Merge pull request #291 from jkowens/clone_input_array

Prevent modification of input array

lib/activerecord-import/import.rb

@@ -367,13 +367,13 @@ def import_helper( *args )
         # supports 2-element array and array
       elsif args.size == 2 && args.first.is_a?( Array ) && args.last.is_a?( Array )
         column_names, array_of_attributes = args
+        array_of_attributes = array_of_attributes.map(&:dup)
       else
         raise ArgumentError, "Invalid arguments!"
       end
 
       # dup the passed in array so we don't modify it unintentionally
       column_names = column_names.dup
-      array_of_attributes = array_of_attributes.dup
 
       # Force the primary key col into the insert if it's not
       # on the list and we are using a sequence and stuff a nil

test/import_test.rb

@@ -29,7 +29,8 @@
 
     it "should not modify the passed in values array" do
       assert_nothing_raised do
-        values = [%w(foo bar)].freeze
+        record = %w(foo bar).freeze
+        values = [record].freeze
         Topic.import %w(title author_name), values
       end
     end