Bug 149251 Inconsistent Handling of a Non-inheritable ROM Property
For a ROM property defined to be non-inheritable, an empty string property value should be consistently handled as an empty string, not as null. For example, an oda.dataSource extension defines a data source property with canInherit=false. When a oda-data-source handle get saved in a report design, it correctly includes the tag for such property, even when an empty string value is specified. <oda-data-source extensionID="my.oda.plugin" name="my Data Source" id="24"> ... <property name="ApplicationServer"></property> </oda-data-source> However, later when using the DE API to read its property value, a null is returned. Then when the report design is subsequently saved, the property tag is lost. Expects that an empty string value of a non-inhertiable property should be preserved.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
assert prop.getTypeCode( ) == PropertyType.ELEMENT_REF_TYPE
				|| prop.getSubTypeCode( ) == PropertyType.ELEMENT_REF_TYPE;
		ElementRefPropertyType refType = null;
		if ( prop.getTypeCode( ) == PropertyType.ELEMENT_REF_TYPE )
			refType = (ElementRefPropertyType) prop.getType( );
		else
			refType = (ElementRefPropertyType) prop.getSubType( );
		refType.resolve( module, prop, ref );
		if ( ref.isResolved( ) )
			ref.getTargetElement( ).addClient( this, prop.getName( ) );
		return ref;
	}
	/**
	 * Checks all value items in the specific property whose type is list
	 * property type. This method is used in command. If any error is found, the
	 * exception will be thrown.
	 * 
	 * @param module
	 *            the module
	 * @param propDefn
	 *            the property definition of the list property
	 * @param list