Status on JDK-8305479 (+ info to reproduce it)

[Dmitrii Markov]

According to the remark in InvokeInputMethodFunction we shouldn’t use async calls like PostMessage() if Drag’n’Drop operation is active. If I got it right in problem case we entered to Drag’nDrop operation right after we started waiting on the InputMethod event object in InvokeInputMethodFunction. I suspect some lack of synchronisation takes place. Perhaps we need to drop and reschedule the InputMethod events that are in progress before we enter Drag’n’Drop.

Dmitrii

On 7 Aug 2024, at 21:16, SWinxy <swinxythecat at gmail.com> wrote:

This appears to be a deadlock. I've been able to replicate it, but it's annoyingly finicky to get it to freeze. A thread gets stuck on WaitForSingleObject at awt_Toolkit.cpp#L3139 (in AwtToolkit::InvokeInputMethodFunction) waiting for an object to be signaled, but the signalling gets lost. And so it waits indefinitely.

dmarkov, do you know more? A possible solution would be to change the timeout to be 1000ms, but that may have unintended effects.

SWinxy

On Mon, Aug 5, 2024 at 5:23 AM Reto Merz <reto.merz at abacus.ch<mailto:reto.merz at abacus.ch>> wrote:
Hello,

Our customers are using Drag & Drop functionality more and more
and reports are increasing that our application is haning.
It starts to escalate since the only workaround is to restart the app right now.

The problem is already reported with JDK-8305479 [1]

Is there any way to increase the priority of that issue
or is a developer here we can hire to search for a fix (and create a pull request)?

Btw, the bug is much easier to reproduce:

1) Start the demo app (see [1])
2) try to drop a document (eg: pdf file) from the windows desktop into the textfield

Repeat step 2 if necessary. For me after 1-2 try this will cause the hang.
If not, move the JFrame to another position and repeat step 2 again.

Tested with latest JDK:
    java version "22.0.2" 2024-07-16
    Java(TM) SE Runtime Environment (build 22.0.2+9-70)
    Java HotSpot(TM) 64-Bit Server VM (build 22.0.2+9-70, mixed mode, sharing)

OS MS Windows:
    Microsoft Windows [Version 10.0.17763.5458]

Regards
Reto Merz

[1] https://bugs.openjdk.org/browse/JDK-8305479


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