Move remaining OS extensions to prepend

Library/Homebrew/development_tools.rb

@@ -177,7 +177,6 @@ class DevelopmentTools
         "cpu_family" => Hardware::CPU.family.to_s,
       }
     end
-    alias generic_build_system_info build_system_info
   end
 end
 

Library/Homebrew/extend/os/linux/cleanup.rbi

@@ -0,0 +1,5 @@
+# typed: strict
+
+# module OS::Linux::Cleanup
+#   include Kernel
+# end

Library/Homebrew/extend/os/linux/dependency_collector.rb

@@ -1,17 +1,15 @@
-# typed: true # rubocop:disable Sorbet/StrictSigil
+# typed: strict
 # frozen_string_literal: true
 
 require "os/linux/glibc"
 
-class DependencyCollector
+module OS
-  undef gcc_dep_if_needed
+  module Linux
-  undef glibc_dep_if_needed
+    module DependencyCollector
-  undef init_global_dep_tree_if_needed!
-
       sig { params(related_formula_names: T::Set[String]).returns(T.nilable(Dependency)) }
       def gcc_dep_if_needed(related_formula_names)
         # gcc is required for libgcc_s.so.1 if glibc or gcc are too old
-    return unless DevelopmentTools.needs_build_formulae?
+        return unless ::DevelopmentTools.needs_build_formulae?
         return if building_global_dep_tree?
         return if related_formula_names.include?(GCC)
         return if global_dep_tree[GCC]&.intersect?(related_formula_names)
@@ -22,7 +20,7 @@ class DependencyCollector
 
       sig { params(related_formula_names: T::Set[String]).returns(T.nilable(Dependency)) }
       def glibc_dep_if_needed(related_formula_names)
-    return unless DevelopmentTools.needs_libc_formula?
+        return unless ::DevelopmentTools.needs_libc_formula?
         return if building_global_dep_tree?
         return if related_formula_names.include?(GLIBC)
         return if global_dep_tree[GLIBC]&.intersect?(related_formula_names)
@@ -38,7 +36,7 @@ class DependencyCollector
 
       sig { void }
       def init_global_dep_tree_if_needed!
-    return unless DevelopmentTools.needs_build_formulae?
+        return unless ::DevelopmentTools.needs_build_formulae?
         return if building_global_dep_tree?
         return unless global_dep_tree.empty?
 
@@ -51,15 +49,15 @@ class DependencyCollector
 
       sig { params(name: String).returns(T.nilable(Formula)) }
       def formula_for(name)
-    @formula_for ||= {}
+        @formula_for ||= T.let({}, T.nilable(T::Hash[String, Formula]))
-    @formula_for[name] ||= Formula[name]
+        @formula_for[name] ||= ::Formula[name]
       rescue FormulaUnavailableError
         nil
       end
 
       sig { params(name: String).returns(T::Array[String]) }
       def global_deps_for(name)
-    @global_deps_for ||= {}
+        @global_deps_for ||= T.let({}, T.nilable(T::Hash[String, T::Array[String]]))
         # Always strip out glibc and gcc from all parts of dependency tree when
         # we're calculating their dependency trees. Other parts of Homebrew will
         # catch any circular dependencies.
@@ -75,8 +73,8 @@ class DependencyCollector
       # Use class variables to avoid this expensive logic needing to be done more
       # than once.
       # rubocop:disable Style/ClassVars
-  @@global_dep_tree = {}
+      @@global_dep_tree = T.let({}, T::Hash[String, T::Set[String]])
-  @@building_global_dep_tree = false
+      @@building_global_dep_tree = T.let(false, T::Boolean)
 
       sig { returns(T::Hash[String, T::Set[String]]) }
       def global_dep_tree
@@ -98,4 +96,8 @@ class DependencyCollector
         @@building_global_dep_tree.present?
       end
       # rubocop:enable Style/ClassVars
+    end
+  end
 end
+
+DependencyCollector.prepend(OS::Linux::DependencyCollector)

Library/Homebrew/extend/os/linux/development_tools.rb

@@ -1,15 +1,22 @@
-# typed: true # rubocop:todo Sorbet/StrictSigil
+# typed: strict
 # frozen_string_literal: true
 
