NSInternalInconsistencyException in PatchedPageViewController

[martin-muller]

Hi, we're using Pageboy through Tabman, both on their latest version, and we've received crash report pointing to Pageboy.

Fatal Exception: NSInternalInconsistencyException
0  CoreFoundation                 0x9e48 __exceptionPreprocess
1  libobjc.A.dylib                0x178d8 objc_exception_throw
2  Foundation                     0x54594c _userInfoForFileAndLine
3  UIKitCore                      0x79cf28 -[_UIQueuingScrollView _enqueueCompletionState:]
4  UIKitCore                      0x79d1f8 -[_UIQueuingScrollView _enqueueAnimatedScrollInDirection:withView:completion:]
5  UIKitCore                      0x79e0b8 -[_UIQueuingScrollView setView:direction:animated:completion:]
6  UIKitCore                      0x791bdc -[UIPageViewController _setViewControllers:withScrollInDirection:animated:completion:]
7  UIKitCore                      0x791da0 -[UIPageViewController setViewControllers:direction:animated:completion:]
8  WorkAngel                      0x166c3e8 PatchedPageViewController.setViewControllers(_:direction:animated:completion:) (<compiler-generated>)
9  WorkAngel                      0x166c848 @objc PatchedPageViewController.setViewControllers(_:direction:animated:completion:) (<compiler-generated>)
10 WorkAngel                      0x1660370 closure #2 in PageboyViewController._updateViewControllers(to:from:to:direction:animated:async:force:completion:) (<compiler-generated>)
11 WorkAngel                      0x1661814 partial apply for closure #2 in PageboyViewController._updateViewControllers(to:from:to:direction:animated:async:force:completion:) (<compiler-generated>)
12 WorkAngel                      0x1661868 partial apply for closure #3 in PageboyViewController._updateViewControllers(to:from:to:direction:animated:async:force:completion:) (<compiler-generated>)
13 WorkAngel                      0x166c284 thunk for @escaping @callee_guaranteed () -> () (<compiler-generated>)
14 libdispatch.dylib              0x24b4 _dispatch_call_block_and_release
15 libdispatch.dylib              0x3fdc _dispatch_client_callout
16 libdispatch.dylib              0x127f4 _dispatch_main_queue_drain
17 libdispatch.dylib              0x12444 _dispatch_main_queue_callback_4CF
18 CoreFoundation                 0x9a6d8 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
19 CoreFoundation                 0x7c03c __CFRunLoopRun
20 CoreFoundation                 0x80ec0 CFRunLoopRunSpecific
21 GraphicsServices               0x1368 GSEventRunModal
22 UIKitCore                      0x3a186c -[UIApplication _run]
23 UIKitCore                      0x3a14d0 UIApplicationMain
24 WorkAngel                      0x7d30 main + 20 (main.m:20)
25 ???                            0x1d863a960 (Missing)

The closest issue I found is relatively recently fixed #277. We weren't able to reproduce the issue locally, but going through the code, I'm thinking if the isSettingsViewControllers (https://github.com/uias/Pageboy/blob/4.0.2/Sources/Pageboy/Utilities/PatchedPageViewController.swift#L13) flag should be locked to avoid any potential races?

[aj2109]

Hi just going to bump the above as haven't seen any progress on making the suggested changes, thanks!