ostruct.rb: fix OpenStruct.allocate

* lib/ostruct.rb (OpenStruct.allocate): initialize an instance
  variable directly, without calling `intialize` method which may
  be overridden in a subclass.  [ruby-core:80292] [Bug #13358]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58077 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/ostruct.rb

@@ -74,7 +74,10 @@
 #
 class OpenStruct
   class << self # :nodoc:
-    alias allocate new
+    def allocate
+      (x = super).instance_variable_set(:@table, {})
+      x
+    end
   end
 
   #

test/ostruct/test_ostruct.rb

@@ -183,4 +183,13 @@ class TC_OpenStruct < Test::Unit::TestCase
     os.foo = 44
     assert_equal(43, os.foo)
   end
+
+  def test_allocate_subclass
+    bug = '[ruby-core:80292] [Bug #13358] allocate should not call initialize'
+    c = Class.new(OpenStruct) {
+      def initialize(x,y={})super(y);end
+    }
+    os = assert_nothing_raised(ArgumentError, bug) {c.allocate}
+    assert_instance_of(c, os)
+  end
 end