[ruby-core:114003] [Ruby master Feature#19742] Introduce `Module#anonymous?`

Issue #19742 has been updated by Eregon (Benoit Daloze). Eregon (Benoit Daloze) wrote in #note-27: It would mean on `remove_const` and on `const_set(name, v)` when there was already a constant `name`, to change the name of the old constant if it is a module. And also do so recursively for any constant in that module, i.e., mirroring what we do when we name a module, it also names all module constant of that module. Then I think we could finally trust without exception that a non-anonymous `Module#name` is a valid way to reach that Module. That would be great. ---------------------------------------- Feature #19742: Introduce `Module#anonymous?` https://bugs.ruby-lang.org/issues/19742#change-103661 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- As a follow-on <from https://bugs.ruby-lang.org/issues/19521>gt;, I'd like propose we introduce `Module#anonymous?`. In some situations, like logging/formatting, serialisation/deserialization, debugging or meta-programming, we might like to know if a class is a proper constant or not. However, this brings about some other issues which might need to be discussed. After assigning a constant, then removing it, the internal state of Ruby still believes that the class name is permanent, even thought it's no longer true. e.g. ``` m = Module.new m.anonymous? # true M = m m.anonyomous # false Object.send(:remove_const, :M) M # uninitialized constant M (NameError) m.anonymous? # false ``` Because RCLASS data structure is not updated after the constant is removed, internally the state still has a "permanent class name". I want to use this proposal to discuss this issue and whether there is anything we should do about such behaviour (or even if it's desirable). Proposed PR: https://github.com/ruby/ruby/pull/7966 cc @fxn -- https://bugs.ruby-lang.org/