diff --git a/Library/Homebrew/cask/lib/hbc.rb b/Library/Homebrew/cask/lib/hbc.rb
index 5530683523..498c3bc885 100644
--- a/Library/Homebrew/cask/lib/hbc.rb
+++ b/Library/Homebrew/cask/lib/hbc.rb
@@ -10,7 +10,6 @@ require "hbc/caskroom"
 require "hbc/checkable"
 require "hbc/cli"
 require "hbc/cask_dependencies"
-require "hbc/container"
 require "hbc/download"
 require "hbc/download_strategy"
 require "hbc/exceptions"
@@ -18,7 +17,6 @@ require "hbc/installer"
 require "hbc/macos"
 require "hbc/pkg"
 require "hbc/staged"
-require "system_command"
 require "hbc/topological_hash"
 require "hbc/utils"
 require "hbc/verify"
diff --git a/Library/Homebrew/cask/lib/hbc/artifact.rb b/Library/Homebrew/cask/lib/hbc/artifact.rb
index 1cbe49cf27..df1bc9b6a8 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact.rb
@@ -10,7 +10,6 @@ require "hbc/artifact/internet_plugin"
 require "hbc/artifact/audio_unit_plugin"
 require "hbc/artifact/vst_plugin"
 require "hbc/artifact/vst3_plugin"
-require "hbc/artifact/nested_container"
 require "hbc/artifact/pkg"
 require "hbc/artifact/postflight_block"
 require "hbc/artifact/preflight_block"
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/abstract_artifact.rb b/Library/Homebrew/cask/lib/hbc/artifact/abstract_artifact.rb
index 0771054689..86643b90d4 100644
--- a/Library/Homebrew/cask/lib/hbc/artifact/abstract_artifact.rb
+++ b/Library/Homebrew/cask/lib/hbc/artifact/abstract_artifact.rb
@@ -29,9 +29,6 @@ module Hbc
           # The `uninstall` stanza should be run first, as it may
           # depend on other artifacts still being installed.
           Uninstall,
-          # We want to extract nested containers before we
-          # handle any other artifacts.
-          NestedContainer,
           Installer,
           [
             App,
diff --git a/Library/Homebrew/cask/lib/hbc/artifact/nested_container.rb b/Library/Homebrew/cask/lib/hbc/artifact/nested_container.rb
deleted file mode 100644
index 23ff9cc9b5..0000000000
--- a/Library/Homebrew/cask/lib/hbc/artifact/nested_container.rb
+++ /dev/null
@@ -1,36 +0,0 @@
-require "hbc/artifact/abstract_artifact"
-
-module Hbc
-  module Artifact
-    class NestedContainer < AbstractArtifact
-      attr_reader :path
-
-      def initialize(cask, path)
-        super(cask)
-        @path = cask.staged_path.join(path)
-      end
-
-      def install_phase(**options)
-        extract(**options)
-      end
-
-      private
-
-      def summarize
-        path.relative_path_from(cask.staged_path).to_s
-      end
-
-      def extract(verbose: nil, **_)
-        container = Container.for_path(path)
-
-        unless container
-          raise CaskError, "Aw dang, could not identify nested container at '#{source}'"
-        end
-
-        ohai "Extracting nested container #{path.relative_path_from(cask.staged_path)}"
-        container.new(cask, path).extract(to: cask.staged_path, verbose: verbose)
-        FileUtils.remove_entry_secure(path)
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/audit.rb b/Library/Homebrew/cask/lib/hbc/audit.rb
index 9ed6f68a96..4e9e489457 100644
--- a/Library/Homebrew/cask/lib/hbc/audit.rb
+++ b/Library/Homebrew/cask/lib/hbc/audit.rb
@@ -113,8 +113,7 @@ module Hbc
       end
       add_error "at least one name stanza is required" if cask.name.empty?
       # TODO: specific DSL knowledge should not be spread around in various files like this
-      # TODO: nested_container should not still be a pseudo-artifact at this point
-      installable_artifacts = cask.artifacts.reject { |k| [:uninstall, :zap, :nested_container].include?(k) }
+      installable_artifacts = cask.artifacts.reject { |k| [:uninstall, :zap].include?(k) }
       add_error "at least one activatable artifact stanza is required" if installable_artifacts.empty?
     end
 
