In-App Messaging Crash - main thread must be used

[djw27]

SDK version: 2.4.2

Environment: Development

Describe the bug
With in-app messaging enabled & with page rules setup as the trigger for displaying the in-app message, the app crashes when trying to show the in-app message.

When logging screen views with customerio, i.e. cio.screen('ScreenName') we're doing so on a background thread. When this eventually calls through to setCurrentRoute of Gist and ultimately invokes a MessageManager which tries to initialise a WKWebView we get the error -[WKWebView .cxx_construct] must be used from main thread only.

To Reproduce

• Create an in-app message in customerio with a page rule trigger
• Setup the app to log screen views with .screen()
• Visit the screen in the app that matches the page rule trigger
• App crashes

Screenshots

Additional context
I can see that the library makes use of DispatchQueue.main.async to execute tasks on the main thread when initializing the library and registering for push notifications.

I can verify that wrapping the main CustomerIO.shared.screen(name: name) call with this 'fixes' the problem, i.e.

func screen(name : String, data : Dictionary<String, AnyHashable>?) -> Void {
...
  DispatchQueue.main.async {
    CustomerIO.shared.screen(name: name)
  }
...
}

To be a bit more specific, the following also works by overriding specifically where we bridge from customerio -> Gist:

extension MessagingInAppImplementation: ScreenTrackingHook {
    public func screenViewed(name: String) {
        logger.debug("setting route for in-app to \(name)")

        DispatchQueue.main.async {
            self.inAppProvider.setRoute(name)
        }
    }
}

I'm not sure on the implications of this as a solution, though. Thoughts? I would have thought that this issue would be impacting everyone trying to use in-app messaging so a little surprised it hasn't been raised before, unless we're doing something obviously incorrect?

[Shahroz16]

Hey @djw27, thank you for reporting this. We are having a look into this and will report back with the findings. Apologies for inconvenience.