Persist Zig build caches in CI

.gitea/workflows/build-and-release.yml

@@ -1,11 +1,19 @@
 name: Build and Release
 
 on:
+  pull_request:
+    branches:
+      - main
   push:
     branches:
       - main
     tags:
       - 'v*'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 permissions:
   contents: write
@@ -14,15 +22,40 @@ jobs:
   build:
     name: Build executables
     runs-on: ubuntu-latest
+    env:
+      ZIG_INSTALL_ROOT: /ci-cache/zig-chess/0.16.0/linux-amd64/tool
+      ZIG_LOCAL_CACHE_DIR: /ci-cache/zig-chess/0.16.0/linux-amd64/local
+      ZIG_GLOBAL_CACHE_DIR: /ci-cache/zig-chess/0.16.0/linux-amd64/global
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: https://github.com/actions/checkout@v4
 
-      - name: Set up Zig
+      - name: Install pinned Zig from the persistent cache
-        uses: mlugg/setup-zig@v2
+        run: |
-        with:
+          set -eu
-          version: 0.16.0
+          cache_parent="$(dirname "$ZIG_INSTALL_ROOT")"
+          mkdir -p "$cache_parent"
+          exec 9>"$cache_parent/.install.lock"
+          flock -x 9
+          if ! test -x "$ZIG_INSTALL_ROOT/zig" || \
+             ! test "$("$ZIG_INSTALL_ROOT/zig" version)" = "0.16.0"; then
+            archive="$(mktemp /tmp/zig-0.16.0.XXXXXXXX.tar.xz)"
+            staging="$(mktemp -d "$cache_parent/.tool.XXXXXXXX")"
+            trap 'rm -f "$archive"; rm -rf "$staging"' EXIT
+            curl --fail --location --retry 3 --retry-all-errors \
+              --output "$archive" \
+              https://ziglang.org/download/0.16.0/zig-x86_64-linux-0.16.0.tar.xz
+            printf '%s  %s\n' \
+              70e49664a74374b48b51e6f3fdfbf437f6395d42509050588bd49abe52ba3d00 \
+              "$archive" | sha256sum --check -
+            tar -xJf "$archive" --strip-components=1 -C "$staging"
+            rm -rf "$ZIG_INSTALL_ROOT"
+            mv "$staging" "$ZIG_INSTALL_ROOT"
+            rm -f "$archive"
+            trap - EXIT
+          fi
+          echo "$ZIG_INSTALL_ROOT" >> "$GITHUB_PATH"
 
       - name: Install shader compiler
         run: |
@@ -34,17 +67,21 @@ jobs:
           zig version
           glslc --version
 
+      - name: Prepare persistent Zig caches
+        run: |
+          mkdir -p "$ZIG_LOCAL_CACHE_DIR" "$ZIG_GLOBAL_CACHE_DIR"
+
       - name: Build GUI executable
         run: |
           zig build \
-            --cache-dir /tmp/zig-chess-cache \
+            --cache-dir "$ZIG_LOCAL_CACHE_DIR" \
-            --global-cache-dir /tmp/zig-global-cache
+            --global-cache-dir "$ZIG_GLOBAL_CACHE_DIR"
 
       - name: Build magic generator executable
         run: |
           zig build magic-numbers \
-            --cache-dir /tmp/zig-chess-cache \
+            --cache-dir "$ZIG_LOCAL_CACHE_DIR" \
-            --global-cache-dir /tmp/zig-global-cache
+            --global-cache-dir "$ZIG_GLOBAL_CACHE_DIR"
 
       - name: Package executables
         run: |
@@ -60,7 +97,7 @@ jobs:
           sha256sum "dist/${artifact_dir}.tar.gz" > "dist/${artifact_dir}.tar.gz.sha256"
 
       - name: Upload build artifact
-        uses: actions/upload-artifact@v3
+        uses: https://github.com/actions/upload-artifact@v3
         with:
           name: zig-chess-${{ github.ref_name }}
           path: |