Regression: AppendIterator/LimitIterator/CachingIterator null TypeError cites IteratorIterator — Zend method+Iterator (ext/spl/spl_iterators.c)

[PurHur]

Category

Regression: · php-src-strict · SPL iterator null-inner TypeError message

Problem

Passing null where an Iterator is required throws on both engines, but VM attributes the TypeError to IteratorIterator::__construct with type Traversable. Zend cites the concrete method (AppendIterator::append, LimitIterator::__construct, CachingIterator::__construct) and type Iterator.

Same message-attribution class as open #31509 (SplObjectStorage::offsetSet citing attach).

Probed 2026-08-16 — host Zend PHP 8.2.32 vs php bin/vm.php.

Repro	Zend 8.2+	VM (2026-08-16)
(new AppendIterator())->append(null)	TypeError: AppendIterator::append(): Argument #1 ($iterator) must be of type Iterator, null given	TypeError: IteratorIterator::__construct(): Argument #1 ($iterator) must be of type Traversable, null given
new LimitIterator(null)	LimitIterator::__construct(): … Iterator, null given	IteratorIterator::__construct(): … Traversable, null given
new CachingIterator(null)	CachingIterator::__construct(): … Iterator, null given	IteratorIterator::__construct(): … Traversable, null given

Also affects siblings that share the same parent check (NoRewindIterator, InfiniteIterator, MultipleIterator::attachIterator, RecursiveIteratorIterator) — fix the shared guard once.

php-src reference

• php/php-src ext/spl/spl_iterators.c — Z_PARAM_OBJ_OF_CLASS / typed Iterator on append/ctors
• Stubs: php/php-src ext/spl/spl_iterators.stub.php

PHP implementation target

• ext/spl/ iterator builtins — type-check with Zend receiver method name + Iterator (not parent IteratorIterator / Traversable)
• Prefer shared PHP guard used by Append/Limit/Caching/NoRewind/Infinite/Multiple/RII
• No new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'php test/repro/maintainer_gap_spl_iterator_null_inner_message.php'
./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_spl_iterator_null_inner_message.php'

Done when

• TypeError messages match Zend method + Iterator for Append/Limit/Caching (and listed siblings)
• Targeted compliance/PHPUnit guard
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: PHP Compiler Ext — I/O & Crypto — starting this run

Implementing AppendIterator/LimitIterator/CachingIterator null-inner TypeError to cite the concrete method + Iterator (not IteratorIterator/Traversable).

[PurHur]

Merged via #31520

Verification (local Docker):

• Zend + VM: test/repro/maintainer_gap_spl_iterator_null_inner_message.php — identical TypeError lines for Append/Limit/Caching/NoRewind/Infinite/Multiple/RII/IteratorIterator
• ./script/phpunit.sh --filter Issue31513SplIteratorNullInnerTypeErrorTest — OK (1 test, 12 assertions)

Shared guard: SplDualIteratorStorage::resolveIterator(..., $function, 'Iterator'|'Traversable'); RII object TypeError; RecursiveFilterIterator → requireRecursiveIteratorArg.