separate setup_tar_and_args method

Library/Homebrew/dev-cmd/bottle.rb

@@ -234,30 +234,13 @@ module Homebrew
     system "/usr/bin/sudo", "--non-interactive", "/usr/sbin/purge"
   end
 
-  def setup_tar_and_args!(args, mtime)
+  def setup_tar_and_args!(args, _mtime)
     # Without --only-json-tab bottles are never reproducible
     default_tar_args = ["tar", [].freeze].freeze
     return default_tar_args unless args.only_json_tab?
-
-    # Use gnu-tar on macOS as it can be set up for reproducibility better than libarchive.
-    begin
-      gnu_tar = Formula["gnu-tar"]
-    rescue FormulaUnavailableError
-      return default_tar_args
   end
 
-    ensure_formula_installed!(gnu_tar, reason: "bottling")
+  alias generic_setup_tar_and_args! setup_tar_and_args!
-
-    # Ensure tar is set up for reproducibility.
-    # https://reproducible-builds.org/docs/archives/
-    gnutar_args = [
-      "--format", "pax", "--owner", "0", "--group", "0", "--sort", "name", "--mtime=#{mtime}",
-      # Set exthdr names to exclude PID (for GNU tar <1.33). Also don't store atime and ctime.
-      "--pax-option", "globexthdr.name=/GlobalHead.%n,exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime"
-    ].freeze
-
-    ["#{gnu_tar.opt_bin}/gtar", gnutar_args].freeze
-  end
 
   def formula_ignores(f)
     ignores = []

Library/Homebrew/extend/os/dev-cmd/bottle.rb

@@ -2,3 +2,9 @@
 # frozen_string_literal: true
 
 require "extend/os/linux/dev-cmd/bottle" if OS.linux?
+
+if OS.mac?
+  require "extend/os/mac/dev-cmd/bottle"
+elsif OS.linux?
+  require "extend/os/linux/dev-cmd/bottle"
+end

Library/Homebrew/extend/os/linux/dev-cmd/bottle.rb

@@ -7,9 +7,7 @@ module Homebrew
   module_function
 
   def setup_tar_and_args!(args, mtime)
-    # Without --only-json-tab bottles are never reproducible
+    generic_setup_tar_and_args!(args, mtime)
-    default_tar_args = ["tar", [].freeze].freeze
-    return default_tar_args unless args.only_json_tab?
 
     # Ensure tar is set up for reproducibility.
     # https://reproducible-builds.org/docs/archives/

Library/Homebrew/extend/os/mac/dev-cmd/bottle.rb

@@ -0,0 +1,31 @@
+# typed: false
+# frozen_string_literal: true
+
+module Homebrew
+  extend T::Sig
+
+  module_function
+
+  def setup_tar_and_args!(args, mtime)
+    generic_setup_tar_and_args!(args, mtime)
+
+    # Use gnu-tar on macOS as it can be set up for reproducibility better than libarchive.
+    begin
+      gnu_tar = Formula["gnu-tar"]
+    rescue FormulaUnavailableError
+      return default_tar_args
+    end
+
+    ensure_formula_installed!(gnu_tar, reason: "bottling")
+
+    # Ensure tar is set up for reproducibility.
+    # https://reproducible-builds.org/docs/archives/
+    gnutar_args = [
+      "--format", "pax", "--owner", "0", "--group", "0", "--sort", "name", "--mtime=#{mtime}",
+      # Set exthdr names to exclude PID (for GNU tar <1.33). Also don't store atime and ctime.
+      "--pax-option", "globexthdr.name=/GlobalHead.%n,exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime"
+    ].freeze
+
+    ["#{gnu_tar.opt_bin}/gtar", gnutar_args].freeze
+  end
+end