github: add buck2 ci build

Signed-off-by: Austin Seipp <aseipp@pobox.com>

.github/actions/install-dotslash/action.yml

@@ -0,0 +1,30 @@
+name: Install DotSlash
+description: Install DotSlash on the current system
+inputs:
+  version:
+    description: "version of dotslash"
+    required: false
+    default: "0.4.1"
+runs:
+  using: "composite"
+  steps:
+    - name: Install DotSlash
+      shell: bash
+      run: |
+        mkdir -p $RUNNER_TEMP/dotslash
+        echo "$RUNNER_TEMP/dotslash" >> $GITHUB_PATH
+
+        if [[ "$RUNNER_OS" == "Windows" ]]; then
+          C:\\msys64\\usr\\bin\\wget.exe https://github.com/facebook/dotslash/releases/download/v0.4.1/dotslash-windows.v0.4.1.tar.gz
+          tar xf dotslash-windows.v0.4.1.tar.gz
+          mv dotslash.exe $RUNNER_TEMP/dotslash
+        else
+          if [[ "$RUNNER_OS" == "macOS" ]]; then
+            wget https://github.com/facebook/dotslash/releases/download/v0.4.1/dotslash-macos.v0.4.1.tar.gz
+            tar xf dotslash-macos.v0.4.1.tar.gz
+          elif [[ "$RUNNER_OS" == "Linux" ]]; then
+            wget https://github.com/facebook/dotslash/releases/download/v0.4.1/dotslash-ubuntu-22.04.x86_64.v0.4.1.tar.gz
+            tar xf dotslash-ubuntu-22.04.x86_64.v0.4.1.tar.gz
+          fi
+          mv dotslash $RUNNER_TEMP/dotslash
+        fi

.github/workflows/build-buck2.yml

@@ -0,0 +1,55 @@
+name: buck2
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions: read-all
+
+jobs:
+  buck2:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-latest
+            abi: x86_64-unknown-linux-gnu
+          - os: windows-latest
+            abi: x86_64-pc-windows-msvc
+          - os: macos-latest
+            abi: aarch64-apple-darwin
+          # NOTE: macos-13 is the most recent x86_64 macos runner
+          #- os: macos-13
+          #  abi: x86_64-apple-darwin
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 15 # NOTE (aseipp): keep in-sync with the build.yml timeout limit
+
+    name: build with buck2
+    steps:
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+      - name: (Linux) Install Mold
+        if: runner.os == 'Linux'
+        run: |
+          sudo apt-get update && sudo apt-get install -y mold
+      - name: Install DotSlash
+        uses: ./.github/actions/install-dotslash
+      - name: Add build tools to $PATH
+        run: echo "$PWD/tools/bin" >> $GITHUB_PATH
+      # FIXME (aseipp): use 'buck2' out of `$PATH` after we have dotslash .exe
+      # shim files for windows. until then just invoke manually
+      - name: buck2 build //...
+        run: |
+          mkdir -p out
+          dotslash ./tools/bin/buck2 build @mode//debug //...
+          cp buck-out/v2/log/*.pb.zst out
+          dotslash ./tools/bin/buck2 build @mode//debug cli --out out/jj.exe
+          ./out/jj.exe version
+
+      - name: "Upload artifact"
+        uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808
+        with:
+          name: jj-${{ matrix.abi }}
+          path: out
+          retention-days: 14

buck/platforms/defs.bzl

@@ -216,6 +216,6 @@ default_platforms = [
     ("arm64", "macos"),
    #("arm64", "windows"),
     ("x86_64", "linux"),
-   #("x86_64", "macos"),
+    ("x86_64", "macos"),
     ("x86_64", "windows"),
 ]