From: ruby-core@... Date: 2019-05-01T17:09:35+00:00 Subject: [ruby-core:92518] [Ruby trunk Feature#15815] Add option to raise NoMethodError for OpenStruct Issue #15815 has been updated by marcandre (Marc-Andre Lafortune). It's hard to decide on features of `OpenStruct` as it's somewhat an antipattern. Note that you might be able to write `users.map{@[:id]}` in the next version and avoid using an `OpenStruct` altogether. That being said, I am wondering if a frozen `OpenStruct` could possibly raise an error upon reading an undefined key. ---------------------------------------- Feature #15815: Add option to raise NoMethodError for OpenStruct https://bugs.ruby-lang.org/issues/15815#change-77882 * Author: mtsmfm (Fumiaki Matsushima) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- GitHub PR: https://github.com/ruby/ruby/pull/2164 Currently, `OpenStruct#method_missing` returns `nil` even if the key isn't registered. ```ruby require 'ostruct' os = OpenStruct.new({a: 1}) os.a #=> 1 os.b #=> nil ``` I'd like to add `exception` option to raise `NoMethodError` in such case. ```ruby require 'ostruct' os = OpenStruct.new({a: 1}, exception: true) os.a #=> 1 os.b #=> NoMethodError ``` ## Use case I sometimes use OpenStruct as a JSON API response wrapper. It's useful to use method call instead of key access (`obj[:key]`) because we can use `Symbol#to_proc` if it's a method (for example `users.map(&:id)`) But I want to prevent typo for a key name. Currently `users.map(&:idd)` just returns `[nil,...]` Even if we have this `exception` option, we can't enable this option for JSON parser easily though: ```ruby JSON.parse(response, object_class: Class.new(OpenStruct) { def initialize(hash); super(hash, exception: true); end }) ``` What do you think? ---- I've searched with "openstruct nomethoderror" on bugs.ruby-lang.org though, please let me know if it's duplicated. https://bugs.ruby-lang.org/search?utf8=%E2%9C%93&scope=&q=nomethoderror+openstruct -- https://bugs.ruby-lang.org/ Unsubscribe: