[ruby-core:116225] [Ruby master Feature#19742] Introduce `Module#anonymous?`

Issue #19742 has been updated by fxn (Xavier Noria). @ko1 I think that is a good direction, because with the introduction of temporary names as a blessed concept with API and all, I believe there are several matching APIs that may arise. One proposal could be: ``` Module#name -> as it is today Module#temporary_name -> there is a temporary name or nil Module#permanent_name -> there is a permanent name or nil Module#anonymous? -> both temporary and permanent names are nil ``` For example, edges case that test how do we think about this: ``` m = Module.new m.name #=> nil m.temporary_name #=> nil m.permanent_name #=> nil m.anonymous? #=> true m::C = Class.new m::C.name #=> "#<Module:0x0000000102cd4620>::C" m::C.temporary_name #=> "#<Module:0x0000000102cd4620>::C" m::C.permanent_name #=> nil m::C.anonymous? #=> false M = m m::C.name #=> "M::C" m::C.temporary_name #=> nil m::C.permanent_name #=> "M::C" m::C.anonymous? #=> false ``` ---------------------------------------- Feature #19742: Introduce `Module#anonymous?` https://bugs.ruby-lang.org/issues/19742#change-106245 * 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/