Bug #19893: OpenStruct#respond_to? when true fails with NameError

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 3.1.4
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN

[msxavi (Emerson Xavier)]

Hello,

I have a case where I overrode respond_to? on a subclass of OpenStruct because I this class to work as fake object.

class Dep
  def a
    "Hello from Dep"
  end
end
class FakeDep < OpenStruct
  def respond_to?(*args)
    super || Dep.new.respond_to?(*args)
  end  
end

FakeDep.new(a: [])

NameError: undefined method `a' for class `FakeDep'

      owner = method!(name).owner
              ^^^^^^^
from /usr/local/lib/ruby/3.1.0/ostruct.rb:245:in `method'

Is this a valid issue?

Also posted in https://github.com/ruby/ostruct/issues/55

[znz (Kazuhiro NISHIYAMA)]

I think you should define respond_to_missing? too.

require 'ostruct'

class Dep
  def a
    "Hello from Dep"
  end
end

class FakeDep < OpenStruct
  def respond_to?(*args)
    super || Dep.new.respond_to?(*args)
  end

  def respond_to_missing?(*args)
    super || Dep.new.respond_to?(*args)
  end
end

FakeDep.new(a: []) # no error

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed

[msxavi (Emerson Xavier)]

Thank you! That's it.