[ruby-core:107848] [Ruby master Feature#11547] remove top-level constant lookup

Issue #11547 has been updated by fxn (Xavier Noria).


I do not know which is the correct definition of `const_get`, Ruby core knows :).

However, let me say that I have always thought about `const_get` as what happens during a _relative_ constant lookup. That is, in my mind, a relative constant lookup is basically: 1) Check the nesting + 2) `const_get` (conceptually, and includes `const_missing` if needed).

Take for example:

```ruby
Module.new.const_get(:String) # => String
```

You get `String` there, but it is not in the ancestors. Why? Because it is checking `Object` by hand, like the relative constant lookup algorithm does.

I believe

```ruby
String.const_get(:Hash) # =>
```

has to be understood that way.

----------------------------------------
Feature #11547: remove top-level constant lookup
https://bugs.ruby-lang.org/issues/11547#change-96788

* Author: gucki1 (Corin Langosch)
* Status: Closed
* Priority: Normal
----------------------------------------
If ruby cannot find a class in the specified scope it uses the top-level constant of the same name if it exists and emits a warning:

~~~
irb(main):006:0> class Auth; end
=> nil
irb(main):007:0> class Twitter; end
=> nil
irb(main):008:0> Twitter::Auth
(irb):8: warning: toplevel constant Auth referenced by Twitter::Auth
=> Auth
~~~

In some cases this is not playing nicely with rails autoloading as can be seen here: https://github.com/rails/rails/issues/6931. Many more issues like this exist.

Imo I don't see any reason why this fallback makes any sense. So I'd like to suggest to remove it completely or at least add an option to disable it.





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