Summary:
Since `dealloc` can be called from any thread, this would result `stopObserving` being called on a different thread/queue than the specified `methodQueue`. We specifically encountered this issue with a module needing the main queue having its `stopObserving` called on a background queue.
Changelog:
[iOS][Fixed] - Call [RCTEventEmitter stopObserving] on specified method queue
Reviewed By: RSNara
Differential Revision: D23821741
fbshipit-source-id: 693c3be6876f863da6dd214a829af2cc13a09c3f
Summary:
A UBN surfaced in v252 because [this assert](https://our.intern.facebook.com/intern/diffusion/FBS/browse/master/xplat/js/react-native-github/React/Modules/RCTEventEmitter.m?commit=e5d1e6375a640d0387bb7016d3becd262c22c327&lines=40) started firing, originating from `RCTAppState`.
This appears to be a race condition during RN teardown. RN receives a memory warning and attempts to forward to JS, but the bridge is already destroyed.
IMO, if the bridge is already destroyed, then there shouldn't be a need to send a memory warning to JS? This is just a hunch though, if anyone feels otherwise, please let me know :)
See the UBN task for further details.
Changelog: [iOS][Internal] Guard against nil bridge during teardown
Reviewed By: shergin
Differential Revision: D19293063
fbshipit-source-id: 566f21af30d3d9bcd25a673ce664f8caddc701ca
Andres Suarez
Scott Kyle
Peter Argany
Ramanpreet Nara