[CAUSEWAY-3315] [Duplicate] Apache Isis sorting fails with: Comparison method violates its general contract!

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.0.0-M7
• Fix Version/s: 2.0.0-RC1
• Component/s: Core
• Environment: OpenJDK 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing) ; OpenJDK 64-Bit Server VM Temurin-18+36 (build 18+36, mixed mode, sharing)
• Assignee: Andi Huber
• Reporter: Miroslav Holubec
• Created: 20/Dec/22 22:22
• Updated: 03/Jan/23 08:38
• Resolved: 21/Dec/22 08:00

Description

Apache ISIS own comparator fails with IllegalArgumentException sorting our data. I've created a sample snippet to proof this.

The comparator used in the snippet is that one from ManagedObjects.NATURAL_NULL_FIRST, I've just put for simplicity the complexity of ManagedObject away.

Occured on 2.0.0-M7, but as I checked the code this affects propably all 2.0.0 versions

Stacktrace:

Caused by: java.lang.IllegalArgumentException: Comparison method violates its general contract!
	at java.util.TimSort.mergeLo(TimSort.java:781) ~[?:?]
	at java.util.TimSort.mergeAt(TimSort.java:518) ~[?:?]
	at java.util.TimSort.mergeCollapse(TimSort.java:448) ~[?:?]
	at java.util.TimSort.sort(TimSort.java:245) ~[?:?]
	at java.util.Arrays.sort(Arrays.java:1307) ~[?:?]
	at java.util.ArrayList.sort(ArrayList.java:1721) ~[?:?]
	at org.apache.isis.commons.collections.Can_Multiple.sorted(Can_Multiple.java:121) ~[isis-commons-2.0.0-M7.jar:2.0.0-M7]
	at org.apache.isis.viewer.wicket.ui.components.collectioncontents.ajaxtable.CollectionContentsSortableDataProvider.sorted(CollectionContentsSortableDataProvider.java:83) ~[isis-viewer-wicket-ui-2.0.0-M7.jar:2.0.0-M7]
	at org.apache.isis.viewer.wicket.ui.components.collectioncontents.ajaxtable.CollectionContentsSortableDataProvider.iterator(CollectionContentsSortableDataProvider.java:73) ~[isis-viewer-wicket-ui-2.0.0-M7.jar:2.0.0-M7]
	at org.apache.wicket.markup.repeater.data.DataViewBase$ModelIterator.<init>(DataViewBase.java:107) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.markup.repeater.data.DataViewBase.getItemModels(DataViewBase.java:74) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.markup.repeater.AbstractPageableView.getItemModels(AbstractPageableView.java:99) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.markup.repeater.RefreshingView.onPopulate(RefreshingView.java:93) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.markup.repeater.AbstractRepeater.onBeforeRender(AbstractRepeater.java:124) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.markup.repeater.AbstractPageableView.onBeforeRender(AbstractPageableView.java:113) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.Component.beforeRender(Component.java:947) ~[wicket-core-8.13.0.jar:8.13.0]
	at org.apache.wicket.MarkupContainer.onBeforeRenderChildren(MarkupContainer.java:1741) ~[wicket-core-8.13.0.jar:8.13.0]
	... 107 more

Issue Links

• duplicates: CAUSEWAY-2969 ManagedObject's NATURAL_NULL_FIRST Comparator cannot handle null well