[ruby-core:121477] [Ruby Bug#17506] Ractor isolation broken by ThreadGroup
From:
"byroot (Jean Boussier) via ruby-core" <ruby-core@...>
Date:
2025-03-30 09:26:10 UTC
List:
ruby-core #121477
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/
______________________________________________
ruby-core mailing list -- ruby-core@ml.ruby-lang.org
To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org
ruby-core info -- https://ml.ruby-lang.org/mailman3/lists/ruby-core.ml.ruby-lang.org/