Bug #79701 [NEW]: getElementById does not correctly work with duplicate definitions

From: beberlei Operating system: PHP version: 7.2.31 Package: DOM XML related Bug Type: Bug Bug description:getElementById does not correctly work with duplicate definitions Description: ------------ A DOM id element is supposed to be unique, but sometimes the world is messy. The DOM specification says: > The getElementById(elementId) method, when invoked, must return the first element, > in tree order, within this’s descendants, whose ID is elementId, and null if there > is no such element otherwise. PHP uses libxmls ID Map functionality, which does not allow duplicates. The return value of "xmlAddID" is not checked for the error, so elements with duplicate ID don't cause a problem. However if you remove the first element with an ID, or re-order the elements, then the specifications assumption of returning the first element in tree order does not work anymore. Test script: --------------- <?php $dom = new DOMDocument(); $root = $dom->createElement('html'); $dom->appendChild($root); $el1 = $dom->createElement('p1'); $el1->setAttribute('id', 'foo'); $el1->setIdAttribute('id', true); $root->appendChild($el1); $el2 = $dom->createElement('p2'); $el2->setAttribute('id', 'foo'); $el2->setIdAttribute('id', true); $root->appendChild($el2); unset($el1, $el2); $root->removeChild($dom->getElementById('foo')); var_dump($dom->getElementById('foo')); Expected result: ---------------- Returns Element <p2 id="foo" /> Actual result: -------------- NULL -- Edit bug report at https://bugs.php.net/bug.php?id=79701&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=79701&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=79701&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=79701&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=79701&r=needscript Try newer version: https://bugs.php.net/fix.php?id=79701&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=79701&r=support Expected behavior: https://bugs.php.net/fix.php?id=79701&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=79701&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=79701&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=79701&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=79701&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=79701&r=dst IIS Stability: https://bugs.php.net/fix.php?id=79701&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=79701&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=79701&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=79701&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=79701&r=mysqlcfg