-class DevelopmentTools
+module OS
-  class << self
+  module Linux
+    module DevelopmentTools
+      extend T::Helpers
+
+      requires_ancestor { ::DevelopmentTools }
+
       sig { params(tool: T.any(String, Symbol)).returns(T.nilable(Pathname)) }
       def locate(tool)
-      (@locate ||= {}).fetch(tool) do |key|
+        @locate ||= T.let({}, T.nilable(T::Hash[T.any(String, Symbol), Pathname]))
-        @locate[key] = if needs_build_formulae? &&
+        @locate.fetch(tool) do |key|
+          @locate[key] = if ::DevelopmentTools.needs_build_formulae? &&
                             (binutils_path = HOMEBREW_PREFIX/"opt/binutils/bin/#{tool}").executable?
             binutils_path
-        elsif needs_build_formulae? && (glibc_path = HOMEBREW_PREFIX/"opt/glibc/bin/#{tool}").executable?
+          elsif ::DevelopmentTools.needs_build_formulae? &&
+                (glibc_path = HOMEBREW_PREFIX/"opt/glibc/bin/#{tool}").executable?
             glibc_path
           elsif (homebrew_path = HOMEBREW_PREFIX/"bin/#{tool}").executable?
             homebrew_path
@@ -20,35 +27,38 @@ class DevelopmentTools
       end
 
       sig { returns(Symbol) }
-    def default_compiler
+      def default_compiler = :gcc
-      :gcc
-    end
 
       sig { returns(T::Boolean) }
       def needs_libc_formula?
-      return @needs_libc_formula if defined? @needs_libc_formula
+        return @needs_libc_formula unless @needs_libc_formula.nil?
 
-      @needs_libc_formula = OS::Linux::Glibc.below_ci_version?
+        @needs_libc_formula = T.let(OS::Linux::Glibc.below_ci_version?, T.nilable(T::Boolean))
+        @needs_libc_formula = !!@needs_libc_formula
       end
 
       sig { returns(T::Boolean) }
       def needs_compiler_formula?
-      return @needs_compiler_formula if defined? @needs_compiler_formula
+        return @needs_compiler_formula unless @needs_compiler_formula.nil?
 
         gcc = "/usr/bin/gcc"
-      @needs_compiler_formula = if File.exist?(gcc)
+        @needs_compiler_formula = T.let(if File.exist?(gcc)
-        gcc_version(gcc) < OS::LINUX_GCC_CI_VERSION
+                                          ::DevelopmentTools.gcc_version(gcc) < OS::LINUX_GCC_CI_VERSION
                                         else
                                           true
-      end
+        end, T.nilable(T::Boolean))
+        !!@needs_compiler_formula
       end
 
       sig { returns(T::Hash[String, T.nilable(String)]) }
       def build_system_info
-      generic_build_system_info.merge({
+        super.merge({
           "glibc_version"     => OS::Linux::Glibc.version.to_s.presence,
           "oldest_cpu_family" => Hardware.oldest_cpu.to_s,
         })
       end
     end
+  end
 end
+
+DevelopmentTools.singleton_class.prepend(OS::Linux::DevelopmentTools)

Library/Homebrew/extend/os/linux/diagnostic.rb

@@ -7,10 +7,13 @@ require "hardware"
 require "os/linux/glibc"
 require "os/linux/kernel"
 
-module Homebrew
+module OS
+  module Linux
     module Diagnostic
-    class Checks
+      module Checks
-      undef fatal_preinstall_checks, supported_configuration_checks
+        extend T::Helpers
+
+        requires_ancestor { Homebrew::Diagnostic::Checks }
 
         def fatal_preinstall_checks
           %w[
@@ -142,7 +145,7 @@ module Homebrew
         end
 
         def check_gcc_dependent_linkage
-        gcc_dependents = Formula.installed.select do |formula|
+          gcc_dependents = ::Formula.installed.select do |formula|
             next false unless formula.tap&.core_tap?
 
