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Stdlib: json_decode() malformed UTF-8 — JsonException message wrong vs Zend (ext/json/php_json.c) #10518
Description
Summary
With JSON_THROW_ON_ERROR, decoding invalid UTF-8 should throw JsonException: Malformed UTF-8 characters, possibly incorrectly encoded. This compiler throws JsonException: Syntax error.
php-src reference
ext/json/php_json.c—php_json_decode_ex()UTF-8 validation / error mapping
Repro
<?php
declare(strict_types=1);
var_dump(json_decode("\xFF", flags: JSON_THROW_ON_ERROR));Zend: JsonException: Malformed UTF-8 characters, possibly incorrectly encoded
VM: JsonException: Syntax error
Expected (php-src-strict)
Match Zend exception message (and code if applicable) for invalid UTF-8 input.
Implementation hints
ext/json/VM path — distinguish UTF-8 validation failure from JSON syntax failure before/alongside parser errors- Related: Stdlib: json_decode()/json_encode() with JSON_THROW_ON_ERROR must throw JsonException (ext/json/php_json.c) #9032 (JSON_THROW_ON_ERROR general parity)
Done when
- Repro matches Zend message on VM
- Targeted test under
test/compliance/or unit test
Activity
PurHur commentedon Jun 24, 2026
Maintainer repro update (2026-06-24): On current master the VM no longer throws
JsonException: Syntax error— it returnsNULLwithout throwing whenJSON_THROW_ON_ERRORis set on malformed UTF-8 (\\xFF). See #11282 +test/repro/maintainer_gap_json_decode_throw_utf8_null.php. Fixing throw path should restore message/code parity described here.PurHur commentedon Jul 4, 2026
claim: cursor-agent-lane-a — starting this run
PurHur commentedon Jul 4, 2026
claim released: repro green on master — maintainer_gap_json_decode_utf8.php prints Malformed UTF-8 message + code 5 on VM.
PurHur commentedon Jul 13, 2026
Maintainer triage 2026-07-13: json_decode("\xFF", JSON_THROW_ON_ERROR) message matches Zend (Malformed UTF-8…). Closing as fixed.