From c24b5e782b3b0e426bd6566eeea0d853899b72e5 Mon Sep 17 00:00:00 2001
From: Lucas Franceschino <lucas.franceschino@inria.fr>
Date: Tue, 13 Feb 2024 09:53:34 +0100
Subject: [PATCH 1/2] fix(engine/dune): disable js build by default

---
 engine/bin/dune    | 12 ++++--------
 engine/bin/dune-js |  8 ++++++++
 engine/default.nix |  2 ++
 3 files changed, 14 insertions(+), 8 deletions(-)
 create mode 100644 engine/bin/dune-js

diff --git a/engine/bin/dune b/engine/bin/dune
index 085686c48..2027c3ab7 100644
--- a/engine/bin/dune
+++ b/engine/bin/dune
@@ -25,14 +25,10 @@
  (modules native_driver)
  (libraries lib))
 
-(executable
- (optional)
- (name js_driver)
- (modes js)
- (modules js_driver)
- (js_of_ocaml
-  (javascript_files js_stubs/mutex.js js_stubs/stdint.js js_stubs/unix.js))
- (libraries zarith_stubs_js js_of_ocaml lib))
+; The following line is commented: by default, we don't want to
+; generate javascript.
+
+; (include dune-js)
 
 (env
  (_
diff --git a/engine/bin/dune-js b/engine/bin/dune-js
new file mode 100644
index 000000000..68df628e7
--- /dev/null
+++ b/engine/bin/dune-js
@@ -0,0 +1,8 @@
+(executable
+ (optional)
+ (name js_driver)
+ (modes js)
+ (modules js_driver)
+ (js_of_ocaml
+  (javascript_files js_stubs/mutex.js js_stubs/stdint.js js_stubs/unix.js))
+ (libraries zarith_stubs_js js_of_ocaml lib))
diff --git a/engine/default.nix b/engine/default.nix
index a9d6c7b3b..9c1405590 100644
--- a/engine/default.nix
+++ b/engine/default.nix
@@ -111,6 +111,8 @@
         name = "hax-engine.js";
         nativeBuildInputs = old.nativeBuildInputs ++ [closurecompiler gnused];
         buildPhase = ''
+          # Enable JS build
+          sed -i "s/; (include dune-js)/(include dune-js)/g" bin/dune
           # Compile JS target
           dune build bin/js_driver.bc.js
           # Optimize the size of the JS file

From 4c70ccab2f4b72cfa135bd1d876e476c3fe2e546 Mon Sep 17 00:00:00 2001
From: Lucas Franceschino <lucas@cryspen.com>
Date: Tue, 7 May 2024 09:29:03 +0200
Subject: [PATCH 2/2] feat(ci): test JS compilation of the engine

---
 .github/workflows/engine_js_build.yml | 18 ++++++++++++++++++
 CI.md                                 |  4 +++-
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 .github/workflows/engine_js_build.yml

diff --git a/.github/workflows/engine_js_build.yml b/.github/workflows/engine_js_build.yml
new file mode 100644
index 000000000..36d7c9498
--- /dev/null
+++ b/.github/workflows/engine_js_build.yml
@@ -0,0 +1,18 @@
+name: Test JS build
+
+on:
+  pull_request:
+  merge_group:
+  workflow_dispatch:
+  push:
+    branches: [main]
+    
+jobs:
+  engine-js-build:
+    if: ${{ github.event_name == 'workflow_dispatch' || github.event_name == 'merge_group' }}
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: DeterminateSystems/nix-installer-action@main
+    - uses: DeterminateSystems/magic-nix-cache-action@main
+    - run: nix build .\#hax-engine.passthru.js -L  
diff --git a/CI.md b/CI.md
index e8aa10b72..d78af2135 100644
--- a/CI.md
+++ b/CI.md
@@ -17,7 +17,9 @@
    FStar, we do not run Coq or FStar on the extractions.
  - [`test_installs`](./.github/workflows/test_installs.yml): compiles
    the toolchain on two versions of Ubuntu and two versions of MacOS
-   using `apt` or `homebrew` and the `setup.sh` script.
+   using `apt` or `homebrew` and the `setup.sh` script;
+ - [`engine-js-build`](./.github/workflows/engine_js_build.yml): tests
+   the build the JS version of the engine.
  
 ## Merge queue
 Additional actions are triggered on pull requests in the merge queue. They are