RFR: 8252863: Spinner keeps spinning if removed from Scene

[Andy Goryachev]

On Thu, 15 Dec 2022 14:23:57 GMT, Karthik P K <kpk at openjdk.org> wrote:

> Spinner was not stopping because it was getting removed from scene before the mouse release event handler was getting invoked.
> 
> Added listener for `sceneProperty` so that when Spinner is removed from the scene, `stopSpinning` method shall be called.
> 
> Added unit test to validate the fix

also, this change should trigger a failure in SkinMemoryLeakTest.
I see the checks are failing.

modules/javafx.controls/src/main/java/javafx/scene/control/skin/SpinnerSkin.java line 254:

> 252:         }));
> 253: 
> 254:         getSkinnable().sceneProperty().addListener((observable, oldValue, newValue) -> {

this will permanently add a listener on the control's scene property, creating a memory leak when skins are replaced.
You probably want to use the newly introduced ListenerHelper (there is an instance of it right there in the constructor):

        lh.addChangeListener(control.sceneProperty(), (x) -> {
            behavior.stopSpinning();
        });


doing this will decouple the listener on Skin.dispose()

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

Changes requested by angorya (Committer).

PR: https://git.openjdk.org/jfx/pull/976