From: "vo.x (Vit Ondruch)" Date: 2013-02-21T23:49:48+09:00 Subject: [ruby-core:52626] [ruby-trunk - Bug #7897] rubygems 2.0 has an incompatibility about installation of extension libraries if gem package does not contain lib directory Issue #7897 has been updated by vo.x (Vit Ondruch). I guess this regression was introduced in r37016 by dropping this line [1] in mkmf. Not sure what was the intention, since creating directory seems unrelated to the timestamp dependencies IMO [1] https://github.com/ruby/ruby/commit/ba3d6005837aab1815131512ca4918f17ee12d07#L1L2135 ---------------------------------------- Bug #7897: rubygems 2.0 has an incompatibility about installation of extension libraries if gem package does not contain lib directory https://bugs.ruby-lang.org/issues/7897#change-36713 Author: mrkn (Kenta Murata) Status: Open Priority: Urgent Assignee: drbrain (Eric Hodel) Category: lib Target version: 2.0.0 ruby -v: ruby 2.0.0dev (2013-02-08 trunk 39161) [x86_64-darwin11.4.2] Hi, rubygems 2.0 has an incompatibility about installation of extension libraries. If a gem package does not contain lib directory, an extension library file is copied as a file named "lib". You can reproduce this problem by installing msgpack version 0.4.7. -- http://bugs.ruby-lang.org/