Decouple spec selection from ARGV

Library/Homebrew/build.rb

@@ -40,7 +40,8 @@ def main
   # can be inconvenient for the user. But we need to be safe.
   system "/usr/bin/sudo", "-k"
 
-  Build.new(Formula.factory($0)).install
+  formula = Formulary.factory($0, ARGV.spec)
+  Build.new(formula).install
 rescue Exception => e
   unless error_pipe.nil?
     e.continuation = nil if ARGV.debug?

Library/Homebrew/extend/ARGV.rb

@@ -8,9 +8,8 @@ module HomebrewArgvExtension
   end
 
   def formulae
-    require 'formula'
-    @formulae ||= downcased_unique_named.map{ |name| Formula.factory name }
-    return @formulae
+    require "formula"
+    @formulae ||= downcased_unique_named.map { |name| Formulary.factory(name, spec) }
   end
 
   def kegs
@@ -179,6 +178,16 @@ module HomebrewArgvExtension
     value 'env'
   end
 
+  def spec
+    if include?("--HEAD")
+      :head
+    elsif include?("--devel")
+      :devel
+    else
+      :stable
+    end
+  end
+
   private
 
   def downcased_unique_named

Library/Homebrew/formula.rb

@@ -36,7 +36,7 @@ class Formula
     set_spec :devel
     set_spec :head
 
-    @active_spec = determine_active_spec
+    @active_spec = determine_active_spec(spec)
     validate_attributes :url, :name, :version
     @build = determine_build_options
     @pkg_version = PkgVersion.new(version, revision)
@@ -52,16 +52,9 @@ class Formula
     end
   end
 
-  def determine_active_spec
-    case
-    when head && ARGV.build_head?   then head    # --HEAD
-    when devel && ARGV.build_devel? then devel   # --devel
-    when stable                     then stable
-    when devel                      then devel
-    when head                       then head    # head-only
-    else
-      raise FormulaSpecificationError, "formulae require at least a URL"
-    end
+  def determine_active_spec(requested)
+    spec = send(requested) || stable || devel || head
+    spec or raise FormulaSpecificationError, "formulae require at least a URL"
   end
 
   def validate_attributes(*attrs)

Library/Homebrew/formula_installer.rb

@@ -471,8 +471,11 @@ class FormulaInstaller
     args << "--debug" if debug?
     args << "--cc=#{ARGV.cc}" if ARGV.cc
     args << "--env=#{ARGV.env}" if ARGV.env
-    args << "--HEAD" if ARGV.build_head?
-    args << "--devel" if ARGV.build_devel?
+
+    case f.active_spec
+    when f.head  then args << "--HEAD"
+    when f.devel then args << "--devel"
+    end
 
     f.build.each do |opt, _|
       name  = opt.name[/\A(.+)=\z$/, 1]

Library/Homebrew/test/test_formula.rb

@@ -92,9 +92,7 @@ class FormulaTests < Homebrew::TestCase
   end
 
   def test_installed_prefix_head_active_spec
-    ARGV.stubs(:build_head? => true)
-
-    f = formula do
+    f = formula("test", Pathname.new(__FILE__).expand_path, :head) do
       head 'foo'
       devel do
         url 'foo'
@@ -106,9 +104,7 @@ class FormulaTests < Homebrew::TestCase
   end
 
   def test_installed_prefix_devel_active_spec
-    ARGV.stubs(:build_devel? => true)
-
-    f = formula do
+    f = formula("test", Pathname.new(__FILE__).expand_path, :devel) do
       head 'foo'
       devel do
         url 'foo'
@@ -244,9 +240,7 @@ class FormulaTests < Homebrew::TestCase
   end
 
   def test_head_ignores_revisions
-    ARGV.stubs(:build_head?).returns(true)
-
-    f = formula do
+    f = formula("test", Pathname.new(__FILE__).expand_path, :head) do
       url 'foo-1.0.bar'
       revision 1
       head 'foo'

Library/Homebrew/test/test_formula_spec_selection.rb

@@ -10,30 +10,6 @@ class FormulaSpecSelectionTests < Homebrew::TestCase
     assert_nil @_f.send(spec)
   end
 
-  def test_selects_head_when_requested
-    ARGV.stubs(:build_head?).returns(true)
-
-    formula do
-      url 'foo-1.0'
-      devel { url 'foo-1.1a' }
-      head 'foo'
-    end
-
-    assert_spec_selected :head
-  end
-
-  def test_selects_devel_when_requested
-    ARGV.stubs(:build_devel?).returns(true)
-
-    formula do
-      url 'foo-1.0'
-      devel { url 'foo-1.1a' }
-      head 'foo'
-    end
-
-    assert_spec_selected :devel
-  end
-
   def test_selects_stable_by_default
     formula do
       url 'foo-1.0'
@@ -98,6 +74,26 @@ class FormulaSpecSelectionTests < Homebrew::TestCase
     assert_spec_selected :devel
   end
 
+  def test_selects_head_when_requested
+    formula("test", Pathname.new(__FILE__).expand_path, :head) do
+      url 'foo-1.0'
+      devel { url 'foo-1.1a' }
+      head 'foo'
+    end
+
+    assert_spec_selected :head
+  end
+
+  def test_selects_devel_when_requested
+    formula("test", Pathname.new(__FILE__).expand_path, :devel) do
+      url 'foo-1.0'
+      devel { url 'foo-1.1a' }
+      head 'foo'
+    end
+
+    assert_spec_selected :devel
+  end
+
   def test_incomplete_devel_not_set
     formula do
       url 'foo-1.0'
@@ -108,4 +104,13 @@ class FormulaSpecSelectionTests < Homebrew::TestCase
     assert_spec_unset :devel
     assert_spec_selected :stable
   end
+
+  def test_does_not_raise_for_missing_spec
+    formula("test", Pathname.new(__FILE__).expand_path, :devel) do
+      url 'foo-1.0'
+      head 'foo'
+    end
+
+    assert_spec_selected :stable
+  end
 end