diff --git a/Library/Homebrew/cask/lib/hbc/container.rb b/Library/Homebrew/cask/lib/hbc/container.rb
deleted file mode 100644
index 8c5d2b4018..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container.rb
+++ /dev/null
@@ -1,79 +0,0 @@
-require "hbc/utils"
-
-require "hbc/container/base"
-require "hbc/container/air"
-require "hbc/container/bzip2"
-require "hbc/container/cab"
-require "hbc/container/dmg"
-require "hbc/container/self_extracting_executable"
-require "hbc/container/executable"
-require "hbc/container/generic_unar"
-require "hbc/container/gzip"
-require "hbc/container/lzma"
-require "hbc/container/naked"
-require "hbc/container/otf"
-require "hbc/container/pkg"
-require "hbc/container/seven_zip"
-require "hbc/container/sit"
-require "hbc/container/svn_repository"
-require "hbc/container/tar"
-require "hbc/container/ttf"
-require "hbc/container/rar"
-require "hbc/container/xar"
-require "hbc/container/xz"
-require "hbc/container/zip"
-
-module Hbc
-  class Container
-    def self.autodetect_containers
-      [
-        Pkg,
-        Ttf,
-        Otf,
-        Air,
-        SelfExtractingExecutable,
-        Cab,
-        Dmg,
-        SevenZip,
-        Sit,
-        Rar,
-        Zip,
-        Xar,   # need to be before tar as tar can also list xar
-        Tar,   # or compressed tar (bzip2/gzip/lzma/xz)
-        Bzip2, # pure bzip2
-        Gzip,  # pure gzip
-        Lzma,  # pure lzma
-        Xz,    # pure xz
-        Executable,
-        SvnRepository,
-      ]
-      # for explicit use only (never autodetected):
-      # Hbc::Container::Naked
-      # Hbc::Container::GenericUnar
-    end
-
-    def self.for_path(path)
-      odebug "Determining which containers to use based on filetype"
-
-      magic_number = if path.directory?
-        ""
-      else
-        File.binread(path, 262) || ""
-      end
-
-      autodetect_containers.find do |c|
-        odebug "Checking container class #{c}"
-        c.can_extract?(path: path, magic_number: magic_number)
-      end
-    end
-
-    def self.from_type(type)
-      odebug "Determining which containers to use based on 'container :type'"
-      begin
-        const_get(type.to_s.split("_").map(&:capitalize).join)
-      rescue NameError
-        nil
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/air.rb b/Library/Homebrew/cask/lib/hbc/container/air.rb
deleted file mode 100644
index 71f9d63cb9..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/air.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Air < Base
-      def self.can_extract?(path:, magic_number:)
-        path.extname == ".air"
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!(
-          "/Applications/Utilities/Adobe AIR Application Installer.app/Contents/MacOS/Adobe AIR Application Installer",
-          args: ["-silent", "-location", unpack_dir, path],
-        )
-      end
-
-      def dependencies
-        @dependencies ||= [CaskLoader.load("adobe-air")]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/base.rb b/Library/Homebrew/cask/lib/hbc/container/base.rb
deleted file mode 100644
index 192ae9cb78..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/base.rb
+++ /dev/null
@@ -1,54 +0,0 @@
-module Hbc
-  class Container
-    class Base
-      extend Predicable
-
-      attr_reader :path
-
-      def initialize(cask, path, nested: false)
-        @cask = cask
-        @path = path
-      end
-
-      def extract(to: nil, basename: nil, verbose: false)
-        basename ||= path.basename
-        unpack_dir = Pathname(to || Dir.pwd).expand_path
-        unpack_dir.mkpath
-        extract_to_dir(unpack_dir, basename: basename, verbose: verbose)
-      end
-
-      def extract_nested_inside(dir, to:, verbose: false)
-        children = Pathname.new(dir).children
-
-        nested_container = children[0]
-
-        unless children.count == 1 &&
-               !nested_container.directory? &&
-               @cask.artifacts.none? { |a| a.is_a?(Artifact::NestedContainer) } &&
-               extract_nested_container(nested_container, to: to, verbose: verbose)
-
-          children.each do |src|
-            dest = @cask.staged_path.join(src.basename)
-            FileUtils.rm_r(dest) if dest.exist?
-            FileUtils.mv(src, dest)
-          end
-        end
-      end
-
-      def extract_nested_container(source, to:, verbose: false)
-        container = Container.for_path(source)
-
-        return false unless container
-
-        ohai "Extracting nested container #{source.basename}"
-        container.new(@cask, source).extract(to: to, verbose: verbose)
-
-        true
-      end
-
-      def dependencies
-        []
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/bzip2.rb b/Library/Homebrew/cask/lib/hbc/container/bzip2.rb
deleted file mode 100644
index 579fabb088..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/bzip2.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Bzip2 < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\ABZh/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        Dir.mktmpdir do |tmp_unpack_dir|
-          tmp_unpack_dir = Pathname(tmp_unpack_dir)
-
-          FileUtils.cp path, tmp_unpack_dir/basename, preserve: true
-          system_command!("bunzip2", args: ["--quiet", "--", tmp_unpack_dir/basename])
-
-          extract_nested_inside(tmp_unpack_dir, to: unpack_dir)
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/cab.rb b/Library/Homebrew/cask/lib/hbc/container/cab.rb
deleted file mode 100644
index d88e0d96cd..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/cab.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Cab < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\A(MSCF|MZ)/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("cabextract",
-                        args: ["-d", unpack_dir, "--", path],
-                        env: { "PATH" => PATH.new(Formula["cabextract"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["cabextract"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/dmg.rb b/Library/Homebrew/cask/lib/hbc/container/dmg.rb
deleted file mode 100644
index 1ce9845df6..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/dmg.rb
+++ /dev/null
@@ -1,152 +0,0 @@
-require "tempfile"
-
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Dmg < Base
-      def self.can_extract?(path:, magic_number:)
-        imageinfo = system_command("/usr/bin/hdiutil",
-                                   # realpath is a failsafe against unusual filenames
-                                   args:         ["imageinfo", path.realpath],
-                                   print_stderr: false).stdout
-
-        !imageinfo.empty?
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        mount(verbose: verbose) do |mounts|
-          begin
-            raise "No mounts found in '#{path}'; perhaps it is a bad disk image?" if mounts.empty?
-            mounts.each do |mount|
-              extract_mount(mount, to: unpack_dir)
-            end
-          ensure
-            mounts.each(&method(:eject))
-          end
-        end
-      end
-
-      def mount(verbose: false)
-        # realpath is a failsafe against unusual filenames
-        realpath = path.realpath
-        path = realpath
-
-        Dir.mktmpdir do |unpack_dir|
-          without_eula = system_command("/usr/bin/hdiutil",
-                                        args:  ["attach", "-plist", "-nobrowse", "-readonly", "-noidme", "-mountrandom", unpack_dir, path],
-                                        input: "qn\n",
-                                        print_stderr: false)
-
-          # If mounting without agreeing to EULA succeeded, there is none.
-          plist = if without_eula.success?
-            without_eula.plist
-          else
-            cdr_path = Pathname.new(unpack_dir).join("#{path.basename(".dmg")}.cdr")
-
-            system_command!("/usr/bin/hdiutil", args: ["convert", "-quiet", "-format", "UDTO", "-o", cdr_path, path])
-
-            with_eula = system_command!("/usr/bin/hdiutil",
-                          args: ["attach", "-plist", "-nobrowse", "-readonly", "-noidme", "-mountrandom", unpack_dir, cdr_path])
-
-            if verbose && !(eula_text = without_eula.stdout).empty?
-              ohai "Software License Agreement for '#{path}':"
-              puts eula_text
-            end
-
-            with_eula.plist
-          end
-
-          yield mounts_from_plist(plist)
-        end
-      end
-
-      def eject(mount)
-        # realpath is a failsafe against unusual filenames
-        mountpath = Pathname.new(mount).realpath
-
-        begin
-          tries ||= 3
-
-          return unless mountpath.exist?
-
-          if tries > 1
-            system_command!("/usr/sbin/diskutil",
-                         args:         ["eject", mountpath],
-                         print_stderr: false)
-          else
-            system_command!("/usr/sbin/diskutil",
-                         args:         ["unmount", "force", mountpath],
-                         print_stderr: false)
-          end
-        rescue ErrorDuringExecution => e
-          raise e if (tries -= 1).zero?
-          sleep 1
-          retry
-        end
-      end
-
-      private
-
-      def extract_mount(mount, to:)
-        Tempfile.open(["", ".bom"]) do |bomfile|
-          bomfile.close
-
-          Tempfile.open(["", ".list"]) do |filelist|
-            filelist.puts(bom_filelist_from_path(mount))
-            filelist.close
-
-            system_command!("/usr/bin/mkbom", args: ["-s", "-i", filelist.path, "--", bomfile.path])
-            system_command!("/usr/bin/ditto", args: ["--bom", bomfile.path, "--", mount, to])
-          end
-        end
-      end
-
-      def bom_filelist_from_path(mount)
-        # We need to use `find` here instead of Ruby in order to properly handle
-        # file names containing special characters, such as “e” + “´” vs. “é”.
-        system_command("/usr/bin/find", args: [".", "-print0"], chdir: mount, print_stderr: false)
-          .stdout
-          .split("\0")
-          .reject { |path| skip_path?(mount, path) }
-          .join("\n")
-      end
-
-      def skip_path?(mount, path)
-        path = Pathname(path.sub(%r{\A\./}, ""))
-        dmg_metadata?(path) || system_dir_symlink?(mount, path)
-      end
-
-      # unnecessary DMG metadata
-      DMG_METADATA_FILES = Set.new %w[
-        .background
-        .com.apple.timemachine.donotpresent
-        .com.apple.timemachine.supported
-        .DocumentRevisions-V100
-        .DS_Store
-        .fseventsd
-        .MobileBackups
-        .Spotlight-V100
-        .TemporaryItems
-        .Trashes
-        .VolumeIcon.icns
-      ].freeze
-
-      def dmg_metadata?(path)
-        relative_root = path.sub(%r{/.*}, "")
-        DMG_METADATA_FILES.include?(relative_root.basename.to_s)
-      end