             # FIXME: This includes formulae that have no runtime dependency on GCC.
@@ -171,4 +174,7 @@ module Homebrew
         end
       end
     end
+  end
 end
+
+Homebrew::Diagnostic::Checks.prepend(OS::Linux::Diagnostic::Checks)

Library/Homebrew/extend/os/linux/formula.rb

@@ -28,7 +28,7 @@ module OS
 
       sig { params(spec: SoftwareSpec).void }
       def add_global_deps_to_spec(spec)
-        return unless DevelopmentTools.needs_build_formulae?
+        return unless ::DevelopmentTools.needs_build_formulae?
 
         @global_deps ||= begin
           dependency_collector = spec.dependency_collector

Library/Homebrew/extend/os/linux/simulate_system.rb

@@ -1,15 +1,12 @@
-# typed: true # rubocop:disable Sorbet/StrictSigil
+# typed: strict
 # frozen_string_literal: true
 
-module Homebrew
+module OS
-  class SimulateSystem
+  module Linux
-    class << self
+    module SimulateSystem
-      undef os
-      undef simulating_or_running_on_linux?
-      undef current_os
-
       sig { returns(T.nilable(Symbol)) }
       def os
+        @os ||= T.let(nil, T.nilable(Symbol))
         return :macos if @os.blank? && Homebrew::EnvConfig.simulate_macos_on_linux?
 
         @os
@@ -27,3 +24,5 @@ module Homebrew
     end
   end
 end
+
+Homebrew::SimulateSystem.singleton_class.prepend(OS::Linux::SimulateSystem)

Library/Homebrew/extend/os/mac/cleanup.rb

@@ -8,7 +8,7 @@ module OS
       def use_system_ruby?
         return false if Homebrew::EnvConfig.force_vendor_ruby?
 
-        Homebrew::EnvConfig.developer? && ENV["HOMEBREW_USE_RUBY_FROM_PATH"].present?
+        ::Homebrew::EnvConfig.developer? && ENV["HOMEBREW_USE_RUBY_FROM_PATH"].present?
       end
     end
   end

Library/Homebrew/extend/os/mac/dependency_collector.rb

@@ -1,10 +1,9 @@
 # typed: true # rubocop:disable Sorbet/StrictSigil
 # frozen_string_literal: true
 
-class DependencyCollector
+module OS
-  undef git_dep_if_needed, subversion_dep_if_needed, cvs_dep_if_needed,
+  module Mac
-        xz_dep_if_needed, unzip_dep_if_needed, bzip2_dep_if_needed
+    module DependencyCollector
-
       def git_dep_if_needed(tags); end
 
       def subversion_dep_if_needed(tags)
@@ -20,4 +19,8 @@ class DependencyCollector
       def unzip_dep_if_needed(tags); end
 
       def bzip2_dep_if_needed(tags); end
+    end
+  end
 end
+
+DependencyCollector.prepend(OS::Mac::DependencyCollector)

Library/Homebrew/extend/os/mac/development_tools.rb

@@ -1,18 +1,20 @@
-# typed: true # rubocop:disable Sorbet/StrictSigil
+# typed: strict
 # frozen_string_literal: true
 
 require "os/mac/xcode"
 
-class DevelopmentTools
+module OS
-  class << self
+  module Mac
-    alias generic_locate locate
+    module DevelopmentTools
-    undef installed?, default_compiler, curl_handles_most_https_certificates?,
+      extend T::Helpers
-          subversion_handles_most_https_certificates?
+
+      requires_ancestor { ::DevelopmentTools }
 
       sig { params(tool: T.any(String, Symbol)).returns(T.nilable(Pathname)) }
       def locate(tool)
-      (@locate ||= {}).fetch(tool) do |key|
+        @locate ||= T.let({}, T.nilable(T::Hash[T.any(String, Symbol), Pathname]))
-        @locate[key] = if (located_tool = generic_locate(tool))
+        @locate.fetch(tool) do |key|
+          @locate[key] = if (located_tool = super(tool))
             located_tool
           else
             path = Utils.popen_read("/usr/bin/xcrun", "-no-cache", "-find", tool, err: :close).chomp
@@ -35,15 +37,15 @@ class DevelopmentTools
       end
 
       sig { returns(Version) }
-    def ld64_version
+      def self.ld64_version
-      @ld64_version ||= begin
+        @ld64_version ||= T.let(begin
           json = Utils.popen_read("/usr/bin/ld", "-version_details")
           if $CHILD_STATUS.success?
             Version.parse(JSON.parse(json)["version"])
           else
             Version::NULL
           end
-      end
+        end, T.nilable(Version))
       end
 
