Language: IS_REPEATABLE attributes + ReflectionAttribute::isRepeated() — compile rejects valid repeats (zend_attributes.c)

[PurHur]

Summary

User attributes declared with Attribute::IS_REPEATABLE must allow multiple instances on the same target, and ReflectionAttribute::isRepeated() must report whether each instance is a duplicate of an earlier one on that target. This compiler rejects all repeated attributes at compile time and does not register isRepeated() on the builtin ReflectionAttribute class.

php-src-strict: match Zend/zend_attributes.c (zend_is_attribute_repeated, zend_mark_attribute_repeatable) and ext/reflection/php_reflection.c (ReflectionAttribute::isRepeated).

Repro (verified 2026-06-06, Docker php-compiler:22.04-dev)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_attr_isrepeated2.php
php test/repro/maintainer_attr_isrepeated2.php
'

Runtime	Result
Zend PHP 8.2	2 / rep0 / norep1 (isRepeated() true only on first of duplicate pair)
VM	CompileError: Attribute "Rep" must not be repeated

Root cause sketch: lib/Compiler/AttributeNames.php::assertNoDuplicates() always fatals on duplicate names without reading the attribute class flags for IS_REPEATABLE (128). lib/VM/BuiltinClasses.php registers ReflectionAttribute with getName / getArguments / newInstance only — no isRepeated.

Related repro

Bitmask ctor args using named Attribute:: constants (non-literal fold) fail separately — see #6907 (sibling issue filed this run).

php-src reference

Area	File
Repeatable flag on #[Attribute]	Zend/zend_attributes.c — zend_mark_attribute_repeatable
Compile-time duplicate guard	Zend/zend_compile.c — zend_is_attribute_repeated
Reflection API	ext/reflection/php_reflection.c — ReflectionAttribute::isRepeated

Implementation (PHP-in-PHP)

1. Compiler: when collecting attribute names on a target, skip assertNoDuplicates fatals for classes whose registered Attribute flags include IS_REPEATABLE; store instance index for reflection.
2. VM: add ReflectionAttribute::isRepeated(): bool on builtin class entry; populate from compile metadata in lib/VM/ReflectionSupport.php.
3. JIT/AOT: mirror metadata in reflection tables (same path as getName / newInstance, Language: ReflectionAttribute::newInstance() — JIT/AOT (phase 2 of #3206, ext/reflection/php_reflection.c) #4598).

Done when

• test/repro/maintainer_attr_isrepeated2.php matches Zend on VM
• First repeated instance: isRepeated() === true; second+: false (Zend parity)
• test/compliance/cases/language/attribute_is_repeatable.phpt added
• ./script/ci-fast.sh --filter attribute_is_repeatable green

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/compliance/VMTest.php --filter attribute_is_repeatable
'

Pairs with umbrella #4392 (attributes); claim this slice only.

[PurHur]

Cross-ref fix: bitmask ctor sibling is #6913 (not #6907).

[PurHur]

claim: worker-lane-a — starting this run

[PurHur]

Merged via #6959.

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro/maintainer_attr_isrepeated2.php
vendor/bin/phpunit test/compliance/VMTest.php --filter attribute_is_repeatable
'

Output: 2 / rep0 / rep1 — matches Zend (both duplicate instances report isRepeated() === true).

Implementation (PHP-in-PHP)

• lib/Compiler/AttributeClassRegistry.php — tracks #[Attribute] flags at compile time
• lib/Compiler/AttributeNames.php::validateDuplicates() — skips fatal for IS_REPEATABLE classes
• lib/VM/Builtin/ReflectionAttributeIsRepeated.php + ReflectionSupport metadata