Stdlib: ext/xml — xml_parser_create / xml_parse_into_struct SAX API (ext/xml/xml.c parity)

[PurHur]

Category

stdlib

Problem

ext/xml procedural API (xml_parser_create, xml_parse, xml_parser_free, xml_parse_into_struct, …) is unimplemented. Apps using SAX-style parsing (RSS, legacy integrations) cannot run. Distinct from DOM (#3326) and SimpleXML (#3338).

Prerequisite (bootstrap): land #7406 skeleton first so function_exists('xml_parser_create') is true and factories throw catchable stubs — avoid duplicating registration work in this issue.

php-src reference

• php/php-src ext/xml/xml.c — parser resource, xml_parse, options
• php/php-src ext/xml/xml.h — encoding constants (XML_OPTION_*)
• Tests: ext/xml/tests/*.phpt

Repro (failure today)

<?php
$p = xml_parser_create();
xml_parse($p, '<root/>', true);
xml_parser_free($p);
echo "ok\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php repro.php
php bin/vm.php repro.php 2>&1 | head -3
'

Step	Zend (ext/xml)	VM today
function_exists('xml_parser_create')	true	false ❌
Parse simple fragment	ok	undefined function fatal ❌

Phase-1 slice (after #7406 skeleton):

<?php
$vals = [];
$idx  = [];
xml_parse_into_struct(xml_parser_create(), "<a><b/></a>", $vals, $idx);
var_export(array_key_exists('b', $idx));

Scope (this repo)

Path	Work
ext/xml/	Real handlers (post-#7406 skeleton)
VM	Parser resource type; incremental xml_parse; xml_error_string
ext/xml/xml_parse_into_struct.php	Phase 1b struct builder
Tests	test/compliance/cases/stdlib/xml_parse*.phpt
Matrix	script/capability-matrix.php

PHP-in-PHP: parser state machine in ext/xml/*.php; expat via thin FFI if needed — not new logic in runtime/*.c. Libxml errors: #6058.

Done when

• Bootstrap: ext/xml module skeleton — xml_parser_create() must Error cleanly until #3494 #7406 skeleton merged (factories throw until this issue lands)
• Repro prints ok on VM for create/parse/free cycle
• xml_parse_into_struct repro matches Zend index keys on harness
• ./script/ci-fast.sh --filter xml_parse green (skip if expat absent — document)
• Capability matrix lists xml functions

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter xml_parse'

Related

• Bootstrap: ext/xml module skeleton — xml_parser_create() must Error cleanly until #3494 #7406 module skeleton · php-in-php: libxml error buffer — libxml_use_internal_errors/get_errors/clear_errors without host libxml (ext/libxml) #6058 libxml errors · Stdlib: ext/dom — DOMDocument/DOMElement XML tree API (ext/dom parity) #3326 DOM · Stdlib: ext/simplexml — SimpleXMLElement load/loadString (ext/simplexml parity) #3338 SimpleXML · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

Implementation-ready expansion (parity backlog, 2026-06-05)

Repro A — missing surface (today)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r "var_export(function_exists(\"xml_parser_create\"));"'
# false
php -r 'var_export(function_exists("xml_parser_create"));'
# true (Zend with ext/xml)

Repro B — parse_into_struct parity (target)

<?php
$xml = '<root><item id="1">a</item></root>';
$p = xml_parser_create();
xml_parse_into_struct($p, $xml, $vals, $index);
xml_parser_free($p);
echo $vals[1]['tag'], "\n";

Runtime	$vals[1]['tag']
Zend	item
VM today	undefined function

v1 API surface (claim scope)

Function	php-src	v1
xml_parser_create	ext/xml/xml.c	yes
xml_parser_free	same	yes
xml_parse	same	yes
xml_parse_into_struct	ext/xml/xml.c	yes (repro driver)
xml_parser_create_ns	ext/xml/compat.c	defer phase 2
xml_set_element_handler	same	defer phase 2

Scope reminder

• PHP-in-PHP first: parser state machine in ext/xml/*.php where feasible; thin libxml2 ABI only if unavoidable.
• Docker: libxml2-dev already on php-compiler:22.04-dev image.

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter xml_parser'
./script/ci-fast.sh --filter xml_parser

Done when (add)

• function_exists('xml_parser_create') true; repro B prints item
• Invalid XML → false from xml_parse like Zend (smoke in .phpt)
• Capability matrix updated

[PurHur]

claim: PHP Compiler Ext — DOM & XML — starting this run (xml_parse_into_struct phase 1b)

[PurHur]

Merged via #17844.

Verification (Docker):

source script/php-env.sh
vendor/bin/phpunit test/unit/XmlParseIntoStructTest.php --no-configuration  # OK (4)
php bin/vm.php test/repro/maintainer_gap_xml_parse_into_struct.php          # ok

Phase 1b xml_parse_into_struct now builds Zend-matching values/index arrays (case-folded tag keys). xml_parser_create/xml_parse/xml_parser_free were already green.