Don't create MacOS.version multiple times

Library/Homebrew/macos.rb

@@ -5,19 +5,25 @@ module MacOS extend self
   # This can be compared to numerics, strings, or symbols
   # using the standard Ruby Comparable methods.
   def version
-    Version.new(MACOS_VERSION)
+    @version ||= Version.new(MACOS_VERSION)
   end
 
   def cat
-    # PowerPC builds per processor, not per OS
-    return Hardware::CPU.family if Hardware::CPU.type == :ppc
+    @cat ||= uncached_cat
+  end
 
-    if version == :mountain_lion then :mountain_lion
-    elsif version == :lion then :lion
-    elsif version == :snow_leopard
+  def uncached_cat
+    case MacOS.version
+    when 10.8
+      :mountain_lion
+    when 10.7
+      :lion
+    when 10.6
       Hardware.is_64_bit? ? :snow_leopard : :snow_leopard_32
-    elsif version == :leopard then :leopard
-    else nil
+    when 10.5
+      :leopard
+    else
+      Hardware::CPU.family if Hardware::CPU.type == :ppc
     end
   end
 

Library/Homebrew/test/test_version_subclasses.rb

@@ -1,6 +1,7 @@
 require 'testing_env'
 require 'version'
 require 'os/mac/version'
+require 'hardware'
 
 class MacOSVersionTests < Test::Unit::TestCase
   def setup
@@ -39,4 +40,38 @@ class MacOSVersionTests < Test::Unit::TestCase
     assert_operator @v, :===, Version.new(10.7)
     assert_operator @v, :<, Version.new(10.8)
   end
+
+  def test_cat_tiger
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.4))
+    Hardware::CPU.stubs(:type).returns(:ppc)
+    Hardware::CPU.stubs(:family).returns(:foo)
+    assert_equal :foo, MacOS.uncached_cat
+  end
+
+  def test_cat_leopard
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.5))
+    assert_equal :leopard, MacOS.uncached_cat
+  end
+
+  def test_cat_snow_leopard_32
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.6))
+    Hardware.stubs(:is_64_bit?).returns(false)
+    assert_equal :snow_leopard_32, MacOS.uncached_cat
+  end
+
+  def test_cat_snow_leopard_64
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.6))
+    Hardware.stubs(:is_64_bit?).returns(true)
+    assert_equal :snow_leopard, MacOS.uncached_cat
+  end
+
+  def test_cat_lion
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.7))
+    assert_equal :lion, MacOS.uncached_cat
+  end
+
+  def test_cat_mountain_lion
+    MacOS.stubs(:version).returns(MacOS::Version.new(10.8))
+    assert_equal :mountain_lion, MacOS.uncached_cat
+  end
 end