RFR: 8351907: [XWayland] [OL10] Robot.mousePress() is delivered to wrong place [v3]

[Harshitha Onkar]

On Mon, 19 May 2025 23:06:39 GMT, Alexander Zvegintsev <azvegint at openjdk.org> wrote:

>> The issue is the inability to move the mouse cursor using `java.awt.Robot` on Oracle Linux 10 (which has not yet been released). FIY, the OL10 is no longer provides an Xorg session, so only Wayland is available.
>> It is a JCK conformance failure. 
>> 
>> ---
>> 
>> In our robot implementation, we emulate mouse/keyboard actions using the XTEST extension protocol.
>> 
>> The XTEST calls are now wired to [libEI](https://libinput.pages.freedesktop.org/libei/api/index.html):
>> 
>> 1.
>> 
>> It now asks for a user confirmation to allow interaction, so we should now be able to click on native applications, window titles, etc.
>> 
>> However, our robot implementation is mostly uses XTEST, but there is an exception:
>> for mouse move we use XWarpPointer, which is not part of the XTEST, thus it is not propagated outside of Xwayland server.
>> 
>> So we have a situation where mouse is moving only inside Xwayland server, and we see the mouse enter/exit events,
>> on mouse press we call XTestFakeButtonEvent and it is handled by libei,
>> so the click happens where is the actual mouse cursor is in the system. That is why the test fails.
>> 
>> To avoid this situation we should use XTestFakeMotionEvent for mouseMove in Xwayland case.
>> 
>> It would be a simple solution, but
>> 
>> 
>> 2.
>> 
>> This permission granted by a user doesn't persist across reboots, it timeouts after a period of inactivity.
>> 
>> It still seems to conform to the specifications, but we will not be able to conveniently run automated tests in this case.
>> 
>> ---
>> 
>> So as a solution we can switch the [Remote Desktop XDG portal](https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.RemoteDesktop.html).
>> It has session and `restore_token` functionality to keep permissions granted by a user, similar to what we use in a [Screencast](https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.ScreenCast.html) for taking screenshots.
>> Most of the code can be reused, and it has everything we need.
>> 
>> 
>> * It is only enabled by default on Wayland and Gnome Shell 47 and higher due to XTEST API complications that first arose in this version. For earlier versions, Screencast is used instead.
>> * A new value has been introduced for the `awt.robot.screenshotMethod` system property - `dbusRemoteDesktop`. It works on Ubuntu 24.04 with Gnome 46, but is not enabled by default.
>> * extra mouse buttons are not supported yet, [JDK-8357142](https://bugs.openjdk.org/browse/JDK-8357142)
>> * Since w...
>
> Alexander Zvegintsev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   call OpenPipeWireRemote even for remote desktop session calls

On Ubuntu 24.04 (Gnome 46) tested using default awt.robot.screenshotMethod(`dbusScreencast`) and by setting it to `dbusRemoteDesktop`, it works well in both cases, no regressions observed.

On Ubuntu25.04 (Gnome 48) the default -  dbusRemoteDesktop works well.

I haven't able to test the fix on OL10 yet.

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PR Comment: https://git.openjdk.org/jdk/pull/25265#issuecomment-2892620300