Issue #19742 has been updated by janosch-x (Janosch Müller).
`#permanent?` is not very descriptive IMO. If I hadn't seen the code above, or the C
code with that vocabulary, I would have a hard time guessing what its about. I'd
probably guess it has to do with GC or so.
As seen in Xavier Noria's example, the word `anonymous` also does not cover *all* the
ways in which a `Module#name` can become useless or wrong.
Then again, it might be really rare that people need to differentiate between the
const-override case and say, classical anonymous modules or removed consts. So maybe it is
not worth it to leak these subtleties to end users and the slightly imprecise `anonymous`
is fine. A short and precise name that covers all cases is hard to find. Something like
`#assigned_to_original_const?` doesn't exactly roll off the tongue...
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Feature #19742: Introduce `Module#anonymous?`
https://bugs.ruby-lang.org/issues/19742#change-103636
* 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
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