App crashes when USB cord is pulled immediately after accessory setup

[NicoleYarroch]

Bug Report

When app is connected to a SDL accessory via a iAP connection, the app crashes when USB cord is pulled right after the icon shows up on the screen, but before the app launches on the SDL HMI. This bug is an edge case is is difficult to reproduce.

There are three issues that may be at play

1. Notifications are not being unsubscribed to properly in the SDLIAPTransport class. As a result, the app crashes
2. A NSException in the SDLStateMachine is force quitting the app because of invalid state transitions. The ones I have found so far are:
   • old state: Reconnecting, new state: SettingUpHMI
   • old state: Ready, new state: Started
   • old state: Shutdown, new state: StartupError
3. NSStreams in the SDLIAPTransport class are not being closed properly before dealloc is being called.
   • This is because the SDLStreamDelegate is being set to nil before the input and output streams are are closed and released.

Reproduction Steps

1. Use a iAP connection to connect the SDL Example app to a TDK.
2. Launch the app on SDL HMI.
3. Wait until the app has launched and the app has completed setup on the SDL HMI.
4. The app should be in the foreground, pull the USB cord.
5. The app should be in the foreground, reconnect the USB cord. As soon as the app-icon appears on the HMI, but before the app launches, pull the USB cord.
6. The app should crash. (It might take several tries for this to happen - repeat 4 and 5 as necessary)

Expected Behavior

The app should never crash

Observed Behavior

The app crashes

OS & Version Information

• iOS Version: iOS 10 and 11
• SDL iOS Version: 5.0.0 and 4.7
• Testing Against: The SDL_Example app and a TDK (SYNC 3.0)

[NicoleYarroch]

This bug can not be recreated on v. 5.2. Closing issue