How to fix iOS 13 beta app crash upon opening the app?

Question

My iOS App in App Store works well on iOS 12, and I tried installing it on my development device with iOS 13 Developer Beta 2, but it crashes on launch. It's impossible to get the crash data using crashlytics as it crashes as soon as it launches.

I tried on Xcode 11 Beta 2, but unfortunately some pre compiled framework (Swift 5.0) doesn't allow me to run on Xcode 11. I managed to get a crash report once using crashlytics, posted below.

# Version: 1.58 (1)
   # Bundle Identifier: ------
   # Issue ID: db3066baxxxxxxxeb956f1be
   # Session ID: 013965e31e2d40xxxxxxxx_v2
   # Date: 2019-06-20T08:18:00Z
   # OS Version: 13.0.0 (17A5508m)
   # Device: iPhone XR
   # RAM Free: 3%
   # Disk Free: 9.2%

   #0. Crashed: com.apple.main-thread
    0  libsystem_kernel.dylib         0x1af2e6f04 __pthread_kill + 8
    1  libsystem_pthread.dylib        0x1af4bec20 pthread_kill + 224
    2  (Missing)                      0x721e0e01af366c00 (Missing)
    3  (Missing)                      0x0 (Missing)
    4  (Missing)                      0xe26c301cfe8a500 (Missing)
    5  (Missing)                      0x0 (Missing)
    6  (Missing)                      0x19607b81cfedc900 (Missing)
    7  (Missing)                      0x4c0f0501048ed400 (Missing)
    8  Libra                          0x104c77988 thunk for @escaping          @callee_guaranteed () -> () (<compiler-generated>)
    9  libdispatch.dylib              0x1af482114 _dispatch_client_callout + 20
    10 (Missing)                      0x0 (Missing)
    11 (Missing)                      0x0 (Missing)
    12 (Missing)                      0x574aff81af494800 (Missing)
    13 (Missing)                      0x0 (Missing)
    14 (Missing)                      0x0 (Missing)
    15 (Missing)                      0x502dbc81aec0ec00 (Missing)
    16 (Missing)                      0x3d78bc81aec0e000 (Missing)
    17 (Missing)                      0x0 (Missing)
    18 (Missing)                      0x0 (Missing)
    19 (Missing)                      0x0 (Missing)
    20 libdyld.dylib                  0x1af178964 start + 4

This is the error in Crashlytics Dashboard

<compiler-generated> line 0
thunk for @escaping @callee_guaranteed () -> ()

Answer 1

Figured out the Crash by myself after many Sleepless nights.

Seems like this has been the issue in some of the controllers where I casted the UISearchbar subview to customise the UITextField

if let searchTextField:UITextField = self.searchView.subviews[0].subviews.last{}

So if you come across this issue on iOS 13, Please remove the customisation.