Only merge extended attributes if required

Library/Homebrew/cask/installer.rb

@@ -161,7 +161,7 @@ module Cask
 
     def primary_container
       @primary_container ||= begin
-        UnpackStrategy.detect(@downloaded_path, type: @cask.container&.type)
+        UnpackStrategy.detect(@downloaded_path, type: @cask.container&.type, merge_xattrs: true)
       end
     end
 
@@ -179,7 +179,7 @@ module Cask
 
           FileUtils.chmod_R "+rw", tmpdir/nested_container, force: true, verbose: verbose?
 
-          UnpackStrategy.detect(tmpdir/nested_container)
+          UnpackStrategy.detect(tmpdir/nested_container, merge_xattrs: true)
                         .extract_nestedly(to: @cask.staged_path, verbose: verbose?)
         end
       else

Library/Homebrew/extend/os/mac/unpack_strategy/zip.rb

@@ -2,6 +2,16 @@ module UnpackStrategy
   class Zip
     prepend Module.new {
       def extract_to_dir(unpack_dir, basename:, verbose:)
+        if merge_xattrs && contains_extended_attributes?(path)
+          # We use ditto directly, because dot_clean has issues if the __MACOSX
+          # folder has incorrect permissions.
+          # (Also, Homebrew's ZIP artifact automatically deletes this folder.)
+          return system_command! "ditto",
+                          args:         ["-x", "-k", path, unpack_dir],
+                          verbose:      verbose,
+                          print_stderr: false
+        end
+
         result = begin
           super
         rescue ErrorDuringExecution => e
@@ -13,18 +23,6 @@ module UnpackStrategy
           return
         end
 
-        if contains_extended_attributes?(path)
-          # Merge ._ files back into extended attributes.
-          # We use ditto, because dot_clean has issues if the __MACOSX
-          # folder has incorrect permissions.
-          # (Also, Homebrew's ZIP artifact automatically deletes this folder.)
-          system_command! "ditto",
-                          args:         ["-x", "-k", path, unpack_dir],
-                          verbose:      verbose,
-                          print_stderr: false
-          return
-        end
-
         volumes = result.stderr.chomp
                         .split("\n")
                         .map { |l| l[/\A   skipping: (.+)  volume label\Z/, 1] }

Library/Homebrew/unpack_strategy.rb

@@ -88,7 +88,7 @@ module UnpackStrategy
     strategies.find { |s| s.can_extract?(path) }
   end
 
-  def self.detect(path, prioritise_extension: false, type: nil, ref_type: nil, ref: nil)
+  def self.detect(path, prioritise_extension: false, type: nil, ref_type: nil, ref: nil, merge_xattrs: nil)
     strategy = from_type(type) if type
 
     if prioritise_extension && path.extname.present?
@@ -102,15 +102,16 @@ module UnpackStrategy
 
     strategy ||= Uncompressed
 
-    strategy.new(path, ref_type: ref_type, ref: ref)
+    strategy.new(path, ref_type: ref_type, ref: ref, merge_xattrs: merge_xattrs)
   end
 
-  attr_reader :path
+  attr_reader :path, :merge_xattrs
 
-  def initialize(path, ref_type: nil, ref: nil)
+  def initialize(path, ref_type: nil, ref: nil, merge_xattrs: nil)
     @path = Pathname(path).expand_path
     @ref_type = ref_type
     @ref = ref
+    @merge_xattrs = merge_xattrs
   end
 
   def extract(to: nil, basename: nil, verbose: false)