From: eregontp@... Date: 2021-01-16T18:00:35+00:00 Subject: [ruby-core:102115] [Ruby master Bug#17543] Ractor isolation broken by `self` in shareable proc Issue #17543 has been updated by Eregon (Benoit Daloze). marcandre (Marc-Andre Lafortune) wrote in #note-4: > Note that they are *not* treated the same way. `Ractor.new{}` forbids any reference to outside variables, while `make_shareable(proc)` allows it as long as the values are themselves shareable. Yes, Ractor.new{} seems special, but actually it seems like the Ractor.make_shareable() semantics would be more useful, that way some frozen data could be passed directly in the new Ractor. > I agree that is the most obvious, but that makes `Ractor.make_shareable(-> { puts "hello" })` fail, which is far from being useful. In my view, `Ractor.make_shareable` should deeply freeze/share some object graph rooted by some initial object. So I think it should freeze captures and self for a Proc. If it's needed to e.g. `Ractor.make_shareable(self); o = Ractor.make_shareable(Object.new); Ractor.make_shareable(-> { p o; ... })`, it feels so redundant. I think `Ractor.make_shareable` should always succeed, except if it sees a truly unshareable object (e.g., a Mutex). ---------------------------------------- Bug #17543: Ractor isolation broken by `self` in shareable proc https://bugs.ruby-lang.org/issues/17543#change-89971 * Author: marcandre (Marc-Andre Lafortune) * Status: Open * Priority: Normal * Assignee: ko1 (Koichi Sasada) * ruby -v: 3.0.0p0 * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN ---------------------------------------- Discussing with @MaxLap we realized that the `self` in a shareable proc is not properly isolated: ``` class Foo attr_accessor :x def pr Ractor.make_shareable(Proc.new { self }) end end f = Foo.new f.x = [1, 2, 3] Ractor.new(f.pr) { |pr| pr.call.x << :oops } p f.x # => [1, 2, 3, :oops] ``` If the `self` refers to a shareable object then it's fine, but for non-shareable objects it has to be reset to `nil` or to a global shareable object that would have an instructive `inspect`. ```ruby Ractor::DETACHED_SELF = Object.new def << Ractor::DETACHED_SELF def inspect '<#detached self>' end alias to_s inspect end Ractor::DETACHED_SELF.freeze ``` -- https://bugs.ruby-lang.org/ Unsubscribe: