From: "Dan0042 (Daniel DeLorme) via ruby-core" <ruby-core@...>
Date: 2024-03-04T15:20:17+00:00
Subject: [ruby-core:117051] [Ruby master Feature#20317] Removing the `allocate` method should cause `new` to fail

Issue #20317 has been updated by Dan0042 (Daniel DeLorme).


May I ask what is the use case for this?
The only reason I can think to undefine `allocate` is if you want to allow only a single instance of the class, and in that case `include Singleton` should do the job fine I think.

----------------------------------------
Feature #20317: Removing the `allocate` method should cause `new` to fail
https://bugs.ruby-lang.org/issues/20317#change-107123

* 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.



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