From: shibata.hiroshi@... Date: 2014-06-05T06:16:16+00:00 Subject: [ruby-core:62943] [ruby-trunk - Bug #9573] descendants of a module don't gain its future ancestors, but descendants of a class, do Issue #9573 has been updated by Hiroshi SHIBATA. ref. https://github.com/ruby/ruby/pull/549 ---------------------------------------- Bug #9573: descendants of a module don't gain its future ancestors, but descendants of a class, do https://bugs.ruby-lang.org/issues/9573#change-47045 * Author: First Last * Status: Open * Priority: Normal * Assignee: * Category: * Target version: * ruby -v: ruby 2.1.1p76 (2014-02-24 revision 45161) [i686-linux] * Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN ---------------------------------------- ```ruby module Mod1 end module Mod2 end class Class1 end class Class2 < Class1 end p Class2.ancestors - Object.ancestors # [Class2, Class1] Class1.include Mod1 p Class2.ancestors - Object.ancestors # [Class2, Class1, Mod1] Mod1.include Mod2 p Mod1.ancestors - Object.ancestors # [Mod1, Mod2] p Class2.ancestors - Object.ancestors # [Class2, Class1, Mod1] ``` ________________________________________________________________ note that descendants of a class do gain its future ancestors so 2 issues: 1. It would seem natural that in dynamic language, dynamically added ancestors should propagate to descendants 2. Why is there a difference in ancestor propagation between modules and classes -- https://bugs.ruby-lang.org/