-
-      def system_dir_symlink?(mount, path)
-        full_path = Pathname(mount).join(path)
-        # symlinks to system directories (commonly to /Applications)
-        full_path.symlink? && MacOS.system_dir?(full_path.readlink)
-      end
-
-      def mounts_from_plist(plist)
-        return [] unless plist.respond_to?(:fetch)
-        plist.fetch("system-entities", []).map { |e| e["mount-point"] }.compact
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/executable.rb b/Library/Homebrew/cask/lib/hbc/container/executable.rb
deleted file mode 100644
index 4f2ebdcc97..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/executable.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-require "hbc/container/naked"
-require "vendor/macho/macho"
-
-module Hbc
-  class Container
-    class Executable < Naked
-      def self.can_extract?(path:, magic_number:)
-        return true if magic_number.match?(/\A#!\s*\S+/n)
-
-        begin
-          path.file? && MachO.open(path).header.executable?
-        rescue MachO::MagicError
-          false
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/generic_unar.rb b/Library/Homebrew/cask/lib/hbc/container/generic_unar.rb
deleted file mode 100644
index 0844057528..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/generic_unar.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class GenericUnar < Base
-      def self.can_extract?(path:, magic_number:)
-        false
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("unar",
-                        args: ["-force-overwrite", "-quiet", "-no-directory", "-output-directory", unpack_dir, "--", path],
-                        env: { "PATH" => PATH.new(Formula["unar"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["unar"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/gzip.rb b/Library/Homebrew/cask/lib/hbc/container/gzip.rb
deleted file mode 100644
index 5f1715eabf..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/gzip.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Gzip < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\A\037\213/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        Dir.mktmpdir do |tmp_unpack_dir|
-          tmp_unpack_dir = Pathname(tmp_unpack_dir)
-
-          FileUtils.cp path, tmp_unpack_dir/basename, preserve: true
-          system_command!("gunzip", args: ["--quiet", "--name", "--", tmp_unpack_dir/basename])
-
-          extract_nested_inside(tmp_unpack_dir, to: unpack_dir)
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/lzma.rb b/Library/Homebrew/cask/lib/hbc/container/lzma.rb
deleted file mode 100644
index 0f656bfe68..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/lzma.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Lzma < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\A\]\000\000\200\000/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("/usr/bin/ditto", args: ["--", path, unpack_dir])
-        system_command!("unlzma",
-                        args: ["-q", "--", Pathname(unpack_dir).join(basename)],
-                        env: { "PATH" => PATH.new(Formula["unlzma"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["unlzma"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/naked.rb b/Library/Homebrew/cask/lib/hbc/container/naked.rb
deleted file mode 100644
index 680ca45f89..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/naked.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Naked < Base
-      def self.can_extract?(path:, magic_number:)
-        false
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("/usr/bin/ditto", args: ["--", path, unpack_dir/basename])
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/otf.rb b/Library/Homebrew/cask/lib/hbc/container/otf.rb
deleted file mode 100644
index d8aa9dbcbe..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/otf.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-require "hbc/container/naked"
-
-module Hbc
-  class Container
-    class Otf < Naked
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\AOTTO/n)
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/pkg.rb b/Library/Homebrew/cask/lib/hbc/container/pkg.rb
deleted file mode 100644
index 98f250c949..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/pkg.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-require "hbc/container/naked"
-
-module Hbc
-  class Container
-    class Pkg < Naked
-      def self.can_extract?(path:, magic_number:)
-        path.extname.match?(/\A.m?pkg\Z/) &&
-          (path.directory? || magic_number.match?(/\Axar!/n))
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/rar.rb b/Library/Homebrew/cask/lib/hbc/container/rar.rb
deleted file mode 100644
index 27bb0def4b..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/rar.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Rar < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\ARar!/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("unrar",
-                        args: ["x", "-inul", path, unpack_dir],
-                        env: { "PATH" => PATH.new(Formula["unrar"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["unrar"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/self_extracting_executable.rb b/Library/Homebrew/cask/lib/hbc/container/self_extracting_executable.rb
deleted file mode 100644
index e620c510d3..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/self_extracting_executable.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-require "hbc/container/generic_unar"
-
-module Hbc
-  class Container
-    class SelfExtractingExecutable < GenericUnar
-      def self.can_extract?(path:, magic_number:)
-        return false unless magic_number.match?(/\AMZ/n)
-
-        SystemCommand.run("file",
-                          args: [path],
-                          print_stderr: false).stdout.include?("self-extracting")
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb b/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb
deleted file mode 100644
index 876b647a4f..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/seven_zip.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class SevenZip < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\A7z\xBC\xAF\x27\x1C/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("7zr",
-                        args: ["x", "-y", "-bd", "-bso0", path, "-o#{unpack_dir}"],
-                        env: { "PATH" => PATH.new(Formula["p7zip"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["p7zip"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/sit.rb b/Library/Homebrew/cask/lib/hbc/container/sit.rb
deleted file mode 100644
index 3a22b48ab9..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/sit.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-require "hbc/container/generic_unar"
-
-module Hbc
-  class Container
-    class Sit < GenericUnar
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\AStuffIt/n)
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/svn_repository.rb b/Library/Homebrew/cask/lib/hbc/container/svn_repository.rb
deleted file mode 100644
index 16fc13cc4d..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/svn_repository.rb
+++ /dev/null
@@ -1,13 +0,0 @@
-module Hbc
-  class Container
-    class SvnRepository < Base
-      def self.can_extract?(path:, magic_number:)
-        (path/".svn").directory?
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("svn", args: ["export", "--force", path, unpack_dir])
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/tar.rb b/Library/Homebrew/cask/lib/hbc/container/tar.rb
deleted file mode 100644
index 8f40a54cdd..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/tar.rb
+++ /dev/null
@@ -1,20 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Tar < Base
-      def self.can_extract?(path:, magic_number:)
-        return true if magic_number.match?(/\A.{257}ustar/n)
-
-        # Check if `tar` can list the contents, then it can also extract it.
-        IO.popen(["tar", "tf", path], err: File::NULL) do |stdout|
-          !stdout.read(1).nil?
-        end
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("tar", args: ["xf", path, "-C", unpack_dir])
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/ttf.rb b/Library/Homebrew/cask/lib/hbc/container/ttf.rb
deleted file mode 100644
index 3a64c796a2..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/ttf.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-require "hbc/container/naked"
-
-module Hbc
-  class Container
-    class Ttf < Naked
-      def self.can_extract?(path:, magic_number:)
-        # TrueType Font
-        magic_number.match?(/\A\000\001\000\000\000/n) ||
-          # Truetype Font Collection
-          magic_number.match?(/\Attcf/n)
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/xar.rb b/Library/Homebrew/cask/lib/hbc/container/xar.rb
deleted file mode 100644
index b688a8f542..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/xar.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Xar < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\Axar!/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("xar", args: ["-x", "-f", @path, "-C", unpack_dir])
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/xz.rb b/Library/Homebrew/cask/lib/hbc/container/xz.rb
deleted file mode 100644
index c5b00ecfb7..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/xz.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Xz < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\A\xFD7zXZ\x00/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        system_command!("/usr/bin/ditto", args: ["--", path, unpack_dir])
-        system_command!("unxz",
-                        args: ["-q", "--", unpack_dir/basename],
-                        env: { "PATH" => PATH.new(Formula["xz"].opt_bin, ENV["PATH"]) })
-      end
-
-      def dependencies
-        @dependencies ||= [Formula["xz"]]
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/container/zip.rb b/Library/Homebrew/cask/lib/hbc/container/zip.rb
deleted file mode 100644
index 98afd0f838..0000000000
--- a/Library/Homebrew/cask/lib/hbc/container/zip.rb
+++ /dev/null
@@ -1,19 +0,0 @@
-require "hbc/container/base"
-
-module Hbc
-  class Container
-    class Zip < Base
-      def self.can_extract?(path:, magic_number:)
-        magic_number.match?(/\APK(\003\004|\005\006)/n)
-      end
-
-      def extract_to_dir(unpack_dir, basename:, verbose:)
-        Dir.mktmpdir do |tmp_unpack_dir|
-          system_command!("/usr/bin/ditto", args: ["-x", "-k", "--", path, tmp_unpack_dir])
-
-          extract_nested_inside(tmp_unpack_dir, to: unpack_dir)
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/cask/lib/hbc/dsl.rb b/Library/Homebrew/cask/lib/hbc/dsl.rb
index 5ed0fb5e99..cee83b1347 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl.rb
@@ -172,16 +172,8 @@ module Hbc
     end
 
