This blog addresses the following use case: "In my OIC Orchestration, when I define a Global variable based on a repeating element (aka unbounded), the global variable is not repeating; I cannot add/append to it"
Choose the parent element when defining the global variable
Because of XML Rules: When a global variable is defined, internally it is defining a reference to a XML Document. Any XML Document must have a single instance root element; in other words it cannot be a collection of root elements, even if they have the same element name.
When defining the Variable, choose the parent element of the unbounded element (repeating). That way the XML Document root element will be the parent element, and one of its children will be the unbounded element
To reference the variable use the location path (xpath) to the unbounded element.
Defining vErrors with the intent to use errorDetails repeating element
Now to reference on expressions, just select errorDetails of $vErrors
A global variable is initialized empty when the orchestration is executed. Then when values get assigned/appended, the values get cloned from the source into the global variable; in other words, the global variable gets its own copy of the values.