Implement fails_with for non-Apple compilers

This adds support for non-Apple GCC compilers in the fails_with code.
A fails_with block for a non-Apple compiler looks like:

fails_with :gcc => '4.8.1' do
  cause 'Foo'
end

Non-Apple compilers don't have build numbers, so compiler failures are
based on version strings instead.

Internally non-Apple compilers can be distinguished because they are
passed around as strings instead of symbols.

In addition, this alters the priority list for compilers, with the
following changes:

* Apple GCC 4.2 and LLVM-GCC swap positions, with GCC now taking
  priority. (Maybe LLVM-GCC should just go away.)
* Non-Apple GCC compilers are ranked below GCC 4.2 but above LLVM-GCC
  and Apple GCC 4.0.

2 files changed, 43 insertions, 8 deletions

diff --git a/Library/Homebrew/test/test_compiler_selector.rb b/Library/Homebrew/test/test_compiler_selector.rb
index 17c3b0449..5374a5452 100644
--- a/Library/Homebrew/test/test_compiler_selector.rb
+++ b/Library/Homebrew/test/test_compiler_selector.rb
@@ -22,16 +22,29 @@ class CompilerSelectorTests < Test::Unit::TestCase
     MacOS.stubs(:gcc_build_version).returns(5666)
     MacOS.stubs(:llvm_build_version).returns(2336)
     MacOS.stubs(:clang_build_version).returns(425)
+    # Yes, this is ugly - we only want one GCC version to be available.
+    MacOS.send(:alias_method, :old_non_apple_gcc_version, :non_apple_gcc_version)
+    MacOS.send(:define_method, :non_apple_gcc_version) do |name|
+      if name == 'gcc-4.8'
+        '4.8.1'
+      else
+        nil
+      end
+    end
     @f  = Double.new
     @cc = :clang
   end
 
+  def teardown
+    MacOS.send(:alias_method, :non_apple_gcc_version, :old_non_apple_gcc_version)
+  end
+
   def actual_cc
     CompilerSelector.new(@f).compiler
   end
 
   def test_all_compiler_failures
-    @f << :clang << :llvm << :gcc
+    @f << :clang << :llvm << :gcc << 'gcc-4.8'
     assert_raise(CompilerSelectionError) { actual_cc }
   end
 
@@ -41,7 +54,7 @@ class CompilerSelectorTests < Test::Unit::TestCase
 
   def test_fails_with_clang
     @f << :clang
-    assert_equal :llvm, actual_cc
+    assert_equal :gcc, actual_cc
   end
 
   def test_fails_with_llvm
@@ -54,13 +67,18 @@ class CompilerSelectorTests < Test::Unit::TestCase
     assert_equal :clang, actual_cc
   end
 
+  def test_fails_with_non_apple_gcc
+    @f << "gcc-4.8"
+    assert_equal :clang, actual_cc
+  end
+
   def test_mixed_failures_1
     @f << :clang << :llvm
     assert_equal :gcc, actual_cc
   end
 
   def test_mixed_failures_2
-    @f << :gcc << :clang
+    @f << :gcc << :clang << 'gcc-4.8'
     assert_equal :llvm, actual_cc
   end
 
@@ -69,22 +87,32 @@ class CompilerSelectorTests < Test::Unit::TestCase
     assert_equal :clang, actual_cc
   end
 
+  def test_mixed_failures_4
+    @f << :clang << "gcc-4.8"
+    assert_equal :gcc, actual_cc
+  end
+
   def test_older_clang_precedence
     MacOS.stubs(:clang_build_version).returns(211)
-    @f << :gcc
+    @f << :gcc << 'gcc-4.8'
     assert_equal :llvm, actual_cc
   end
 
+  def test_non_apple_gcc_precedence
+    @f << :clang << :gcc
+    assert_equal 'gcc-4.8', actual_cc
+  end
+
   def test_missing_gcc
     MacOS.stubs(:gcc_build_version).returns(nil)
-    @f << :clang << :llvm
+    @f << :clang << :llvm << 'gcc-4.8'
     assert_raise(CompilerSelectionError) { actual_cc }
   end
 
   def test_missing_llvm_and_gcc
     MacOS.stubs(:gcc_build_version).returns(nil)
     MacOS.stubs(:llvm_build_version).returns(nil)
-    @f << :clang
+    @f << :clang << 'gcc-4.8'
     assert_raise(CompilerSelectionError) { actual_cc }
   end
 end
diff --git a/Library/Homebrew/test/test_fails_with.rb b/Library/Homebrew/test/test_fails_with.rb
index 2b344cc3d..31f318a4c 100644
--- a/Library/Homebrew/test/test_fails_with.rb
+++ b/Library/Homebrew/test/test_fails_with.rb
@@ -3,7 +3,7 @@ require 'test/testball'
 
 class FailsWithTests < Test::Unit::TestCase
   class Double < Compiler
-    attr_accessor :name, :build
+    attr_accessor :name, :build, :version
   end
 
   def assert_fails_with(cc)
@@ -18,10 +18,11 @@ class FailsWithTests < Test::Unit::TestCase
     @f.send(:fails_with, *args, &block)
   end
 
-  def build_cc(sym, build)
+  def build_cc(sym, build, version=nil)
     cc = Double.new
     cc.name = sym
     cc.build = build
+    cc.version = version
     cc
   end
 
@@ -47,6 +48,12 @@ class FailsWithTests < Test::Unit::TestCase
     assert_fails_with cc
   end
 
+  def test_non_apple_gcc_version
+    fails_with(:gcc => '4.8.2')
+    cc = build_cc("gcc-4.8", nil, "4.8.1")
+    assert_fails_with cc
+  end
+
   def test_multiple_failures
     fails_with(:llvm)
     fails_with(:clang)