Ruby

Hopefully this illustrates this small, weird issue a bit more:

fails = 0 a = Object.new # non-shareable value pr_maker = Ractor.current.instance_eval do # instance eval allows make_shareable to work Proc.new do Proc.new do |sym| # line 'x', let's call it. See below. if sym == :eval p 'evaling' eval('a') else p 'not evaling' end end end end PROC = pr_maker.call # so we can access in non-main ractor, we set constant Ractor.make_shareable(PROC) begin PROC.call(:eval) # this gives an error because the proc is now isolated. That's good. It shouldn't be # a SyntaxError, but so far so good. Ruby also sets a flag on the compilation node of line 'x' that it accesses outers. rescue SyntaxError => e fails +=1 if e.message.match?(/can not access variable `a' from isolated Proc/) end p fails # The flag is actually set somewhere during compilation, not on the proc object. If we # make a new proc, the issue stays the same. PROC = pr_maker.call # can't make it shareable now, even though it won't access outers if called without :eval symbol # This error should be during runtime of the proc IMO, not statically on the nodes themselves. Ractor.make_shareable(PROC) # this call fails fails += Ractor.new do fails = 0 begin PROC.call(:no_eval) # We don't reach here, but this should give the same error as above (for now, it's SyntaxError) rescue SyntaxError => e fails +=1 if e.message.match?(/can not access variable `a' from isolated Proc/) end fails end.take fails p fails