Bug #17344: `Ractor#shareable?` confused by recursive structures

• Status: Closed
• Assignee: ko1 (Koichi Sasada)
• Target version: 3.0
• ruby -v: ruby 3.0.0dev (2020-11-26T00:37:38Z master af80df1820) [x86_64-darwin17]
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN

[marcandre (Marc-Andre Lafortune)]

y = []; x = [y, {}].freeze; y << x; y.freeze
Ractor.shareable?(y) # => false, ok, the `{}` is not frozen
Ractor.shareable?(x) # => false, ok
Ractor.shareable?(y) # => true, not ok!

The error is that we can not mark anything as shareable until the whole tree has been searched successfully. Only when the full traversal is successful, then all visited objects can be marked as shareable. There might be a more clever way, but I couldn't think of one when working on my backport.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|930a135524382ddd80c0608a7593b6cdfceee846.

---

Fixed Ractor.shareable? on cross-recursive objects [Bug #17344]

[marcandre (Marc-Andre Lafortune)]

Thanks Nobu.

Same issue was still present with Ractor.make_shareable, which I fixed in https://github.com/ruby/ruby/pull/3827

Please let me know if I missed something.