From: "forthoney (Seong-Heon Jung) via ruby-core" Date: 2023-12-23T01:35:44+00:00 Subject: [ruby-core:115874] [Ruby master Bug#20078] StringIO cannot be moved between Ractors Issue #20078 has been updated by forthoney (Seong-Heon Jung). luke-gru (Luke Gruber) wrote in #note-3: > I think this is due to not currently being able to move any T_DATA objects between ractors. StringIO is defined in a C extension and is a T_DATA object internally. See https://github.com/ruby/ruby/blob/master/ractor.c#L3417C1-L3417C13. This isn't a fundamental limitation (I don't think?), it's just it hasn't been implemented yet. But certain errors could happen, for example if the C extension allows you to move an object to another Ractor, but then uses this same object internally in the original Ractor, maybe it could cause errors. > > The documentation should mention this, without going into too much detail. Something like: > Currently, most types that are implemented in C extensions cannot be moved. I agree. The documentation does mention T_DATA, but does not really mention the implications of being unable to move T_DATA, which is that "most types that are implemented in C extensions cannot be moved". Additionally, I am wondering if it makes sense to make a `Ractor.movable?` module function similar to `Ractor.shareable?` This would greatly save developer time since they can check if a object is movable in IRB rather than having to dig through the source code. ---------------------------------------- Bug #20078: StringIO cannot be moved between Ractors https://bugs.ruby-lang.org/issues/20078#change-105831 * Author: forthoney (Seong-Heon Jung) * Status: Open * Priority: Normal * ruby -v: 3.2 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- The following code will raise an unusual Ractor error. ``` ruby require 'stringio' r = Ractor.new { loop { Ractor.receive } } Ractor.shareable?(StringIO.new) #=> false r.send(StringIO.new) # passing it via copy works r.send(StringIO.new, move: true) # :587:in `send': can not move StringIO object. (Ractor::Error) ``` I'm not 100% sure but I believe that this probably not the intended behavior considering * The error raised is a generic `Ractor::Error` rather than something specific like Ractor::MovedError or Ractor::IsolationError * It can be copied * [No documentation](https://docs.ruby-lang.org/en/master/ractor_md.html) exists for this error * I have yet to seen this happen on any other class instance * Typo (can not -> cannot) -- 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/postorius/lists/ruby-core.ml.ruby-lang.org/