Stdlib: DateTime object identity — instanceof false and instance methods fail (ext/date/php_datetime.c)

[PurHur]

Category

stdlib

Problem

new DateTime(...) is partially wired (#3072 closed) but instances are broken at runtime:

• ($dt instanceof DateTime) is false (Zend: true)
• $dt->getTimestamp() / $dt->format(...) fail with Method call on non-object

Procedural date() works; OOP DateTime is required for timezone-aware code, sessions, and bootstrap inventory paths that construct DateTime objects.

Verified 2026-06-04 on master:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r "
\$d = new DateTime(\"2020-01-01\");
echo (\$d instanceof DateTime) ? \"instanceof_ok\n\" : \"instanceof_fail\n\";
"'
# → instanceof_fail

php-src reference

• php/php-src ext/date/php_datetime.c
• php/php-src ext/date/php_datetime.stub.php — DateTime, method signatures
• php/php-src ext/date/php_date.c — shared parse/format helpers

Repro (failure today)

test/repro-maintainer/datetime_instanceof_methods.php:

<?php
$d = new DateTime('2020-01-01');
echo ($d instanceof DateTime) ? 'instanceof_ok' : 'instanceof_fail', "\n";
echo $d->getTimestamp(), "\n";
echo $d->format('U.u'), "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/datetime_instanceof_methods.php
php bin/vm.php test/repro-maintainer/datetime_instanceof_methods.php
'

Engine	Output
Zend PHP 8.x	instanceof_ok, 1577836800, 1577836800.000000
bin/vm.php	instanceof_fail, then method-call fatal

Scope (this repo)

Module	Path	Notes
Builtin class registry	lib/VM/BuiltinClasses.php	DateTime must register as builtin with correct ClassEntry identity for instanceof
DateTime VM	lib/VM/DateTimeSupport.php, lib/VM/Builtin/DateTime*.php	object wrapper + method dispatch
Compiler	lib/Compiler.php	new DateTime lowering
JIT/AOT	lib/JIT/Builtin/StringDateTime.php	phase 2: #4043; fix VM identity first
Tests	test/compliance/cases/stdlib/datetime_instanceof_methods.phpt	add if missing
Matrix	script/capability-syntax.php	DateTime row

PHP-in-PHP: keep parse/format in PHP/VM helpers; host date extension acceptable for v1 (same as #3072).

Done when

• ($d instanceof DateTime) is true for new DateTime(...) on VM
• $d->getTimestamp(), $d->format('U.u'), $d->setTimezone(new DateTimeZone('UTC')) work without "Method call on non-object"
• Repro script passes under php bin/vm.php
• ./script/ci-fast.sh --filter datetime_instanceof green
• docs/capabilities-syntax.md DateTime row accurate (VM ✅; JIT defer Stdlib: DateTime / DateTimeZone — JIT/AOT method lowering (phase 2 of #3072) #4043)

Verification

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

Related

• Stdlib: DateTime / DateTimeImmutable OOP (ext/date parity) #3072 (closed) — phase 1 DateTime VM
• Stdlib: DateTimeImmutable / DateInterval — ext/date OOP phase 2 (#3072 follow-up) #3162 DateTimeImmutable / DateInterval follow-up
• Stdlib: DateTime / DateTimeZone — JIT/AOT method lowering (phase 2 of #3072) #4043 DateTime JIT/AOT lowering
• Stdlib: DateTime::createFromInterface() / DateTimeImmutable::createFromInterface() (ext/date/php_date.c) #5936 DateTime::createFromInterface()
• North star: Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

Verified on master (2026-06-08): repro passes — instanceof_ok, getTimestamp/format match Zend. No code change needed; closing as already fixed.

[PurHur]

Closing: fixed on master before this run. VM repro green.