Stdlib: json_validate() — validate JSON without full decode (PHP 8.3, ext/json parity)

[PurHur]

Category

stdlib

Status (refreshed 2026-06-07 — implementation-ready)

Phase 0 landed: json_validate() is registered in ext/standard/Module.php; VM returns true/false for valid/invalid JSON via VmJsonScanner / ext/standard/json_validate.php.

Remaining gaps (worker targets):

• Stdlib: json_validate() — flags argument parity (phase 2 of #3101) #4085 — $flags argument parity (phase 2)
• Stdlib: json_validate()/preg_split()/preg_grep()/preg_quote() — enum operands must TypeError not LogicException (php-src-strict) #5999 — enum-case operands must TypeError (php-src-strict)
• JIT/AOT lowering still deferred (VM-only in matrix)

Problem

PHP 8.3 added json_validate(string $json, int $depth = 512, int $flags = 0): bool. Phase 0 exists; behavior must match php-src for depth/ValueError and strict operand guards.

php-src reference

• php/php-src ext/json/json.c — PHP_FUNCTION(json_validate), php_json_validate_ex
• Parser-only path (no zval tree)

Repro (verify today)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php -r "var_export(json_validate(\"{\\\"a\\\":1}\")); echo PHP_EOL; var_export(json_validate(\"{\")); echo PHP_EOL;"
php bin/vm.php -r "var_export(json_validate(str_repeat(\"{\", 600)));" 2>&1 | head -1
'

Check	Zend PHP 8.3+	VM (2026-06-07)
json_validate('{"a":1}')	true	true ✅
json_validate('{')	false	false ✅
depth exceeded	ValueError	verify / fix if diverges

Scope (this repo)

Path	Work
ext/standard/json_validate.php	Depth limit + flags (#4085)
ext/standard/VmJsonScanner.php	Shared scanner with json_decode
JIT	lib/JIT/Builtin/StringJson*.php when required
Tests	test/compliance/cases/stdlib/json_validate*.phpt

Done when

• Repro depth/ValueError matches Zend
• $flags subset documented + tested (Stdlib: json_validate() — flags argument parity (phase 2 of #3101) #4085)
• Enum operands TypeError under php-src-strict (Stdlib: json_validate()/preg_split()/preg_grep()/preg_quote() — enum operands must TypeError not LogicException (php-src-strict) #5999)
• Capability matrix: JIT/AOT when lowered

Verification

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

Related

• Stdlib: json_validate() — validate JSON without full decode (PHP 8.3, ext/json parity) #3101 (this) · Stdlib: json_validate() — flags argument parity (phase 2 of #3101) #4085 flags · Stdlib: json_validate()/preg_split()/preg_grep()/preg_quote() — enum operands must TypeError not LogicException (php-src-strict) #5999 enum strict · Bootstrap: VmJson json_encode/json_decode — native serialization without host json extension #4795 bootstrap native JSON · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: lane-c-worker — starting this run