Add cask support to brew unpack command

Co-authored-by: p-linnane <105994585+p-linnane@users.noreply.github.com>

Library/Homebrew/dev-cmd/unpack.rb

@@ -5,6 +5,8 @@ require "abstract_command"
 require "fileutils"
 require "stringio"
 require "formula"
+require "cask/download"
+require "unpack_strategy"
 
 module Homebrew
   module DevCmd
@@ -13,7 +15,7 @@ module Homebrew
 
       cmd_args do
         description <<~EOS
-          Unpack the source files for <formula> into subdirectories of the current
+          Unpack the source files for <formula> and binaries for <cask> into subdirectories of the current
           working directory.
         EOS
         flag   "--destdir=",
@@ -25,15 +27,22 @@ module Homebrew
                             "patches for the software."
         switch "-f", "--force",
                description: "Overwrite the destination directory if it already exists."
+        switch "--formula", "--formulae",
+               description: "Treat all named arguments as formulae."
+        switch "--cask", "--casks",
+               description: "Treat all named arguments as casks."
 
         conflicts "--git", "--patch"
+        conflicts "--formula", "--cask"
+        conflicts "--cask", "--patch"
+        conflicts "--cask", "--git"
 
-        named_args :formula, min: 1
+        named_args [:formula, :cask], min: 1
       end
 
       sig { override.void }
       def run
-        formulae = args.named.to_formulae
+        formulae_and_casks = args.named.to_formulae_and_casks
 
         if (dir = args.destdir)
           unpack_dir = Pathname.new(dir).expand_path
@@ -44,8 +53,21 @@ module Homebrew
 
         odie "Cannot write to #{unpack_dir}" unless unpack_dir.writable?
 
-        formulae.each do |f|
-          stage_dir = unpack_dir/"#{f.name}-#{f.version}"
+        formulae_and_casks.each do |formula_or_cask|
+          case formula_or_cask
+          when Formula
+            unpack_formula(formula_or_cask, unpack_dir)
+          when Cask::Cask
+            unpack_cask(formula_or_cask, unpack_dir)
+          end
+        end
+      end
+
+      private
+
+      sig { params(formula: Formula, unpack_dir: Pathname).void }
+      def unpack_formula(formula, unpack_dir)
+        stage_dir = unpack_dir/"#{formula.name}-#{formula.version}"
 
         if stage_dir.exist?
           odie "Destination #{stage_dir} already exists!" unless args.force?
@@ -53,17 +75,47 @@ module Homebrew
           rm_rf stage_dir
         end
 
-          oh1 "Unpacking #{Formatter.identifier(f.full_name)} to: #{stage_dir}"
+        oh1 "Unpacking #{Formatter.identifier(formula.full_name)} to: #{stage_dir}"
 
         # show messages about tar
         with_env VERBOSE: "1" do
-            f.brew do
-              f.patch if args.patch?
+          formula.brew do
+            formula.patch if args.patch?
             cp_r getwd, stage_dir, preserve: true
           end
         end
 
-          next unless args.git?
+        return unless args.git?
+
+        ohai "Setting up Git repository"
+        cd(stage_dir) do
+          system "git", "init", "-q"
+          system "git", "add", "-A"
+          system "git", "commit", "-q", "-m", "brew-unpack"
+        end
+      end
+
+      sig { params(cask: Cask::Cask, unpack_dir: Pathname).void }
+      def unpack_cask(cask, unpack_dir)
+        stage_dir = unpack_dir/"#{cask.token}-#{cask.version}"
+
+        if stage_dir.exist?
+          odie "Destination #{stage_dir} already exists!" unless args.force?
+
+          rm_rf stage_dir
+        end
+
+        oh1 "Unpacking #{Formatter.identifier(cask.full_name)} to: #{stage_dir}"
+
+        # Download the cask
+        download = Cask::Download.new(cask, quarantine: false)
+        downloaded_path = download.fetch(quiet: false)
+
+        # Extract to destination
+        stage_dir.mkpath
+        UnpackStrategy.detect(downloaded_path).extract_nestedly(to: stage_dir, verbose: true)
+
+        return unless args.git?
 
         ohai "Setting up Git repository"
         cd(stage_dir) do
@@ -74,5 +126,4 @@ module Homebrew
       end
     end
   end
-  end
 end

Library/Homebrew/test/dev-cmd/unpack_spec.rb

@@ -16,4 +16,13 @@ RSpec.describe Homebrew::DevCmd::Unpack do
       expect(path/"testball-0.1").to be_a_directory
     end
   end
+
+  it "unpacks a given Cask's archive", :integration_test do
+    mktmpdir do |path|
+      expect { brew "unpack", "local-caffeine", "--destdir=#{path}", "--cask" }
+        .to be_a_success
+
+      expect(path/"local-caffeine-1.2.3").to be_a_directory
+    end
+  end
 end