Update buf to use binary releases

Formula/buf.rb

@@ -1,17 +1,45 @@
 class Buf < Formula
   desc "The best way of working with Protocol Buffers."
   homepage "https://buf.build"
-  head "https://github.com/bufbuild/buf.git", branch: "main"
-  url "https://github.com/bufbuild/buf/archive/v1.70.0.tar.gz"
-  sha256 "7da0f12d42d00a4a4fabf89af37e2e02ad5958bc7e977a713e4bc01b2a232899"
   version "1.70.0"
 
-  depends_on "go" => :build
+  # sha256 of the prebuilt release archive for each Homebrew-supported platform,
+  # keyed by "#{OS.kernel_name}-#{Hardware::CPU.arch}". Each archive unpacks to
+  # the same layout as a source build (bin/, etc/, share/, LICENSE), so the two
+  # install paths below are equivalent.
+  SHA256S = {
+    "Darwin-arm64"  => "9cec23658df093d50f3318580e17f1e309d45b817927f22e9de30f78f3d4d45b",
+    "Darwin-x86_64" => "ebeed1af15bcb145c35c5e51eadc8fe0bdba9311e08fd6abca8c23294929d20b",
+    "Linux-arm64"   => "ff3c79a6bb44c41a8053ec0d863234cee82378ea4c29ed5292c852dbf829fec0",
+    "Linux-x86_64"  => "18498bdadbdce80792ce08c2c59e0c49f157aa3f5d9b0f9c6e3db795be208b9d",
+  }.freeze
+
+  if (sha = SHA256S["#{OS.kernel_name}-#{Hardware::CPU.arch}"])
+    # Homebrew reports 64-bit ARM as "arm64"; the Linux asset is named "aarch64".
+    asset_arch = Hardware::CPU.arch.to_s
+    asset_arch = "aarch64" if OS.linux? && Hardware::CPU.arm?
+    url "https://github.com/bufbuild/buf/releases/download/v#{version}/buf-#{OS.kernel_name}-#{asset_arch}.tar.gz"
+    sha256 sha
+  else
+    # No prebuilt binary for this platform: fall back to building from source.
+    url "https://github.com/bufbuild/buf/archive/v#{version}.tar.gz"
+    sha256 "7da0f12d42d00a4a4fabf89af37e2e02ad5958bc7e977a713e4bc01b2a232899"
+    depends_on "go" => :build
+  end
+
+  head do
+    url "https://github.com/bufbuild/buf.git", branch: "main"
+    depends_on "go" => :build
+  end
 
   def install
-    ENV["GOPATH"] = HOMEBREW_CACHE/"go_cache"
-    system "sh", "make/buf/scripts/brew.sh", ".build/brew"
-    prefix.install Dir[".build/brew/*"]
+    if build.head? || !SHA256S.key?("#{OS.kernel_name}-#{Hardware::CPU.arch}")
+      ENV["GOPATH"] = HOMEBREW_CACHE/"go_cache"
+      system "sh", "make/buf/scripts/brew.sh", ".build/brew"
+      prefix.install Dir[".build/brew/*"]
+    else
+      prefix.install Dir["*"]
+    end
   end
 
   test do

update.bash

@@ -24,26 +24,74 @@ if [ -z "${1}" ]; then
 fi
 
 VERSION="${1}"
-URL="https://github.com/bufbuild/buf/archive/v${VERSION}.tar.gz"
-SHA256=$(curl -sSL "${URL}" | sha256 | cut -f 1 -d ' ')
+RELEASE="https://github.com/bufbuild/buf/releases/download/v${VERSION}"
+
+# Source archive checksum, used by the build-from-source fallback.
+SOURCE_URL="https://github.com/bufbuild/buf/archive/v${VERSION}.tar.gz"
+SOURCE_SHA256=$(curl -sSL "${SOURCE_URL}" | sha256 | cut -f 1 -d ' ')
+
+# Prebuilt archive checksums, sourced in one fetch from the release sha256.txt.
+SHA256_TXT=$(curl -sSL "${RELEASE}/sha256.txt")
+binary_sha256() {
+  echo "${SHA256_TXT}" | awk -v f="${1}" '$2 == f { print $1 }'
+}
+DARWIN_ARM64_SHA256=$(binary_sha256 "buf-Darwin-arm64.tar.gz")
+DARWIN_X86_64_SHA256=$(binary_sha256 "buf-Darwin-x86_64.tar.gz")
+LINUX_ARM64_SHA256=$(binary_sha256 "buf-Linux-aarch64.tar.gz")
+LINUX_X86_64_SHA256=$(binary_sha256 "buf-Linux-x86_64.tar.gz")
+
+for name in SOURCE_SHA256 DARWIN_ARM64_SHA256 DARWIN_X86_64_SHA256 LINUX_ARM64_SHA256 LINUX_X86_64_SHA256; do
+  if [ -z "${!name}" ]; then
+    echo "error: could not determine ${name} for v${VERSION}" >&2
+    exit 1
+  fi
+done
 
 rm -rf Formula
 mkdir -p Formula
 cat <<EOF >Formula/buf.rb
 class Buf < Formula
   desc "The best way of working with Protocol Buffers."
   homepage "https://buf.build"
-  head "https://github.com/bufbuild/buf.git", branch: "main"
-  url "${URL}"
-  sha256 "${SHA256}"
   version "${VERSION}"
 
-  depends_on "go" => :build
+  # sha256 of the prebuilt release archive for each Homebrew-supported platform,
+  # keyed by "#{OS.kernel_name}-#{Hardware::CPU.arch}". Each archive unpacks to
+  # the same layout as a source build (bin/, etc/, share/, LICENSE), so the two
+  # install paths below are equivalent.
+  SHA256S = {
+    "Darwin-arm64"  => "${DARWIN_ARM64_SHA256}",
+    "Darwin-x86_64" => "${DARWIN_X86_64_SHA256}",
+    "Linux-arm64"   => "${LINUX_ARM64_SHA256}",
+    "Linux-x86_64"  => "${LINUX_X86_64_SHA256}",
+  }.freeze
+
+  if (sha = SHA256S["#{OS.kernel_name}-#{Hardware::CPU.arch}"])
+    # Homebrew reports 64-bit ARM as "arm64"; the Linux asset is named "aarch64".
+    asset_arch = Hardware::CPU.arch.to_s
+    asset_arch = "aarch64" if OS.linux? && Hardware::CPU.arm?
+    url "https://github.com/bufbuild/buf/releases/download/v#{version}/buf-#{OS.kernel_name}-#{asset_arch}.tar.gz"
+    sha256 sha
+  else
+    # No prebuilt binary for this platform: fall back to building from source.
+    url "https://github.com/bufbuild/buf/archive/v#{version}.tar.gz"
+    sha256 "${SOURCE_SHA256}"
+    depends_on "go" => :build
+  end
+
+  head do
+    url "https://github.com/bufbuild/buf.git", branch: "main"
+    depends_on "go" => :build
+  end
 
   def install
-    ENV["GOPATH"] = HOMEBREW_CACHE/"go_cache"
-    system "sh", "make/buf/scripts/brew.sh", ".build/brew"
-    prefix.install Dir[".build/brew/*"]
+    if build.head? || !SHA256S.key?("#{OS.kernel_name}-#{Hardware::CPU.arch}")
+      ENV["GOPATH"] = HOMEBREW_CACHE/"go_cache"
+      system "sh", "make/buf/scripts/brew.sh", ".build/brew"
+      prefix.install Dir[".build/brew/*"]
+    else
+      prefix.install Dir["*"]
+    end
   end
 
   test do