Issue #7844 has been updated by mame (Yusuke Endoh). matz (Yukihiro Matsumoto) wrote: > I believe the behavior is undefined (or implementation defined) when module dependency has contradiction. > And preferably error should be raised when contradiction detected. Thank you, I agree with the policy. However, is there any 'contradiction' in this case? No pair of these dependencies conflicts. There are no cycles. Actually, they are satisfiable. A solution can be found by using the topological sorting. -- Yusuke Endoh <mame / tsg.ne.jp> ---------------------------------------- Bug #7844: include/prepend satisfiable module dependencies are not satisfied https://bugs.ruby-lang.org/issues/7844#change-36239 Author: mame (Yusuke Endoh) Status: Assigned Priority: Normal Assignee: matz (Yukihiro Matsumoto) Category: Target version: next minor ruby -v: ruby 2.0.0dev (2013-02-13 trunk 39225) [x86_64-linux] Hello, module P def m; puts "P"; super; end end module Q def m; puts "Q"; super; end include P end module R def m; puts "R"; super; end prepend Q end module S def m; puts "S"; super; end include R end class A def m; puts "A"; super; end prepend P include S end A.new.m #=> P, R, A, S, Q This code has five module dependencies, but only two are satisfied. - Q includes P, which is not satisfied: P#m precedes Q#m. - R prepends Q, which is not satisfied: R#m precedes Q#m. - S includes R, which is not satisfied: R#m precedes S#m. - A prepends P, which is satisfied: P#m precedes A#m. - A includes S, which is satisfied: A#m precedes S#m. Note that all the dependencies can be satisfied at all: A.new.m #=> Q, P, A, S, R -- Yusuke Endoh <mame / tsg.ne.jp> -- http://bugs.ruby-lang.org/