Swift Modal Self Becomes Nil

Question

I have a UIViewController that when a button is pressed I open another View from a segue. When it opens everything is fine and all the functionality works. However, if I close the modal and then try to re-open it, self is nil.

This is the code I'm using to open the Modal:

self.performSegueWithIdentifier("Search", sender: self)

My modal has a segue defined as:

Present Modally

Over Full Screen

I then have a close button within the modal that does the following:

dismissViewControllerAnimated(true, completion: nil)

Finally, when I try to open the modal again with the "Search" segue self within the modal's UIViewController is nil .

Therefore, when I try to use it, I get this message:

fatal error: unexpectedly found nil while unwrapping an Optional value

I assume I'm keeping a reference to the UIViewController somewhere, I just don't know how.

Any advice is appreciated.

Answer 1

Okay,

So it turns out the code that I omitted was causing the issue. My apologies, I just did not think it would be caused by it, as it was working in all other use cases.

I am using Socket.IO to communicate with a NodeJS server in real time.

Within a socket.on:

var user = User.sharedInstance

user.socket!.on("search") {[weak self]data, ack in

        var json = JSON(data!)

        self.songs.removeAll() // <- Caused the error.

...

So it turns out that the [weak self] causes the self to be nil if it was already set before. So the first time I would open the Modal, the user.socket!.on('search') {[weak self] data, ack in ... worked fine, although the second time, when I referred to self within the socket call again, it caused it to be null.

Thank you!