Issue #20317 has been updated by tenderlovemaking (Aaron Patterson). jeremyevans0 (Jeremy Evans) wrote in #note-1:
The current behavior may be what you want if you want to ensure that new instances of the class have `#initialize` called on them. I suppose you could switch to making `allocate` private, but that still would allow for `send(:allocate)`.
If we disallow `.new` if `.allocate` is undefined, should we also disallow `#dup` and `#clone`, both of which also need to allocate an object?
I think that makes sense. For example if you wanted to ensure a particular instance is a singleton: ```ruby class Foo; end singleton = Foo.new Foo.singleton_class.undef_method(:allocate) # now there can only be one instance of `Foo` as new / allocate / dup / clone will raise ``` ---------------------------------------- Feature #20317: Removing the `allocate` method should cause `new` to fail https://bugs.ruby-lang.org/issues/20317#change-107104 * Author: tenderlovemaking (Aaron Patterson) * Status: Open ---------------------------------------- When you remove the `allocate` method from a class the you can't allocate the class via the `allocate` method. However, you _can_ allocate the class via the `new` method: ```ruby class Foo; end Foo.singleton_class.undef_method(:allocate) begin Foo.allocate # doesn't work, of course rescue NoMethodError end begin Class.instance_method(:allocate).bind_call(Foo) # also doesn't work rescue TypeError end Foo.new # works? ``` I think that when we remove the `allocate` method, the `new` method should also fail as there is no `allocate` method for `new` to call. -- https://bugs.ruby-lang.org/