rescript-lang · cknitt · Jul 18, 2025 · Jul 18, 2025 · Jul 19, 2025 · Jul 18, 2025
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -18,6 +18,7 @@ concurrency:
 
 env:
   OCAMLRUNPARAM: b
+  RUST_BACKTRACE: "1"
 
 jobs:
   build-compiler:
@@ -75,11 +76,9 @@ jobs:
     runs-on: ${{matrix.os}}
 
     env:
-      # setup-ocaml opam version cannot be configured
-      # we do track its version manually
-      OPAM_VERSION: 2.3.0
-      DUNE_PROFILE: release
-      RUST_BACKTRACE: "1"
+      # When changing the setup-ocaml version, also adjust it in the setup step further below
+      # and update the comment about the OPAM version if it changed.
+      SETUP_OCAML_VERSION: 3.4.0 # comes with OPAM 2.4.0
 
     steps:
       - name: "Windows: Set git config"
@@ -106,11 +105,12 @@ jobs:
 
       - name: Install dependencies (Linux)
         if: runner.os == 'Linux'
-        uses: awalsh128/cache-apt-pkgs-action@v1.4.3
+        uses: awalsh128/cache-apt-pkgs-action@v1.5.1
         with:
-          # See https://github.com/ocaml/setup-ocaml/blob/b2105f9/packages/setup-ocaml/src/unix.ts#L9
-          packages: bubblewrap darcs g++-multilib gcc-multilib mercurial musl-tools rsync
-          version: v3
+          # https://github.com/ocaml/setup-ocaml/blob/2f57267f071bc8547dfcb9433ff21d44fffef190/packages/setup-ocaml/src/unix.ts#L48
+          # plus OPAM wants cmake
+          packages: bubblewrap darcs g++-multilib gcc-multilib mercurial musl-tools rsync cmake
+          version: v4
 
       - name: Restore rewatch build cache
         id: rewatch-build-cache
@@ -147,7 +147,7 @@ jobs:
       # matrix.ocaml_compiler may contain commas
       - name: Get OPAM cache key
         shell: bash
-        run: echo "opam_cache_key=opam-env-v8-${{ matrix.os }}-${{ matrix.ocaml_compiler }}-${{ hashFiles('*.opam') }}" | sed 's/,/-/g' >> $GITHUB_ENV
+        run: echo "opam_cache_key=opam-env-v8-${{ matrix.os }}-${{ env.SETUP_OCAML_VERSION }}-${{ matrix.ocaml_compiler }}-${{ hashFiles('*.opam') }}" | sed 's/,/-/g' >> $GITHUB_ENV
 
       - name: Restore OPAM environment
         id: cache-opam-env
@@ -163,7 +163,7 @@ jobs:
           key: ${{ env.opam_cache_key }}
 
       - name: Use OCaml ${{matrix.ocaml_compiler}}
-        uses: ocaml/setup-ocaml@v3.3.2
+        uses: ocaml/setup-ocaml@v3.4.0
         if: steps.cache-opam-env.outputs.cache-hit != 'true'
         with:
           ocaml-compiler: ${{matrix.ocaml_compiler}}
@@ -181,9 +181,13 @@ jobs:
             await fs.writeFile('.opam-path', opamPath, 'utf-8');
             console.log('stored path to .opam-path');
 
+      # With OPAM 2.4, it is not sufficient to have the flow-parser package in `pin-depends` in rescript.opam.template,
+      # we need to pin it explicitly using `opam pin add`.
       - name: Install OPAM dependencies
         if: steps.cache-opam-env.outputs.cache-hit != 'true'
-        run: opam install . --deps-only --with-test
+        run: |
+          opam pin add flow_parser git+https://github.com/rescript-lang/flow.git#9ea4062c0b7e037415c4413a7634c459ebd5c31b --no-action
+          opam install . --deps-only --with-test
 
       - name: Cache OPAM environment
         if: steps.cache-opam-env.outputs.cache-hit != 'true'
@@ -201,13 +205,17 @@ jobs:
       - name: Use cached OPAM environment
         if: steps.cache-opam-env.outputs.cache-hit == 'true'
         run: |
-          # https://github.com/ocaml/setup-ocaml/blob/b2105f9/packages/setup-ocaml/src/installer.ts#L33
-          echo "OPAMVERBOSE=$RUNNER_DEBUG"   >> "$GITHUB_ENV"
-          echo "OPAMCOLOR=always"            >> "$GITHUB_ENV"
-          echo "OPAMCONFIRMLEVEL=unsafe-yes" >> "$GITHUB_ENV"
-          echo "OPAMERRLOGLEN=0"             >> "$GITHUB_ENV"
-          echo "OPAMPRECISETRACKING=1"       >> "$GITHUB_ENV"
-          echo "OPAMYES=1"                   >> "$GITHUB_ENV"
+          # https://github.com/ocaml/setup-ocaml/blob/1629342/packages/setup-ocaml/src/installer.ts#L36
+          echo "OPAMVERBOSE=$RUNNER_DEBUG"     >> "$GITHUB_ENV"
+          echo "OPAMCOLOR=always"              >> "$GITHUB_ENV"
+          echo "OPAMCONFIRMLEVEL=unsafe-yes"   >> "$GITHUB_ENV"
+          echo "OPAMDOWNLOADJOBS=4"            >> "$GITHUB_ENV"
+          echo "OPAMERRLOGLEN=0"               >> "$GITHUB_ENV"
+          echo "OPAMEXTERNALSOLVER=unsafe-yes" >> "$GITHUB_ENV"
+          echo "OPAMPRECISETRACKING=1"         >> "$GITHUB_ENV"
+          echo "OPAMRETRIES=10"                >> "$GITHUB_ENV"
+          echo "OPAMSOLVERTIMEOUT=600"         >> "$GITHUB_ENV"
+          echo "OPAMYES=1"                     >> "$GITHUB_ENV"
 
