PHPLIB-501: Prevent memory leaks from generators #694
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alcaeus
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| @@ -61,8 +64,7 @@ class CachingIterator implements Countable, Iterator | |||
| */ | |||
| public function __construct(Traversable $traversable) | |||
| { | |||
| $this->iterator = $this->wrapTraversable($traversable); | |||
| $this->storeCurrentItem(); | |||
| $this->iterator = new IteratorIterator($traversable); | |||
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Would it make sense to just prepare the iterator here and store the current item? That might allow you to remove the prepareIterator() calls from other methods.
As-is, there might be a subtle behavioral change, since the original implementation did rewind the traversable, create the generator, and iterate once to store the current item?
jmikola
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Renamed the issue to reflect the actual change and title in JIRA. Also, re: your comment in doctrine/mongodb-odm#2100 (comment), can you elaborate on the subtle behavioral change by switching to IteratorIterator? Does it relate to my earlier comment about removing the |
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That is correct. When using the generator, we immediately start iterating the wrapped traversable. When switching to IteratorIterator, we can still do that (by calling |
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PR adapted to replicate previous behaviour: iteration of the traversable starts when |
https://jira.mongodb.org/browse/PHPLIB-501
This was discovered while investigating doctrine/mongodb-odm#2092. The different behaviour can be seen in action here: https://3v4l.org/UIfIb. Note that when we don't specifically unset the generator, it stays around much longer even though the wrapping iterator has already been garbage collected.