RFR: 8342782: AWTEventMulticaster throws StackOverflowError using AquaButtonUI [v5]

[Laurent Bourgès]

On Sun, 24 Nov 2024 08:10:28 GMT, Jeremy <duke at openjdk.org> wrote:

>> src/java.desktop/share/classes/java/awt/AWTEventMulticaster.java line 991:
>> 
>>> 989:         while (true) {
>>> 990:             if (++level > 500)
>>> 991:                 return true;
>> 
>> our coding standards require that you always include the body in { .. }
>
> @prrace : I added { .. }
> 
> @bourgesl : I'm struggling to define this as a constant in a helpful way. Is there an example of a similar constant somewhere in the codebase you could refer me to for comparison?
> 
> I think part of my challenge here is the AWTEventMulticaster doesn't promise to be any particular kind of tree. (For example: if it promised it was a self-balancing tree, then we'd know what our obligations were to meet that expectation.)
> 
> This PR's implementation is intended to be a fast heuristic/educated guess, but it does not scan the entire height of the left or right node. This makes it ... hard for me to name.
> 
> (Relatedly: the value 500 is arbitrary, and I'm happy to change it if someone would rather it be closer to 50 or 1000.)

Here is a constant declaration (hotspot friendly):
https://github.com/bourgesl/jdk-official/blob/d0b770c938be6b5b3a0176148265ef33184a9b8b/src/java.desktop/share/classes/sun/java2d/marlin/Renderer.java#L38

private static final int ALL_BUT_LSB = 0xFFFFFFFE;

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/21962#discussion_r1855397860