From: "Earlopain (Earlopain _) via ruby-core" <ruby-core@...>
Date: 2025-08-08T07:42:49+00:00
Subject: [ruby-core:122935] [Ruby Bug#21535] `NoMethodError` becomes `NameError`when using `...` delegation and method call indirection

Issue #21535 has been reported by Earlopain (Earlopain _).

----------------------------------------
Bug #21535: `NoMethodError` becomes `NameError`when using `...` delegation and method call indirection
https://bugs.ruby-lang.org/issues/21535

* Author: Earlopain (Earlopain _)
* Status: Open
* ruby -v: ruby 3.5.0dev (2025-08-08T02:57:23Z master 3ad26d0501) +PRISM [x86_64-linux]
* Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
Consider this code:

```rb
class Test
  def foo(...)
    nil.foo(...)
  end

  def foo_indirect
    foo
  end
end

begin
  Test.new.foo
rescue => e
  puts e.class
end

begin
  Test.new.foo_indirect
rescue => e
  puts e.class
end
```

```sh
$ ruby -v foo.rb 
ruby 3.3.6 (2024-11-05 revision 75015d4c1f) [x86_64-linux]
NoMethodError
NoMethodError

$ ruby -v foo.rb 
ruby 3.5.0dev (2025-08-08T02:57:23Z master 3ad26d0501) +PRISM [x86_64-linux]
NoMethodError
NameError
```

On ruby 3.3 it used to always raise a `NoMethodError`. Starting with Ruby 3.4, it raises a `NoMethodError` when calling the method directly, and a `NameError` when the method is called indirectly via a different method.

The context is the `delegate` method from rails (original issue https://github.com/rails/rails/issues/55463), which rescues the `NoMethodError` to raise a more specific error class.

The problem is the `...` delegation. If the method accepts no arguments, `*, **`, or something else, it behaves as expected.



-- 
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