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Paige Sun
5ed6ac1f25
Summary: Changelog: [iOS][Fixed][Internal] - Protect handlers in RCTNetworking with mutex even if RCTNetworking has been deallocated # The Logview We get this error in LogView: `Unhandled JS Exception: Error: Exception in HostFunction: mutex lock failed: Invalid argument`, which is an C++ std::error. "This typically happens when .lock() is called on a mutex that is not yet constructed, or has already been destructed." # Hypothesis of issue The LogView says the line that throws this softerror is [RCTNetworking.ios.js](https://github.com/facebook/react-native/blob/8bd3edec88148d0ab1f225d2119435681fbbba33/Libraries/Network/RCTNetworking.ios.js#L87). Inside RCTNetworking, there's only [one mutex and only one line where is is being used](https://github.com/facebook/react-native/blob/8bd3edec88148d0ab1f225d2119435681fbbba33/Libraries/Network/RCTNetworking.mm#L207-L215 ), to protect the _handlers array. My guess is that RCTNetworking was deallocated, which made `_handlersLock` nil, so it resulted in this error when we tried to lock it. # This diff * Add `std::lock_guard<std::mutex> lock(_handlersLock);` to `invalidate()` * Move `_handlersLock` logic to its own method instead of using a lambda. If `self` is being deallocated, I would guess that this method (`[self prioritizedHandlers]`) would return nil. Referencing this for correct ways to use lock_guard with mutex: https://devblogs.microsoft.com/oldnewthing/20210709-00/?p=105425 Reviewed By: fkgozali Differential Revision: D36886233 fbshipit-source-id: 60246f4d9bbc1d834497e4fb8a61d9c0e9623510