Update wasm exception handling model (migration to emsdk 4-x) (#416)

anutosh491 · web-flow · commit c357fd66e047 · 2025-12-10T09:59:56.000+01:00
* Update wasm exception handling model (use wasm-exceptions instead of exceptions)
Add tests

* Use jupyterlite-xeus 4.3.0

* Update host env install command
diff --git a/.github/workflows/deploy-github-page.yml b/.github/workflows/deploy-github-page.yml
@@ -45,7 +45,10 @@ jobs:
       - name: Build and test xeus-cpp in node, then install
         shell: bash -l {0}
         run: |
-          micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32
+          micromamba create -f environment-wasm-host.yml \
+          --platform=emscripten-wasm32 \
+          -c https://prefix.dev/emscripten-forge-4x \
+          -c https://prefix.dev/conda-forge
 
           mkdir build
           pushd build
@@ -56,9 +59,6 @@ jobs:
           echo "PREFIX=$PREFIX" >> $GITHUB_ENV
           export SYSROOT_PATH=$BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot
 
-          micromamba create -n node-env -c conda-forge nodejs=22
-          export PATH="$MAMBA_ROOT_PREFIX/envs/node-env/bin:$PATH"
-
           emcmake cmake \
             -DCMAKE_BUILD_TYPE=Release                        \
             -DCMAKE_INSTALL_PREFIX=$PREFIX                    \
@@ -142,7 +142,7 @@ jobs:
       - name: Jupyter Lite integration
         shell: bash -l {0}
         run: |
-          micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server jupyterlite-xeus -c conda-forge
+          micromamba create -n xeus-lite-host jupyter_server jupyterlite-xeus -c conda-forge
           micromamba activate xeus-lite-host
           jupyter lite build \
               --XeusAddon.prefix=${{ env.PREFIX }} \
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -230,7 +230,10 @@ jobs:
       - name: Build and test xeus-cpp in node, then install
         shell: bash -l {0}
         run: |
-          micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32
+          micromamba create -f environment-wasm-host.yml \
+          --platform=emscripten-wasm32 \
+          -c https://prefix.dev/emscripten-forge-4x \
+          -c https://prefix.dev/conda-forge
           
           mkdir build
           pushd build
@@ -241,9 +244,6 @@ jobs:
           echo "PREFIX=$PREFIX" >> $GITHUB_ENV
           export SYSROOT_PATH=$BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot
 
-          micromamba create -n node-env -c conda-forge nodejs=22
-          export PATH="$MAMBA_ROOT_PREFIX/envs/node-env/bin:$PATH"
-
           emcmake cmake \
             -DCMAKE_BUILD_TYPE=Release                        \
             -DCMAKE_INSTALL_PREFIX=$PREFIX                    \
@@ -332,7 +332,7 @@ jobs:
       - name: Jupyter Lite integration
         shell: bash -l {0}
         run: |
-          micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyterlite-xeus -c conda-forge
+          micromamba create -n xeus-lite-host jupyterlite-xeus -c conda-forge
           micromamba activate xeus-lite-host
           jupyter lite build --XeusAddon.prefix=${{ env.PREFIX }}
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -219,6 +219,8 @@ macro(xeus_cpp_set_common_options target_name)
         target_compile_options(${target_name} PUBLIC /wd4251 /wd4141)
         target_compile_options(${target_name} PUBLIC /wd4018 /wd4267 /wd4715 /wd4146 /wd4129)
         target_compile_options(${target_name} PUBLIC /EHsc)
+    elseif (EMSCRIPTEN)
+        target_compile_options(${target_name} PUBLIC -fwasm-exceptions)
     else ()
         target_compile_options(${target_name} PUBLIC -fexceptions)
     endif ()
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -71,19 +71,20 @@ micromamba create -f environment-wasm-build.yml -y
 micromamba activate xeus-cpp-wasm-build
 ```
 
-You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Prefer using node 22 and above as prior versions lead to flaky test runs. Once the test pass, run the install command.
+You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Once the test pass, run the install command.
 
 ```bash
-micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32
+micromamba create -f environment-wasm-host.yml \
+--platform=emscripten-wasm32 \
+-c https://prefix.dev/emscripten-forge-4x \
+-c https://prefix.dev/conda-forge
+
 mkdir build
 cd build
 export BUILD_PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-build
 export PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-host
 export SYSROOT_PATH=$BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot
 
-micromamba create -n node-env -c conda-forge nodejs=22
-export PATH="$MAMBA_ROOT_PREFIX/envs/node-env/bin:$PATH"
-
 emcmake cmake \
         -DCMAKE_BUILD_TYPE=Release                        \
         -DCMAKE_INSTALL_PREFIX=$PREFIX                    \
@@ -154,7 +155,7 @@ python $BUILD_PREFIX/bin/emrun.py --browser="google-chrome" --kill_exit --timeou
 
