Remove more code for Mojave and older

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

@@ -7,11 +7,7 @@ module DevCmd
       module Bottle
         sig { returns(T::Array[String]) }
         def tar_args
-          if MacOS.version >= :catalina
-            ["--no-mac-metadata", "--no-acls", "--no-xattrs"].freeze
-          else
-            [].freeze
-          end
+          ["--no-mac-metadata", "--no-acls", "--no-xattrs"].freeze
         end
 
         sig { params(gnu_tar_formula: Formula).returns(String) }

Library/Homebrew/os/mac.rb

@@ -100,13 +100,6 @@ def self.active_developer_dir
 
     sig { returns(T::Boolean) }
     def self.sdk_root_needed?
-      if MacOS::CLT.installed?
-        # If there's no CLT SDK, return false
-        return false unless MacOS::CLT.provides_sdk?
-        # If the CLT is installed and headers are provided by the system, return false
-        return false unless MacOS::CLT.separate_header_package?
-      end
-
       true
     end
 
@@ -122,7 +115,7 @@ def self.sdk_root_needed?
 
     sig { returns(T.any(CLTSDKLocator, XcodeSDKLocator)) }
     def self.sdk_locator
-      if CLT.installed? && CLT.provides_sdk?
+      if CLT.installed?
         CLT.sdk_locator
       else
         Xcode.sdk_locator

Library/Homebrew/os/mac/sdk.rb

@@ -167,20 +167,11 @@ def source
 
       private
 
-      # While CLT SDKs existed prior to Xcode 10, those packages also
-      # installed a traditional Unix-style header layout and we prefer
-      # using that.
       # As of Xcode 10, the Unix-style headers are installed via a
       # separate package, so we can't rely on their being present.
-      # This will only look up SDKs on Xcode 10 or newer and still
-      # return `nil` SDKs for Xcode 9 and older.
       sig { override.returns(String) }
       def sdk_prefix
-        @sdk_prefix ||= if CLT.provides_sdk?
-          "#{CLT::PKG_PATH}/SDKs"
-        else
-          ""
-        end
+        @sdk_prefix ||= "#{CLT::PKG_PATH}/SDKs"
       end
     end
   end

Library/Homebrew/os/mac/xcode.rb

@@ -205,12 +205,6 @@ def self.detect_version
 
             xcode_version = xcodebuild_output[/Xcode (\d+(\.\d+)*)/, 1]
             return xcode_version if xcode_version
-
-            # Xcode 2.x's xcodebuild has a different version string
-            case xcodebuild_output[/DevToolsCore-(\d+\.\d)/, 1]
-            when "798.0" then return "2.5"
-            when "515.0" then return "2.0"
-            end
           end
         end
 
@@ -226,17 +220,6 @@ def self.detect_version_from_clang_version(version = ::DevelopmentTools.clang_ve
         # simultaneously so workarounds need to apply to both based on their
         # comparable version.
         case version
-        when "6.0.0"  then "6.2"
-        when "6.1.0"  then "6.4"
-        when "7.0.0"  then "7.1"
-        when "7.0.2"  then "7.2.1"
-        when "7.3.0"  then "7.3.1"
-        when "8.0.0"  then "8.2.1"
-        when "8.1.0"  then "8.3.3"
-        when "9.0.0"  then "9.2"
-        when "9.1.0"  then "9.4.1"
-        when "10.0.0" then "10.1"
-        when "10.0.1" then "10.3"
         when "11.0.0" then "11.3.1"
         when "11.0.3" then "11.7"
         when "12.0.0" then "12.4"
@@ -259,6 +242,8 @@ def self.default_prefix?
 
     # Helper module for querying macOS Command Line Tools information.
     module CLT
+      extend Utils::Output::Mixin
+
       # The original Mavericks CLT package ID
       EXECUTABLE_PKG_ID = "com.apple.pkg.CLTools_Executables"
       MAVERICKS_NEW_PKG_ID = "com.apple.pkg.CLTools_Base" # obsolete
@@ -272,12 +257,8 @@ def self.installed?
 
       sig { returns(T::Boolean) }
       def self.separate_header_package?
-        version >= "10" && MacOS.version >= "10.14"
-      end
-
-      sig { returns(T::Boolean) }
-      def self.provides_sdk?
-        version >= "8"
+        odeprecated "MacOS::CLT.separate_header_package?"
+        true
       end
 
       sig { returns(CLTSDKLocator) }

Library/Homebrew/test/os/mac_spec.rb

@@ -24,30 +24,9 @@
       described_class.sdk_path_if_needed
     end
 
-    it "does not call sdk_path on Xcode-and-CLT systems with system headers" do
-      allow(OS::Mac::Xcode).to receive(:installed?).and_return(true)
-      allow(OS::Mac::CLT).to receive_messages(installed?: true, separate_header_package?: false)
-      expect(described_class).not_to receive(:sdk_path)
-      described_class.sdk_path_if_needed
-    end
-
-    it "does not call sdk_path on CLT-only systems with no CLT SDK" do
-      allow(OS::Mac::Xcode).to receive(:installed?).and_return(false)
-      allow(OS::Mac::CLT).to receive_messages(installed?: true, provides_sdk?: false)
-      expect(described_class).not_to receive(:sdk_path)
-      described_class.sdk_path_if_needed
-    end
-
-    it "does not call sdk_path on CLT-only systems with a CLT SDK if the system provides headers" do
-      allow(OS::Mac::Xcode).to receive(:installed?).and_return(false)
-      allow(OS::Mac::CLT).to receive_messages(installed?: true, provides_sdk?: true, separate_header_package?: false)
-      expect(described_class).not_to receive(:sdk_path)
-      described_class.sdk_path_if_needed
-    end
-
-    it "calls sdk_path on CLT-only systems with a CLT SDK if the system does not provide headers" do
+    it "calls sdk_path on CLT-only systems" do
       allow(OS::Mac::Xcode).to receive(:installed?).and_return(false)
-      allow(OS::Mac::CLT).to receive_messages(installed?: true, provides_sdk?: true, separate_header_package?: true)
+      allow(OS::Mac::CLT).to receive_messages(installed?: true)
       expect(described_class).to receive(:sdk_path)
       described_class.sdk_path_if_needed
     end