Hello!
I've been maintaining a Cordova-based calling application for years. Cordova uses a webview to show the user interface and has a bridge for calling native iOS API from JavaScript. The application uses CallKit and VoIP push notifications to handle the calling functionality.
Before the iOS 17.5 update, calling worked relatively stable. However, starting from this version and on, Safari instantly force-closes all open websocket connections when the "Answer" button on the calling UI is hit. So, basically, the call ends right after it answers, because in our case websockets are crucial for the SIP negotiation process.
Firstly, I inspected the Safari console, and there is a new red error saying: WebSocket connection to 'wss://home.thirdlane.com/wss' failed: The operation couldn’t be completed. Software caused connection abort.
Secondly, I checked the Xcode logs, and there are several warnings saying Invalidating grant <invalid NS/CF object> failed every time the call is answered.
And, I'm afraid this is all that I have to cling to.
I managed to mitigate the effect by connecting the websockets only when the call is answered and the application is focused. However, this approach has its own drawbacks and doesn't solve all the problematic cases.
I must mention that the behavior has slightly improved in iOS 17.6 – now the websockets are cut after the "Answer" button hit whereas in 17.5.1 they were cut in ~3 seconds after the VoIP push regardless of whether the answer was made.
This looks like a Safari/WebView bug to me and I would like bring it to the Apple's attention. I've never filed a bug before, so hopefully this is the right place to write.
I can provide more logs or vidoes upon request.
Thank you!