From: tagomoris@... Date: 2017-03-02T11:34:41+00:00 Subject: [ruby-core:79871] [Ruby trunk Bug#13257] Symbol#singleton_class should be undef Issue #13257 has been updated by Satoshi TAGOMORI. My motivation is to know whether there is an class/module in ancestors or not. I needed it at this patch: https://github.com/msgpack/msgpack-ruby/pull/132/files The feature implemented in this patch serialize/deserialize objects in a configured format if the object is an kind of registered classes or modules. It should consider about the order of inheritance, so it can't use `#is_a?` method, and it should consider about modules added by `#extend`, so it should check ancestors of singleton classes. ---------------------------------------- Bug #13257: Symbol#singleton_class should be undef https://bugs.ruby-lang.org/issues/13257#change-63304 * Author: Satoshi TAGOMORI * Status: Feedback * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin15] * Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN ---------------------------------------- Objects of some classes doesn't have singleton classes (e.g., Symbol, Integer, Float...). Symbol#singleton_class raises TypeError. But Symbol#respond_to?(:singleton_class) returns true, and we cannot know when #singleton_class returns a valid class or raise errors in any way (except for calling it). I think that such #singleton_class methods should be undef. -- https://bugs.ruby-lang.org/ Unsubscribe: