From: "fxn (Xavier Noria)" Date: 2022-01-24T14:11:05+00:00 Subject: [ruby-core:107263] [Ruby master Feature#18273] Class#subclasses Issue #18273 has been updated by fxn (Xavier Noria). > In the sense that, as a programmer, if I do not change the collection, it should stay the same. Of course, removing a subclass is ill-defined and that is the root problem I see here. And in Ruby that makes sense, because the link only went upwards only. On the other hand, `Module#ancestors` can be a linearized cache because there is no API or way to remove ancestors. Ruby doesn't have API/semantics to provide a similar `Class#subclasses`. ---------------------------------------- Feature #18273: Class#subclasses https://bugs.ruby-lang.org/issues/18273#change-96124 * Author: byroot (Jean Boussier) * Status: Closed * Priority: Normal ---------------------------------------- Ref: https://github.com/rails/rails/pull/43481 Something we forgot to mention in [Feature #14394], is either a parameter or another method to only get direct descendants. Active Support has been offering `Class.subclasses` as: ```ruby def subclasses descendants.select { |descendant| descendant.superclass == self } end ``` It seems a bit silly to grab all descendants and then restrict the list when `Class#descendants` had to do some recursion to get them all in the first place. ### Proposal We could either implement `Class#subclasses` directly, or accept a parameter in `Class#descendants`, e.g. `descendants(immediate = false)`. cc @eregon -- https://bugs.ruby-lang.org/ Unsubscribe: