Cache library deps on Windows

Besides the immediate performance improvement, reducing
the frequency of downloads should make spurious
failures (network, rate-limiting...) less bothersome.

.github/scripts/get_win_deps.ps1

@@ -1,18 +0,0 @@
-function getlibrary ([string] $URI, [string] $filename, [string] $hash, [string] $destdir) {
-	$wc = New-Object Net.WebClient
-	[string] $downloadhash = $null
-	try {
-		$wc.DownloadFile($URI, $filename)
-		$downloadhash = $(Get-FileHash $filename -Algorithm SHA256).Hash
-	} catch {
-		Write-Host "${filename}: failed to download"
-		exit 1
-	}
-	if ($hash -ne $downloadhash) {
-		Write-Host "${filename}: SHA256 mismatch ($downloadhash)"
-		exit 1
-	}
-	Expand-Archive -DestinationPath $destdir $filename
-}
-
-getlibrary 'https://github.com/lexxmark/winflexbison/releases/download/v2.5.25/win_flex_bison-2.5.25.zip' 'winflexbison.zip' '8d324b62be33604b2c45ad1dd34ab93d722534448f55a16ca7292de32b6ac135' bison

.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

.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
@@ -35,17 +39,21 @@ 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 --preset msvc${{ matrix.bits }} -DFETCHCONTENT_BASE_DIR="$TEMP/cmake-deps" -DBISON_EXECUTABLE=bison/win_bison.exe
+          cmake -S . -B build --preset msvc${{ matrix.bits }} -DFETCHCONTENT_BASE_DIR="${{ env.DEPS_ROOT_DIR }}"
           cmake --build build
-          cmake --install build --config Release --prefix install_dir --verbose
       - name: Package binaries
         run: |
+          cmake --install build --config Release --prefix install_dir --verbose
           Compress-Archive -LiteralPath @("install_dir/bin/rgbasm.exe", "install_dir/bin/rgblink.exe", "install_dir/bin/rgbfix.exe", "install_dir/bin/rgbgfx.exe", "install_dir/bin/z.dll", "install_dir/bin/libpng16.dll") "rgbds-win${{ matrix.bits }}.zip"
       - name: Upload Windows binaries
         uses: actions/upload-artifact@v4

.github/workflows/testing.yml

@@ -12,6 +12,10 @@ env:
   CMAKE_INSTALL_PARALLEL_LEVEL: 4 # `cmake --install` now implies `--parallel 4`.
   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:
     strategy:
@@ -20,9 +24,7 @@ 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: ${{ matrix.os }}
     steps:
@@ -67,7 +69,7 @@ jobs:
           tee -a <<<"hash=${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 }}
@@ -124,7 +126,7 @@ 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 }}
@@ -158,18 +160,23 @@ 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${{ matrix.bits }} -DFETCHCONTENT_BASE_DIR="${{ env.DEPS_ROOT_DIR }}" -DSANITIZERS=OFF
           cmake --build build
-          cmake --install build --config Debug --prefix install_dir --verbose
       - name: Package binaries
         shell: bash
         run: |
+          cmake --install build --config Debug --prefix install_dir --verbose
           mkdir bins
           cp -v install_dir/bin/{rgb*.exe,*.dll} bins
       - name: Upload Windows binaries
@@ -187,7 +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 }}-${{ steps.test-deps-cache-params.outputs.hash }}
@@ -296,7 +303,7 @@ jobs:
           tee -a <<<"hash=${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 }}