 To build and test Jupyter Lite with this kernel locally you can execute the following
 ```bash
-micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server jupyterlite-xeus -c conda-forge
+micromamba create -n xeus-lite-host jupyter_server jupyterlite-xeus -c conda-forge
 micromamba activate xeus-lite-host
 jupyter lite serve --XeusAddon.prefix=$PREFIX \
                    --XeusAddon.mounts="$PREFIX/share/xeus-cpp/tagfiles:/share/xeus-cpp/tagfiles" \
diff --git a/README.md b/README.md
@@ -87,18 +87,19 @@ micromamba create -f environment-wasm-build.yml -y
 micromamba activate xeus-cpp-wasm-build
 ```
 
-You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Prefer using node 22 and above as prior versions lead to flaky test runs. Once the test pass, run the install command.
+You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Once the test pass, run the install command.
 ```bash
-micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32
+micromamba create -f environment-wasm-host.yml \
+--platform=emscripten-wasm32 \
+-c https://prefix.dev/emscripten-forge-4x \
+-c https://prefix.dev/conda-forge
+
 mkdir build
 cd build
 export BUILD_PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-build
 export PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-host
 export SYSROOT_PATH=$BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot
 
-micromamba create -n node-env -c conda-forge nodejs=22
-export PATH="$MAMBA_ROOT_PREFIX/envs/node-env/bin:$PATH"
-
 emcmake cmake \
         -DCMAKE_BUILD_TYPE=Release                        \
         -DCMAKE_INSTALL_PREFIX=$PREFIX                    \
@@ -169,7 +170,7 @@ python $BUILD_PREFIX/bin/emrun.py --browser="google-chrome" --kill_exit --timeou
 
 To build and test Jupyter Lite with this kernel locally you can execute the following
 ```bash
-micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server jupyterlite-xeus -c conda-forge
+micromamba create -n xeus-lite-host jupyter_server jupyterlite-xeus -c conda-forge
 micromamba activate xeus-lite-host
 jupyter lite serve --XeusAddon.prefix=$PREFIX \            
                    --XeusAddon.mounts="$PREFIX/share/xeus-cpp/tagfiles:/share/xeus-cpp/tagfiles" \
diff --git a/docs/source/InstallationAndUsage.rst b/docs/source/InstallationAndUsage.rst
@@ -66,20 +66,21 @@ the following
     micromamba create -f environment-wasm-build.yml -y
     micromamba activate xeus-cpp-wasm-build
 
-You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Prefer using node 22 and above as prior versions lead to flaky test runs. Once the test pass, run the install command.
+You are now in a position to build the xeus-cpp kernel. You build and test it in node by executing the following. Once the test pass, run the install command.
 
 .. code-block:: bash
 
-    micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32
+    micromamba create -f environment-wasm-host.yml \
+    --platform=emscripten-wasm32 \
+    -c https://prefix.dev/emscripten-forge-4x \
+    -c https://prefix.dev/conda-forge
+
     mkdir build
     cd build
     export BUILD_PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-build
     export PREFIX=$MAMBA_ROOT_PREFIX/envs/xeus-cpp-wasm-host
     export SYSROOT_PATH=$BUILD_PREFIX/opt/emsdk/upstream/emscripten/cache/sysroot
 
-    micromamba create -n node-env -c conda-forge nodejs=22
-    export PATH="$MAMBA_ROOT_PREFIX/envs/node-env/bin:$PATH"
-
     emcmake cmake \
 		-DCMAKE_BUILD_TYPE=Release                        \
 		-DCMAKE_INSTALL_PREFIX=$PREFIX                    \
@@ -151,7 +152,7 @@ To build and test Jupyter Lite with this kernel locally you can execute the foll
 
