On Thu, 11 Jan 2024 23:54:13 GMT, Kevin Rushforth <k...@openjdk.org> wrote:
>> As described in the JBS bug, there is a long-standing deadlock that happens >> on macOS between the AWT EDT and the JavaFX Application thread (which on >> macOS is the AppKit thread) when processing Input Method Events (IME) in a >> WebView node in a JFXPanel. >> >> This PR fixes the deadlock by adding `"AWTRunLoopMode"` to the list of modes >> that will accept the calls to `performSelectorOnMainThread` used by >> `_submitForLaterInvocation` and `_invokeAndWait`. These two native methods >> are the macOS implemention `runLater` and `runAndWait`, respectively, and >> are used to run Java Runnables on the JavaFX Application Thread. >> >> This deadlock is happening much more often on recent macOS versions, and in >> macOS 14, pressing CAPS LOCK is sufficient to trigger IME calls. >> >> The OS calls the AWT IME methods on the AppKit thread, which is also the >> JavaFX Application Thread. The AWT IME callback methods, for example >> `characterIndexForPoint`, call invokeAndWait to run the IME handler on the >> AWT Event thread. In the case of JFXPanel, the registered IME handler is in >> JavaFX code and we often need to run something on the JavaFX Application >> Thread to avoid threading problems or crashes. See >> [JDK-8196011](https://bugs.openjdk.org/browse/JDK-8196011) and >> [JDK-8322703](https://bugs.openjdk.org/browse/JDK-8322703). >> >> A similar deadlock was observed while trying to fix a threading problem in >> JFXPanel's handling of the IME calls as described in >> [JDK-8322784](https://bugs.openjdk.org/browse/JDK-8322784), so it isn't >> necessarily limited to using WebView. >> >> Anton Tarasov @forantar proposed a fix (in a comment in the JBS bug) in AWT >> that would change the invokeAndWait calls used by the IME methods in >> CInputMethod to call `doAWTRunLoop` with the `processEvents` flag set to >> true, which will allow all events to be processed while in `doAWTRunLoop`. >> >> NOTE: I had created Draft PR openjdk/jdk#17290 with Anton's proposed fix, >> expanded to cover all of the cases, but during the discussion it was pointed >> out that `doAWTRunLoop` should already be able to run selectors via >> `performSelectorOnMainThread` -- see [this >> comment](https://github.com/openjdk/jdk/pull/17290#issuecomment-1880001813). >> The reason `doAWTRunLoop` doesn't process our messages is that it runs the >> loop in a mode that only handles messages that include a custom >> `"AWTRunLoopMode"` mode. >> >> Adding `"AWTRunLoopMode"` to the `performSelectorOnMainThread` calls used by >> `_submitForLaterInvocation` and `_invokeAndWa... > > Kevin Rushforth has updated the pull request incrementally with one > additional commit since the last revision: > > Remove reference to JBS bug ID Looks good to me.. ------------- Marked as reviewed by psadhukhan (Reviewer). PR Review: https://git.openjdk.org/jfx/pull/1327#pullrequestreview-1817352905
