RFR: JDK-8269921 Text in Textflow and listeners on bounds can cause endless loop/crash and other performance issues [v4]

[Kevin Rushforth]

On Wed, 21 Sep 2022 12:05:25 GMT, Florian Kirmaier <fkirmaier at openjdk.org> wrote:

>> Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   JDK-8269921
>>   Reverted the change to the layout, so we can fix the main-bug without further discussions.
>
> The simple null check helps in this case.
> But sometimes I see the exception, posted by @Maran23 .
> So the root cause is probably not fixed - but the symptoms are.
> I guess, this PR is then a good progress.
> 
> Imo the main issue is, that having listeners on the bounds causes a change in the behavior of TextFlow and Group - causing unpredictable behavior.

@FlorianKirmaier this one fell off my radar. The updated fix seems fine as long the check for null `runs` isn't making some other problem. Btw, the title of the bug doesn't match the problem being fixed, so I recommend changing it to something like "TextFlow: listeners on bounds can throw NPE while computing text bounds".

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PR Comment: https://git.openjdk.org/jfx/pull/564#issuecomment-1492959231