Issue #20279 has been updated by byroot (Jean Boussier).

because I was under the impression it was called by method_missing.

`respond_to_missing?` isn't called by `method_missing` but by `Kernel#respond_to?`, and `BasicObject` doesn't define `respond_to?`. If you want to implement a delegator that responds to `respond_to?`, you need to copy the method over from `Kernel`: ```ruby class Proxy < BasicObject DELEGATE = [:puts, :p] define_method(:respond_to?, ::Kernel.instance_method(:respond_to?)) private define_method(:respond_to_missing?, ::Kernel.instance_method(:respond_to_missing?)) def method_missing(name, *args, &block) return super unless DELEGATE.include? name ::Kernel.send(name, *args, &block) end def respond_to_missing?(name, include_private = false) DELEGATE.include?(name) or super end end proxy = Proxy.new p proxy.respond_to?(:puts) proxy.puts "Hello" ``` ``` true Hello ``` ---------------------------------------- Misc #20279: Is the implementation of `respond_to_missing?` in BasicObject documentation correct? https://bugs.ruby-lang.org/issues/20279#change-106865 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- Considering the documentation here: https://ruby-doc.org/3.2.2/BasicObject.html Introduced in: https://github.com/ruby/ruby/commit/3eb7d2b33e3f8555d81db5369eb6fb7100a91e63 I wondered if `or super` is correct in `respond_to_missing?`. For example: ``` irb(main):001* class MyObjectSystem < BasicObject irb(main):002* DELEGATE = [:puts, :p] irb(main):003* irb(main):004* def method_missing(name, *args, &block) irb(main):005* return super unless DELEGATE.include? name irb(main):006* ::Kernel.send(name, *args, &block) irb(main):007* end irb(main):008* irb(main):009* public def respond_to_missing?(name, include_private = false) irb(main):010* DELEGATE.include?(name) or super irb(main):011* end irb(main):012> end => :respond_to_missing? irb(main):013> MyObjectSystem.new.respond_to_missing?(:foo) (irb):5:in `method_missing': super: no superclass method `respond_to_missing?' for an instance of MyObjectSystem (NoMethodError) from (irb):10:in `respond_to_missing?' from (irb):13:in `<main>' from <internal:kernel>:187:in `loop' from /home/samuel/.gem/ruby/3.3.0/gems/irb-1.11.2/exe/irb:9:in `<top (required)>' from /home/samuel/.gem/ruby/3.3.0/bin/irb:25:in `load' from /home/samuel/.gem/ruby/3.3.0/bin/irb:25:in `<main>' ``` It looks wrong to me. In addition, I'd like to know in what situations `BasicObject` should define `respond_to_missing?` - because I was under the impression it was called by `method_missing`. Does `BasicObject#method_missing` have this behaviour? Maybe we can improve the documentation cc @burdettelamar -- https://bugs.ruby-lang.org/

Issue #20279 has been updated by ioquatix (Samuel Williams). Do you want to submit a PR? You already wrote most of the code... however: ```ruby define_method(:respond_to_missing?, ::Kernel.instance_method(:respond_to_missing?)) def respond_to_missing?(name, include_private = false) DELEGATE.include?(name) or super end ``` Won't these clobber each other? ---------------------------------------- Misc #20279: Is the implementation of `respond_to_missing?` in BasicObject documentation correct? https://bugs.ruby-lang.org/issues/20279#change-106867 * Author: ioquatix (Samuel Williams) * Status: Open * Priority: Normal ---------------------------------------- Considering the documentation here: https://ruby-doc.org/3.2.2/BasicObject.html Introduced in: https://github.com/ruby/ruby/commit/3eb7d2b33e3f8555d81db5369eb6fb7100a91e63 I wondered if `or super` is correct in `respond_to_missing?`. For example: ``` irb(main):001* class MyObjectSystem < BasicObject irb(main):002* DELEGATE = [:puts, :p] irb(main):003* irb(main):004* def method_missing(name, *args, &block) irb(main):005* return super unless DELEGATE.include? name irb(main):006* ::Kernel.send(name, *args, &block) irb(main):007* end irb(main):008* irb(main):009* public def respond_to_missing?(name, include_private = false) irb(main):010* DELEGATE.include?(name) or super irb(main):011* end irb(main):012> end => :respond_to_missing? irb(main):013> MyObjectSystem.new.respond_to_missing?(:foo) (irb):5:in `method_missing': super: no superclass method `respond_to_missing?' for an instance of MyObjectSystem (NoMethodError) from (irb):10:in `respond_to_missing?' from (irb):13:in `<main>' from <internal:kernel>:187:in `loop' from /home/samuel/.gem/ruby/3.3.0/gems/irb-1.11.2/exe/irb:9:in `<top (required)>' from /home/samuel/.gem/ruby/3.3.0/bin/irb:25:in `load' from /home/samuel/.gem/ruby/3.3.0/bin/irb:25:in `<main>' ``` It looks wrong to me. In addition, I'd like to know in what situations `BasicObject` should define `respond_to_missing?` - because I was under the impression it was called by `method_missing`. Does `BasicObject#method_missing` have this behaviour? Maybe we can improve the documentation cc @burdettelamar -- https://bugs.ruby-lang.org/