RFR: 8189354: ArrayIndexOutOfBoundsException when listening to selection changes on TreeTableView [v3]

[Jeanette Winzenburg]

On Sun, 25 Apr 2021 15:36:49 GMT, mstr2 <github.com+43553916+mstr2 at openjdk.org> wrote:

> 
> 
> You're right that removing `ControlUtils.reducingChange` is enough to solve the problem. Maybe the method was created because it might be confusing that, while the indices are often not adjacent, they _are_ (as you correctly say) adjacent with respect to `selectedIndices`.
> 
> I have tested the change with [8189354](https://bugs.openjdk.java.net/browse/JDK-8189354) and [8189228](https://bugs.openjdk.java.net/browse/JDK-8189228), and both issues seem to be solved.

yeah, coordinate spaces can be confusing, been there :)

A couple of notes to your test - my personal preferences:

- they should cover all changes, that is test both Tree- and TreeTableView
- if possible, have a test that really cover the report: here that would be throwing a AIOOP on expanding again (with a filter to re-select all children)
- have a test for underlying reason of the reported misbehavior: here the incorrect change
- testing the change should be complete (in testing its state)

I have seen you using the MockListObserver in an earlier version of this PR - which is perfect for the last bullet, we should use it always in asserting the correctness of listChange notification :) The only very minor drawback is that it requires to update the Eclipse classpath to add-exports for the base testing package (not a big deal).

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PR: https://git.openjdk.java.net/jfx/pull/480