decorator.rb in tqdm-0.4.1

- old
+ new

@@ -1,8 +1,13 @@
 require 'tqdm/printer'
 
+CLONE_UNFROZEN_SUPPORTED = RUBY_VERSION.split('.')[0..1].join('.').to_f >= 2.4
+
 module Tqdm
+  
+  class DecoratorError < StandardError
+  end
 
   # Decorates the #each method of an `Enumerable` by wrapping it so that each
   # iteration produces a pretty progress bar printed to the console or a file handle.
   #
   # @note The `Enumerable` is cloned before it is enhanced; it is not modified directly.
@@ -110,19 +115,26 @@
     def enhanced
       @enhanced ||= enumerable_unfrozen
     end
 
     # Uses progressively more invasive techniques to return an unfrozen copy of @enumerable
-    # Significantly, for some classes like Sequel::Dataset, both #clone and #dup re-freeze
-    #    the object, so we have to drop back to Object#clone
     def enumerable_unfrozen
-      unfrozen = enumerable.clone(freeze: false)
-      return unfrozen unless unfrozen.frozen?
-      unfrozen = enumerable.dup
-      return unfrozen unless unfrozen.frozen?
+      to_unfreeze = CLONE_UNFROZEN_SUPPORTED ? enumerable.clone(freeze: false) : enumerable.clone
+      return to_unfreeze unless to_unfreeze.frozen?
+      to_unfreeze = to_unfreeze.dup
+      return to_unfreeze unless to_unfreeze.frozen?
+      
+      # Significantly, for some classes like Sequel::Dataset, both #clone and #dup re-freeze
+      # the object before returning it, so we have to drop back to Object#clone to avoid this
       @force_refreeze = true
-      unfrozen = Object.instance_method(:clone).bind(enumerable).call(freeze: false)
-      unfrozen
+      if CLONE_UNFROZEN_SUPPORTED
+        to_unfreeze = Object.instance_method(:clone).bind(enumerable).call(freeze: false)
+      end
+      if Object.instance_method(:frozen?).bind(to_unfreeze).call
+        raise DecoratorError.new("could not create an unfrozen clone")
+      end
+      
+      to_unfreeze
     end
 
     def total!
       enumerable.size rescue enumerable.count rescue nil
     end