From: "alexeymuranov (Alexey Muranov)" <redmine@...>
Date: 2013-02-07T16:46:27+09:00
Subject: [ruby-core:51968] [ruby-trunk - Feature #7795] Symbol.defined? and/or to_existing_symbol


Issue #7795 has been updated by alexeymuranov (Alexey Muranov).


I think also that finding a symbol in a set is related to (can be used in) Hash With Indifferent Access. HWIA are implemented in RoR and Sinatra in different ways. Would be nice if Ruby itself had Hash With Indifferent Access.
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Feature #7795: Symbol.defined? and/or to_existing_symbol
https://bugs.ruby-lang.org/issues/7795#change-35968

Author: Student (Nathan Zook)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: next minor


I'm pulling this out from deep in the discussions of issue http://bugs.ruby-lang.org/issues/7791, Let Symbols be Garbage Collected.

The problem is that the extreme utility of symbols makes them enticed to use, which results in a DOS vulnerability.  My proposal is to add either of a pair of methods that would make it easy to defend against a DOS along these lines.

#1) Symbol.defined?

In existing code, it would might like this:
class Symbol
  def self.defined?(string)
   all_symbols.any?{|sym| sym.to_s == string}
  end
end 

#2) to_existing_sym.  This would be defined in the same places as to_sym, but would through an argument error if the symbol did not already exist.



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