Why order is important in items.xml?

We need to follow an order in items.xml, when we declare item types in items.xml. Below are the reasons for it.

  • Each items.xml is parsed in single pass. This means, more specific types are dependent on general types. In such case they should have been defined before we use them. For example,

items

Here we see that, item type product is using other item types, like catalog. To make this file successfully, it is mandatory that catalog exist before product is declared. We must defines types in order of inheritance.

Please note that impex files are parsed in multiple pass, so order is not important there.

  • Each xml file is validated against a items.xsd during build. If the xml file does not conforms to xsd file, build will fail.