[bugfix] passing DB stored nodes to fn:transform

passing persistent nodes from XQuery to fn:transform as parameters doesn’t work.

NodeProxy objects were not being considered; dereference their nodes and use the result appropriately.

Author: alanpaxton

exist-core/src/main/java/org/exist/xquery/functions/fn/transform/Convert.java

@@ -26,6 +26,7 @@
 import net.sf.saxon.type.BuiltInAtomicType;
 import org.exist.dom.QName;
 import org.exist.dom.memtree.DocumentImpl;
+import org.exist.dom.persistent.NodeProxy;
 import org.exist.xquery.ErrorCodes;
 import org.exist.xquery.XPathException;
 import org.exist.xquery.functions.array.ArrayType;
@@ -150,7 +151,7 @@ private XdmValue ofNode(final Node node) throws XPathException {
 
             final DocumentBuilder sourceBuilder = newDocumentBuilder();
             try {
-                if (node instanceof DocumentImpl) {
+                if (node instanceof Document) {
                     return sourceBuilder.build(new DOMSource(node));
                 } else {
                     //The source must be part of a document
@@ -178,6 +179,9 @@ XdmValue[] of(final ArrayType values) throws XPathException {
         }
 
         XdmValue of(final Sequence value) throws XPathException {
+            if (value instanceof NodeProxy nodeProxy) {
+                return ofNode(nodeProxy.getNode());
+            }
             return XdmValue.makeSequence(listOf(value));
         }