Crash in UIView(Genie) transformationsForSlices:edge:startPosition:totalSize:firstBezier:secondBezier:finalRectDepth:

[objectiveSee]

We see a crash in production inside transformationsForSlices:edge:startPosition:totalSize:firstBezier:secondBezier:finalRectDepth: using version 1.1 of this library via CocoaPods. This crash account for about 4% of our app's total crashes. The crash is SIGABRT on UIView+Genie.m:357:

assert(sign*(startPosition - rectPartStart) <= 0.0);

Here is a sample full stack trace:

Thread 0 Crashed:
0   libsystem_kernel.dylib               0x3787bc84 __pthread_kill + 8
1   libsystem_pthread.dylib              0x3791bb47 pthread_kill + 60
2   libsystem_c.dylib                    0x37813f41 abort + 106
3   libsystem_c.dylib                    0x377f36cf __assert_rtn + 300
4   appname                           0x00211e77 -[UIView(Genie) transformationsForSlices:edge:startPosition:totalSize:firstBezier:secondBezier:finalRectDepth:] (UIView+Genie.m:357)
5   appname                           0x00210ef5 -[UIView(Genie) genieTransitionWithDuration:edge:destinationRect:reverse:completion:] (UIView+Genie.m:226)
6   appname                           0x002103d7 -[UIView(Genie) genieOutTransitionWithDuration:startRect:startEdge:completion:] (UIView+Genie.m:128)
7   appname                           0x0010e2f3 -[EAStoreViewController transitionInWithCompletion:] (EAStoreViewController.m:165)
8   appname                           0x000f6291 __63-[EAFamilyViewController _popChildAnimated:options:completion:]_block_invoke (EAFamilyViewController.m:418)
9   UIKit                                0x29b0ca55 -[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 538
10  UIKit                                0x29b0c531 -[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 202
11  UIKit                                0x29b0c42b -[UIViewAnimationState animationDidStop:finished:] + 76
12  QuartzCore                           0x2939c5cf CA::Layer::run_animation_callbacks(void*) + 252
13  libdispatch.dylib                    0x37783e1b _dispatch_client_callout + 20
14  libdispatch.dylib                    0x377886c9 _dispatch_main_queue_callback_4CF + 1530
15  CoreFoundation                       0x25960535 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 6
16  CoreFoundation                       0x2595ea2f __CFRunLoopRun + 1588
17  CoreFoundation                       0x258b10d9 CFRunLoopRunSpecific + 514
18  CoreFoundation                       0x258b0ecd CFRunLoopRunInMode + 106
19  GraphicsServices                     0x2ec26af9 GSEventRunModal + 158
20  UIKit                                0x29b3a2dd UIApplicationMain + 142
21  appname                           0x0007b02f main (main.m:16)
22  libdyld.dylib                        0x377ac873 start + 0