Improve Xcode and CLT config reporting

We support three configurations: Xcode-only, CLT-only, and Xcode with
CLT. Our configuration output should correctly reflect this.

While MacOS::Xcode.version has to continue to return a guess if Xcode is
not installed in order to maintain backwards compatibility, this is an
implementation detail that we don't need to expose to the user. And it
makes `brew --config` output confusing.

So let's only print the "Xcode" line when an actual Xcode installation
is present. This makes it easy to quickly figure out which of the three
possible configurations the user is running.

Addresses Homebrew/homebrew#14941, more or less.

2 files changed, 26 insertions, 24 deletions

diff --git a/Library/Homebrew/cmd/--config.rb b/Library/Homebrew/cmd/--config.rb
index 1781d33a7..342d837f0 100644
--- a/Library/Homebrew/cmd/--config.rb
+++ b/Library/Homebrew/cmd/--config.rb
@@ -29,24 +29,22 @@ module Homebrew extend self
     @clang_build ||= MacOS.clang_build_version
   end
 
-  def describe_xcode
-    @describe_xcode ||= begin
-      default_prefix = case MacOS.version
-        when 10.5, 10.6 then '/Developer'
-        else '/Applications/Xcode.app/Contents/Developer'
-        end
-
-      guess = '(guessed)' unless MacOS::Xcode.installed?
-      prefix = if MacOS::Xcode.installed?
-        "=> #{MacOS::Xcode.prefix}" unless MacOS::Xcode.prefix.to_s == default_prefix
-      end
-
-      [MacOS::Xcode.version, guess, prefix].compact.join(' ')
+  def xcode
+    if instance_variable_defined?(:@xcode)
+      @xcode
+    elsif MacOS::Xcode.installed?
+      @xcode = MacOS::Xcode.version
+      @xcode += " => #{MacOS::Xcode.prefix}" unless MacOS::Xcode.default_prefix?
+      @xcode
     end
   end
 
-  def describe_clt
-    @describe_clt ||= if MacOS::CLT.installed? then MacOS::CLT.version else 'N/A' end
+  def clt
+    if instance_variable_defined?(:@clt)
+      @clt
+    elsif MacOS::CLT.installed? && MacOS::Xcode.version.to_f >= 4.3
+      @clt = MacOS::CLT.version
+    end
   end
 
   def head
@@ -95,8 +93,8 @@ module Homebrew extend self
     puts "HOMEBREW_CELLAR: #{HOMEBREW_CELLAR}" if HOMEBREW_CELLAR.to_s != "#{HOMEBREW_PREFIX}/Cellar"
     puts hardware
     puts "OS X: #{MACOS_FULL_VERSION}-#{kernel}"
-    puts "Xcode: #{describe_xcode}"
-    puts "CLT: #{describe_clt}" if MacOS::Xcode.version.to_f >= 4.3
+    puts "Xcode: #{xcode}" if xcode
+    puts "CLT: #{clt}" if clt
     puts "/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby:\n  #{RUBY_VERSION}-#{RUBY_PATCHLEVEL}" if RUBY_VERSION.to_f != 1.8
 
     unless MacOS.compilers_standard?
@@ -127,8 +125,8 @@ module Homebrew extend self
     puts "HOMEBREW_CELLAR: #{HOMEBREW_CELLAR}"
     puts hardware
     puts "OS X: #{MACOS_FULL_VERSION}-#{kernel}"
-    puts "Xcode: #{describe_xcode}"
-    puts "CLT: #{describe_clt}\n" if MacOS::Xcode.version.to_f >= 4.3
+    puts "Xcode: #{xcode}" if xcode
+    puts "CLT: #{clt}" if clt
     puts "GCC-4.0: build #{gcc_40}" if gcc_40
     puts "GCC-4.2: build #{gcc_42}" if gcc_42
     puts "LLVM-GCC: #{llvm ? "build #{llvm}" : "N/A"}"
@@ -147,11 +145,7 @@ module Homebrew extend self
     print MACOS_FULL_VERSION
     print "-#{kernel}" if MacOS.version < :lion
     print ' '
-    if MacOS::Xcode.version > "4.3"
-      print MacOS::Xcode.prefix unless MacOS::Xcode.prefix.to_s =~ %r{^/Applications/Xcode.app}
-    else
-      print MacOS::Xcode.prefix unless MacOS::Xcode.prefix.to_s =~ %r{^/Developer}
-    end
+    print MacOS::Xcode.prefix unless MacOS::Xcode.default_prefix?
     print "#{MacOS::Xcode.version}"
     print "-noclt" unless MacOS::CLT.installed?
     print " clang-#{clang_build} llvm-#{llvm} "
diff --git a/Library/Homebrew/macos/xcode.rb b/Library/Homebrew/macos/xcode.rb
index 3640f1a68..ab297f2c5 100644
--- a/Library/Homebrew/macos/xcode.rb
+++ b/Library/Homebrew/macos/xcode.rb
@@ -147,6 +147,14 @@ module MacOS::Xcode extend self
   def provides_gcc?
     version.to_f < 4.3
   end
+
+  def default_prefix?
+    if version.to_f < 4.3
+      %r{^/Developer} === prefix
+    else
+      %r{^/Applications/Xcode.app} === prefix
+    end
+  end
 end
 
 module MacOS::CLT extend self