On Wed, 2 Aug 2023 21:46:32 GMT, Harshitha Onkar <hon...@openjdk.org> wrote:

>> **Problem:**
>> 
>> On macOS, Robot erroneously produces lowercase letter when mouse is moved 
>> (manually) in unison with Robot's keyEvents. 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
>> 
>> This 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)
>> 
>> **Proposed Fix:**
>> 
>> - 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.
>> The test runs in 2 modes - as automated and manual test.
>> 
>> CASE 1 : ...
>
> Harshitha Onkar has updated the pull request incrementally with one 
> additional commit since the last revision:
> 
>   changed allModifiersMask datatype

Changed allModifiersMask from int32 to `CGEventFlags` (uint64) as the following 
bit operation can produce undesired results especially (~allModifiersMask).

` flags = (initFlags & allModifiersMask) | (flags & (~allModifiersMask));`

-------------

PR Comment: https://git.openjdk.org/jdk/pull/14744#issuecomment-1663014981

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