Cache library deps on Windows

ISSOtm · ISSOtm · commit 74e739c5b98e · 2026-03-19T14:54:10.000+01:00
Besides the immediate performance improvement, reducing
the frequency of downloads should make spurious
failures (network, rate-limiting...) less bothersome.
diff --git a/.github/scripts/get_win_deps.ps1 b/.github/scripts/get_win_deps.ps1
diff --git a/.github/scripts/install_deps.sh b/.github/scripts/install_deps.sh
@@ -7,7 +7,7 @@ case "${1%-*}" in
 		sudo apt-get -qq update
 		sudo apt-get install -yq bison libpng-dev pkg-config
 		;;
-		macos)
+	macos)
 		# macOS bundles GNU Make 3.81, which doesn't support synced output.
 		# We leave it as the default in `PATH`, to test that our Makefile works with it.
 		# However, CMake automatically uses Homebrew's `gmake`, so our CI has synced output.
@@ -20,11 +20,17 @@ case "${1%-*}" in
 	freebsd)
 		pkg install -y bash bison cmake git png
 		;;
+	windows)
+		choco install -y winflexbison3
+		# The below expects the base name, not the Windows-specific name.
+		bison() { win_bison "$@"; } # An alias doesn't work, so we use a function instead.
+		;;
 	*)
 		echo "WARNING: Cannot install deps for OS '$1'"
 		;;
 esac
 
+echo "PATH=($PATH)" | sed 's/:/\n      /g'
 bison --version
 make --version
 cmake --version
diff --git a/.github/workflows/create-release-artifacts.yml b/.github/workflows/create-release-artifacts.yml
@@ -14,6 +14,10 @@ env:
   CMAKE_BUILD_TYPE: Release # `cmake -S` now implies `-DCMAKE_BUILD_TYPE=Release`.
   CMAKE_CONFIG_TYPE: Release # `cmake --build` now implies `--config Release`.
 
+  # We instruct CMake to download and build third-party projects in the same place as in `testing.yml`
+  # for the sources cache to remain valid.
+  DEPS_ROOT_DIR: ~/_deps # Note that this needs to be used in a position where Bash will trigger tilde expansion!
+
 jobs:
   windows:
     runs-on: windows-2022
@@ -35,11 +39,15 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
       - name: Install deps
-        run: .github/scripts/get_win_deps.ps1
+        run: .github/scripts/install_deps.sh windows
+      - name: Cache library deps
+        uses: actions/cache@v5
+        with:
+          path: ${{ env.DEPS_ROOT_DIR }}/*-tmp/
+          key: dep-srcs-${{ hashFiles('cmake/deps.cmake') }}
+          enableCrossOsArchive: true
       - name: Build Windows binaries
         shell: bash
-        # We instruct CMake to download and build third-party projects outside of our source tree,
-        # otherwise they can trigger `-Werror=dev` (from the `develop` preset).
         run: |
           cmake -S . -B build -A ${{ matrix.platform }} --preset develop -DFETCHCONTENT_BASE_DIR="$TEMP/cmake-deps" -DBISON_EXECUTABLE=bison/win_bison.exe -DSANITIZERS=OFF
           cmake --build build --config Release
diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
@@ -12,6 +12,10 @@ env:
   CMAKE_INSTALL_PARALLEL_LEVEL: 4 # `cmake --install` now implies `--parallel 4`.
   CMAKE_BUILD_TYPE: Debug # `cmake -S` now implies `-DCMAKE_BUILD_TYPE=Debug`.
   CMAKE_CONFIG_TYPE: Debug # `cmake --build` now implies `--config Debug`.
+  
+  # We instruct CMake to download and build third-party projects outside of our source tree,
+  # otherwise they can trigger `-Werror=dev` (from the `develop` preset).
+  DEPS_ROOT_DIR: ~/_deps # Note that this needs to be used in a position where Bash will trigger tilde expansion!
 