     def container(*args)
-      # TODO: remove this constraint, and instead merge multiple container stanzas
       set_unique_stanza(:container, args.empty?) do
-        begin
-          DSL::Container.new(*args).tap do |container|
-            # TODO: remove this backward-compatibility section after removing nested_container
-            if container&.nested
-              artifacts.add(Artifact::NestedContainer.new(cask, container.nested))
-            end
-          end
-        end
+        DSL::Container.new(*args)
       end
     end
 
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/appcast.rb b/Library/Homebrew/cask/lib/hbc/dsl/appcast.rb
index 2472c88e49..9174cca5ea 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/appcast.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/appcast.rb
@@ -1,5 +1,3 @@
-require "system_command"
-
 module Hbc
   class DSL
     class Appcast
diff --git a/Library/Homebrew/cask/lib/hbc/dsl/container.rb b/Library/Homebrew/cask/lib/hbc/dsl/container.rb
index caaf25bcaf..ef2c8d2c38 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl/container.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl/container.rb
@@ -1,4 +1,4 @@
-require "hbc/container"
+require "unpack_strategy"
 
 module Hbc
   class DSL
@@ -19,7 +19,7 @@ module Hbc
         end
 
         return if type.nil?
-        return unless Hbc::Container.from_type(type).nil?
+        return unless UnpackStrategy.from_type(type).nil?
         raise "invalid container type: #{type.inspect}"
       end
 
diff --git a/Library/Homebrew/cask/lib/hbc/installer.rb b/Library/Homebrew/cask/lib/hbc/installer.rb
index 5e16eb234b..342313b0b9 100644
--- a/Library/Homebrew/cask/lib/hbc/installer.rb
+++ b/Library/Homebrew/cask/lib/hbc/installer.rb
@@ -1,6 +1,7 @@
 require "rubygems"
 
 require "formula_installer"
+require "unpack_strategy"
 
 require "hbc/cask_dependencies"
 require "hbc/staged"
@@ -148,17 +149,7 @@ module Hbc
 
     def primary_container
       @primary_container ||= begin
-        container = if @cask.container&.type
-          Container.from_type(@cask.container.type)
-        else
-          Container.for_path(@downloaded_path)
-        end
-
-        unless container
-          raise CaskError, "Uh oh, could not figure out how to unpack '#{@downloaded_path}'."
-        end
-
-        container.new(@cask, @downloaded_path)
+        UnpackStrategy.detect(@downloaded_path, type: @cask.container&.type)
       end
     end
 
@@ -168,7 +159,18 @@ module Hbc
       odebug "Using container class #{primary_container.class} for #{@downloaded_path}"
 
       basename = CGI.unescape(File.basename(@cask.url.path))
-      primary_container.extract(to: @cask.staged_path, basename: basename, verbose: verbose?)
+
+      if nested_container = @cask.container&.nested
+        Dir.mktmpdir do |tmpdir|
+          tmpdir = Pathname(tmpdir)
+          primary_container.extract(to: tmpdir, basename: basename, verbose: verbose?)
+
+          UnpackStrategy.detect(tmpdir/nested_container)
+                        .extract_nestedly(to: @cask.staged_path, verbose: verbose?)
+        end
+      else
+        primary_container.extract_nestedly(to: @cask.staged_path, basename: basename, verbose: verbose?)
+      end
     end
 
     def install_artifacts
diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 14458727cb..10fab11f4f 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -20,6 +20,8 @@ require "messages"
 require "pp"
 require "extend/ARGV"
 
+require "system_command"
+
 ARGV.extend(HomebrewArgvExtension)
 
 HOMEBREW_PRODUCT = ENV["HOMEBREW_PRODUCT"]
diff --git a/Library/Homebrew/system_command.rb b/Library/Homebrew/system_command.rb
index a57c0513cc..c49d773a90 100644
--- a/Library/Homebrew/system_command.rb
+++ b/Library/Homebrew/system_command.rb
@@ -1,10 +1,12 @@
 require "open3"
+require "ostruct"
 require "vendor/plist/plist"
 require "shellwords"
 
 require "extend/io"
 require "extend/hash_validator"
 using HashValidator
+require "extend/predicable"
 
 def system_command(*args)
   SystemCommand.run(*args)
@@ -27,18 +29,15 @@ class SystemCommand
 
   def run!
     @merged_output = []
-    @processed_output = { stdout: "", stderr: "" }
     odebug command.shelljoin
 
     each_output_line do |type, line|
       case type
       when :stdout
         puts line.chomp if print_stdout?
-        processed_output[:stdout] << line
         @merged_output << [:stdout, line]
       when :stderr
         $stderr.puts Formatter.error(line.chomp) if print_stderr?
-        processed_output[:stderr] << line
         @merged_output << [:stderr, line]
       end
     end
@@ -70,7 +69,7 @@ class SystemCommand
 
   private
 
-  attr_reader :executable, :args, :input, :options, :processed_output, :processed_status, :env
+  attr_reader :executable, :args, :input, :options, :env
 
   attr_predicate :sudo?, :print_stdout?, :print_stderr?, :must_succeed?
 
