Integrated: JDK-8311983: ListView sometimes throws an IndexOutOfBoundsException

[Marius Hanl]

On Wed, 2 Aug 2023 22:21:20 GMT, Marius Hanl <mhanl at openjdk.org> wrote:

> An IOOBE was thrown when scrolling up via the trough (-> `VirtualScrollBar#adjustValue`).
> This happened only when it has bigger cells than the viewport. 
> If the the uppermost cell with the index 0 is only visible (although not completely scrolled to the top) and then an attempt is made to scroll up again, the `VirtualFlow` will try to scroll to the next cell, subtracting index 0 by 1, resulting in -1 -> IOOBE.
> 
> The code now guards against any under or overflow.
> 
> This is technically a regression from https://bugs.openjdk.org/browse/JDK-8173321
> 
> Note: While testing with very big cells, I found out that scrolling via the trough may not work after the first time. 
> This is because the `VirtualFlow` still creates 2 cells, although only one can be visible at a time (at least when scrolling to the next cell) (and `VirtualScrollBar` does this check, which will never be true then: `firstVisibleCell == lastVisibleCell`). This is unrelated to this fix. I can create a ticket when I have more information.

This pull request has now been integrated.

Changeset: e5bb4e14
Author:    Marius Hanl <mhanl at openjdk.org>
URL:       https://git.openjdk.org/jfx/commit/e5bb4e141cba5f49e0bdcc788d1751c8770d17d5
Stats:     83 lines in 3 files changed: 74 ins; 0 del; 9 mod

8311983: ListView sometimes throws an IndexOutOfBoundsException

Reviewed-by: angorya, mstrauss

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PR: https://git.openjdk.org/jfx/pull/1194