Issue #20165 has been updated by luke-gru (Luke Gruber). I sent a fix for this here https://github.com/ruby/ruby/pull/9475. There were other issues with moving as well, it wasn't just for structs. ---------------------------------------- Bug #20165: Ractors moving a Struct breaks beyond the first 3 fields https://bugs.ruby-lang.org/issues/20165#change-106163 * Author: codekitchen (Brian Palmer) * Status: Open * Priority: Normal * ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Experimenting with Ractors on ruby 3.3.0, and I'm seeing a bug where if you move a struct between ractors, all but the first 3 fields are set to nil. ``` ruby Foo = Struct.new(:a,:b,:c,:d,:e,:f) r = Ractor.new { foo = Foo[0,0,0,0,0,0] p foo Ractor.yield(foo, move: true) } p r.take ``` ``` ❯ ruby -v ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23] ❯ ruby rbug.rb rbug.rb:3: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues. #<struct Foo a=0, b=0, c=0, d=0, e=0, f=0> #<struct Foo a=0, b=0, c=0, d=nil, e=nil, f=nil> ``` This seems specific to moving, if I set `move: false` the struct makes it across OK. -- https://bugs.ruby-lang.org/