Regression: CachingIterator::setFlags() clears CALL_TOSTRING — Zend InvalidArgumentException (ext/spl/spl_iterators.c)

[PurHur]

Category

Regression · php-src-strict · stdlib (SPL iterators)

Problem

When a CachingIterator was constructed with CachingIterator::CALL_TOSTRING (or the flag is set), php-src refuses to clear that flag via setFlags(): it throws InvalidArgumentException with message Unsetting flag CALL_TO_STRING is not possible. On VM (2026-07-28), setFlags(CachingIterator::FULL_CACHE) and setFlags(0) succeed and drop CALL_TOSTRING.

Repro	Zend 8.2	VM (2026-07-28)
construct with CALL_TOSTRING, then setFlags(FULL_CACHE)	InvalidArgumentException	flags become 256
then setFlags(0)	same exception	flags become 0

php-src reference

• php/php-src ext/spl/spl_iterators.c — CachingIterator::setFlags / CIT_CALL_TOSTRING guard ("Unsetting flag CALL_TO_STRING is not possible")

PHP implementation target

• ext/spl/ CachingIterator setFlags implementation (PHP) — reject clearing CALL_TOSTRING like php-src
• Keep construct/getFlags parity; no new C runtime logic

Repro

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

<?php
$it = new CachingIterator(new ArrayIterator([1]), CachingIterator::CALL_TOSTRING);
$it->setFlags(CachingIterator::FULL_CACHE); // Zend: InvalidArgumentException

Done when

• setFlags that would clear CALL_TOSTRING throws InvalidArgumentException with Zend message
• Flags unchanged after the rejected call
• Compliance or test/repro/ guard
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: PHP Compiler STD Lib Advanced — batch (issues #24273, #24295, #24271, #24272, #24245, #24252)

Sequential PRs in ext/spl iterator surface:

1. Regression: ParentIterator(ArrayIterator) throws InvalidArgumentException — Zend TypeError (ext/spl/spl_iterators.c) #24273 ParentIterator ctor → TypeError
2. Regression: LimitIterator rewind past inner end silent — Zend OutOfBoundsException (ext/spl/spl_iterators.c) #24295 LimitIterator rewind past end → OutOfBoundsException
3. Regression: LimitIterator current()/key() when invalid returns inner value — Zend NULL (ext/spl/spl_iterators.c) #24271 LimitIterator invalid current()/key() → NULL
4. Regression: FilterIterator current() on invalid position throws — Zend NULL (ext/spl/spl_iterators.c) #24272 FilterIterator invalid current() → NULL
5. Regression: AppendIterator::getIteratorIndex() after foreach returns int — Zend null (ext/spl/spl_iterators.c) #24245 AppendIterator getIteratorIndex after foreach → null
6. Regression: CachingIterator::setFlags() clears CALL_TOSTRING — Zend InvalidArgumentException (ext/spl/spl_iterators.c) #24252 CachingIterator setFlags clears CALL_TOSTRING → InvalidArgumentException

Working #24273 first.

[PurHur]

Handoff — batch progressed 4 merges this run (#24273, #24295, #24271, #24272). This issue remains open for the next advanced-stdlib pass; claim still held unless you take over.

Prior merges: ParentIterator TypeError, LimitIterator OOB rewind, LimitIterator invalid current/key NULL, FilterIterator invalid current NULL.

[PurHur]

claim: PHP Compiler STD Lib Advanced — batch (issues #24245, #24252, #24325, #24326, #24327, #24328)

Sequential PRs in ext/spl iterator/heap surface:

1. Regression: AppendIterator::getIteratorIndex() after foreach returns int — Zend null (ext/spl/spl_iterators.c) #24245 AppendIterator::getIteratorIndex() exhausted → null
2. Regression: CachingIterator::setFlags() clears CALL_TOSTRING — Zend InvalidArgumentException (ext/spl/spl_iterators.c) #24252 CachingIterator::setFlags() CALL_TOSTRING clear guard
3. Regression: ArrayIterator::current()/key() on invalid position throw — Zend NULL (ext/spl/spl_array.c) #24325 ArrayIterator invalid current()/key() → NULL
4. Regression: SplDoublyLinkedList::current() on invalid position throws — Zend NULL (ext/spl/spl_dllist.c) #24326 SplDoublyLinkedList invalid current() → NULL
5. Regression: SplObjectStorage::key() always false — Zend returns iterator index (ext/spl/spl_observer.c) #24327 SplObjectStorage::key() iterator index
6. Regression: extending SplPriorityQueue fails construct — Zend allows subclass (ext/spl/spl_heap.c) #24328 SplPriorityQueue subclass construct

Continuing prior handoff on #24245/#24252.

[PurHur]

Merged via squash PR (see linked PR).

Verification: VM repro + vendor/bin/phpunit --filter cachingiterator_setflags_call_tostring OK (2).

Next in batch: #24325 ArrayIterator invalid current()/key() → NULL.