Crash tapping bottom tab button with a stack with a pop sharedElementTransition

[lumenlunae]

Issue Description

On a tab + stack layout with the stack containing 3 screens (ScreenA -> Screen B -> Screen C), with a shared element transition for push/pop between B and C, tapping the bottom tab button to go from C back to the root A causes a crash.

---

Environment

• React Native Navigation version: 6.4.0
• React Native version: 0.61.5
• Platform(s) (iOS, Android, or both?): Tested on iOS
• Device info (Simulator/Device? OS version? Debug/Release?): iOS Device 13.3.1 Debug and Release

I was able to fix by adding

if (fromView != nil && toView != nil) {}

in SharedElementTransitionsCreator.m line 18.

Would that be the best place to add a check like that?