Repository navigation
Dom\XMLDocument::C14N() seems broken compared to DOMDocument::C14N() #20444
Description
Description
The following code:
$xml = <<<EOF
<?xml version="1.0" encoding="UTF-8"?>
<test:root xmlns:test="http://example.com/dummy/ns">
<test:a/>
<test:b test:kind="123">abc</test:b>
</test:root>
EOF;
$d = \Dom\XMLDocument::createFromString($xml);
var_dump($d->C14N(true));Resulted in this output:
<test:root xmlns:test="http://example.com/dummy/ns" xmlns:xmlns="http://www.w3.org/2000/xmlns/" xmlns:test="http://example.com/dummy/ns">
<test:a></test:a>
<test:b test:kind="123">abc</test:b>
</test:root>
But I expected this output instead:
<test:root xmlns:test="http://example.com/dummy/ns">
<test:a></test:a>
<test:b test:kind="123">abc</test:b>
</test:root>
However, this code works:
$xml = <<<EOF
<?xml version="1.0" encoding="UTF-8"?>
<test:root xmlns:test="http://example.com/dummy/ns">
<test:a/>
<test:b test:kind="123">abc</test:b>
</test:root>
EOF;
$d = new DOMDocument();
$d->loadXML($xml);
var_dump($d->C14N(true));Shouldn't the new \Dom\XMLDocument class give the same result as the "old" \DOMDocument class?
PHP Version
PHP 8.4.14 (cli) (built: Oct 24 2025 19:07:34) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.4.14, Copyright (c) Zend Technologies
with Zend OPcache v8.4.14, Copyright (c), by Zend Technologies
Operating System
Alpine Linux v3.22.2 (php:8.4-fpm-alpine docker image)
Activity
[-]`Dom\XMLDocument::C14N()` seems broken[/-][+]`Dom\XMLDocument::C14N()` seems broken compared to `DOMDocument::C14N()`[/+]ndossche commentedon Nov 11, 2025
Didn't yet find something better than this https://gist.github.com/ndossche/34a44c33f54d253ebe961203ef59a2e6
aprat84 commentedon Nov 11, 2025
The non-exclusive variant also produces weird results, repeating the namespace declaration in every first level node:
The first one outputs this:
While the second one outputs this:
Also note that the
DOMDocument::C14N()method produces the same results as thexmllint [--c14n|--exc-c14n] <file>command (libxml2-2.13.9-r0).ndossche commentedon Nov 11, 2025
Yes I figured that out too when I experimented with the code yesterday evening.
The root cause is that the new DOM code stores namespaces in a different way, and C14N has very strict rules about how namespaces should get stored. So I need to manually insert fake temporary declarations to satisfy the constraints of the C14N engine.
I tried other tricks but the problem is that in the modern DOM specification there are no real namespace declarations nodes (they're proper attributes), so we don't have a fixed insertion point.
Fix phpGH-20444: Dom\XMLDocument::C14N() seems broken compared to DOM…
Fix GH-20444: Dom\XMLDocument::C14N() seems broken compared to DOMDoc…
Merge branch 'PHP-8.4' into PHP-8.5
Merge branch 'PHP-8.5'