       sig { returns(T::Boolean) }
@@ -80,7 +82,10 @@ class DevelopmentTools
           "clt"            => MacOS::CLT.version.to_s.presence,
           "preferred_perl" => MacOS.preferred_perl_version,
         }
-      generic_build_system_info.merge build_info
+        super.merge build_info
+      end
     end
   end
 end
+
+DevelopmentTools.singleton_class.prepend(OS::Mac::DevelopmentTools)

Library/Homebrew/extend/os/mac/diagnostic.rb

@@ -1,7 +1,8 @@
 # typed: true # rubocop:disable Sorbet/StrictSigil
 # frozen_string_literal: true
 
-module Homebrew
+module OS
+  module Mac
     module Diagnostic
       class Volumes
         def initialize
@@ -41,10 +42,10 @@ module Homebrew
         end
       end
 
-    class Checks
+      module Checks
-      undef fatal_preinstall_checks, fatal_build_from_source_checks,
+        extend T::Helpers
-            fatal_setup_build_environment_checks, supported_configuration_checks,
+
-            build_from_source_checks
+        requires_ancestor { Homebrew::Diagnostic::Checks }
 
         def fatal_preinstall_checks
           checks = %w[
@@ -52,7 +53,7 @@ module Homebrew
           ]
 
           # We need the developer tools for `codesign`.
-        checks << "check_for_installed_developer_tools" if Hardware::CPU.arm?
+          checks << "check_for_installed_developer_tools" if ::Hardware::CPU.arm?
 
           checks.freeze
         end
@@ -91,7 +92,7 @@ module Homebrew
         end
 
         def check_for_non_prefixed_findutils
-        findutils = Formula["findutils"]
+          findutils = ::Formula["findutils"]
           return unless findutils.any_version_installed?
 
           gnubin = %W[#{findutils.opt_libexec}/gnubin #{findutils.libexec}/gnubin]
@@ -206,7 +207,7 @@ module Homebrew
 
           <<~EOS
             Xcode alone is not sufficient on #{MacOS.version.pretty_name}.
-          #{DevelopmentTools.installation_instructions}
+            #{::DevelopmentTools.installation_instructions}
           EOS
         end
 
@@ -307,7 +308,7 @@ module Homebrew
 
           if gettext&.linked_keg&.directory?
             allowlist = ["#{HOMEBREW_CELLAR}/gettext"]
-          if Hardware::CPU.physical_cpu_arm64?
+            if ::Hardware::CPU.physical_cpu_arm64?
               allowlist += %W[
                 #{HOMEBREW_MACOS_ARM_DEFAULT_PREFIX}/Cellar/gettext
                 #{HOMEBREW_DEFAULT_PREFIX}/Cellar/gettext
@@ -403,7 +404,7 @@ module Homebrew
         end
 
         def check_if_supported_sdk_available
-        return unless DevelopmentTools.installed?
+          return unless ::DevelopmentTools.installed?
           return unless MacOS.sdk_root_needed?
           return if MacOS.sdk
 
@@ -464,4 +465,7 @@ module Homebrew
         end
       end
     end
+  end
 end
+
+Homebrew::Diagnostic::Checks.prepend(OS::Mac::Diagnostic::Checks)

Library/Homebrew/extend/os/mac/extend/ENV/shared.rb

@@ -37,6 +37,6 @@ module SharedEnvExtension
     # This is supported starting Xcode 13, which ships ld64-711.
     # https://developer.apple.com/documentation/xcode-release-notes/xcode-13-release-notes
     # https://en.wikipedia.org/wiki/Xcode#Xcode_11.0_-_14.x_(since_SwiftUI_framework)_2
-    DevelopmentTools.ld64_version >= 711
+    OS::Mac::DevelopmentTools.ld64_version >= 711
   end
 end

Library/Homebrew/extend/os/mac/extend/ENV/std.rb

@@ -1,8 +1,12 @@
 # typed: true # rubocop:disable Sorbet/StrictSigil
 # frozen_string_literal: true
 
