Issue #13358 has been updated by nobu (Nobuyoshi Nakada). Eregon (Benoit Daloze) wrote: > But not only, after all it is a public and well-known method (many hits on GitHub code search). > Many deserializing libraries will use it, Methods of constructed objects will be used more than construction usually. > but also various libraries which need to build an instance without passing in state, > or use it as a way to replicate `Class#new` without using super like (maybe to use a different initializing method): It doesn't need `allocate`, `CACHE[name] || super`. > The performance hit on `respond_to?` is not significant, it's just an extra `NIL_P`. And a branch. > On the other hand, the one on `allocate` is, and affects every caller of `OpenStruct.allocate`. Why do you think the performance of `allocate` matters? Note that it is never used in common, since `Class#new` never calls `allocate` overridden in ruby level. ---------------------------------------- Bug #13358: OpenStruct overriding allocate https://bugs.ruby-lang.org/issues/13358#change-63787 * Author: sitter (Harald Sitter) * Status: Closed * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux] * Backport: 2.2: DONTNEED, 2.3: REQUIRED, 2.4: DONTNEED ---------------------------------------- In https://github.com/ruby/ruby/commit/15960b37e82ba60455c480b1c23e1567255d3e05 OpenStruct gained ~~~ruby class << self # :nodoc: alias allocate new end ~~~ Which is rather severely conflicting with expected behavior as `Class.allocate` is meant to [not call initialize](http://ruby-doc.org/core-2.4.0/Class.html#method-i-allocate). So, in fact, the change made `allocate` of `OpenStruct` do what `allocate` is asserting not to do :-/ For `OpenStruct` itself that isn't that big a deal, for classes inheriting from `OpenStruct` it breaks `allocate` though. Example: ~~~ruby require 'ostruct' class A < OpenStruct def initialize(x, y = {}) super(y) end end A.allocate ~~~ As `allocate` is alias'd to `new` in `OpenStruct` this will attempt to initialize `A` which will raise an `ArgumentError` because `A` cannot be initialized without arguments. ~~~ $ ruby x.rb x.rb:4:in `initialize': wrong number of arguments (given 0, expected 1..2) (ArgumentError) from x.rb:9:in `new' from x.rb:9:in `<main>' ~~~ OpenStruct at the very least should document the fact that its allocate is behaving differently. Ideally, `OpenStruct` should not alias allocate at all. -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>