Fix warning and add emscripten CI step (#4738)

* 🚨 fix warning

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 👷 add emscripten

Signed-off-by: Niels Lohmann <[email protected]>

* 📝 add compiler to list

Signed-off-by: Niels Lohmann <[email protected]>

---------

Signed-off-by: Niels Lohmann <[email protected]>

Author: nlohmann

Diff for: .github/workflows/ubuntu.yml

@@ -233,6 +233,24 @@ jobs:
           . /opt/intel/oneapi/setvars.sh
           cmake --build build --target ci_icpc
 
+  ci_emscripten:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@c6295a65d1254861815972266d5933fd6e532bdf # v2.11.1
+        with:
+          egress-policy: audit
+
+      - name: Install emscripten
+        uses: mymindstorm/setup-emsdk@v14
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Get latest CMake and ninja
+        uses: lukka/get-cmake@57c20a23a6cac5b90f31864439996e5b206df9dc # v4.0.1
+      - name: Run CMake
+        run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$EMSDK/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -GNinja
+      - name: Build
+        run: cmake --build build
+
   ci_test_documentation:
     runs-on: ubuntu-latest
     strategy:

Diff for: docs/mkdocs/docs/community/quality_assurance.md

@@ -57,6 +57,7 @@ violations will result in a failed build.
         | Clang 19.1.7                                 | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | Clang 20.1.1                                 | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | Clang 21.0.0                                 | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
+        | Emscripten 4.0.6                             | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | GNU 4.8.5                                    | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | GNU 4.9.3                                    | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |
         | GNU 5.5.0                                    | x86_64       | Ubuntu 22.04.1 LTS       | GitHub    |

Diff for: include/nlohmann/detail/output/serializer.hpp

@@ -762,7 +762,7 @@ class serializer
 
         // jump to the end to generate the string from backward,
         // so we later avoid reversing the result
-        buffer_ptr += n_chars;
+        buffer_ptr += static_cast<typename decltype(number_buffer)::difference_type>(n_chars);
 
         // Fast int2ascii implementation inspired by "Fastware" talk by Andrei Alexandrescu
         // See: https://www.youtube.com/watch?v=o4-CwDo2zpg

Diff for: single_include/nlohmann/json.hpp

@@ -19483,7 +19483,7 @@ class serializer
 
         // jump to the end to generate the string from backward,
         // so we later avoid reversing the result
-        buffer_ptr += n_chars;
+        buffer_ptr += static_cast<typename decltype(number_buffer)::difference_type>(n_chars);
 
         // Fast int2ascii implementation inspired by "Fastware" talk by Andrei Alexandrescu
         // See: https://www.youtube.com/watch?v=o4-CwDo2zpg