There's a retain loop between SubscriptionListener and ListenerToken if listener is added by SubscriptionSession.add(_:ListenerType)

[AirBlack]

SubscriptionListener has a strong reference to SubscriptionToken, SubscriptionToken has a strong reference to SubscriptionListener through it's cancellation closure capture group.

[dterekhov]

It crashed for me at the same line: self?.privateListeners.remove(listener)
Here is a hint of how it was precisely caught: before the app was in the state sceneWillResignActive and on switching to sceneDidBecomeActive it crashed.

[AirBlack]

It didn't crash for me but cos of retain loop and caching the subscription didn't clean itself and was stuck providing the app with duplicate/invalid values. I fixed it by somehow cleaning the subscription manually. I will post a workaround when I'll be next time around my working device.

[parfeon]

There will be fix for this, so as soon as subscription listener instance will go out of scope, it will be removed from list of listeners and free-up resources properly.

[pubnub-release-bot]

@AirBlack this issue is addressed in 6.0.3

[luisescamilla13]

Still getting the error with 6.0.3 :(
In $specialized Set._Variant.update(with:)

[parfeon]

@luisescamilla13 hello. What exactly error do you get?
This issue was about retain cycle.

[parfeon]

@luisescamilla13 is it possible to show place. where you experience issue in same way, as shown in first message?

[luisescamilla13]

@parfeon sure
This is the crash:

SIGSEGV : Crash due to signal: SIGSEGV(SEGV_MAPERR) at 00000010
$specialized Set._Variant.update(with:) (<compiler-generated>:0 )

This is the code where I initialize pubnub:

        // Setup PNConfiguration
        var configuration = PubNubConfiguration(publishKey: keys.publishKey, subscribeKey: keys.subscriptionKey, uuid: email)
        configuration.authKey = keys.token
        pubnub =  PubNub(configuration: configuration)
        listener = SubscriptionListener(queue: .main)
        pubnub.add(listener)

And here is the stack trace:

[parfeon]

@luisescamilla13 do you store somewhere reference on listener? Without reference to it, the object will be deallocated right away.

[luisescamilla13]

@parfeon yes sir, my class has the following variable
let listener: SubscriptionListener
And the value is initialized in the init of my class

[parfeon]

@luisescamilla13 is there any chance to have some minimum app which is able to reproduce this issue? With memory leak, we were able to reproduce it and fix, but I can't reproduce this one.

[luisescamilla13]

@parfeon to be honest I haven't been able to reproduce it by myself, we just get this random crash every two or three weeks from different users. I'll let you know if I get more details. Thanks for the response.

[parfeon]

@luisescamilla13 thank you!
If possible, can you create a new issue, so we won't bother issue author on a non-related topic?

[dterekhov]

Continue getting crashes with the 6.0.5 latest version.
Please pay attention that the app crashes on com.apple.root.user-initiated-qos.cooperative thread + when going to the background state.

cc @parfeon
Can you please re-open this issue?