From b9986cdadfca866130fc3dda1b8c4b80f29a740a Mon Sep 17 00:00:00 2001
From: rubidium42 <rubidium42@users.noreply.github.com>
Date: Sat, 27 Jun 2026 17:00:51 +0200
Subject: [PATCH] Change: upgrade emscripten from 3.1.57 to 6.0.1 (#15780)

---
 .github/workflows/ci-emscripten.yml | 11 ++---------
 .github/workflows/preview-build.yml | 11 ++---------
 CMakeLists.txt                      |  2 +-
 os/emscripten/Dockerfile            |  5 +----
 4 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/.github/workflows/ci-emscripten.yml b/.github/workflows/ci-emscripten.yml
index 271fc01638..b310c3a0cf 100644
--- a/.github/workflows/ci-emscripten.yml
+++ b/.github/workflows/ci-emscripten.yml
@@ -14,7 +14,7 @@ jobs:
     container:
       # If you change this version, change the numbers in the cache step,
       # .github/workflows/preview-build.yml (2x) and os/emscripten/Dockerfile too.
-      image: emscripten/emsdk:3.1.57
+      image: emscripten/emsdk:6.0.1
 
     steps:
     - name: Checkout
@@ -24,20 +24,13 @@ jobs:
       run: |
         git config --global --add safe.directory ${GITHUB_WORKSPACE}
 
-    - name: Update to modern GCC
-      run: |
-        apt-get update
-        apt-get install -y gcc-12 g++-12
-        update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-12 100
-        update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-12 100
-
     - name: Setup cache
       uses: actions/cache@v5
       with:
         # If you change this version, change the numbers in the image configuration step,
         # .github/workflows/preview-build.yml (2x) and os/emscripten/Dockerfile too.
         path: /emsdk/upstream/emscripten/cache
-        key: 3.1.57-${{ runner.os }}
+        key: 6.0.1-${{ runner.os }}
 
     - name: Add liblzma support
       run: |
diff --git a/.github/workflows/preview-build.yml b/.github/workflows/preview-build.yml
index 0018e182a5..9c6b929d52 100644
--- a/.github/workflows/preview-build.yml
+++ b/.github/workflows/preview-build.yml
@@ -11,7 +11,7 @@ jobs:
     container:
       # If you change this version, change the numbers in the cache step,
       # .github/workflows/ci-emscripten.yml (2x) and os/emscripten/Dockerfile too.
-      image: emscripten/emsdk:3.1.57
+      image: emscripten/emsdk:6.0.1
 
     steps:
     - name: Checkout
@@ -24,20 +24,13 @@ jobs:
         git config --global --add safe.directory ${GITHUB_WORKSPACE}
         git checkout -b pr${{ github.event.pull_request.number }}
 
-    - name: Update to modern GCC
-      run: |
-        apt-get update
-        apt-get install -y gcc-12 g++-12
-        update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-12 100
-        update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-12 100
-
     - name: Setup cache
       uses: actions/cache@v5
       with:
         path: /emsdk/upstream/emscripten/cache
         # If you change this version, change the numbers in the image configuration step,
         # .github/workflows/ci-emscripten.yml (2x) and os/emscripten/Dockerfile too.
-        key: 3.1.57-${{ runner.os }}
+        key: 6.0.1-${{ runner.os }}
 
     - name: Add liblzma support
       run: |
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ce018f5bf9..46914bc78f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -370,7 +370,7 @@ if(EMSCRIPTEN)
     add_definitions(-s DISABLE_EXCEPTION_CATCHING=0)
 
     # Export functions to Javascript.
-    target_link_libraries(WASM::WASM INTERFACE "-s EXPORTED_FUNCTIONS='[\"_main\", \"_em_openttd_add_server\"]' -s EXPORTED_RUNTIME_METHODS='[\"cwrap\"]'")
+    target_link_libraries(WASM::WASM INTERFACE "-s EXPORTED_FUNCTIONS='[\"_main\", \"_em_openttd_add_server\"]' -s EXPORTED_RUNTIME_METHODS='[\"cwrap\", \"HEAPU8\"]'")
 
     # Preload all the files we generate during build.
     # As we do not compile with FreeType / FontConfig, we also have no way to
diff --git a/os/emscripten/Dockerfile b/os/emscripten/Dockerfile
index e429867f1d..713e01f0f0 100644
--- a/os/emscripten/Dockerfile
+++ b/os/emscripten/Dockerfile
@@ -1,11 +1,8 @@
 # If you change this version, change the numbers in .github/workflows/ci-emscripten.yml (2x)
 # and .github/workflows/preview-build.yml (2x) too.
-FROM emscripten/emsdk:3.1.57
+FROM emscripten/emsdk:6.0.1
 
 RUN apt-get update \
-    && apt-get install -y gcc-12 g++-12 \
-    && update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-12 100 \
-    && update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-12 100 \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*