Reduce allocations in dependency construction

By always passing around a single, unnested array rather than splatting
and then defensively flattening and compacting things, we can avoid
allocating a bunch of unnecessary arrays. This gives a performance boost
of roughly 4% when enumerating 2500 formulae, and has the side effect of
cleaning up the dependency API.

4 files changed, 11 insertions, 15 deletions

diff --git a/Library/Homebrew/test/test_comparableset.rb b/Library/Homebrew/test/test_comparableset.rb
index ee3f46f93..3e823597c 100644
--- a/Library/Homebrew/test/test_comparableset.rb
+++ b/Library/Homebrew/test/test_comparableset.rb
@@ -17,25 +17,25 @@ class ComparableSetTests < Test::Unit::TestCase
 
   def test_comparison_prefers_larger
     @set << X11Dependency.new
-    @set << X11Dependency.new('x11', '2.6')
+    @set << X11Dependency.new('x11', %w{2.6})
     assert_equal 1, @set.count
-    assert_equal [X11Dependency.new('x11', '2.6')], @set.to_a
+    assert_equal [X11Dependency.new('x11', %w{2.6})], @set.to_a
   end
 
   def test_comparison_does_not_merge_smaller
-    @set << X11Dependency.new('x11', '2.6')
+    @set << X11Dependency.new('x11', %w{2.6})
     @set << X11Dependency.new
     assert_equal 1, @set.count
-    assert_equal [X11Dependency.new('x11', '2.6')], @set.to_a
+    assert_equal [X11Dependency.new('x11', %w{2.6})], @set.to_a
   end
 
   def test_merging_sets
     @set << X11Dependency.new
     @set << Requirement.new
-    reqs = Set.new [X11Dependency.new('x11', '2.6'), Requirement.new]
+    reqs = Set.new [X11Dependency.new('x11', %w{2.6}), Requirement.new]
     assert_same @set, @set.merge(reqs)
 
     assert_equal 2, @set.count
-    assert_equal X11Dependency.new('x11', '2.6'), @set.find {|r| r.is_a? X11Dependency}
+    assert_equal X11Dependency.new('x11', %w{2.6}), @set.find {|r| r.is_a? X11Dependency}
   end
 end
diff --git a/Library/Homebrew/test/test_dependency.rb b/Library/Homebrew/test/test_dependency.rb
index 2eac358e6..0f030afd6 100644
--- a/Library/Homebrew/test/test_dependency.rb
+++ b/Library/Homebrew/test/test_dependency.rb
@@ -20,7 +20,7 @@ end
 
 class DependencyTests < Test::Unit::TestCase
   def test_accepts_single_tag
-    dep = Dependency.new("foo", "bar")
+    dep = Dependency.new("foo", %w{bar})
     assert_equal %w{bar}, dep.tags
   end
 
@@ -30,7 +30,7 @@ class DependencyTests < Test::Unit::TestCase
   end
 
   def test_preserves_symbol_tags
-    dep = Dependency.new("foo", :build)
+    dep = Dependency.new("foo", [:build])
     assert_equal [:build], dep.tags
   end
 
diff --git a/Library/Homebrew/test/test_dependency_collector.rb b/Library/Homebrew/test/test_dependency_collector.rb
index bf2612cfe..e780ed5a3 100644
--- a/Library/Homebrew/test/test_dependency_collector.rb
+++ b/Library/Homebrew/test/test_dependency_collector.rb
@@ -30,7 +30,7 @@ class DependencyCollectorTests < Test::Unit::TestCase
   end
 
   def test_dependency_tags
-    assert Dependency.new('foo', :build).build?
+    assert Dependency.new('foo', [:build]).build?
     assert Dependency.new('foo', [:build, :optional]).optional?
     assert Dependency.new('foo', [:universal]).options.include? '--universal'
     assert_empty Dependency.new('foo').tags
diff --git a/Library/Homebrew/test/test_requirement.rb b/Library/Homebrew/test/test_requirement.rb
index 682ee432e..ccf137e4d 100644
--- a/Library/Homebrew/test/test_requirement.rb
+++ b/Library/Homebrew/test/test_requirement.rb
@@ -3,27 +3,23 @@ require 'requirement'
 
 class RequirementTests < Test::Unit::TestCase
   def test_accepts_single_tag
-    dep = Requirement.new("bar")
+    dep = Requirement.new(%w{bar})
     assert_equal %w{bar}, dep.tags
   end
 
   def test_accepts_multiple_tags
     dep = Requirement.new(%w{bar baz})
     assert_equal %w{bar baz}.sort, dep.tags.sort
-    dep = Requirement.new(*%w{bar baz})
-    assert_equal %w{bar baz}.sort, dep.tags.sort
   end
 
   def test_preserves_symbol_tags
-    dep = Requirement.new(:build)
+    dep = Requirement.new([:build])
     assert_equal [:build], dep.tags
   end
 
   def test_accepts_symbol_and_string_tags
     dep = Requirement.new([:build, "bar"])
     assert_equal [:build, "bar"], dep.tags
-    dep = Requirement.new(:build, "bar")
-    assert_equal [:build, "bar"], dep.tags
   end
 
   def test_dsl_fatal