Issue #17506 has been updated by byroot (Jean Boussier). Assignee set to ractor Retested on 3.4.2, and it seems the bug is still present. ---------------------------------------- Bug #17506: Ractor isolation broken by ThreadGroup https://bugs.ruby-lang.org/issues/17506#change-112495 * Author: marcandre (Marc-Andre Lafortune) * Status: Open * Assignee: ractor * ruby -v: ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin18] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- Ractors currently share the ThreadGroup. This doesn't seem very useful as there is no possible communication between the Threads of different Ractors. It is also an isolation error: ```ruby ThreadGroup.attr_accessor :foo var = Thread.current.group.foo = [:example] Ractor.new { Thread.current.group.foo << [:oops] }.take var # => [:example, [:oops]] ``` Should `Ractor.new` create a new `ThreadGroup`? Should `ThreadGroup` not have (non-shareable) instance variables? Or should `Ractor.new { Thread.current.group }.take` be `nil`? See also https://bugs.ruby-lang.org/issues/17505 about `nil`. Note that `Ractor` respects the `ThreadGroup`'s state: ```ruby Thread.current.group.enclose Ractor.new { Thread.current.group.add(Thread.current) }.take # => can't move to the enclosed thread group Thread.current.group.freeze Ractor.new {} # => ThreadError (can't start a new thread (frozen ThreadGroup)) ``` I am not sure what is the best behavior as I don't have enough experience with how ThreadGroups are used, especially enclosed ThreadGroups. -- https://bugs.ruby-lang.org/