-module Stdenv
+module OS
-  undef homebrew_extra_pkg_config_paths
+  module Mac
+    module Stdenv
+      extend T::Helpers
+
+      requires_ancestor { ::Stdenv }
 
       sig { returns(T::Array[Pathname]) }
       def homebrew_extra_pkg_config_paths
@@ -12,7 +16,7 @@ module Stdenv
 
       sig {
         params(
-      formula:         T.nilable(Formula),
+          formula:         T.nilable(::Formula),
           cc:              T.nilable(String),
           build_bottle:    T.nilable(T::Boolean),
           bottle_arch:     T.nilable(String),
@@ -20,8 +24,8 @@ module Stdenv
           debug_symbols:   T.nilable(T::Boolean),
         ).void
       }
-  def setup_build_environment(formula: nil, cc: nil, build_bottle: false, bottle_arch: nil, testing_formula: false,
+      def setup_build_environment(formula: nil, cc: nil, build_bottle: false, bottle_arch: nil,
-                              debug_symbols: false)
+                                  testing_formula: false, debug_symbols: false)
         generic_setup_build_environment(formula:, cc:, build_bottle:, bottle_arch:,
                                         testing_formula:, debug_symbols:)
 
@@ -114,4 +118,8 @@ module Stdenv
       def no_fixup_chains
         append "LDFLAGS", "-Wl,-no_fixup_chains" if no_fixup_chains_support?
       end
+    end
+  end
 end
+
+Stdenv.prepend(OS::Mac::Stdenv)

Library/Homebrew/extend/os/mac/extend/ENV/super.rb

@@ -1,29 +1,26 @@
 # typed: true # rubocop:disable Sorbet/StrictSigil
 # frozen_string_literal: true
 
-module Superenv
+module OS
-  class << self
+  module Mac
+    module Superenv
+      extend T::Helpers
+
+      requires_ancestor { ::Superenv }
+
+      module ClassMethods
         # The location of Homebrew's shims on macOS.
         def shims_path
           HOMEBREW_SHIMS_PATH/"mac/super"
         end
 
-    undef bin
-
         def bin
-      return unless DevelopmentTools.installed?
+          return unless ::DevelopmentTools.installed?
 
           shims_path.realpath
         end
       end
 
-  undef homebrew_extra_pkg_config_paths,
-        homebrew_extra_isystem_paths, homebrew_extra_library_paths,
-        homebrew_extra_cmake_include_paths,
-        homebrew_extra_cmake_library_paths,
-        homebrew_extra_cmake_frameworks_paths,
-        determine_cccfg
-
       sig { returns(T::Array[Pathname]) }
       def homebrew_extra_pkg_config_paths
         [Pathname("/usr/lib/pkgconfig"), Pathname("#{HOMEBREW_LIBRARY}/Homebrew/os/mac/pkgconfig/#{MacOS.version}")]
@@ -51,7 +48,7 @@ module Superenv
         paths = []
         if compiler == :llvm_clang
           paths << "#{self["HOMEBREW_SDKROOT"]}/usr/lib"
-      paths << Formula["llvm"].opt_lib.to_s
+          paths << ::Formula["llvm"].opt_lib.to_s
         end
         paths << "#{self["HOMEBREW_SDKROOT"]}/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries"
         paths
@@ -66,7 +63,9 @@ module Superenv
       end
 
       def homebrew_extra_cmake_library_paths
-    [Pathname("#{self["HOMEBREW_SDKROOT"]}/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries")]
+        [Pathname(
+          "#{self["HOMEBREW_SDKROOT"]}/System/Library/Frameworks/OpenGL.framework/Versions/Current/Libraries",
+        )]
       end
 
       def homebrew_extra_cmake_frameworks_paths
@@ -83,8 +82,8 @@ module Superenv
       end
 
       # @private
-  def setup_build_environment(formula: nil, cc: nil, build_bottle: false, bottle_arch: nil, testing_formula: false,
+      def setup_build_environment(formula: nil, cc: nil, build_bottle: false, bottle_arch: nil,
-                              debug_symbols: false)
+                                  testing_formula: false, debug_symbols: false)
         sdk = formula ? MacOS.sdk_for_formula(formula) : MacOS.sdk
         is_xcode_sdk = sdk&.source == :xcode
 
