Replace CompilerQueue with predetermined priority lists

Library/Homebrew/compilers.rb

@@ -68,74 +68,65 @@ class CompilerFailure
   }
 end
 
-class CompilerQueue
-  def initialize
-    @array = []
-  end
-
-  def <<(o)
-    @array << o
-    self
-  end
-
-  def pop
-    @array.delete(@array.max { |a, b| a.priority <=> b.priority })
-  end
-
-  def empty?
-    @array.empty?
-  end
-end
-
 class CompilerSelector
-  Compiler = Struct.new(:name, :version, :priority)
+  include CompilerConstants
 
-  attr_reader :formula
+  Compiler = Struct.new(:name, :version)
 
-  def initialize(formula, versions=MacOS)
+  COMPILER_PRIORITY = {
+    :clang   => [:clang, :gcc, :llvm, :gnu, :gcc_4_0],
+    :gcc     => [:gcc, :llvm, :gnu, :clang, :gcc_4_0],
+    :llvm    => [:llvm, :gcc, :gnu, :clang, :gcc_4_0],
+    :gcc_4_0 => [:gcc_4_0, :gcc, :llvm, :gnu, :clang],
+  }
+
+  def self.select_for(formula)
+    compilers = COMPILER_PRIORITY.fetch(MacOS.default_compiler)
+    new(formula, MacOS, compilers).compiler
+  end
+
+  attr_reader :formula, :failures, :versions, :compilers
+
+  def initialize(formula, versions, compilers)
     @formula = formula
     @failures = formula.compiler_failures
     @versions = versions
-    @compilers = CompilerQueue.new
-    %w{clang llvm gcc gcc_4_0}.map(&:to_sym).each do |cc|
-      version = @versions.send("#{cc}_build_version")
-      unless version.nil?
-        @compilers << Compiler.new(cc, version, priority_for(cc))
-      end
+    @compilers = compilers
   end
 
-    # non-Apple GCC 4.x
-    CompilerConstants::GNU_GCC_VERSIONS.each do |v|
-      name = "gcc-4.#{v}"
-      version = @versions.non_apple_gcc_version(name)
-      unless version.nil?
-        # priority is based on version, with newest preferred first
-        @compilers << Compiler.new(name, version, 1.0 + v/10.0)
-      end
-    end
-  end
-
-  # Attempts to select an appropriate alternate compiler, but
-  # if none can be found raises CompilerError instead
   def compiler
-    while cc = @compilers.pop
-      return cc.name unless fails_with?(cc)
-    end
+    find_compiler { |c| return c.name unless fails_with?(c) }
     raise CompilerSelectionError.new(formula)
   end
 
   private
 
-  def fails_with?(compiler)
-    @failures.any? { |failure| failure === compiler }
+  def find_compiler
+    compilers.each do |compiler|
+      case compiler
+      when :gnu
+        GNU_GCC_VERSIONS.reverse_each do |v|
+          name = "gcc-4.#{v}"
+          version = compiler_version(name)
+          yield Compiler.new(name, version) if version
+        end
+      else
+        version = compiler_version(compiler)
+        yield Compiler.new(compiler, version) if version
+      end
+    end
   end
 
-  def priority_for(cc)
-    case cc
-    when :clang   then @versions.clang_build_version >= 318 ? 3 : 0.5
-    when :gcc     then 2.5
-    when :llvm    then 2
-    when :gcc_4_0 then 0.25
+  def fails_with?(compiler)
+    failures.any? { |failure| failure === compiler }
+  end
+
+  def compiler_version(name)
+    case name
+    when GNU_GCC_REGEXP
+      versions.non_apple_gcc_version(name)
+    else
+      versions.send("#{name}_build_version")
     end
   end
 end

Library/Homebrew/extend/ENV/shared.rb

@@ -131,7 +131,7 @@ module SharedEnvExtension
   # an alternate compiler, altering the value of environment variables.
   # If no valid compiler is found, raises an exception.
   def validate_cc!(formula)
-    send CompilerSelector.new(formula).compiler
+    send CompilerSelector.select_for(formula)
   end
 
