From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-2.6 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, FORGED_GMAIL_RCVD,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=no autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id 8FF661F461 for ; Fri, 23 Aug 2019 22:41:27 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 12D6F120B28; Sat, 24 Aug 2019 07:41:20 +0900 (JST) Received: from o1678916x28.outbound-mail.sendgrid.net (o1678916x28.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 67525120B25 for ; Sat, 24 Aug 2019 07:41:18 +0900 (JST) Received: by filter0025p3iad2.sendgrid.net with SMTP id filter0025p3iad2-8039-5D606B8F-F 2019-08-23 22:41:19.212572058 +0000 UTC m=+683912.966294357 Received: from herokuapp.com (unknown [3.81.9.76]) by ismtpd0003p1iad1.sendgrid.net (SG) with ESMTP id Olj5_QT3QTChQTUOwi8UNw for ; Fri, 23 Aug 2019 22:41:19.159 +0000 (UTC) Date: Fri, 23 Aug 2019 22:41:19 +0000 (UTC) From: esparta@gmail.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 70063 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 15815 X-Redmine-Issue-Author: mtsmfm X-Redmine-Sender: esparta X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?Bh4oNJRo5TOzr+OLPpAjOfBRm5XReXyfQOtFc0R5Wkf=2Fx08r8bjBJBE9JW+=2FKn?= =?us-ascii?Q?s04aaYlZIcau0jZkZB9SwOl1pEch3BRS+hJn8IV?= =?us-ascii?Q?iErPBOl0ZosuwXaSPgn9IdC2rzG4oDPBHVAvyCJ?= =?us-ascii?Q?UCzRj0zu8vZhjv8mqWpg7FxiSHgMi27usafsa8A?= =?us-ascii?Q?Rpmy6r7wVrVwmFY8zhevpKEqTHjcy7JGmqg=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 94514 Subject: [ruby-core:94514] [Ruby master Feature#15815] Add option to raise NoMethodError for OpenStruct X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #15815 has been updated by esparta (Espartaco Palma). Personally I found the proposed signature confusing, more when taking in account that OpenStruct calls: ```ruby os = OpenStruct.new(a: 1, exception: true) # vs os = OpenStruct.new({a: 1}, exception: true) ``` > 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 > ``` How about a subclass of OpenStruct to take this feature? ``` ruby class ExceptionalOpenStruct < OpenStruct def method_missing(mid, *args) if args.length == 0 raise NoMethodError unless @table.key?(mid) @table[mid] else super end end end eostr = ExceptionalOpenStruct.new(a: 1) eostr.a # => 1 eostr.b # NoMethodError: NoMethodError ebstr.b = 2 eostr.b # => 2 ``` (I'm probably missing some feature, but that's the idea...) Another concern is probably the performance: OpenStruct will check another branch just to verify if now it also need to raise an exception. The flexibility of OpenStruct makes it not exactly fast, handling exception would make all other uses cases more slow performance wise.[*benchmark needed] osyo (manga osyo) wrote: > What about adding block arguments to `OpenStruct.new` like `Hash` instead of options? > > ```ruby > h = Hash.new {|hash, key| > raise(IndexError, "hash[#{key}] has no value") > } > > # Error: in `block in
': hash[1] has no value (IndexError) > h[1] > > > require "ostruct" > > # Adding block arguments like Hash > os = OpenStruct.new({a: 1}) {|open_struct, method_name| > raise(NoMethdError, "undefined method `#{method_name}' for #{open_struct}") > } > > # Error: in `block in
': undefined method `b' for # (NoMethodError) > os.b > ``` ---------------------------------------- Feature #15815: Add option to raise NoMethodError for OpenStruct https://bugs.ruby-lang.org/issues/15815#change-80950 * 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/