<AWT Dev> Review request for 8165829: Android Studio 2.x crashes with NPE at sun.lwawt.macosx.CAccessibility.getAccessibleIndexInParent
anton.tarasov at jetbrains.com
Thu Sep 15 10:21:43 UTC 2016
On 9/15/2016 12:45 PM, Anton Tarasov wrote:
> Please review the fix:
> bug: https://bugs.openjdk.java.net/browse/JDK-8165829
> webrev: http://cr.openjdk.java.net/~ant/JDK-8165829/jdk9/webrev.0
> (The bug is currently closed as “not an issue”, which is not quite
> true. So once and if the fix is approved I can take the ownership of
> the bug).
> The problem is this. Sometimes when a frame is closed there may appear
> a race condition:
> - removeNotify() is called on the frame on EDT and it removes all the
> events associated with the frame from the event queue.
> - The frame is requested by accessibility via the CAccessibility
> static methods (like CAccessibility.getAccessibleIndexInParent). Those
> methods are called from native on AppKit thread and they perform via
> invokeAndWait. The latter is wrapped with an InvocationEvent whose
> source is set to the frame. But, once the event is put on the event
> queue, it's purged by the removeNotify() call. As the result,
> invokeAndWait returns null. Then, in some of the mentioned methods
> 'null' is unboxed to a primitive 'int' or 'boolean' which results in
> NPE propagated to native. On the native side, the NPE is not properly
> handled and is just re-thrown.
I forgot to add, as a comment to the fix, that createWithAccessible() is
ok to return nil, it's checked.
> I don't have a simple and safe solution for the race. So, I suggest to
> fix the NPE/crash at least.
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