Bug #80917 [Com]: LimitIterator does not end at count

Edit report at https://bugs.php.net/bug.php?id=80917&edit=1 ID: 80917 Comment by: rowan dot collins at gmail dot com Reported by: alexandreparent_dev at outlook dot com Summary: LimitIterator does not end at count Status: Open Type: Bug Package: SPL related Operating System: All PHP Version: Irrelevant Block user comment: N Private report: N New Comment: A possibly clearer demonstration of what's happening, using an explicit Iterator rather than a Generator: https://3v4l.org/IrAWU Until the limit is reached, each call to next() on the LimitIterator calls next(), valid(), current(), and key() on the wrapped iterator, in that order. After the limit is reached, it continues to call next(), but none of the other methods. In a foreach loop, this results in exactly one extra call to next(), but it actually passes through *every* call to next(), unconditionally. Previous Comments: ------------------------------------------------------------------------ [2021-03-29 20:36:54] levim@php.net Actually, I agree with you; this _is_ a bug! It should check the limit before iterating to the next value. ------------------------------------------------------------------------ [2021-03-29 20:19:46] levim@php.net I'm pretty sure the test code is wrong based on your expectations; you are incrementing $count and then checking if the count is greater than 2: yield 0; if (1 > 2) // false yield 1; if (2 > 2) // false yield 2; if (3 > 2) // true, but your limit is 3, meaning that you asked for this! You need to reduce the limit to 2, or increase the comparison to $count > 3. ------------------------------------------------------------------------ [2021-03-29 20:11:29] alexandreparent_dev at outlook dot com I inverted actual and expected results. ------------------------------------------------------------------------ [2021-03-29 20:08:53] alexandreparent_dev at outlook dot com Description: ------------ LimitIterator will try to iterate beyond $count. If its inner iterator never yield another item nor return, the LimitIterator will not limit at the expected count. Test script: --------------- <?php function generator(): iterable { $count = 0; while (true) { yield $count++; echo 'Yielded: ', $count - 1, \PHP_EOL; if ($count > 2) { while(true); } } } foreach (new \LimitIterator($generator(), 0, 3) as $count) { echo 'Iterating: ', $count, \PHP_EOL; } Expected result: ---------------- Iterating: 0 Yielded: 0 Iterating: 1 Yielded: 1 Iterating: 2 Yielded: 2 // Hanging here Actual result: -------------- Iterating: 0 Yielded: 0 Iterating: 1 Yielded: 1 Iterating: 2 // Exiting here ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=80917&edit=1