Bug #55098 [Opn->Ver]: SimpleXML iteration produces infinite loop

Edit report at https://bugs.php.net/bug.php?id=55098&edit=1 ID: 55098 Updated by: cmb@php.net Reported by: karl dot raab at elements dot at Summary: SimpleXML iteration produces infinite loop -Status: Open +Status: Verified Type: Bug Package: SimpleXML related Operating System: Linux PHP Version: 5.3.6 Block user comment: N Private report: N New Comment: Even simpler reproduce script: <?php $xml = simplexml_load_string('<root><a>1</a><a>2</a></root>'); $as = $xml->a; foreach ($as as $a) { var_dump($as); } ?> Generally, when iterating over SimpleXMLElement, you must not access this object inside the loop. That may may work in some cases, but usually accessing a SimpleXMLElement calls php_sxe_get_first_node()[1], which calls php_sxe_reset_iterator()[2], when the element is currently iterated over. Obviously, this leads to an infinite loop. [1] <http://lxr.php.net/xref/PHP_5_6/ext/simplexml/simplexml.c#php_sxe_get_first_node> [2] <http://lxr.php.net/xref/PHP_5_6/ext/simplexml/simplexml.c#php_sxe_reset_iterator> Previous Comments: ------------------------------------------------------------------------ [2015-09-04 14:32:04] cmb@php.net Related To: Bug #64917 ------------------------------------------------------------------------ [2011-07-01 05:16:58] karl dot raab at elements dot at already noticed an orphan comment in the test script. just ignore the line "//iteration_breaker($nodes);" cheers, karl ------------------------------------------------------------------------ [2011-07-01 04:23:29] karl dot raab at elements dot at Description: ------------ see the test script. inside the foreach-loop the call of e.g. $nodes->asXml() will reset the iteration to the beginning and therefore the loop will forever remain on the second element. this may be related to bug #50670 and #51846 greets, karl Test script: --------------- $xmlString = "<root><a><b>1</b><b>2</b><b>3</b></a></root>"; $xml = simplexml_load_string($xmlString); $nodes = $xml->a->b; foreach ($nodes as $nodeData) { echo "nodeData: " . $nodeData . "\n"; //the following code will break the iteration on the second element and resets the pointer //happens by any of these methods $xml = $nodes->asXml(); //$nodes->getName(); //$nodes->attributes(); //$nodes->children(); //$nodes->getNamespaces(); //iteration_breaker($nodes); } Expected result: ---------------- nodeData: 1 nodeData: 2 nodeData: 3 Actual result: -------------- nodeData: 1 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 nodeData: 2 and so on... ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=55098&edit=1