Regression: var_export() array keys with NUL bytes — stripped labels not php-src concatenation (ext/standard/var.c) #13875

Summary

var_export() on arrays whose keys contain NUL bytes (e.g. output of get_mangled_object_vars()) must emit php-src’s concatenation form for those keys. This compiler prints stripped key labels (NUL bytes omitted from the exported source), breaking round-trip/debug parity.

php-src reference: ext/standard/var.c — php_var_export() / hash key export with \0 bytes ('' . "\0" . '*' . "\0" . 'w' style).

PHP implementation target: ext/standard/VmVarExport.php (VM SSOT) + JIT route through shared helper (#9189); no new C runtime logic.

Repro (verified 2026-06-30)

test/repro/maintainer_gap_var_export_mangled_array_keys.php

<?php
declare(strict_types=1);
class C { protected $w = 1; private $p = 2; }
$exported = var_export(get_mangled_object_vars(new C()), true);
if (!str_contains($exported, '\0')) { exit(1); }
echo "ok\n";

./script/docker-exec.sh -- php test/repro/maintainer_gap_var_export_mangled_array_keys.php   # Zend: ok
./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer_gap_var_export_mangled_array_keys.php  # VM: fail

Note: underlying array keys from get_mangled_object_vars() are correct (NUL bytes present); only export formatting diverges.

Done when (php-src-strict)

• var_export() emits php-src concatenation for keys containing \0 (VM)
• JIT/AOT match VM when var_export is lowered
• Compliance guard under test/compliance/ or committed test/repro/
• PR cites var.c and notes any LLVM shrink if JIT path touched

Related

• php-in-php: JIT StringVarExportJit — route var_export() through VmVar PHP not __compiler_var_export LLVM (#1492) #9189 (JIT var_export php-in-PHP migration)
• Stdlib: get_mangled_object_vars() — private/protected mangled keys (ext/standard/var.c parity) #3497 / Stdlib: get_mangled_object_vars() on enum case — name/value array not TypeError (ext/standard/var.c) #10152 (get_mangled_object_vars enum operand — distinct)
• Epic Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492