@@ -93,9 +92,9 @@ class SystemCommand
   end
 
   def assert_success
-    return if processed_status&.success?
+    return if @status.success?
     raise ErrorDuringExecution.new(command,
-                                   status: processed_status,
+                                   status: @status,
                                    output: @merged_output)
   end
 
@@ -121,7 +120,10 @@ class SystemCommand
     raw_stdin.close_write
     each_line_from [raw_stdout, raw_stderr], &b
 
-    @processed_status = raw_wait_thr.value
+    @status = raw_wait_thr.value
+  rescue SystemCallError => e
+    @status = $CHILD_STATUS
+    @merged_output << [:stderr, e.message]
   end
 
   def write_input_to(raw_stdin)
@@ -151,10 +153,11 @@ class SystemCommand
   end
 
   def result
-    Result.new(command,
-               processed_output[:stdout],
-               processed_output[:stderr],
-               processed_status.exitstatus)
+    output = @merged_output.each_with_object(stdout: "", stderr: "") do |(type, line), hash|
+      hash[type] << line
+    end
+
+    Result.new(command, output[:stdout], output[:stderr], @status.exitstatus)
   end
 
   class Result
diff --git a/Library/Homebrew/test/cask/artifact/nested_container_spec.rb b/Library/Homebrew/test/cask/artifact/nested_container_spec.rb
deleted file mode 100644
index 92486fc7f8..0000000000
--- a/Library/Homebrew/test/cask/artifact/nested_container_spec.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-describe Hbc::Artifact::NestedContainer, :cask do
-  describe "install" do
-    it "extracts the specified paths as containers" do
-      cask = Hbc::CaskLoader.load(cask_path("nested-app")).tap do |c|
-        InstallHelper.install_without_artifacts(c)
-      end
-
-      cask.artifacts.select { |a| a.is_a?(described_class) }.each do |artifact|
-        artifact.install_phase(command: NeverSudoSystemCommand, force: false)
-      end
-
-      expect(cask.staged_path.join("MyNestedApp.app")).to be_a_directory
-    end
-  end
-end
diff --git a/Library/Homebrew/test/cask/container/dmg_spec.rb b/Library/Homebrew/test/cask/container/dmg_spec.rb
deleted file mode 100644
index 7eee7c49fc..0000000000
--- a/Library/Homebrew/test/cask/container/dmg_spec.rb
+++ /dev/null
@@ -1,16 +0,0 @@
-describe Hbc::Container::Dmg, :cask do
-  describe "#mount" do
-    let(:transmission) { Hbc::CaskLoader.load(cask_path("local-transmission")) }
-    subject(:dmg) { described_class.new(transmission, Pathname(transmission.url.path)) }
-
-    it "does not store nil mounts for dmgs with extra data" do
-      dmg.mount do |mounts|
-        begin
-          expect(mounts).not_to include nil
-        ensure
-          mounts.each(&dmg.public_method(:eject))
-        end
-      end
-    end
-  end
-end
diff --git a/Library/Homebrew/test/cask/container/naked_spec.rb b/Library/Homebrew/test/cask/container/naked_spec.rb
deleted file mode 100644
index 1acdb7a069..0000000000
--- a/Library/Homebrew/test/cask/container/naked_spec.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-describe Hbc::Container::Naked, :cask do
-  it "saves files with spaces in them from uris with encoded spaces" do
-    cask = Hbc::Cask.new("spacey") do
-      url "http://example.com/kevin%20spacey.pkg"
-      version "1.2"
-    end
-
-    path                 = Pathname("/tmp/downloads/kevin-spacey.pkg")
-    expected_destination = cask.staged_path.join("kevin spacey.pkg")
-
-    container = Hbc::Container::Naked.new(cask, path)
-
-    expect(container).to receive(:system_command!)
-      .with("/usr/bin/ditto", args: ["--", path, expected_destination])
-
-    container.extract(to: cask.staged_path, basename: "kevin spacey.pkg")
-  end
-end
diff --git a/Library/Homebrew/test/system_command_spec.rb b/Library/Homebrew/test/system_command_spec.rb
index f57d22f612..0b74d1fbfe 100644
--- a/Library/Homebrew/test/system_command_spec.rb
+++ b/Library/Homebrew/test/system_command_spec.rb
@@ -208,4 +208,12 @@ describe SystemCommand do
       expect(described_class.run("tool", env: { "PATH" => path }).stdout).to include "Hello, world!"
     end
   end
+
+  describe "#run" do
+    it "does not raise a `SystemCallError` when the executable does not exist" do
+      expect {
+        described_class.run("non_existent_executable")
+      }.not_to raise_error
+    end
+  end
 end
diff --git a/Library/Homebrew/test/unpack_strategy/dmg_spec.rb b/Library/Homebrew/test/unpack_strategy/dmg_spec.rb
new file mode 100644
index 0000000000..a572ea3a08
--- /dev/null
+++ b/Library/Homebrew/test/unpack_strategy/dmg_spec.rb
@@ -0,0 +1,10 @@
+require_relative "shared_examples"
+
+describe UnpackStrategy::Dmg, :needs_macos do
+  describe "#mount" do
+    let(:path) { TEST_FIXTURE_DIR/"cask/container.dmg" }
+
+    include_examples "UnpackStrategy::detect"
+    include_examples "#extract", children: ["container"]
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy.rb b/Library/Homebrew/unpack_strategy.rb
index b341292cdf..154724ec0a 100644
--- a/Library/Homebrew/unpack_strategy.rb
+++ b/Library/Homebrew/unpack_strategy.rb
@@ -5,15 +5,23 @@ module UnpackStrategy
 
   def self.strategies
     @strategies ||= [
+      Pkg,
+      Ttf,
+      Otf,
+      Air,
+      Executable,
+      SelfExtractingExecutable,
       Jar,
       LuaRock,
       MicrosoftOfficeXml,
       Zip,
+      Dmg,
       Xar,
       Compress,
       Tar,
-      Gzip,
       Bzip2,
+      Gzip,
+      Lzma,
       Xz,
       Lzip,
       Git,
@@ -22,14 +30,29 @@ module UnpackStrategy
       Cvs,
       Fossil,
       Bazaar,
+      Cab,
       P7Zip,
+      Sit,
       Rar,
       Lha,
     ].freeze
   end
   private_class_method :strategies
 
-  def self.detect(path, ref_type: nil, ref: nil)
+  def self.from_type(type)
+    type = {
+      naked: :uncompressed,
+      seven_zip: :p7zip,
+    }.fetch(type, type)
+
+    begin
+      const_get(type.to_s.split("_").map(&:capitalize).join)
+    rescue NameError
+      nil
+    end
+  end
+
+  def self.from_path(path)
     magic_number = if path.directory?
       ""
     else
@@ -50,6 +73,11 @@ module UnpackStrategy
       Uncompressed
     end
 
+    strategy
+  end
+
+  def self.detect(path, type: nil, ref_type: nil, ref: nil)
+    strategy = type ? from_type(type) : from_path(path)
     strategy.new(path, ref_type: ref_type, ref: ref)
   end
 
@@ -86,26 +114,41 @@ module UnpackStrategy
       Directory.new(tmp_unpack_dir).extract(to: to, verbose: verbose)
     end
   end
+
+  def dependencies
+    []
+  end
 end
 