 jobs:
   unix:
@@ -21,9 +25,7 @@ jobs:
         cxx: [g++, clang++]
         buildsys: [make, cmake]
         exclude:
-          # Don't use `g++` on macOS; it's just an alias to `clang++`.
-          - os: macos-14
-            cxx: g++
+          - {os: macos-14, cxx: g++} # Don't use `g++` on macOS; it's just an alias to `clang++`.
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
@@ -68,7 +70,7 @@ jobs:
           tee -a <<<"hash=${hash%-}" $GITHUB_OUTPUT
       - name: Check test dependency repositories cache
         id: test-deps-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ fromJSON(steps.test-deps-cache-params.outputs.paths) }}
           key: ${{ matrix.os }}-${{ steps.test-deps-cache-params.outputs.hash }}
@@ -125,7 +127,7 @@ jobs:
           tee -a <<<"hash=${hash%-}" $GITHUB_OUTPUT
       - name: Check test dependency repositories cache
         id: test-deps-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ fromJSON(steps.test-deps-cache-params.outputs.paths) }}
           key: ${{ matrix.os }}-${{ steps.test-deps-cache-params.outputs.hash }}
@@ -159,18 +161,22 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v4
       - name: Install deps
-        run: .github/scripts/get_win_deps.ps1
+        run: bash .github/scripts/install_deps.sh ${{ matrix.os }}
+      - name: Cache library deps
+        uses: actions/cache@v5
+        with:
+          path: ${{ env.DEPS_ROOT_DIR }}/*-tmp/
+          key: dep-srcs-${{ hashFiles('cmake/deps.cmake') }}
+          enableCrossOsArchive: true
       - name: Build Windows binaries
         shell: bash
-        # We instruct CMake to download and build third-party projects outside of our source tree,
-        # otherwise they can trigger `-Werror=dev` (from the `develop` preset).
         run: | # ASan seems to be broken on Windows, so we disable it.
-          cmake -S . -B build --preset develop-msvc${{ matrix.bits }} -DFETCHCONTENT_BASE_DIR="$TEMP/cmake-deps" -DBISON_EXECUTABLE=bison/win_bison.exe -DSANITIZERS=OFF
+          cmake -S . -B build --preset develop-msvc${{ matrix.bits }} -DFETCHCONTENT_BASE_DIR="$(echo "${{ env.DEPS_ROOT_DIR }}")" -DSANITIZERS=OFF
           cmake --build build
-          cmake --install build --prefix install_dir --config Debug --verbose
       - name: Package binaries
         shell: bash
         run: |
+          cmake --install build --prefix install_dir --config Debug --verbose
           mkdir bins
           cp -v install_dir/bin/{rgb*.exe,*.dll} bins
       - name: Upload Windows binaries
@@ -188,7 +194,7 @@ jobs:
           tee -a <<<"hash=${hash%-}" $GITHUB_OUTPUT
       - name: Check test dependency repositories cache
         id: test-deps-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ fromJSON(steps.test-deps-cache-params.outputs.paths) }}
           key: ${{ matrix.os }}-${{ matrix.bits }}-${{ steps.test-deps-cache-params.outputs.hash }}
@@ -297,7 +303,7 @@ jobs:
           tee -a <<<"hash=${hash%-}" $GITHUB_OUTPUT
       - name: Check test dependency repositories cache
         id: test-deps-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ fromJSON(steps.test-deps-cache-params.outputs.paths) }}
           key: mingw-${{ matrix.bits }}-${{ steps.test-deps-cache-params.outputs.hash }}
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -137,24 +137,13 @@ endif()
 ## Dependencies.
 
 include(FetchContent)
-FetchContent_Declare(PNG
-                     URL https://download.sourceforge.net/libpng/libpng-1.6.55.tar.xz
-                     URL_HASH SHA256=d925722864837ad5ae2a82070d4b2e0603dc72af44bd457c3962298258b8e82d
-                     FIND_PACKAGE_ARGS 1.5.4)
-FetchContent_Declare(ZLIB
-                     URL https://www.zlib.net/zlib-1.3.2.tar.xz
-                     URL_HASH SHA256=d7a0654783a4da529d1bb793b7ad9c3318020af77667bcae35f95d0e42a792f3
-                     FIND_PACKAGE_ARGS)
-set(ZLIB_BUILD_SHARED ON CACHE INTERNAL "")
-set(ZLIB_BUILD_STATIC OFF CACHE INTERNAL "")
+include(cmake/deps.cmake)
+
 FetchContent_MakeAvailable(ZLIB)
 if(NOT DEFINED ZLIB_INCLUDE_DIRS)
   set(ZLIB_INCLUDE_DIRS "${zlib_BINARY_DIR};${zlib_SOURCE_DIR}") # libpng's `genout` script relies on this variable to be set.
 endif()
-set(PNG_TESTS OFF CACHE INTERNAL "") # We do not care for these two (and they can even cause compile errors!)
-set(PNG_TOOLS OFF CACHE INTERNAL "")
-set(PNG_SHARED ON CACHE INTERNAL "") # Upstream seems to favour the dynamic lib over the static one?
-set(PNG_STATIC OFF CACHE INTERNAL "")
+
 FetchContent_MakeAvailable(PNG)
 if(NOT TARGET PNG::PNG)
   if(PNG_SHARED)
diff --git a/cmake/deps.cmake b/cmake/deps.cmake
@@ -0,0 +1,21 @@
+# This file declares the dependencies we use, using `FetchContent`.
+# https://cmake.org/cmake.help/latest/guide/using-dependencies/index.html#downloading-and-building-from-source-with-fetchcontent
+# This is offloaded to a separate file so that it can be hashed, the hash serving as a cache key.
+
+FetchContent_Declare(PNG
+                     URL https://download.sourceforge.net/libpng/libpng-1.6.55.tar.xz
+                     URL_HASH SHA256=d925722864837ad5ae2a82070d4b2e0603dc72af44bd457c3962298258b8e82d
+                     FIND_PACKAGE_ARGS 1.5.4)
+
+set(PNG_TESTS OFF CACHE INTERNAL "") # We do not care for these two (and they can even cause compile errors!)
+set(PNG_TOOLS OFF CACHE INTERNAL "")
+set(PNG_SHARED ON CACHE INTERNAL "") # Upstream seems to favour the dynamic lib over the static one?
+set(PNG_STATIC OFF CACHE INTERNAL "")
+
+FetchContent_Declare(ZLIB
+                     URL https://www.zlib.net/zlib-1.3.2.tar.xz
+                     URL_HASH SHA256=d7a0654783a4da529d1bb793b7ad9c3318020af77667bcae35f95d0e42a792f3
+                     FIND_PACKAGE_ARGS)
+
+set(ZLIB_BUILD_SHARED ON CACHE INTERNAL "")
+set(ZLIB_BUILD_STATIC OFF CACHE INTERNAL "")
