Fix using Dom\Node with Dom\XPath callbacks

This code was introduced when the Dom\Node and DOMNode classes were
still aliases, so the type check was never updated.
We fix this by checking if the doc pointer follows the spec and pick the
right node CE based on that.

Closes phpGH-17888.

Author: ndossche

NEWS

@@ -24,6 +24,7 @@ PHP                                                                        NEWS
   . Fixed bug GH-17802 (\Dom\HTMLDocument querySelector attribute name is case
     sensitive in HTML). (nielsdos)
   . Fixed bug GH-17847 (xinclude destroys live node). (nielsdos)
+  . Fix using Dom\Node with Dom\XPath callbacks. (nielsdos)
 
 - GD:
   . Fixed bug GH-17703 (imagescale with both width and height negative values

ext/dom/tests/modern/xml/return_dom_node_from_xpath.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Returning a Dom\Node from Dom\XPath callback
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+
+$dom = Dom\XMLDocument::createFromString('<root/>');
+$xpath = new Dom\XPath($dom);
+$xpath->registerPhpFunctionNs('urn:x', 'test', fn() => $dom->createElement('foo'));
+$xpath->registerNamespace('x', 'urn:x');
+$test = $xpath->query('x:test()');
+var_dump($test[0]->nodeName);
+
+?>
+--EXPECT--
+string(3) "foo"

ext/dom/xpath_callbacks.c

@@ -24,6 +24,7 @@
 #if defined(HAVE_LIBXML) && defined(HAVE_DOM)
 
 #include "php_dom.h"
+#include "internal_helpers.h"
 #include <libxml/parserInternals.h>
 
 static void xpath_callbacks_entry_dtor(zval *zv)
@@ -425,7 +426,8 @@ static zend_result php_dom_xpath_callback_dispatch(php_dom_xpath_callbacks *xpat
 	}
 
 	if (Z_TYPE(callback_retval) != IS_UNDEF) {
-		if (Z_TYPE(callback_retval) == IS_OBJECT && instanceof_function(Z_OBJCE(callback_retval), dom_node_class_entry)) {
+		if (Z_TYPE(callback_retval) == IS_OBJECT
+		 && (instanceof_function(Z_OBJCE(callback_retval), dom_get_node_ce(php_dom_follow_spec_node((const xmlNode *) ctxt->context->doc))))) {
 			xmlNode *nodep;
 			dom_object *obj;
 			if (xpath_callbacks->node_list == NULL) {
@@ -439,7 +441,7 @@ static zend_result php_dom_xpath_callback_dispatch(php_dom_xpath_callbacks *xpat
 		} else if (Z_TYPE(callback_retval) == IS_FALSE || Z_TYPE(callback_retval) == IS_TRUE) {
 			valuePush(ctxt, xmlXPathNewBoolean(Z_TYPE(callback_retval) == IS_TRUE));
 		} else if (Z_TYPE(callback_retval) == IS_OBJECT) {
-			zend_type_error("Only objects that are instances of DOMNode can be converted to an XPath expression");
+			zend_type_error("Only objects that are instances of DOM nodes can be converted to an XPath expression");
 			zval_ptr_dtor(&callback_retval);
 			return FAILURE;
 		} else {

ext/xsl/tests/xslt_non_dom_node.phpt

@@ -28,4 +28,4 @@ try {
 }
 ?>
 --EXPECT--
-Only objects that are instances of DOMNode can be converted to an XPath expression
+Only objects that are instances of DOM nodes can be converted to an XPath expression