# rubocop:disable Style/BlockComments # rubocop:disable Lint/HandleExceptions # https://github.com/rails/rails/blob/e120d21211f9644e9b832e51ba7aa6c45448b782/activesupport/lib/active_support/core_ext/object/duplicable.rb =begin Copyright (c) 2005-2011 David Heinemeier Hansson Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. =end #-- # Most objects are cloneable, but not all. For example you can't dup +nil+: # # nil.dup # => TypeError: can't dup NilClass # # Classes may signal their instances are not duplicable removing +dup+/+clone+ # or raising exceptions from them. So, to dup an arbitrary object you normally # use an optimistic approach and are ready to catch an exception, say: # # arbitrary_object.dup rescue object # # Rails dups objects in a few critical spots where they are not that arbitrary. # That rescue is very expensive (like 40 times slower than a predicate), and it # is often triggered. # # That's why we hardcode the following cases and check duplicable? instead of # using that rescue idiom. #++ class Object # Can you safely dup this object? # # False for +nil+, +false+, +true+, symbol, and number objects; # true otherwise. def duplicable? true end end class NilClass # +nil+ is not duplicable: # # nil.duplicable? # => false # nil.dup # => TypeError: can't dup NilClass def duplicable? false end end class FalseClass # +false+ is not duplicable: # # false.duplicable? # => false # false.dup # => TypeError: can't dup FalseClass def duplicable? false end end class TrueClass # +true+ is not duplicable: # # true.duplicable? # => false # true.dup # => TypeError: can't dup TrueClass def duplicable? false end end class Symbol # Symbols are not duplicable: # # :my_symbol.duplicable? # => false # :my_symbol.dup # => TypeError: can't dup Symbol def duplicable? false end end class Numeric # Numbers are not duplicable: # # 3.duplicable? # => false # 3.dup # => TypeError: can't dup Fixnum def duplicable? false end end require 'bigdecimal' class BigDecimal # Needed to support Ruby 1.9.x, as it doesn't allow dup on BigDecimal, instead # raises TypeError exception. Checking here on the runtime whether BigDecimal # will allow dup or not. begin BigDecimal.new('4.56').dup def duplicable? true end rescue TypeError # can't dup, so use superclass implementation end end