 .. code-block:: bash
 
-    micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server jupyterlite-xeus -c conda-forge
+    micromamba create -n xeus-lite-host jupyter_server jupyterlite-xeus -c conda-forge
     micromamba activate xeus-lite-host
     jupyter lite serve --XeusAddon.prefix=$PREFIX
                        --XeusAddon.mounts="$PREFIX/share/xeus-cpp/tagfiles:/share/xeus-cpp/tagfiles" \
diff --git a/docs/source/conf.py b/docs/source/conf.py
@@ -19,7 +19,10 @@
 alias micromamba="$MAMBA_EXE";
 micromamba create -f environment-wasm-build.yml -y;
 micromamba activate xeus-cpp-wasm-build;
-micromamba create -f environment-wasm-host.yml --platform=emscripten-wasm32;
+micromamba create -f environment-wasm-host.yml \
+--platform=emscripten-wasm32 \
+-c https://prefix.dev/emscripten-forge-4x \
+-c https://prefix.dev/conda-forge
 mkdir -p build;
 cd build;
 export BUILD_PREFIX=$MAMBA_ROOT_PREFIX/xeus-cpp-wasm-build;
@@ -34,9 +37,8 @@
               {XEUS_CPP_ROOT};
 emmake make -j $(nproc --all) install;
 cd {XEUS_CPP_ROOT};
-micromamba create -n xeus-lite-host jupyterlite-core=0.6 jupyter_server jupyterlite-xeus -c conda-forge -y;
+micromamba create -n xeus-lite-host jupyter_server jupyterlite-xeus -c conda-forge -y;
 micromamba activate xeus-lite-host;
-python -m pip install jupyterlite-xeus jupyter_server;
 jupyter lite build --XeusAddon.prefix=$PREFIX \\
                    --XeusAddon.mounts="$PREFIX/share/xeus-cpp/tagfiles:/share/xeus-cpp/tagfiles" \
                    --XeusAddon.mounts="$PREFIX/etc/xeus-cpp/tags.d:/etc/xeus-cpp/tags.d" \
diff --git a/environment-wasm-build.yml b/environment-wasm-build.yml
@@ -1,7 +1,7 @@
 name: xeus-cpp-wasm-build
 channels:
-  - https://prefix.dev/emscripten-forge-dev
+  - https://prefix.dev/emscripten-forge-4x
   - https://prefix.dev/conda-forge
 dependencies:
   - cmake
-  - emscripten_emscripten-wasm32==3.1.73
+  - emscripten_emscripten-wasm32==4.0.9
diff --git a/environment-wasm-host.yml b/environment-wasm-host.yml
@@ -1,6 +1,6 @@
 name: xeus-cpp-wasm-host
 channels:
-  - https://prefix.dev/emscripten-forge-dev
+  - https://prefix.dev/emscripten-forge-4x
   - https://prefix.dev/conda-forge
 dependencies:
   - nlohmann_json
diff --git a/share/jupyter/kernels/xc11/wasm_kernel.json.in b/share/jupyter/kernels/xc11/wasm_kernel.json.in
@@ -6,7 +6,8 @@
       "-Xclang", "-iwithsysroot/include/compat",
       "-xc",
       "-std=c11",
-      "-mllvm", "-enable-emscripten-sjlj",
+      "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj",
       "-msimd128"
   ],
   "language": "c",
diff --git a/share/jupyter/kernels/xc17/wasm_kernel.json.in b/share/jupyter/kernels/xc17/wasm_kernel.json.in
@@ -6,7 +6,8 @@
       "-Xclang", "-iwithsysroot/include/compat",
       "-xc",
       "-std=c17",
-      "-mllvm", "-enable-emscripten-sjlj",
+      "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj",
       "-msimd128"
   ],
   "language": "c",
diff --git a/share/jupyter/kernels/xc23/wasm_kernel.json.in b/share/jupyter/kernels/xc23/wasm_kernel.json.in
@@ -6,7 +6,8 @@
       "-Xclang", "-iwithsysroot/include/compat",
       "-xc",
       "-std=c23",
-      "-mllvm", "-enable-emscripten-sjlj",
+      "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj",
       "-msimd128"
   ],
   "language": "c",
diff --git a/share/jupyter/kernels/xcpp17/wasm_kernel.json.in b/share/jupyter/kernels/xcpp17/wasm_kernel.json.in
@@ -4,8 +4,8 @@
       "@XEUS_CPP_KERNELSPEC_PATH@xcpp",
       "-resource-dir", "/lib/clang/@CPPINTEROP_LLVM_VERSION_MAJOR@",
       "-Xclang", "-iwithsysroot/include/compat",
-      "-std=c++17", "-mllvm", "-enable-emscripten-cxx-exceptions",
-      "-mllvm", "-enable-emscripten-sjlj", "-msimd128"
+      "-std=c++17", "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj", "-msimd128"
   ],
   "language": "cpp",
   "metadata": {
diff --git a/share/jupyter/kernels/xcpp20/wasm_kernel.json.in b/share/jupyter/kernels/xcpp20/wasm_kernel.json.in
@@ -4,8 +4,8 @@
       "@XEUS_CPP_KERNELSPEC_PATH@xcpp",
       "-resource-dir", "/lib/clang/@CPPINTEROP_LLVM_VERSION_MAJOR@",
       "-Xclang", "-iwithsysroot/include/compat",
-      "-std=c++20", "-mllvm", "-enable-emscripten-cxx-exceptions",
-      "-mllvm", "-enable-emscripten-sjlj", "-msimd128"
+      "-std=c++20", "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj", "-msimd128"
   ],
   "language": "cpp",
   "metadata": {
diff --git a/share/jupyter/kernels/xcpp23/wasm_kernel.json.in b/share/jupyter/kernels/xcpp23/wasm_kernel.json.in
@@ -4,8 +4,8 @@
       "@XEUS_CPP_KERNELSPEC_PATH@xcpp",
       "-resource-dir", "/lib/clang/@CPPINTEROP_LLVM_VERSION_MAJOR@",
       "-Xclang", "-iwithsysroot/include/compat",
-      "-std=c++23", "-mllvm", "-enable-emscripten-cxx-exceptions",
-      "-mllvm", "-enable-emscripten-sjlj", "-msimd128"
+      "-std=c++23", "-fwasm-exceptions",
+      "-mllvm", "-wasm-enable-sjlj", "-msimd128"
   ],
   "language": "cpp",
   "metadata": {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
@@ -54,7 +54,7 @@ if(EMSCRIPTEN)
     target_link_libraries(test_xeus_cpp PRIVATE xeus-cpp-static doctest::doctest)
 
