RFR: JDK-8269921 TextFlow: listeners on bounds can throw NPE while computing text bounds [v4]

[Florian Kirmaier]

On Sat, 1 Apr 2023 12:38:53 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> 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".

@kevinrushforth 
I guess it also fell under my radar too.

I've merged the branch with master!
I also changed the title as suggested.

**Testing:**
I've extensively tested the Change since the PR was created.
All JPro versions use this bugfix, and a very big Desktop application uses these fixes.
So I'm sure this doesn't cause any instability.

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PR Comment: https://git.openjdk.org/jfx/pull/564#issuecomment-1735099439