@@ -105,7 +104,7 @@ module Superenv
         if deps.none? { |d| d.name == "m4" } &&
            MacOS.active_developer_dir == MacOS::CLT::PKG_PATH &&
            !File.exist?("#{MacOS::CLT::PKG_PATH}/usr/bin/m4") &&
-       (gm4 = DevelopmentTools.locate("gm4").to_s).present?
+           (gm4 = ::DevelopmentTools.locate("gm4").to_s).present?
           self["M4"] = gm4
         end
 
@@ -152,11 +151,13 @@ module Superenv
         no_fixup_chains
 
         # Strip build prefixes from linker where supported, for deterministic builds.
-    append_to_cccfg "o" if DevelopmentTools.ld64_version >= 512
+        append_to_cccfg "o" if OS::Mac::DevelopmentTools.ld64_version >= 512
 
         # Pass `-ld_classic` whenever the linker is invoked with `-dead_strip_dylibs`
         # on `ld` versions that don't properly handle that option.
-    append_to_cccfg "c" if DevelopmentTools.ld64_version >= "1015.7" && DevelopmentTools.ld64_version <= "1022.1"
+        if OS::Mac::DevelopmentTools.ld64_version >= "1015.7" && OS::Mac::DevelopmentTools.ld64_version <= "1022.1"
+          append_to_cccfg "c"
+        end
       end
 
       def no_weak_imports
@@ -166,4 +167,9 @@ module Superenv
       def no_fixup_chains
         append_to_cccfg "f" if no_fixup_chains_support?
       end
+    end
+  end
 end
+
+Superenv.singleton_class.prepend(OS::Mac::Superenv::ClassMethods)
+Superenv.prepend(OS::Mac::Superenv)

Library/Homebrew/extend/os/mac/formula_cellar_checks.rb

@@ -97,7 +97,7 @@ module FormulaCellarChecks
     return unless formula.prefix.directory?
     return if formula.tap&.audit_exception(:flat_namespace_allowlist, formula.name)
 
-    keg = Keg.new(formula.prefix)
+    keg = ::Keg.new(formula.prefix)
     flat_namespace_files = keg.mach_o_files.reject do |file|
       next true unless file.dylib?
 

Library/Homebrew/extend/os/mac/formula_installer.rb

@@ -10,7 +10,7 @@ module OS
 
       sig { params(formula: Formula).returns(T.nilable(T::Boolean)) }
       def fresh_install?(formula)
-        !Homebrew::EnvConfig.developer? && !OS::Mac.version.outdated_release? &&
+        !::Homebrew::EnvConfig.developer? && !OS::Mac.version.outdated_release? &&
           (!installed_as_dependency? || !formula.any_version_installed?)
       end
     end

Library/Homebrew/extend/os/mac/hardware/cpu.rb

@@ -3,10 +3,11 @@
 
 require "macho"
 
-module Hardware
+module OS
-  class CPU
+  module Mac
-    class << self
+    module Hardware
-      undef type, family, features, sse4?
+      module CPU
+        extend T::Helpers
 
         # These methods use info spewed out by sysctl.
         # Look in <mach/machine.h> for decoding info.
@@ -22,9 +23,9 @@ module Hardware
         end
 
         def family
-        if arm?
+          if ::Hardware::CPU.arm?
             arm_family
-        elsif intel?
+          elsif ::Hardware::CPU.intel?
             intel_family
           else
             :dunno
@@ -174,4 +175,7 @@ module Hardware
         end
       end
     end
+  end
 end
+
+Hardware::CPU.singleton_class.prepend(OS::Mac::Hardware::CPU)

Library/Homebrew/extend/os/mac/keg.rb

@@ -23,17 +23,17 @@ class Keg
     GENERIC_MUST_BE_WRITABLE_DIRECTORIES +
     [HOMEBREW_PREFIX/"Frameworks"]
   ).sort.uniq.freeze
+end
 
