lib/traject_plus/extraction.rb in traject_plus-0.0.1 vs lib/traject_plus/extraction.rb in traject_plus-0.0.2

@@ -35,10 +35,11 @@
       # to_field 'x', encode: 'UTF-8' # 'abc' to 'abc'
       # to_field 'x', insert: [1, 'x'] # 'abc' to 'axbc'
       ['split', 'concat', 'prepend', 'gsub', 'encode', 'insert'].each do |method|
         define_method(method) do |values, *args|
           values.flat_map do |v|
-            v.public_send(method, *args)
+            # Cannot prepend to frozen string; use #dup to effectively unfreeze
+            v.dup.public_send(method, *args)
           end
         end
       end
 
       # to_field 'x', strip: true # ' abc ' to 'abc'