RFR: JDK-8302618: Problem typing uppercase letters with java.awt.Robot on Mac when moving mouse
Alexander Zuev
kizune at openjdk.org
Sat Jul 1 00:14:53 UTC 2023
On Fri, 30 Jun 2023 22:29:05 GMT, Harshitha Onkar <honkar at openjdk.org> wrote:
> **Problem:**
>
> Robot erroneously produces lowercase letter when mouse is moved (manually) in unison with Robot's keyEvents on MacOS. This issue was originally logged by a developer of an on-screen accessibility keyboard - TouchBoard. Originally reported at https://github.com/adoptium/adoptium-support/issues/710
>
> The issue is reproducible on JDK versions 22 to 11, but works fine on JDK-8. (details below)
>
> This issue is not restricted to the Shift modifier key and causes problems with other modifier keys as well and in some scenarios without any external mouse movement.
>
> - This works correctly on JDK-8 up to JDK-9+129 when Accessibility APIs (AXUIElementCreateSystemWide/ AXUIElementPostKeyboardEvent) were used. Later on it was changed to CGEvents.
>
> - With the present code, the issue occurs at [CRobot.m#L295](https://github.com/openjdk/jdk/blob/ac6af6a64099c182e982a0a718bc1b780cef616e/src/java.desktop/macosx/native/libawt_lwawt/awt/CRobot.m#L295.) The flags gets reset or cleared when mouse is moved physically in unison with Robot's key events.
>
> - The physical mouse movement causes the event flags to be reset.
>
> **Impact:**
>
> Modifier keys don't work as expected when using Robot with any simultaneous physical mouse movement and in case of TouchBoard, this behavior breaks the usability of the on-screen a11y keyboard. There is no known workaround for this particular use case except for reverting to JDK-8. More details on this use case [here.](https://github.com/adoptium/adoptium-support/issues/710#issuecomment-1594103280)
>
> **Solution:**
>
> - In order to avoid resetting of the CGEventFlags here [CRobot.m#L295](https://github.com/openjdk/jdk/blob/ac6af6a64099c182e982a0a718bc1b780cef616e/src/java.desktop/macosx/native/libawt_lwawt/awt/CRobot.m#L295.), the CGEvent flag state is obtained in `initRobot` (stored in initFlags) which is later used within `CRobot_keyEvent`.
>
> - The incoming keyCode is used to determine whether it is a modifier key and the corresponding modifierFlagMask is either added or cleared from the initFlags based on whether the modifier key was pressed or released.
>
> - Finally, only the required and known flag bits from initFlag are copied over to local flag which is used in `CGEventSetFlags()`.
>
> **Testing:**
>
> The newly added test - RobotModifierMaskTest.java tests for Shift, Caps, Control, Option and Command keys.
> It should be tested for two cases:
>
> CASE 1 : Run the test as an automated test WITHOUT any mouse movement and let the Robot go through al...
src/java.desktop/macosx/native/libawt_lwawt/awt/CRobot.m line 69:
> 67: static int allModifiersMask = kCGEventFlagMaskShift | kCGEventFlagMaskControl
> 68: | kCGEventFlagMaskAlternate | kCGEventFlagMaskCommand
> 69: | kCGEventFlagMaskAlphaShift;
You need to add kCGEventFlagMaskSecondaryFn here otherwise the "secondary fn fix" might catch regression.
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PR Review Comment: https://git.openjdk.org/jdk/pull/14744#discussion_r1248350915
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