-  undef binary_executable_or_library_files
+module OS
-
+  module Mac
-  def binary_executable_or_library_files
+    module Keg
-    mach_o_files
+      def binary_executable_or_library_files = mach_o_files
-  end
 
       def codesign_patched_binary(file)
         return if MacOS.version < :big_sur
 
-    unless Hardware::CPU.arm?
+        unless ::Hardware::CPU.arm?
           result = system_command("codesign", args: ["--verify", file], print_stderr: false)
           return unless result.stderr.match?(/invalid signature/i)
         end
@@ -94,8 +94,6 @@ class Keg
         end
       end
 
-  undef prepare_debug_symbols
-
       def prepare_debug_symbols
         binary_executable_or_library_files.each do |file|
           odebug "Extracting symbols #{file}"
@@ -111,8 +109,6 @@ class Keg
         end
       end
 
-  undef consistent_reproducible_symlink_permissions!
-
       # Needed to make symlink permissions consistent on macOS and Linux for
       # reproducible bottles.
       def consistent_reproducible_symlink_permissions!
@@ -120,4 +116,8 @@ class Keg
           File.lchmod 0777, file if file.symlink?
         end
       end
+    end
+  end
 end
+
+Keg.prepend(OS::Mac::Keg)

Library/Homebrew/extend/os/mac/keg_relocate.rb

@@ -1,10 +1,14 @@
 # typed: true # rubocop:disable Sorbet/StrictSigil
 # frozen_string_literal: true
 
-class Keg
+module OS
-  class << self
+  module Mac
-    undef file_linked_libraries
+    module Keg
+      extend T::Helpers
 
+      requires_ancestor { ::Keg }
+
+      module ClassMethods
         def file_linked_libraries(file, string)
           # Check dynamic library linkage. Importantly, do not perform for static
           # libraries, which will falsely report "linkage" to themselves.
@@ -16,8 +20,6 @@ class Keg
         end
       end
 
-  undef relocate_dynamic_linkage
-
       def relocate_dynamic_linkage(relocation)
         mach_o_files.each do |file|
           file.ensure_writable do
@@ -112,10 +114,10 @@ class Keg
       # bad_name relative to the lib directory, so that we can skip the more
       # expensive recursive search if possible.
       def fixed_name(file, bad_name)
-    if bad_name.start_with? PREFIX_PLACEHOLDER
+        if bad_name.start_with? ::Keg::PREFIX_PLACEHOLDER
-      bad_name.sub(PREFIX_PLACEHOLDER, HOMEBREW_PREFIX)
+          bad_name.sub(::Keg::PREFIX_PLACEHOLDER, HOMEBREW_PREFIX)
-    elsif bad_name.start_with? CELLAR_PLACEHOLDER
+        elsif bad_name.start_with? ::Keg::CELLAR_PLACEHOLDER
-      bad_name.sub(CELLAR_PLACEHOLDER, HOMEBREW_CELLAR)
+          bad_name.sub(::Keg::CELLAR_PLACEHOLDER, HOMEBREW_CELLAR)
         elsif (file.dylib? || file.mach_o_bundle?) && (file.dirname/bad_name).exist?
           "@loader_path/#{bad_name}"
         elsif file.mach_o_executable? && (lib/bad_name).exist?
@@ -209,11 +211,11 @@ class Keg
         else
           "/usr/bin/perl#{MacOS.preferred_perl_version}"
         end
-    relocation.add_replacement_pair(:perl, PERL_PLACEHOLDER, perl_path)
+        relocation.add_replacement_pair(:perl, ::Keg::PERL_PLACEHOLDER, perl_path)
 
         if (openjdk = openjdk_dep_name_if_applicable)
           openjdk_path = HOMEBREW_PREFIX/"opt"/openjdk/"libexec/openjdk.jdk/Contents/Home"
-      relocation.add_replacement_pair(:java, JAVA_PLACEHOLDER, openjdk_path.to_s)
+          relocation.add_replacement_pair(:java, ::Keg::JAVA_PLACEHOLDER, openjdk_path.to_s)
         end
 
         relocation
@@ -252,4 +254,9 @@ class Keg
 
         filename.start_with?(HOMEBREW_TEMP.to_s) || filename.start_with?(HOMEBREW_TEMP.realpath.to_s)
       end
+    end
+  end
 end
+
+Keg.singleton_class.prepend(OS::Mac::Keg::ClassMethods)
+Keg.prepend(OS::Mac::Keg)