+require "unpack_strategy/air"
 require "unpack_strategy/bazaar"
 require "unpack_strategy/bzip2"
+require "unpack_strategy/cab"
 require "unpack_strategy/compress"
 require "unpack_strategy/cvs"
 require "unpack_strategy/directory"
+require "unpack_strategy/dmg"
+require "unpack_strategy/executable"
 require "unpack_strategy/fossil"
+require "unpack_strategy/generic_unar"
 require "unpack_strategy/git"
 require "unpack_strategy/gzip"
 require "unpack_strategy/jar"
 require "unpack_strategy/lha"
 require "unpack_strategy/lua_rock"
 require "unpack_strategy/lzip"
+require "unpack_strategy/lzma"
 require "unpack_strategy/mercurial"
 require "unpack_strategy/microsoft_office_xml"
+require "unpack_strategy/otf"
 require "unpack_strategy/p7zip"
+require "unpack_strategy/pkg"
 require "unpack_strategy/rar"
+require "unpack_strategy/self_extracting_executable"
+require "unpack_strategy/sit"
 require "unpack_strategy/subversion"
 require "unpack_strategy/tar"
+require "unpack_strategy/ttf"
 require "unpack_strategy/uncompressed"
 require "unpack_strategy/xar"
 require "unpack_strategy/xz"
diff --git a/Library/Homebrew/unpack_strategy/air.rb b/Library/Homebrew/unpack_strategy/air.rb
new file mode 100644
index 0000000000..4fd819c888
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/air.rb
@@ -0,0 +1,22 @@
+module UnpackStrategy
+  class Air
+    include UnpackStrategy
+
+    def self.can_extract?(path:, magic_number:)
+      path.extname == ".air"
+    end
+
+    def dependencies
+      @dependencies ||= [Hbc::CaskLoader.load("adobe-air")]
+    end
+
+    private
+
+    def extract_to_dir(unpack_dir, basename:, verbose:)
+      system_command!(
+        "/Applications/Utilities/Adobe AIR Application Installer.app/Contents/MacOS/Adobe AIR Application Installer",
+        args: ["-silent", "-location", unpack_dir, path],
+      )
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/bzip2.rb b/Library/Homebrew/unpack_strategy/bzip2.rb
index aa401368ce..60378b7003 100644
--- a/Library/Homebrew/unpack_strategy/bzip2.rb
+++ b/Library/Homebrew/unpack_strategy/bzip2.rb
@@ -11,7 +11,7 @@ module UnpackStrategy
     def extract_to_dir(unpack_dir, basename:, verbose:)
       FileUtils.cp path, unpack_dir/basename, preserve: true
       quiet_flags = verbose ? [] : ["-q"]
-      safe_system "bunzip2", *quiet_flags, unpack_dir/basename
+      system_command! "bunzip2", args: [*quiet_flags, unpack_dir/basename]
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/cab.rb b/Library/Homebrew/unpack_strategy/cab.rb
new file mode 100644
index 0000000000..1daf219f4a
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/cab.rb
@@ -0,0 +1,19 @@
+module UnpackStrategy
+  class Cab
+    include UnpackStrategy
+
+    def self.can_extract?(path:, magic_number:)
+      magic_number.match?(/\A(MSCF|MZ)/n)
+    end
+
+    def extract_to_dir(unpack_dir, basename:, verbose:)
+      system_command! "cabextract",
+                      args: ["-d", unpack_dir, "--", path],
+                      env: { "PATH" => PATH.new(Formula["cabextract"].opt_bin, ENV["PATH"]) }
+    end
+
+    def dependencies
+      @dependencies ||= [Formula["cabextract"]]
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/dmg.rb b/Library/Homebrew/unpack_strategy/dmg.rb
new file mode 100644
index 0000000000..1068c93486
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/dmg.rb
@@ -0,0 +1,158 @@
+require "tempfile"
+
+module UnpackStrategy
+  class Dmg
+    include UnpackStrategy
+
+    module Bom
+      DMG_METADATA = Set.new %w[
+        .background
+        .com.apple.timemachine.donotpresent
+        .com.apple.timemachine.supported
+        .DocumentRevisions-V100
+        .DS_Store
+        .fseventsd
+        .MobileBackups
+        .Spotlight-V100
+        .TemporaryItems
+        .Trashes
+        .VolumeIcon.icns
+      ].freeze
+      private_constant :DMG_METADATA
+
+      refine Pathname do
+        def dmg_metadata?
+          DMG_METADATA.include?(cleanpath.ascend.to_a.last.to_s)
+        end
+
+        # symlinks to system directories (commonly to /Applications)
+        def system_dir_symlink?
+          symlink? && MacOS.system_dir?(readlink)
+        end
+
+        def bom
+          # We need to use `find` here instead of Ruby in order to properly handle
+          # file names containing special characters, such as “e” + “´” vs. “é”.
+          system_command("find", args: [".", "-print0"], chdir: self, print_stderr: false)
+            .stdout
+            .split("\0")
+            .reject { |path| Pathname(path).dmg_metadata? }
+            .reject { |path| (self/path).system_dir_symlink? }
+            .join("\n")
+        end
+      end
+    end
+    private_constant :Bom
+
+    using Bom
+
+    class Mount
+      include UnpackStrategy
+
+      def eject
+        tries ||= 3
+
+        return unless path.exist?
+
+        if tries > 1
+          system_command! "diskutil",
+                          args: ["eject", path],
+                          print_stderr: false
+        else
+          system_command! "diskutil",
+                          args: ["unmount", "force", path],
+                          print_stderr: false
+        end
+      rescue ErrorDuringExecution => e
+        raise e if (tries -= 1).zero?
+        sleep 1
+        retry
+      end
+
+      private
+
+      def extract_to_dir(unpack_dir, basename:, verbose:)
+        Tempfile.open(["", ".bom"]) do |bomfile|
+          bomfile.close
+
+          Tempfile.open(["", ".list"]) do |filelist|
+            filelist.puts(path.bom)
+            filelist.close
+
+            system_command! "mkbom", args: ["-s", "-i", filelist.path, "--", bomfile.path]
+          end
+
+          system_command! "ditto", args: ["--bom", bomfile.path, "--", path, unpack_dir]
+        end
+      end
+    end
+    private_constant :Mount
+
+    def self.can_extract?(path:, magic_number:)
+      imageinfo = system_command("hdiutil",
+                                 args: ["imageinfo", path],
+                                 print_stderr: false).stdout
+
+      !imageinfo.empty?
+    end
+
+    private
+
+    def extract_to_dir(unpack_dir, basename:, verbose:)
+      mount(verbose: verbose) do |mounts|
+        raise "No mounts found in '#{path}'; perhaps it is a bad disk image?" if mounts.empty?
+
+        mounts.each do |mount|
+          mount.extract(to: unpack_dir)
+        end
+      end
+    end
+
+    def mount(verbose: false)
+      Dir.mktmpdir do |mount_dir|
+        mount_dir = Pathname(mount_dir)
+
+        without_eula = system_command("hdiutil",
+                                      args: ["attach", "-plist", "-nobrowse", "-readonly", "-noidme", "-mountrandom", mount_dir, path],
+                                      input: "qn\n",
+                                      print_stderr: false)
+
+        # If mounting without agreeing to EULA succeeded, there is none.
+        plist = if without_eula.success?
+          without_eula.plist
+        else
+          cdr_path = mount_dir/path.basename.sub_ext(".cdr")
+
+          system_command!("hdiutil", args: ["convert", "-quiet", "-format", "UDTO", "-o", cdr_path, path])
+
+          with_eula = system_command!(
+            "/usr/bin/hdiutil",
+            args: ["attach", "-plist", "-nobrowse", "-readonly", "-noidme", "-mountrandom", mount_dir, cdr_path],
+          )
+
+          if verbose && !(eula_text = without_eula.stdout).empty?
+            ohai "Software License Agreement for '#{path}':"
+            puts eula_text
+          end
+
+          with_eula.plist
+        end
+
+        mounts = if plist.respond_to?(:fetch)
+          plist.fetch("system-entities", [])
+               .map { |entity| entity["mount-point"] }
+               .compact
+               .map { |path| Mount.new(path) }
+        else
+          []
+        end
+
+        begin
+          yield mounts
+        ensure
+          mounts.each(&:eject)
+        end
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/executable.rb b/Library/Homebrew/unpack_strategy/executable.rb
new file mode 100644
index 0000000000..85964fcd06
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/executable.rb
@@ -0,0 +1,17 @@
+require_relative "uncompressed"
+
+require "vendor/macho/macho"
+
+module UnpackStrategy
+  class Executable < Uncompressed
+    def self.can_extract?(path:, magic_number:)
+      return true if magic_number.match?(/\A#!\s*\S+/n)
+
+      begin
+        path.file? && MachO.open(path).header.executable?
+      rescue MachO::NotAMachOError
+        false
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/fossil.rb b/Library/Homebrew/unpack_strategy/fossil.rb
index e72908c401..49b480ceab 100644
--- a/Library/Homebrew/unpack_strategy/fossil.rb
+++ b/Library/Homebrew/unpack_strategy/fossil.rb
@@ -7,7 +7,7 @@ module UnpackStrategy
 
