FIX: 🐛 Saving the same custom field array twice would raise an error

app/models/concerns/has_custom_fields.rb

@@ -117,7 +117,7 @@ module HasCustomFields
       array_fields.each do |field_name, fields|
         if fields.length == dup[field_name].length &&
             fields.map{|f| f.value} == dup[field_name]
-          dup.delete(f.name)
+          dup.delete(field_name)
         else
           fields.each{|f| f.destroy }
         end

spec/components/concern/has_custom_fields_spec.rb

@@ -115,6 +115,14 @@ describe HasCustomFields do
       db_item.save
       expect(db_item.custom_fields).to eq({"a" => ["c", "d"]})
 
+      # It can be updated to the exact same value
+      db_item.custom_fields.update('a' => ['c'])
+      db_item.save
+      expect(db_item.custom_fields).to eq({"a" => "c"})
+      db_item.custom_fields.update('a' => ['c'])
+      db_item.save
+      expect(db_item.custom_fields).to eq({"a" => "c"})
+
       db_item.custom_fields.delete('a')
       expect(db_item.custom_fields).to eq({})