[ruby-core:110483] [Ruby master Bug#19079] Modules included in a DelegateClass cannot override delegate methods

["jonathanhefner (Jonathan Hefner)" <noreply@ruby-lang.org>]

Issue #19079 has been reported by jonathanhefner (Jonathan Hefner).

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Bug #19079: Modules included in a DelegateClass cannot override delegate methods
https://bugs.ruby-lang.org/issues/19079

* Author: jonathanhefner (Jonathan Hefner)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.2p20
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
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Because `DelegateClass` defines delegate methods on the class itself, those delegate methods come first in the method lookup chain.  This prevents included modules from overriding delegate methods:

  ```ruby
  Base = Class.new do
    def foo
      "base"
    end
  end

  Helper = Module.new do
    def foo
      "helper"
    end
  end

  WithHelper = DelegateClass(Base) { include Helper }

  WithHelper.new(Base.new).foo
  # => "base"
  ```

One possible solution would be to define the delegate methods in a separate module.  That way, other modules could come before it in the method lookup chain.



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