Issue #21721 has been updated by Eregon (Benoit Daloze). Thanks for the link, that's helpful to discuss this.
So I'd be happy to get rid of all that code.
https://github.com/rails/rails/blob/f5b981e6390a2574e63cf0889c421cdd4e446df0... isn't that complicated. And I think we could move that to concurrent-ruby if you'd like. https://github.com/rails/rails/blob/f5b981e6390a2574e63cf0889c421cdd4e446df0... looks complicated, and this proposal wouldn't help for that AFAIK. byroot (Jean Boussier) wrote in #note-3:
But `Queue` is a much nicer and simpler interface,
The first link seems about the same API as Queue.
and more importantly, is way more performant.
With the BiasableQueue on top I guess it wouldn't make much of a change. ---------------------------------------- Feature #21721: Allow `Queue` and `SizedQueue` to be used as LIFO queues https://bugs.ruby-lang.org/issues/21721#change-115406 * Author: byroot (Jean Boussier) * Status: Open ---------------------------------------- ### Context Since `Queue` and `SizedQueue` gained a proper timeout mechanism, I've been wanting to use them to implement simpler and more efficient connection pools. However for connection pools you ideally want a LIFO queue because it's preferable to checkout the most recently used connection. ### Problem Both `Queue` and `SizedQueue` only support FIFO because you can only enqueue elements at the beginning of the backing array, and only dequeue at the end. `Queue#push` (aliased as `Queue#<<` and `Queue#enq`) calls `Array#unshift` on the backing array and `Queue#pop` (aliased as `Queue#deq` and `Queue#shift`) calls `Array#pop`. Hence it is impossible to use these two classes for anything other than FIFO queues. I tried to use `git blame` to see if there was a justification for this, but I ended up in a git blame loop around May 2000 https://github.com/ruby/ruby/commit/9da4f78db46764be6dae5e7e83ff48cbecb3fb23 ### Feature I'd like to introduce either of two new methods (or both) to allow for LIFO: - A method to dequeue from the beginning of the backing array (`array_shift`). - A method to enqueue from the end of the backing array (`array_push`). A difficulty I have however is that since the common `shift/pop/push` terms are already used with uncommon meaning, it's hard to come up with good names. Ideas welcome. ### Possible alternatives - Define different classes for LIFO queues - But I find that less flexible, and it means exposing new constant names in the global namespace. - Add an initializer argument to define the queue ordering, e.g. `Queue.new([], lifo: true)` - Similarly, I find this less flexible than to decide the order during enqueue/dequeue - Add an argument to `Queue#pop` and `Queue#push`, e.g. `queue.push(element, front: true)`. -- https://bugs.ruby-lang.org/