[ruby-core:116259] [Ruby master Feature#19742] Introduce `Module#anonymous?`

Issue #19742 has been updated by Dan0042 (Daniel DeLorme). @ioquatix I think your definition of "permanent" doesn't quite work, semantically. A name can be said to be permanent if doesn't change (even after remove_const for example). What you have there is the opposite; if a module stops being permanent after remove_const, it can't really be said to have been permanent in the first place. Maybe something like `#namespace?` would be a better name for that, in the sense of "this module can currently be used as a namespace". ---------------------------------------- Feature #19742: Introduce `Module#anonymous?` https://bugs.ruby-lang.org/issues/19742#change-106280 * 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/