       # Fossil database is made up of artifacts, so the `artifact` table must exist.
       query = "select count(*) from sqlite_master where type = 'view' and name = 'artifact'"
-      Utils.popen_read("sqlite3", path, query).to_i == 1
+      system_command("sqlite3", args: [path, query]).stdout.to_i == 1
     end
 
     private
@@ -19,9 +19,10 @@ module UnpackStrategy
         []
       end
 
-      with_env "PATH" => PATH.new(Formula["fossil"].opt_bin, ENV["PATH"]) do
-        safe_system "fossil", "open", path, *args, chdir: unpack_dir
-      end
+      system_command! "fossil",
+                      args: ["open", path, *args],
+                      chdir: unpack_dir,
+                      env: { "PATH" => PATH.new(Formula["fossil"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/generic_unar.rb b/Library/Homebrew/unpack_strategy/generic_unar.rb
new file mode 100644
index 0000000000..3b11df94a4
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/generic_unar.rb
@@ -0,0 +1,21 @@
+module UnpackStrategy
+  class GenericUnar
+    include UnpackStrategy
+
+    def self.can_extract?(path:, magic_number:)
+      false
+    end
+
+    def dependencies
+      @dependencies ||= [Formula["unar"]]
+    end
+
+    private
+
+    def extract_to_dir(unpack_dir, basename:, verbose:)
+      system_command! "unar",
+                      args: ["-force-overwrite", "-quiet", "-no-directory", "-output-directory", unpack_dir, "--", path],
+                      env: { "PATH" => PATH.new(Formula["unar"].opt_bin, ENV["PATH"]) }
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/gzip.rb b/Library/Homebrew/unpack_strategy/gzip.rb
index e83feccfe3..6ae5517603 100644
--- a/Library/Homebrew/unpack_strategy/gzip.rb
+++ b/Library/Homebrew/unpack_strategy/gzip.rb
@@ -11,7 +11,8 @@ module UnpackStrategy
     def extract_to_dir(unpack_dir, basename:, verbose:)
       FileUtils.cp path, unpack_dir/basename, preserve: true
       quiet_flags = verbose ? [] : ["-q"]
-      safe_system "gunzip", *quiet_flags, "-N", unpack_dir/basename
+      system_command! "gunzip",
+                      args: [*quiet_flags, "-N", "--", unpack_dir/basename]
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/lha.rb b/Library/Homebrew/unpack_strategy/lha.rb
index b5d7f8b16b..9f71e75613 100644
--- a/Library/Homebrew/unpack_strategy/lha.rb
+++ b/Library/Homebrew/unpack_strategy/lha.rb
@@ -13,7 +13,9 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system Formula["lha"].opt_bin/"lha", "xq2w=#{unpack_dir}", path
+      system_command! "lha",
+                      args: ["xq2w=#{unpack_dir}", path],
+                      env: { "PATH" => PATH.new(Formula["lha"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/lzip.rb b/Library/Homebrew/unpack_strategy/lzip.rb
index 5454423269..21200c556d 100644
--- a/Library/Homebrew/unpack_strategy/lzip.rb
+++ b/Library/Homebrew/unpack_strategy/lzip.rb
@@ -15,7 +15,9 @@ module UnpackStrategy
     def extract_to_dir(unpack_dir, basename:, verbose:)
       FileUtils.cp path, unpack_dir/basename, preserve: true
       quiet_flags = verbose ? [] : ["-q"]
-      safe_system Formula["lzip"].opt_bin/"lzip", "-d", *quiet_flags, unpack_dir/basename
+      system_command! "lzip",
+                      args: ["-d", *quiet_flags, unpack_dir/basename],
+                      env: { "PATH" => PATH.new(Formula["lzip"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/lzma.rb b/Library/Homebrew/unpack_strategy/lzma.rb
new file mode 100644
index 0000000000..f759b0cb66
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/lzma.rb
@@ -0,0 +1,21 @@
+module UnpackStrategy
+  class Lzma
+    include UnpackStrategy
+
+    def self.can_extract?(path:, magic_number:)
+      magic_number.match?(/\A\]\000\000\200\000/n)
+    end
+
+    def extract_to_dir(unpack_dir, basename:, verbose:)
+      FileUtils.cp path, unpack_dir/basename, preserve: true
+      quiet_flags = verbose ? [] : ["-q"]
+      system_command! "unlzma",
+                      args: [*quiet_flags, "--", unpack_dir/basename],
+                      env: { "PATH" => PATH.new(Formula["xz"].opt_bin, ENV["PATH"]) }
+    end
+
+    def dependencies
+      @dependencies ||= [Formula["xz"]]
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/mercurial.rb b/Library/Homebrew/unpack_strategy/mercurial.rb
index 8f71fdc95e..518878fdb2 100644
--- a/Library/Homebrew/unpack_strategy/mercurial.rb
+++ b/Library/Homebrew/unpack_strategy/mercurial.rb
@@ -9,9 +9,9 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      with_env "PATH" => PATH.new(Formula["mercurial"].opt_bin, ENV["PATH"]) do
-        safe_system "hg", "--cwd", path, "archive", "--subrepos", "-y", "-t", "files", unpack_dir
-      end
+      system_command! "hg",
+                      args: ["--cwd", path, "archive", "--subrepos", "-y", "-t", "files", unpack_dir],
+                      env: { "PATH" => PATH.new(Formula["mercurial"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/otf.rb b/Library/Homebrew/unpack_strategy/otf.rb
new file mode 100644
index 0000000000..f8f4ee531f
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/otf.rb
@@ -0,0 +1,9 @@
+require_relative "uncompressed"
+
+module UnpackStrategy
+  class Otf < Uncompressed
+    def self.can_extract?(path:, magic_number:)
+      magic_number.match?(/\AOTTO/n)
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/p7zip.rb b/Library/Homebrew/unpack_strategy/p7zip.rb
index c299756601..4a8d7d093b 100644
--- a/Library/Homebrew/unpack_strategy/p7zip.rb
+++ b/Library/Homebrew/unpack_strategy/p7zip.rb
