git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@23337 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r23190 from trunk into ruby_1_9_1.¶
fail if bytes are invalid. [ruby-dev:38307]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@23337 b2dd03c8-39d4-4d8f-98ff-823fe69b080e