Issue #17146 has been updated by mame (Yusuke Endoh). I would like to add a point that came up during the dev meeting: if a thread is waiting for `Queue#pop`, and another thread freezes the Queue, what should the first thread do? Wait forever? Raise a FrozenError? To raise a FrozenError, it needs to be told that the Queue was asynchronously frozen by another thread. In other words, `Queue#freeze` needs to wake up the thread waiting for the Queue, which is likely to do more than `#freeze` would normally be expected to do. ---------------------------------------- Bug #17146: Queue operations are allowed after it is frozen https://bugs.ruby-lang.org/issues/17146#change-104587 * Author: Eregon (Benoit Daloze) * Status: Open * Priority: Normal * ruby -v: ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-linux] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- ``` [1] pry(main)> q = Queue.new => #<Thread::Queue:0x000056263683aee8> [2] pry(main)> q.freeze => #<Thread::Queue:0x000056263683aee8> [3] pry(main)> q << 1 => #<Thread::Queue:0x000056263683aee8> [4] pry(main)> q.pop => 1 [5] pry(main)> q.frozen? => true ``` Found by @ko1 in https://bugs.ruby-lang.org/issues/17100#note-28 I think it's a bug, since those are clear mutations. I guess old Thread::Queue implemented in Ruby did not have this bug. -- https://bugs.ruby-lang.org/