Stdlib: DOMDocument::loadHTML()/saveHTML() missing — HTML parse/serialize fatal (ext/dom/php_dom.c) #14356

Summary

DOMDocument registers loadXML() / saveXML() but not the HTML counterparts. Calling loadHTML() fatals (undefined method); Zend parses HTML and saveHTML() round-trips.

Blocks typical HTML DOM workflows (scraping, templating) even when XML paths work.

php-src reference

• ext/dom/php_dom.c — dom_document_load_html(), dom_document_save_html()
• libxml HTML parser options (LIBXML_HTML_NOIMPLIED, etc.) for parity follow-ups

PHP implementation target

• ext/dom/VmDom.php — register loadhtml / savehtml on DOMDocument
• New handlers under ext/dom/ (e.g. DocumentLoadHTML.php, DocumentSaveHTML.php)
• Reuse existing DomRegistry / element tree where possible; prefer PHP HTML lowering over new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_dom_document_load_html.php'
# VM: Fatal undefined method DOMDocument::loadHTML()
# Zend: html + serialized HTML document

test/repro/maintainer_gap_dom_document_load_html.php

Expected (php-src-strict)

• loadHTML('<p>hi</p>') succeeds; documentElement->nodeName is html
• saveHTML() returns HTML string (DOCTYPE + body markup like Zend)

Done when

• loadHTML / saveHTML registered and behave like Zend for the repro
• Related: loadHTMLFile / saveHTMLFile can be follow-up issues
• Targeted test; note any runtime/ lines removed if HTML path bypasses C