@@ -13,7 +13,9 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system "7zr", "x", "-y", "-bd", "-bso0", path, "-o#{unpack_dir}"
+      system_command! "7zr",
+                      args: ["x", "-y", "-bd", "-bso0", path, "-o#{unpack_dir}"],
+                      env: { "PATH" => PATH.new(Formula["p7zip"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/pkg.rb b/Library/Homebrew/unpack_strategy/pkg.rb
new file mode 100644
index 0000000000..dceee1ef56
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/pkg.rb
@@ -0,0 +1,10 @@
+require_relative "uncompressed"
+
+module UnpackStrategy
+  class Pkg < Uncompressed
+    def self.can_extract?(path:, magic_number:)
+      path.extname.match?(/\A.m?pkg\Z/) &&
+        (path.directory? || magic_number.match?(/\Axar!/n))
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/rar.rb b/Library/Homebrew/unpack_strategy/rar.rb
index 326caeffe0..d7ecbbf64a 100644
--- a/Library/Homebrew/unpack_strategy/rar.rb
+++ b/Library/Homebrew/unpack_strategy/rar.rb
@@ -13,7 +13,9 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system Formula["unrar"].opt_bin/"unrar", "x", "-inul", path, unpack_dir
+      system_command! "unrar",
+                      args: ["x", "-inul", path, unpack_dir],
+                      env: { "PATH" => PATH.new(Formula["unrar"].opt_bin, ENV["PATH"]) }
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/self_extracting_executable.rb b/Library/Homebrew/unpack_strategy/self_extracting_executable.rb
new file mode 100644
index 0000000000..a7de316716
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/self_extracting_executable.rb
@@ -0,0 +1,13 @@
+require_relative "generic_unar"
+
+module UnpackStrategy
+  class SelfExtractingExecutable < GenericUnar
+    def self.can_extract?(path:, magic_number:)
+      return false unless magic_number.match?(/\AMZ/n)
+
+      system_command("file",
+                     args: [path],
+                     print_stderr: false).stdout.include?("self-extracting")
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/sit.rb b/Library/Homebrew/unpack_strategy/sit.rb
new file mode 100644
index 0000000000..48098bb8cb
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/sit.rb
@@ -0,0 +1,9 @@
+require_relative "generic_unar"
+
+module UnpackStrategy
+  class Sit < GenericUnar
+    def self.can_extract?(path:, magic_number:)
+      magic_number.match?(/\AStuffIt/n)
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/subversion.rb b/Library/Homebrew/unpack_strategy/subversion.rb
index a1937183b1..02599f01e2 100644
--- a/Library/Homebrew/unpack_strategy/subversion.rb
+++ b/Library/Homebrew/unpack_strategy/subversion.rb
@@ -9,7 +9,7 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system "svn", "export", "--force", path, unpack_dir
+      system_command! "svn", args: ["export", "--force", path, unpack_dir]
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/tar.rb b/Library/Homebrew/unpack_strategy/tar.rb
index a8865ec3e9..704e3890f4 100644
--- a/Library/Homebrew/unpack_strategy/tar.rb
+++ b/Library/Homebrew/unpack_strategy/tar.rb
@@ -14,7 +14,7 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system "tar", "xf", path, "-C", unpack_dir
+      system_command! "tar", args: ["xf", path, "-C", unpack_dir]
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/ttf.rb b/Library/Homebrew/unpack_strategy/ttf.rb
new file mode 100644
index 0000000000..8d1421a106
--- /dev/null
+++ b/Library/Homebrew/unpack_strategy/ttf.rb
@@ -0,0 +1,12 @@
+require_relative "uncompressed"
+
+module UnpackStrategy
+  class Ttf < Uncompressed
+    def self.can_extract?(path:, magic_number:)
+      # TrueType Font
+      magic_number.match?(/\A\000\001\000\000\000/n) ||
+        # Truetype Font Collection
+        magic_number.match?(/\Attcf/n)
+    end
+  end
+end
diff --git a/Library/Homebrew/unpack_strategy/xar.rb b/Library/Homebrew/unpack_strategy/xar.rb
index c78233f4f5..b631aba77d 100644
--- a/Library/Homebrew/unpack_strategy/xar.rb
+++ b/Library/Homebrew/unpack_strategy/xar.rb
@@ -9,7 +9,7 @@ module UnpackStrategy
     private
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
-      safe_system "xar", "-x", "-f", path, "-C", unpack_dir
+      system_command! "xar", args: ["-x", "-f", path, "-C", unpack_dir]
     end
   end
 end
diff --git a/Library/Homebrew/unpack_strategy/xz.rb b/Library/Homebrew/unpack_strategy/xz.rb
index a629de237b..c7f418cede 100644
--- a/Library/Homebrew/unpack_strategy/xz.rb
+++ b/Library/Homebrew/unpack_strategy/xz.rb
@@ -15,7 +15,9 @@ module UnpackStrategy
     def extract_to_dir(unpack_dir, basename:, verbose:)
       FileUtils.cp path, unpack_dir/basename, preserve: true
       quiet_flags = verbose ? [] : ["-q"]
-      safe_system Formula["xz"].opt_bin/"unxz", *quiet_flags, "-T0", unpack_dir/basename
+      system_command! "unxz",
+                      args: [*quiet_flags, "-T0", "--", unpack_dir/basename],
+                      env: { "PATH" => PATH.new(Formula["xz"].opt_bin, ENV["PATH"]) }
       extract_nested_tar(unpack_dir)
     end
 
diff --git a/Library/Homebrew/unpack_strategy/zip.rb b/Library/Homebrew/unpack_strategy/zip.rb
index c5544a30c8..df3a0c1220 100644
--- a/Library/Homebrew/unpack_strategy/zip.rb
+++ b/Library/Homebrew/unpack_strategy/zip.rb
@@ -10,7 +10,7 @@ module UnpackStrategy
 
     def extract_to_dir(unpack_dir, basename:, verbose:)
       quiet_flags = verbose ? [] : ["-qq"]
-      safe_system "unzip", *quiet_flags, path, "-d", unpack_dir
+      system_command! "unzip", args: [*quiet_flags, path, "-d", unpack_dir]
     end
   end
 end