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Regression: json_decode() JSON_THROW_ON_ERROR on malformed UTF-8 — returns NULL, no JsonException (ext/json/php_json.c) #11282
Description
Category
stdlib · php-src-strict · regression
Problem
With JSON_THROW_ON_ERROR, invalid UTF-8 input must throw JsonException (message Malformed UTF-8 characters, possibly incorrectly encoded, code 5). This compiler’s VM returns NULL and does not throw, so try/catch (JsonException) never runs and scripts continue as if decode succeeded.
Related: #10518 (wrong exception message when throw path exists) — current master behavior is worse (silent NULL). #9032 (general JSON_THROW_ON_ERROR parity).
php-src reference
- php/php-src
ext/json/php_json.c—php_json_decode_ex()UTF-8 validation before parse
Repro
test/repro/maintainer_gap_json_decode_throw_utf8_null.php
<?php
declare(strict_types=1);
try {
json_decode("\xFF", flags: JSON_THROW_ON_ERROR);
echo "no_exception\n";
} catch (JsonException $e) {
echo $e->getMessage(), "\n";
echo $e->getCode(), "\n";
}
$r = json_decode("\xFF", flags: JSON_THROW_ON_ERROR);
echo 'result=', var_export($r, true), "\n";./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro/maintainer_gap_json_decode_throw_utf8_null.php
php bin/vm.php test/repro/maintainer_gap_json_decode_throw_utf8_null.php'| Step | Zend PHP 8.2 | This compiler VM |
|---|---|---|
try/catch block |
prints message + code 5 |
prints no_exception ❌ |
bare json_decode |
JsonException fatal |
result=NULL, exit 0 ❌ |
Scope (PHP-in-PHP)
| Layer | Path |
|---|---|
| VM | ext/standard/VmJson*.php / ext/json/ — enforce UTF-8 validation when JSON_THROW_ON_ERROR set |
| Tests | repro + compliance; close or narrow #10518 once throw path restored |
Done when (php-src-strict)
- Malformed UTF-8 with
JSON_THROW_ON_ERRORalways throwsJsonException(never silentNULL). - Message/code match Zend; may subsume Stdlib: json_decode() malformed UTF-8 — JsonException message wrong vs Zend (ext/json/php_json.c) #10518 when verified.
Activity
PurHur commentedon Jun 24, 2026
claim: PHP Compiler STD Lib — batch (issues #11272, #11280, #11282)
PurHur commentedon Jun 24, 2026
Verified on current master —
json_decode("\xFF", flags: JSON_THROW_ON_ERROR)throwsJsonExceptionwith code 5 on VM. No code change needed this run.PurHur commentedon Jul 5, 2026
claim: PHP Compiler STD Lib — starting this run
PurHur commentedon Jul 5, 2026
claim released: repro green on master — maintainer_gap_json_decode_utf8.php and compliance json_decode_utf8_error.phpt throw JsonException with message + code 5 on VM. Pivoting.
PurHur commentedon Jul 10, 2026
claim: PHP Compiler Ext — I/O & Crypto — starting this run (pivot from #17679 already green on master)
PurHur commentedon Jul 10, 2026
Handoff: repro green on master —
json_decode("\xFF", flags: JSON_THROW_ON_ERROR)throws JsonException with code 5; compliancejson_decode_utf8_errorpasses. Pivoting to #17721.PurHur commentedon Jul 12, 2026
Stale: verified green on master (2026-07-12, lane-C hygiene run).
VM throws
JsonExceptionon malformed UTF-8 with JSON_THROW_ON_ERROR — matches Zend.