Bug #79404 [Com]: Referencing to SplFixedArray interrupts foreach loop

Edit report at https://bugs.php.net/bug.php?id=79404&edit=1 ID: 79404 Comment by: alexinbeijing at gmail dot com Reported by: vlad dot turchinskiy at yandex dot ru Summary: Referencing to SplFixedArray interrupts foreach loop Status: Verified Type: Bug Package: SPL related Operating System: all PHP Version: 5.4.0 - 7.4.4 Block user comment: N Private report: N New Comment: > I do think we should ensure that multiple parallel get_iterator()s are supported independently > of that. Nikita, I don't understand how SplFixedArray could possibly support multiple parallel get_iterator()s while still following the contract of the Iterator interface. Could you explain what you mean? Previous Comments: ------------------------------------------------------------------------ [2020-03-23 14:04:26] nikic@php.net SplFixedArray should probably be IteratorAggregate rather than Iterator... I do think we should ensure that multiple parallel get_iterator()s are supported independently of that. ------------------------------------------------------------------------ [2020-03-23 11:03:27] cmb@php.net Yes, a single foreach loop works certainly as expected; the problem is *nesting* of foreach loops: <?php $spl = SplFixedArray::fromArray([0, 1]); foreach ($spl as $el1) { foreach ($spl as $el2) { echo "$el1.$el2\n"; } } ?> outputs 0.0 0.1 while you want to get 0.0 0.1 1.0 1.1 It seems to me that this behavior is correct for Iterators; maybe not for IteratorAggregates. ------------------------------------------------------------------------ [2020-03-23 01:51:35] vlad dot turchinskiy at yandex dot ru cmb@php.net, as far as SPLFixedArray implements Traversable, it is expected to support foreach. I updated code, to make the difference more obvious: https://3v4l.org/N9k7P Please, note, that in the test code i provided, unless we use $collection->getSum() inside the loop - it works as expected. ------------------------------------------------------------------------ [2020-03-22 23:32:58] cmb@php.net Presuming for Iterators foreach ($it as $el) { var_dump($el); } is equivalent to for ($it->rewind(); $it->valid(); $it->next()) { $el = $it->current(); var_dump($el); } the behavior is correct. On the other hand, SplDoublyLinkedList, for instance, supports nested traversal via foreach ... ------------------------------------------------------------------------ [2020-03-22 15:50:30] vlad dot turchinskiy at yandex dot ru Description: ------------ Referencing to SplFixedArray interrupts foreach loop. Test script: --------------- https://3v4l.org/FdN4i Expected result: ---------------- 3 iterations executed. Actual result: -------------- 1 iteration executed. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=79404 -- Edit this bug report at https://bugs.php.net/bug.php?id=79404&edit=1