FormulaInstaller: allow formulae to pass options to deps

Formulae can now pass build options to dependencies. The following
syntax is supported:

  depends_on 'foo' => 'with-bar'
  depends_on 'foo' => ['with-bar', 'with-baz']

If a dependency is already installed but lacks the required build
options, an exception is raised. Eventually we may be able to just stash
the existing keg and reinstall it with the combined set of used_options
and passed options, but enabling that is left for another day.

Library/Homebrew/build_options.rb

@@ -3,7 +3,7 @@ require 'options'
 # This class holds the build-time options defined for a Formula,
 # and provides named access to those options during install.
 class BuildOptions
-  attr_writer :args
+  attr_accessor :args
   include Enumerable
 
   def initialize args

Library/Homebrew/dependencies.rb

@@ -138,7 +138,7 @@ module Dependable
   end
 
   def options
-    tags.reject { |tag| RESERVED_TAGS.include? tag }.map { |tag| '--'+tag.to_s }
+    Options.new((tags - RESERVED_TAGS).map { |o| Option.new(o) })
   end
 end
 
@@ -171,13 +171,24 @@ class Dependency
   end
 
   def to_formula
-    Formula.factory(name)
+    f = Formula.factory(name)
+    # Add this dependency's options to the formula's build args
+    f.build.args = f.build.args.concat(options)
+    f
+  end
+
+  def installed?
+    to_formula.installed?
   end
 
   def requested?
     ARGV.formulae.include?(to_formula) rescue false
   end
 
+  def universal!
+    tags << 'universal' if to_formula.build.has_option? 'universal'
+  end
+
   # Expand the dependencies of f recursively, optionally yielding
   # [f, dep] to allow callers to apply arbitrary filters to the list.
   # The default filter, which is used when a block is not supplied,

Library/Homebrew/formula_installer.rb

@@ -8,6 +8,7 @@ require 'caveats'
 class FormulaInstaller
   attr :f
   attr :tab, true
+  attr :options, true
   attr :show_summary_heading, true
   attr :ignore_deps, true
   attr :show_header, true
@@ -116,20 +117,6 @@ class FormulaInstaller
     end
   end
 
-  def dep_needed? dep
-    dep_f = dep.to_formula
-    if dep_f.installed?
-      # If the dep is already installed, skip it.
-      false
-    elsif install_bottle and dep.build?
-      # We skip build-time deps when installing bottles.
-      false
-    else
-      # Otherwise, we need to install it.
-      true
-    end
-  end
-
   def effective_deps
     @deps ||= begin
       deps = Set.new
@@ -138,15 +125,34 @@ class FormulaInstaller
       # any influential flags (--HEAD, --devel, etc.) the user has passed
       # when we check the installed status.
       requested_deps = f.recursive_dependencies.select do |dep|
-        dep_f = dep.to_formula
-        dep_f.requested? and not dep_f.installed?
+        dep.requested? && !dep.installed?
       end
 
       # Otherwise, we filter these influential flags so that they do not
       # affect installation prefixes and other properties when we decide
       # whether or not the dep is needed.
       necessary_deps = ARGV.filter_for_dependencies do
-        f.recursive_dependencies.select { |d| dep_needed? d }
+        f.recursive_dependencies do |dependent, dep|
+          if dep.optional? || dep.recommended?
+            Dependency.prune unless dependent.build.with?(dep.name)
+          elsif dep.build?
+            Dependency.prune if pour_bottle?
+          end
+
+          dep.universal! if f.build.universal?
+
+          dep_f = dep.to_formula
+          dep_tab = Tab.for_formula(dep)
+          missing = dep.options - dep_tab.used_options
+
+          if dep.installed?
+            if missing.empty?
+              Dependency.prune
+            else
+              raise "#{f} dependency #{dep} not installed with:\n  #{missing*', '}"
+            end
+          end
+        end
       end
 
       deps.merge(requested_deps)
@@ -171,12 +177,14 @@ class FormulaInstaller
 
   def install_dependency dep
     dep_tab = Tab.for_formula(dep)
+    dep_options = dep.options
     dep = dep.to_formula
 
     outdated_keg = Keg.new(dep.linked_keg.realpath) rescue nil
 
     fi = FormulaInstaller.new(dep)
     fi.tab = dep_tab
+    fi.options = dep_options
     fi.ignore_deps = true
     fi.show_header = false
     oh1 "Installing #{f} dependency: #{Tty.green}#{dep}#{Tty.reset}"
@@ -258,7 +266,10 @@ class FormulaInstaller
     # FIXME: enforce the download of the non-bottled package
     # in the spawned Ruby process.
     args << '--build-from-source'
-    args.uniq! # Just in case some dupes were added
+    # Add any options that were passed into this FormulaInstaller instance.
+    # Usually this represents options being passed by a dependent formula.
+    args.concat options
+    args.uniq!
 
     fork do
       begin

Library/Homebrew/test/test_dependency.rb

@@ -1,5 +1,6 @@
 require 'testing_env'
 require 'dependencies'
+require 'options'
 
 class DependableTests < Test::Unit::TestCase
   def setup
@@ -8,7 +9,7 @@ class DependableTests < Test::Unit::TestCase
   end
 
   def test_options
-    assert_equal %w{--foo --bar}.sort, @dep.options.sort
+    assert_equal %w{--foo --bar}.sort, @dep.options.as_flags.sort
   end
 
   def test_interrogation

Library/Homebrew/test/test_dependency_collector.rb

@@ -1,5 +1,6 @@
 require 'testing_env'
 require 'dependencies'
+require 'options'
 require 'extend/set'
 
 module DependencyCollectorTestExtension