Stdlib: parse_str() — second argument must accept uninitialized by-ref $result (ext/standard/basic_functions.c)

[PurHur]

Category

stdlib · php-src-strict · spec refresh 2026-06-20

Problem

Two gaps in parse_str($encoded, $result) vs Zend:

1. Uninitialized by-ref $result (original scope)

Zend accepts an uninitialized variable passed by reference, allocates/populates the array. VM requires $result to already be an array (LogicException: argument #2 must be an array).

2. Return value — PHP 8+ void return (added 2026-06-20)

Since PHP 8.0, parse_str() returns null (void). VM returns true (ext/standard/parse_str.php sets $frame->returnVar->bool(true)).

Verified:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php -r "parse_str(\"a=1\", \$out); var_export(\$out);"
php bin/vm.php -r "parse_str(\"a=1\", \$out); var_export(\$out);"
'

Call	Zend	VM today
parse_str('a=1', $out); var_export($out);	array('a'=>'1')	same array ✓
Return value of parse_str(...)	null	true ❌

Distinct from #4050 (one-arg form) and #4219 (third-arg prefix).

php-src reference

• php/php-src ext/standard/basic_functions.c — PHP_FUNCTION(parse_str) / php_parse_str()
• By-ref $result may be undefined; Zend creates the array in place
• PHP 8+: function return type void (returns null in userland)

Repro

By-ref uninitialized:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parse_str_byref.php 2>&1
php bin/vm.php test/repro-maintainer/parse_str_byref.php 2>&1
'

Call	Zend PHP 8.x	VM today
parse_str('a=1&b=2', $result) (uninit $result)	populated array	LogicException ❌

Return value:

<?php
declare(strict_types=1);
$out = [];
var_export(parse_str('a=1', $out));
echo "\n";
var_export($out);
echo "\n";

Scope (this repo)

Area	Files
VM	ext/standard/parse_str.php, VmParseStr.php — void return + uninit by-ref
JIT	JitParseStr.php — write through by-ref slot when unset; no bool return
Tests	test/compliance/cases/stdlib/parse_str_byref.phpt, parse_str_return_null.phpt

PHP-in-PHP: #9295 routes JIT through VmHttp — VM semantics first.

Done when

• Uninitialized / non-array by-ref target replaced with parsed array (Zend semantics)
• parse_str() return is null, not true
• Existing array target merged/replaced per php-src rules
• JIT/AOT match VM
• ./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter parse_str' green

Links

• Stdlib: parse_str() — reject one-argument form in all scopes (PHP 8+ ext/standard/basic_functions.c) #4050, Stdlib: parse_str() — third-argument prefix (ext/standard/basic_functions.c parity) #4219, php-in-php: JIT StringParseStrJit — route parse_str() through VmHttp PHP not __compiler_parse_str LLVM (#1492) #9295, Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: worker-lane-a — starting this run

[PurHur]

claim released: repro green on master — parse_str returns NULL and uninitialized by-ref works; compliance tests parse_str_byref_uninit + parse_str_return_void pass. Pivoting to next lane-A issue.

[PurHur]

Closing as stale — repro green on master 2026-07-13 (lane-A queue scan).

./script/phpunit.sh --filter 'parse_str_byref_uninit|parse_str_return_void'
# OK (5 tests, 9 assertions)

Uninitialized by-ref $result and PHP 8+ null return both match Zend. Prior Jul-2026 unclaim comment confirmed; left open in error.