runblock retain self reference cause memory dealloc issue

Question

Here is my code:

ship.runAction(SKAction.waitForDuration(5), completion: {
    self.ship.flyStraight()//retain self
})

After several days googling for the memory issues, finally I found that I had a self retain in this block. When I create the new scene before the block has run, the deinit function won't be called because the reference in the block.

I have to write in this way in my game, and what can I do to avoid this issue. What did you with code like this?

The Swift documentation has a section about ["Resolving Strong Reference Cycles for Closures"](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/AutomaticReferenceCounting.html#//apple_ref/doc/uid/TP40014097-CH20-ID57) ... — Martin R, Jan 25 '15 at 17:31
Can you confirm that `deinit` is not called? since 'self' does not have a reference to the block (no strong reference cycle) wouldn't the block get reallocated when the action finishes? — , Jan 25 '15 at 17:32
^ Deallocated not reallocated (sorry typo, too late to edit) — , Jan 25 '15 at 17:39
@Okapi "When I create the new scene before the block has run" This is why the deinit won't be called. After the block finished, deinit will be called. — Alfred, Jan 26 '15 at 02:19
@MartinR You can edit your comment and post an answer. I added `[unowned self] in` to my code and everything looks fine! Thanks a lot! — Alfred, Jan 26 '15 at 06:07

score 6 · Accepted Answer · edited May 23 '17 at 12:09

6

For anyone who got the same issue. I changed my code to :

ship.runAction(SKAction.waitForDuration(5), completion: {
        [unowned self] in
        self.ship.flyStraight()        
    })

Use [unowned self] in in your block won't add a strong reference to self.

Thanks for Martin's link: "Resolving Strong Reference Cycles for Closures"

You can also take a look at this question

edited May 23 '17 at 12:09

Community

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answered Jan 26 '15 at 06:13

Alfred

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runblock retain self reference cause memory dealloc issue

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