Project

General

Profile

Actions

Bug #18243

closed

Ractor.make_shareable does not freeze the receiver of a Proc but allows accessing ivars of it

Added by Eregon (Benoit Daloze) 4 months ago. Updated about 2 months ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Target version:
-
[ruby-core:105573]

Description

class C
  attr_accessor :foo
  def setter_proc
    Ractor.make_shareable(-> v { @foo = v })
  end
end

c = C.new
c.foo = 1
p c
proc = c.setter_proc
p c.frozen?
Ractor.new(proc) { |s| s.call(42) }.take
p c

gives

#<C:0x00007f2a3aae7a98 @foo=1>
false
#<C:0x00007f2a3aae7a98 @foo=42> # BUG

But that must be a bug, it means the non-main Ractor can directly mutate an object from the main Ractor.

I found this while thinking about https://github.com/ruby/ostruct/pull/29/files and
whether Ractor.make_shareable would freeze @table and the OpenStruct instance (I think it needs to).

Repro code for ostruct and changing ostruct.rb to $setter = ::Ractor.make_shareable(setter_proc):

require 'ostruct'

os = OpenStruct.new
os.foo = 1

$setter.call(2)
p os

Ractor.new($setter) { |s| s.call(42) }.take
p os

gives

#<OpenStruct foo=2>
<internal:ractor>:267: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues.
#<OpenStruct foo=42> # BUG

Related issues

Related to Ruby master - Bug #18232: Ractor.make_shareable is broken in code loaded with RubyVM::InstructionSequence.load_from_binaryClosedActions
Related to Ruby master - Feature #18276: `Proc#bind_call(obj)` same as `obj.instance_exec(..., &proc_obj)`RejectedActions
Actions

Also available in: Atom PDF