   # Snow Leopard defines an NCURSES value the opposite of most distros

Library/Homebrew/test/test_compiler_queue.rb

@@ -1,38 +0,0 @@
-require 'testing_env'
-require 'compilers'
-
-class CompilerQueueTests < Homebrew::TestCase
-  FakeCompiler = Struct.new(:name, :priority)
-
-  def setup
-    @q = CompilerQueue.new
-  end
-
-  def test_shovel_returns_self
-    assert_same @q, @q << Object.new
-  end
-
-  def test_empty
-    assert_empty @q
-  end
-
-  def test_queues_items
-    a = FakeCompiler.new(:foo, 0)
-    b = FakeCompiler.new(:bar, 0)
-    @q << a << b
-    assert_equal a, @q.pop
-    assert_equal b, @q.pop
-    assert_nil @q.pop
-  end
-
-  def test_pops_items_by_priority
-    a = FakeCompiler.new(:foo, 0)
-    b = FakeCompiler.new(:bar, 0.5)
-    c = FakeCompiler.new(:baz, 1)
-    @q << a << b << c
-    assert_equal c, @q.pop
-    assert_equal b, @q.pop
-    assert_equal a, @q.pop
-    assert_nil @q.pop
-  end
-end

Library/Homebrew/test/test_compiler_selector.rb

@@ -14,17 +14,18 @@ class CompilerSelectorTests < Homebrew::TestCase
     attr_accessor :gcc_4_0_build_version, :gcc_build_version,
       :llvm_build_version, :clang_build_version
 
-    def initialize(versions={})
-      {
-        :gcc_4_0_build_version => nil,
-        :gcc_build_version     => 5666,
-        :llvm_build_version    => 2336,
-        :clang_build_version   => 425,
-      }.merge(versions).each { |k, v| instance_variable_set("@#{k}", v) }
+    def initialize
+      @gcc_4_0_build_version = nil
+      @gcc_build_version = 5666
+      @llvm_build_version = 2336
+      @clang_build_version = 425
     end
 
     def non_apple_gcc_version(name)
-      name == "gcc-4.8" ? "4.8.1" : nil
+      case name
+      when "gcc-4.8" then "4.8.1"
+      when "gcc-4.7" then "4.7.1"
+      end
     end
   end
 
@@ -32,14 +33,17 @@ class CompilerSelectorTests < Homebrew::TestCase
     @f  = Double.new
     @cc = :clang
     @versions = CompilerVersions.new
+    @selector = CompilerSelector.new(
+      @f, @versions, [:clang, :gcc, :llvm, :gnu]
+    )
   end
 
   def actual_cc
-    CompilerSelector.new(@f, @versions).compiler
+    @selector.compiler
   end
 
   def test_all_compiler_failures
-    @f << :clang << :llvm << :gcc << { :gcc => "4.8" }
+    @f << :clang << :llvm << :gcc << { :gcc => "4.8" } << { :gcc => "4.7" }
     assert_raises(CompilerSelectionError) { actual_cc }
   end
 
@@ -68,17 +72,17 @@ class CompilerSelectorTests < Homebrew::TestCase
   end
 
   def test_mixed_failures_1
+    @f << :clang << :gcc
+    assert_equal :llvm, actual_cc
+  end
+
+  def test_mixed_failures_2
     @f << :clang << :llvm
     assert_equal :gcc, actual_cc
   end
 
-  def test_mixed_failures_2
-    @f << :gcc << :clang << { :gcc => "4.8" }
-    assert_equal :llvm, actual_cc
-  end
-
   def test_mixed_failures_3
-    @f << :llvm << :gcc
+    @f << :gcc << :llvm
     assert_equal :clang, actual_cc
   end
 
@@ -87,10 +91,9 @@ class CompilerSelectorTests < Homebrew::TestCase
     assert_equal :gcc, actual_cc
   end
 
-  def test_older_clang_precedence
-    @versions.clang_build_version = 211
-    @f << :gcc << { :gcc => "4.8" }
-    assert_equal :llvm, actual_cc
+  def test_mixed_failures_5
+    @f << :clang << :gcc << :llvm << { :gcc => "4.8" }
+    assert_equal "gcc-4.7", actual_cc
   end
 
   def test_llvm_precedence
@@ -100,13 +103,13 @@ class CompilerSelectorTests < Homebrew::TestCase
 
   def test_missing_gcc
     @versions.gcc_build_version = nil
-    @f << :clang << :llvm << { :gcc => "4.8" }
+    @f << :clang << :llvm << { :gcc => "4.8" } << { :gcc => "4.7" }
     assert_raises(CompilerSelectionError) { actual_cc }
   end
 
   def test_missing_llvm_and_gcc
     @versions.gcc_build_version = @versions.llvm_build_version = nil
-    @f << :clang << { :gcc => "4.8" }
+    @f << :clang << { :gcc => "4.8" } << { :gcc => "4.7" }
     assert_raises(CompilerSelectionError) { actual_cc }
   end
 end