weakly hold key window for KVO frame listener#50231
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Summary: Changelog: [Internal] RCTDeviceInfo uses KVO to listen to frame changes in the application's keyWindow. On initialization, it reads the global keyWindow and adds itself as a listener. When RCTDeviceInfo is cleaned up, it reads the global keyWindow again, and removes itself as an observer. However, this makes an assumption that the keyWindow is always the same. This is not always true - for example, when a UIAlert is presented, the OS creates a new temporary keyWindow to host the alert in order to make sure it is the first responder. If the cleanup is called then, the app will crash because there is no RCTDeviceInfo observing it. Another example is the LogBox, which also temporarily creates a new keyWindow. The fix is simple, we can capture a reference to the application's keyWindow on initialization, but make sure it is weakly held as the keyWindow is usually managed by iOS. Then, when we remove the listener, it is always guaranteed it is the window that we are observing. Reviewed By: javache, cipolleschi, realsoelynn Differential Revision: D71667722
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This pull request was exported from Phabricator. Differential Revision: D71667722 |
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This pull request has been merged in 90fce63. |
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This pull request was successfully merged by @philIip in 90fce63 When will my fix make it into a release? | How to file a pick request? |
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Summary:
Changelog: [Internal]
RCTDeviceInfo uses KVO to listen to frame changes in the application's keyWindow. On initialization, it reads the global keyWindow and adds itself as a listener. When RCTDeviceInfo is cleaned up, it reads the global keyWindow again, and removes itself as an observer.
However, this makes an assumption that the keyWindow is always the same. This is not always true - for example, when a UIAlert is presented, the OS creates a new temporary keyWindow to host the alert in order to make sure it is the first responder. If the cleanup is called then, the app will crash because there is no RCTDeviceInfo observing it. Another example is the LogBox, which also temporarily creates a new keyWindow.
The fix is simple, we can capture a reference to the application's keyWindow on initialization, but make sure it is weakly held as the keyWindow is usually managed by iOS. Then, when we remove the listener, it is always guaranteed it is the window that we are observing.
Reviewed By: javache, cipolleschi, realsoelynn
Differential Revision: D71667722