From: "ed_ (Ed Mangimelli)" <noreply@...>
Date: 2022-03-10T06:12:47+00:00
Subject: [ruby-core:107816] [Ruby master Feature#18618] no clobber def

Issue #18618 has been updated by ed_ (Ed Mangimelli).


@Dan0042 I like that syntax --much more convenient-- but I don't know if it would be useful to me if it were just toggling the existing warning.

But that syntax seems great:
```ruby
class MyClass < LibraryProvidedClass
  no_clobber

  def a; end
  def b; super; end    # no effect (`super` being called) 
  def c; end
  override def d; end  # maybe an override keyword to use in conjunction with `no_clobber`?
end

=> #<MethodAlreadyDefined: Method `c' already defined.>
```

```ruby
class MyClass < LibraryProvidedClass

  def a; end
  no_clobber def b; end  # can also be used in a one-off way like `private`
  def c; end
end
```

----------------------------------------
Feature #18618: no clobber def
https://bugs.ruby-lang.org/issues/18618#change-96746

* Author: ed_ (Ed Mangimelli)
* Status: Open
* Priority: Normal
----------------------------------------
Sometimes I want to be certain I'm not clobbering/masking a method:

```
class Dog
  def bark
    'bark!'
  end
end

class Poodle < Dog
  raise if method_defined? :bark
  def bark
    'bow-wow'
  end
end
```

I propose creating a shorthand. Maybe something like:

```
class Dog
  def bark
    'bark!'
  end
end

class Poodle < Dog
  ncdef bark        # "no clobber" def
    'bow-wow'
  end
end

=> #<MethodAlreadyDefined: Method `bark' already defined.>
```

This would be useful in scenarios where subclassing a class (or including a mixin) ***you don't own*** is common practice --for instance, subclassing `ApplicationRecord` for your model in Rails.

I agree that `ncdef` is pretty ugly. Maybe `def!` 







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