KVO crash introduced in 7.3.0 / 7.3.1 (JSQMessagesKeyboardController)

[nickdowell]

This crash appears to have been introduced in release 7.3.0.
I cannot reproduce the crash with release 7.2.0.

An exception is thrown when the app loses focus, for example due to swiping down on an incoming SMS banner;

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x13803c8e0 of class UIInputSetHostView was deallocated while key value observers were still registered with it. Current observation info: <NSKeyValueObservationInfo 0x13818c690> (
<NSKeyValueObservance 0x13818c660: Observer: 0x137e1e630, Key path: frame, Options: <New: YES, Old: YES, Prior: NO> Context: 0x1008e9218, Property: 0x138076f20>
)'

(lldb) po 0x137e1e630
<JSQMessagesKeyboardController: 0x137e1e630>

(lldb) po 0x138076f20
<NSKeyValueUnnestedProperty: Container class: UIInputSetHostView, Key: frame, isa for autonotifying: NSKVONotifying_UIInputSetHostView, Key paths of directly and indirectly affecting properties: none>

(lldb) bt
* thread #1: tid = 0x30631e, 0x00000001822b7f48 libobjc.A.dylib`objc_exception_throw, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x00000001822b7f48 libobjc.A.dylib`objc_exception_throw
    frame #1: 0x0000000182c52cf8 CoreFoundation`+[NSException raise:format:] + 120
    frame #2: 0x00000001835a6d80 Foundation`NSKVODeallocate + 300
    frame #3: 0x00000001822d1ae8 libobjc.A.dylib`(anonymous namespace)::AutoreleasePoolPage::pop(void*) + 508
    frame #4: 0x00000001845f37b4 FrontBoardServices`__FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 44
    frame #5: 0x00000001845f3618 FrontBoardServices`-[FBSSerialQueue _performNext] + 168
    frame #6: 0x00000001845f39c8 FrontBoardServices`-[FBSSerialQueue _performNextFromRunLoopSource] + 56
    frame #7: 0x0000000182c0909c CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
    frame #8: 0x0000000182c08b30 CoreFoundation`__CFRunLoopDoSources0 + 540
    frame #9: 0x0000000182c06830 CoreFoundation`__CFRunLoopRun + 724
    frame #10: 0x0000000182b30c50 CoreFoundation`CFRunLoopRunSpecific + 384
    frame #11: 0x0000000184418088 GraphicsServices`GSEventRunModal + 180
    frame #12: 0x0000000187e1a088 UIKit`UIApplicationMain + 204
    frame #13: 0x00000001000ca2a0 Test App`main(argc=1, argv=0x000000016fdb7ae8) + 144 at main.m:37
    frame #14: 0x00000001826ce8b8 libdyld.dylib`start + 4

[jessesquires]

Thanks @nixxcode !

To clarify:

You have to receive a notification banner while JSQMessagesViewController is the top-most controller?

[nickdowell]

@jessesquires that appears to be the case; in my scenario JSQMessagesViewController was being used to send an SMS that was then immediately delivered to the phone, swiping down on the banner then triggered the crash. Hope that helps!

[jessesquires]

👍

Possible fixes here:

Maybe we listen for app did background/foreground to add/remove observers. This assumes that these notifications fire when interacting with a notification. (Not sure if that's the case)

Or maybe better, we simply resignFirstResponder on the textView

[nickdowell]

This crash was introduced by commit b7f487c

Specifically, -[JSQMessagesKeyboardController jsq_didReceiveKeyboardDidShowNotification:] now looks for a UIInputSetHostView - this is the deallocated object that was identified in the exception.

Changing JSQMessagesKeyboardController's keyboardView property to strong fixes the crash for me.