applit @ndossche suggestion

Author: devnexen

ext/xsl/tests/gh21496.phpt

@@ -16,9 +16,17 @@ $doc->documentElement->appendChild($comment);
 unset($doc);
 $proc = new XSLTProcessor();
 var_dump($proc->importStylesheet($comment));
+$sxe = simplexml_load_string('<container/>');
+$proc = new XSLTProcessor();
+$proc->importStylesheet($sxe);
 ?>
 --EXPECTF--
 Warning: XSLTProcessor::importStylesheet(): compilation error: file %s line 1 element container in %s on line %d
 
 Warning: XSLTProcessor::importStylesheet(): xsltParseStylesheetProcess : document is not a stylesheet in %s on line %d
 bool(false)
+
+Warning: XSLTProcessor::importStylesheet(): compilation error: element container in %s on line %d
+
+Warning: XSLTProcessor::importStylesheet(): xsltParseStylesheetProcess : document is not a stylesheet in %s on line %d
+

ext/xsl/xsltprocessor.c

@@ -196,7 +196,11 @@ PHP_METHOD(XSLTProcessor, importStylesheet)
 			RETURN_THROWS();
 		}
 
-		php_dom_create_object((xmlNodePtr) nodep->doc, &owner_zv, php_dom_obj_from_obj(Z_OBJ_P(docp)));
+		/* See dom_import_simplexml_common */
+
+		dom_object *nodeobj = (dom_object *) ((char *) Z_OBJ_P(docp) - Z_OBJ_HT_P(docp)->offset);
+
+		php_dom_create_object((xmlNodePtr) nodep->doc, &owner_zv, nodeobj);
 		docp = &owner_zv;
 	}