From: "jhawthorn (John Hawthorn) via ruby-dev" <ruby-dev@...>
Date: 2024-03-01T00:38:27+00:00
Subject: [ruby-dev:52076]  [Ruby master Bug#16297] calling undefined allocator by `Class.instance_method(:allocate)`

Issue #16297 has been updated by jhawthorn (John Hawthorn).


I'm not sure if there's a deeper problem this causes, but it is still possible after this patch to call the allocator on a Rational through defining an arbitrary `allocate` method.

``` ruby
>> def Rational.allocate; end
=> :allocate
>> Class.instance_method(:allocate).bind_call(Rational)
=> (0/1)
```

----------------------------------------
Bug #16297: calling undefined allocator by `Class.instance_method(:allocate)`
https://bugs.ruby-lang.org/issues/16297#change-107083

* Author: nobu (Nobuyoshi Nakada)
* Status: Closed
* Backport: 2.5: REQUIRED, 2.6: DONE
----------------------------------------
For instance, `Rational.allocate` is undefined.

```ruby
Rational.allocate #=> undefined method `allocate' for Rational:Class (NoMethodError)
```

But it can be called by `Class.instance_method(:allocate)`.

```ruby
Class.instance_method(:allocate).bind_call(Rational) #=> (0/1)
Class.instance_method(:allocate).bind(Rational).call #=> (0/1)
```

These allocators are defined for Marshal, and undefined as methods.




-- 
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