[ruby-core:117626] [Ruby master Bug#20440] `super` from child class passing keyword arg as Hash if in a method with passthrough args called from base class

20 Apr 2024

      Issue #20440 has been updated by nobu (Nobuyoshi Nakada).

You need to make `foo` `ruby2_keywords` to let it work as same as 2.7 or earlier.

```rb
class Child < Base
  ruby2_keywords def foo(*)
    puts "Child: calling foo"
    super
  end
end
Child.new.foo!
```
```
Base: calling foo! with x: 1
Child: calling foo
Base: calling foo with args: [], x: 1
```

Note that `require 'ruby2_keyword'` is necessary before ruby 2.7.

----------------------------------------
Bug #20440: `super` from child class passing keyword arg as Hash if in a method with passthrough args called from base class
https://bugs.ruby-lang.org/issues/20440#change-108033

* Author: ozydingo (Andrew Schwartz)
* Status: Open
* ruby -v: 3.3.0
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Apologies for the verbose title, but that's the specific set of conditions that AFAICT are required to reproduce the bug!

Here's the simplest setup I can reproduce:

```rb
class Base
  def foo(*args, x: 1)
    puts "Base: calling foo with args: #{args}, x: #{x}"
  end

  def foo!(x: 1)
    puts "Base: calling foo! with x: #{x}"
    foo(x: x)
  end
end

class Child < Base
  def foo(*)
    puts "Child: calling foo"
    super
  end
end
```

When I call `Child.new.foo!`, I expect it to call the base class method `foo!`, which will use the default keyword arg `x: 1`; then the child method `foo` with `x: 1`, and finally the base method `foo` with `x: 1`. However, this is not what I observe:

```rb
Child.new.foo!

Base: calling foo! with x: 1
Child: calling foo
Base: calling foo with args: [{:x=>1}], x: 1
```

So when the child `foo` method called `super`, it passed not only `x: 1` as a keyword arg, but *also* `{x: 1}` as a Hash positional arg to the super method.

This is breaking my upgrade to Ruby 3.0 as I have a similar setup but without the `*args` param, this I am getting the error "wrong number of arguments (given 1, expected 0)".

-- 
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