     target_compile_options(test_xeus_cpp
-        PUBLIC "SHELL: -fexceptions"
+        PUBLIC "SHELL: -fwasm-exceptions"
     )
     # So we create a html file, as well as the javascript file
     set_target_properties(test_xeus_cpp PROPERTIES
@@ -67,10 +67,10 @@ if(EMSCRIPTEN)
     # Without this MINIFY_HTML=0 flag you end up with the situation where the creation of the
     # test_xeus_cpp.html file breaks on MacOS, but not Ubuntu
     target_link_options(test_xeus_cpp
-        PUBLIC "SHELL: -fexceptions"
+        PUBLIC "SHELL: -fwasm-exceptions"
         PUBLIC "SHELL: -s MAIN_MODULE=1"
         PUBLIC "SHELL: -s WASM_BIGINT"
-        PUBLIC "SHELL: -s ASSERTIONS=1"
+        PUBLIC "SHELL: -s ASSERTIONS=0"
         PUBLIC "SHELL: -s ALLOW_MEMORY_GROWTH=1"
         PUBLIC "SHELL: -s STACK_SIZE=32mb"
         PUBLIC "SHELL: -s INITIAL_MEMORY=128mb"
diff --git a/test/test_interpreter.cpp b/test/test_interpreter.cpp
@@ -70,7 +70,10 @@ TEST_SUITE("execute_request")
 {
     TEST_CASE("stl")
     {
-        std::vector<const char*> Args = {"stl-test-case", "-v"};
+        std::vector<const char*> Args = {
+            "-v",
+            "-Xclang", "-iwithsysroot/include/compat"
+        };
         xcpp::interpreter interpreter((int)Args.size(), Args.data());
         std::string code = "#include <vector>";
         nl::json user_expressions = nl::json::object();
@@ -136,6 +139,45 @@ TEST_SUITE("execute_request")
     }
 #endif
 
+#if defined(XEUS_CPP_EMSCRIPTEN_WASM_BUILD)
+    TEST_CASE("Emscripten Exception Handling")
+    {
+        std::vector<const char*> Args = {
+            "-std=c++20",
+            "-v",
+            "-fwasm-exceptions",
+            "-mllvm", "-wasm-enable-sjlj"
+        };
+
+        xcpp::interpreter interpreter((int)Args.size(), Args.data());
+        std::string code = "try { throw 1; } catch (...) { 0; }";
+        nl::json user_expressions = nl::json::object();
+        xeus::execute_request_config config;
+        config.silent = false;
+        config.store_history = false;
+        config.allow_stdin = false;
+        nl::json header = nl::json::object();
+        xeus::xrequest_context::guid_list id = {};
+        xeus::xrequest_context context(header, id);
+
+        std::promise<nl::json> promise;
+        std::future<nl::json> future = promise.get_future();
+        auto callback = [&promise](nl::json result) {
+            promise.set_value(result);
+        };
+
+        interpreter.execute_request(
+            std::move(context),
+            std::move(callback),
+            code,
+            std::move(config),
+            user_expressions
+        );
+        nl::json result = future.get();
+        REQUIRE(result["status"] == "ok");
+    }
+#endif
+
     TEST_CASE("fetch_documentation")
     {
         std::vector<const char*> Args = {/*"-v", "resource-dir", "....."*/};
@@ -810,7 +852,10 @@ TEST_SUITE("complete_request")
 {
     TEST_CASE("completion_test")
     {
-        std::vector<const char*> Args = {/*"-v", "resource-dir", "....."*/};
+        std::vector<const char*> Args = {
+            "-v",
+            "-Xclang", "-iwithsysroot/include/compat"
+        };
         xcpp::interpreter interpreter((int)Args.size(), Args.data());
         std::string code1 = "#include <iostream>";
         nl::json user_expressions = nl::json::object();
