Issue #19742 has been updated by ioquatix (Samuel Williams). The concepts are discussed in the code, but they shouldn't be assumed as canonical, IMHO. ```c /** * Returns +classpath+ of _klass_, if it is named, or +nil+ for * anonymous +class+/+module+. A named +classpath+ may contain * an anonymous component, but the last component is guaranteed * to not be anonymous. <code>*permanent</code> is set to 1 * if +classpath+ has no anonymous components. There is no builtin * Ruby level APIs that can change a permanent +classpath+. */ static VALUE classname(VALUE klass, bool *permanent) ``` A class/module that is assigned a name via `set_temporary_name` may still be anonymous, so I believe the above comment needs to be updated. In the code, when something is not `permanent`, a `temporary` class path may be generated: ```c static VALUE make_temporary_path(VALUE obj, VALUE klass) { VALUE path; switch (klass) { case Qnil: path = rb_sprintf("#<Class:%p>", (void*)obj); break; case Qfalse: path = rb_sprintf("#<Module:%p>", (void*)obj); break; default: path = rb_sprintf("#<%"PRIsVALUE":%p>", klass, (void*)obj); break; } OBJ_FREEZE(path); return path; } ``` To clarify, the documentation states that when `mod.name == nil`, the `mod` is anonymous. But it does not state that when `mod.name =! nil`, the module is permanent AFAICT. In any case, we should probably clarify this in the documentation. ---------------------------------------- Feature #19742: Introduce `Module#anonymous?` https://bugs.ruby-lang.org/issues/19742#change-103639 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- As a follow-on <from https://bugs.ruby-lang.org/issues/19521>, 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/