECK_NOTHROW(json::to_ubjson(j, true, false));
+        CHECK_NOTHROW(json::to_ubjson(j, true, true));
+    }
+}
+
 TEST_CASE("UBJSON roundtrips" * doctest::skip())
 {
    SECTION("input from self-generated UBJSON files")
@@ -125,6 +125,16 @@ TEST_CASE("wide strings")
            std::u32string const w = U"\"\x110000";
            json _;
            CHECK_THROWS_AS(_ = json::parse(w), json::parse_error&);
+
+            // a code unit above U+10FFFF must not be narrowed onto the EOF
+            // sentinel: 0xFFFFFFFF would otherwise end the document silently and
+            // let everything following it pass the strict end-of-input check
+            std::u32string const trailing{U'[', U'1', U']', static_cast<char32_t>(0xFFFFFFFF), U'x'};
+            CHECK_THROWS_WITH_AS(_ = json::parse(trailing), "[json.exception.parse_error.101] parse error at line 1, column 4: syntax error while parsing value - invalid literal; last read: '1]\xFF'; expected end of input", json::parse_error&);
+            CHECK(!json::accept(trailing));
+
+            // the same unit inside a string is reported as an ill-formed byte
+            CHECK_THROWS_WITH_AS(_ = json::parse(std::u32string{U'"', static_cast<char32_t>(0xFFFFFFFF), U'"'}), "[json.exception.parse_error.101] parse error at line 1, column 2: syntax error while parsing value - invalid string: ill-formed UTF-8 byte; last read: '\"\xFF'", json::parse_error&);
        }
    }
 }