On Sat, 4 May 2024 22:55:13 GMT, Martin Fox <m...@openjdk.org> wrote:
> This PR is based on a discussion that happened over in PR #1324. Some of this
> explanation is copied from that thread.
>
> When `exitNestedEventLoop` is called on the innermost loop the
> invokeLaterDispatcher suspends operation until the loop finishes. But if you
> immediately start a new event loop the previous one won't finish and the
> dispatcher will jam up and stop dispatching indefinitely.
>
> When the invokeLaterDispatcher is told that the innermost loop is exiting it
> sets `leavingNestedEventLoop` to true expecting it to be set to false when
> the loop actually exits. When the dispatcher is told that a new event loop
> has started it is not clearing `leavingNestedEventLoop` which is causing the
> jam. Basically it should follow the same logic used in glass; leaving the
> innermost loop updates a boolean indicating that the loop should exit but if
> a new loop is started the boolean is set back to a running state since it now
> applies to the new loop, not the previous one.
>
> I suspect the invokeLaterDispatcher exists in part to deal with the specifics
> of how deferred runnables are handled on the Mac. I investigated this a bit
> and wrote up some comments in the Mac glass code.
I get the following internal assertion failure when running the test on Linux:
NestedEventLoopTest > testCanExitAndThenEnterNewLoop FAILED
java.lang.AssertionError: Internal inconsistency - wrong EventLoop
at
javafx.graphics@23-ea/com.sun.glass.ui.EventLoop.enter(EventLoop.java:108)
at
javafx.graphics@23-ea/com.sun.javafx.tk.quantum.QuantumToolkit.enterNestedEventLoop(QuantumToolkit.java:656)
at
javafx.graphics@23-ea/javafx.application.Platform.enterNestedEventLoop(Platform.java:310)
at
test.javafx.stage.NestedEventLoopTest.lambda$testCanExitAndThenEnterNewLoop$29(NestedEventLoopTest.java:326
It ran cleanly on Mac and Windows.
-------------
PR Comment: https://git.openjdk.org/jfx/pull/1449#issuecomment-2096641134