           if [[ "$RUNNER_OS" != "Windows" ]]; then
             echo "OPAMROOT=$HOME/.opam"      >> "$GITHUB_ENV"
@@ -224,22 +232,19 @@ jobs:
             fsutil behavior set symlinkEvaluation R2L:1 R2R:1
             fsutil behavior query SymlinkEvaluation
 
-            CYGWIN="winsymlinks:native"
-            CYGWIN_ROOT="D:\\cygwin"
-            CYGWIN_ROOT_BIN="D:\\cygwin\\bin"
-            CYGWIN_ROOT_WRAPPERBIN="D:\\cygwin\\wrapperbin"
-
             echo "HOME=$USERPROFILE" >> "$GITHUB_ENV"
             echo "MSYS=winsymlinks:native" >> "$GITHUB_ENV"
-            echo "CYGWIN=$CYGWIN" >> "$GITHUB_ENV"
-            echo "CYGWIN_ROOT=$CYGWIN_ROOT" >> "$GITHUB_ENV"
-            echo "CYGWIN_ROOT_BIN=$CYGWIN_ROOT_BIN" >> "$GITHUB_ENV"
-            echo "CYGWIN_ROOT_WRAPPERBIN=$CYGWIN_ROOT_WRAPPERBIN" >> "$GITHUB_ENV"
-
-            echo "$CYGWIN_ROOT_WRAPPERBIN" >> "$GITHUB_PATH"
+            echo "CYGWIN=winsymlinks:native" >> "$GITHUB_ENV"
           fi
         shell: bash
 
+      - name: Log environment info
+        run: |
+          echo OPAM version: $(opam --version)
+          echo System: $(uname -s)
+          echo Path: $PATH
+        shell: bash
+
       - name: Compiler build state key
         id: compiler-build-state-key
         shell: bash
@@ -546,8 +551,6 @@ jobs:
           - os: ubuntu-24.04-arm
           - os: windows-latest
     runs-on: ${{ matrix.os }}
-    env:
-      RUST_BACKTRACE: "1"
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -597,8 +600,6 @@ jobs:
           - os: ubuntu-24.04-arm
           - os: windows-latest
     runs-on: ${{ matrix.os }}
-    env:
-      RUST_BACKTRACE: "1"
     steps:
       - name: Install pnpm
         uses: pnpm/action-setup@v4
@@ -652,8 +653,6 @@ jobs:
           - os: ubuntu-24.04-arm
           - os: windows-latest
     runs-on: ${{ matrix.os }}
-    env:
-      RUST_BACKTRACE: "1"
     steps:
       - name: Checkout
         uses: actions/checkout@v4

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -53,7 +53,10 @@ opam init
 # then you need to run `opam update && opam upgrade` first
 opam switch create 5.3.0
 
-# Install dev dependencies from OPAM
+# Pin flow parser
+opam pin add flow_parser git+https://github.com/rescript-lang/flow.git#9ea4062c0b7e037415c4413a7634c459ebd5c31b --no-action
+
+# Install dependencies from OPAM, including dev/test dependencies
 opam install . --deps-only --with-test --with-dev-setup -y
 ```
 
@@ -397,7 +400,7 @@ To build a new version and release it on NPM, follow these steps:
 
 To reproduce issues, it can be helpful to the team to install a specific version of the compiler.
 
-ReScript uses [pkg.pr.new](https://github.com/stackblitz-labs/pkg.pr.new) for continuous releases. Once tests are passed successfully, the bot comment is available. 
+ReScript uses [pkg.pr.new](https://github.com/stackblitz-labs/pkg.pr.new) for continuous releases. Once tests are passed successfully, the bot comment is available.
 
 Follow the instructions from the comment, which are like:
 

diff --git a/rescript.opam.template b/rescript.opam.template
@@ -14,5 +14,7 @@ depends: [
   "wasm_of_ocaml-compiler" {os != "win32" & with-test & = "6.0.1"}
 ]
 pin-depends: [
+  # If using OPAM 2.4.0, this also needs to be pre-pinned using
+  # opam pin add flow_parser git+https://github.com/rescript-lang/flow.git#9ea4062c0b7e037415c4413a7634c459ebd5c31b --no-action
   ["flow_parser.0.267.0" "git+https://github.com/rescript-lang/flow.git#9ea4062c0b7e037415c4413a7634c459ebd5c31b"]
 ]