RFR: 8313956: focusWithin on parents of a newly-added focused node is not updated [v2]

[Michael Strauß]

On Fri, 18 Aug 2023 09:19:34 GMT, John Hendrikx <jhendrikx at openjdk.org> wrote:

>> I also noticed this code, which I think will not do the correct thing when `change` is not 1 or -1:
>> 
>>         void adjust(int change) {
>>             count += change;
>> 
>>             if (count == 1) {
>>                 set(true);
>>             } else if (count == 0) {
>>                 set(false);
>>             }
>>         }
>> 
>> For example, if focus within currently is `false`, and it is "adjusted" by 5, the count goes from 0 to 5 in one go.  It will remain `false` then.  Is this intended?
>
>> Is it possible a user can interfere with this process by adding a listener to `focusWithinProperty`? It fires events when it goes from `true` to `false` and vice versa.
> 
> Can disregard this, it seems the property uses a special base class that breaks with the general property contract.

> I also noticed this code, which I think will not do the correct thing when `change` is not 1 or -1:
> 
> ```
>     void adjust(int change) {
>         count += change;
> 
>         if (count == 1) {
>             set(true);
>         } else if (count == 0) {
>             set(false);
>         }
>     }
> ```
> 
> For example, if focus within currently is `false`, and it is "adjusted" by 5, the count goes from 0 to 5 in one go. It will remain `false` then. Is this intended?

Good catch! I've added another test for this edge case.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1210#discussion_r1298460756