[CNSMR-1748] Attempt to fix crash in NSISEngine on deinit

[AliSoftware]

Why?

Recent versions of Bento seem to crash in BentoReusableView.deinit, triggering autolayout (NSISEngine) while the view is being removed.

Here's one of the (partially demangled) stacktraces that happens when such a crash happens

``` 0 CoreFoundation __exceptionPreprocess + 331 1 libobjc.A.dylib objc_exception_throw + 48 2 CoreFoundation +[NSException raise:format:arguments:] + 98 3 Foundation -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 166 4 Foundation -[NSISEngine removeConstraintWithMarker:] + 1651 5 Foundation -[NSLayoutConstraint _removeFromEngine:] + 229 6 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 217 7 Foundation -[NSISEngine withBehaviors:performModifications:] + 110 8 UIKitCore -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 217 9 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 213 10 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 571 11 Foundation -[NSISEngine withBehaviors:performModifications:] + 110 12 UIKitCore -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 217 13 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 213 14 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 571 15 Foundation -[NSISEngine withBehaviors:performModifications:] + 110 16 UIKitCore -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 217 17 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 213 18 UIKitCore __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 571 19 Foundation -[NSISEngine withBehaviors:performModifications:] + 110 20 UIKitCore -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 217 21 UIKitCore __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 112 22 UIKitCore -[UIView(Hierarchy) _postMovedFromSuperview:] + 795 23 UIKitCore __UIViewWasRemovedFromSuperview + 172 24 UIKitCore -[UIView(Hierarchy) removeFromSuperview] + 493 25 Bento (extension in Bento):Bento.BentoReusableView.containerViewDidChange(from: __C.UIView?, to: __C.UIView?) -> () + 1094 26 Bento Bento.TableViewContainerCell.containedView.didset : __C.UIView? + 189 27 Bento Bento.TableViewContainerCell.containedView.setter : __C.UIView? + 288 28 Bento protocol witness for Bento.BentoReusableView.containedView.setter : __C.UIView? in conformance Bento.TableViewContainerCell : Bento.BentoReusableView in Bento + 9 29 Bento (extension in Bento):Bento.BentoReusableView.(unbindIfNeeded in _C920B861C8A0418300F3C0EC0904FFD1)(removesView: Swift.Bool) -> Bento.AnyRenderable? + 847 30 Bento (extension in Bento):Bento.BentoReusableView.unbindIfNeeded() + 72 31 Bento Bento.TableViewContainerCell.__deallocating_deinit + 79 32 Bento @objc Bento.TableViewContainerCell.__deallocating_deinit + 36 33 CoreFoundation -[__NSArrayM dealloc] + 159 34 libobjc.A.dylib _ZN11objc_object17sidetable_releaseEb + 202 35 UIKitCore -[UITableView .cxx_destruct] + 1561 36 libobjc.A.dylib _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127 37 libobjc.A.dylib objc_destructInstance + 134 38 libobjc.A.dylib object_dispose + 19 39 UIKitCore -[UIResponder dealloc] + 145 40 UIKitCore -[UIView dealloc] + 1041 41 UIKitCore -[UIScrollView dealloc] + 900 42 UIKitCore -[UITableView dealloc] + 473 43 libsystem_blocks.dylib _Block_release + 105 44 UIKitCore -[UIViewAnimationBlockDelegate .cxx_destruct] + 58 45 libobjc.A.dylib _ZL27object_cxxDestructFromClassP11objc_objectP10objc_class + 127 46 libobjc.A.dylib objc_destructInstance + 134 47 libobjc.A.dylib object_dispose + 19 48 libobjc.A.dylib _ZN11objc_object17sidetable_releaseEb + 202 49 CoreFoundation -[__NSDictionaryI dealloc] + 126 50 libobjc.A.dylib _ZN11objc_object17sidetable_releaseEb + 202 51 libobjc.A.dylib _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 779 52 CoreFoundation _CFAutoreleasePoolPop + 22 53 CoreFoundation __CFRunLoopRun + 2318 54 CoreFoundation CFRunLoopRunSpecific + 626 55 XCTest -[XCTWaiter waitForExpectations:timeout:enforceOrder:] + 996 56 XCTest +[XCTWaiter waitForExpectations:timeout:enforceOrder:] + 104 57 XCTest -[XCTTestRunSession runTestsAndReturnError:] + 895 58 XCTest -[XCTestDriver runTestsAndReturnError:] + 446 59 XCTest _XCTestMain + 2333 60 xctest main + 263 61 libdyld.dylib start + 1 62 ??? 0x0 + 5 ```

The crash seems to be triggered by this sequence of events:

• TableViewContainerCell.deinit ...
• ... calls unbindIfNeeded()
• ... which sets containedView = nil at some point
• ... which triggers the containedView.didSet
• ... which makes a call to BentoReusableView.containerViewDidChange(from: , to: )
• ... which ends up triggering some AutoLayout code – which is probably not ready to handle such a deinit context where things are in the process of being deallocated.

How

The proposed fix calls unbindIfNeeded(removesView: false) in deinit instead of just unbindIfNeeded() (which was internally calling unbindIfNeeded(removesView: true)).

This prevents the self.containedView = nil affectation and prevents triggering AutoLayout and the NSISEngine, thus preventing the crash

(This required unbindIfNeeded(removesView:) to be turned internal instead of private)

[dmcrodrigues]

@andersio @sergdort please have a look on this when you guys have time but it's going to be merged.