Library/Homebrew/extend/os/mac/readall.rb

@@ -9,7 +9,7 @@ module OS
       requires_ancestor { Kernel }
 
       sig { params(tap: Tap, os_name: T.nilable(Symbol), arch: T.nilable(Symbol)).returns(T::Boolean) }
-      def valid_casks?(tap, os_name: nil, arch: Hardware::CPU.type)
+      def valid_casks?(tap, os_name: nil, arch: ::Hardware::CPU.type)
         return true if os_name == :linux
 
         current_macos_version = if os_name.is_a?(Symbol)

Library/Homebrew/extend/os/mac/simulate_system.rb

@@ -13,7 +13,7 @@ module OS
 
       sig { returns(Symbol) }
       def current_os
-        Homebrew::SimulateSystem.os || MacOS.version.to_sym
+        ::Homebrew::SimulateSystem.os || MacOS.version.to_sym
       end
     end
   end

Library/Homebrew/extend/os/mac/system_config.rb

@@ -3,20 +3,26 @@
 
 require "system_command"
 
+module OS
+  module Mac
+    module SystemConfig
+      sig { returns(String) }
+      def describe_clang
+        return "N/A" if ::SystemConfig.clang.null?
+
+        clang_build_info = ::SystemConfig.clang_build.null? ? "(parse error)" : ::SystemConfig.clang_build
+        "#{::SystemConfig.clang} build #{clang_build_info}"
+      end
+    end
+  end
+end
+
+SystemConfig.prepend(OS::Mac::SystemConfig)
+
 module SystemConfig
   class << self
     include SystemCommand::Mixin
 
-    undef describe_clang
-
-    sig { returns(String) }
-    def describe_clang
-      return "N/A" if clang.null?
-
-      clang_build_info = clang_build.null? ? "(parse error)" : clang_build
-      "#{clang} build #{clang_build_info}"
-    end
-
     def xcode
       @xcode ||= if MacOS::Xcode.installed?
         xcode = MacOS::Xcode.version.to_s

Library/Homebrew/hardware.rbi

@@ -0,0 +1,9 @@
+# typed: strict
+
+module Hardware
+  class CPU
+    class << self
+      include OS::Mac::Hardware::CPU
+    end
+  end
+end

Library/Homebrew/keg.rbi

@@ -0,0 +1,5 @@
+# typed: strict
+
+class Keg
+  include OS::Mac::Keg
+end

Library/Homebrew/keg_relocate.rb

@@ -210,7 +210,6 @@ class Keg
     # for GNU grep; overridden for BSD grep on OS X
     "-lr"
   end
-  alias generic_recursive_fgrep_args recursive_fgrep_args
 
   def egrep_args
     grep_bin = "grep"

Library/Homebrew/os/mac/sdk.rb

@@ -151,7 +151,7 @@ module OS
           # Xcode.prefix is pretty smart, so let's look inside to find the sdk
           sdk_prefix = "#{Xcode.prefix}/Platforms/MacOSX.platform/Developer/SDKs"
           # Finally query Xcode itself (this is slow, so check it last)
-          sdk_platform_path = Utils.popen_read(DevelopmentTools.locate("xcrun"), "--show-sdk-platform-path").chomp
+          sdk_platform_path = Utils.popen_read(::DevelopmentTools.locate("xcrun"), "--show-sdk-platform-path").chomp
           sdk_prefix = File.join(sdk_platform_path, "Developer", "SDKs") unless File.directory? sdk_prefix
 
           sdk_prefix

Library/Homebrew/os/mac/xcode.rb

@@ -227,7 +227,7 @@ module OS
 
       sig { returns(String) }
       def self.detect_version_from_clang_version
-        version = DevelopmentTools.clang_version
+        version = ::DevelopmentTools.clang_version
 
         return "dunno" if version.null?
 

Library/Homebrew/tab.rb

@@ -87,7 +87,7 @@ class AbstractTab
         "tap"          => nil,
         "tap_git_head" => nil,
       },
-      "built_on"                => DevelopmentTools.generic_build_system_info,
+      "built_on"                => DevelopmentTools.build_system_info,
     }
 
     new(attributes)