CommonViewerSorter broken since 2026-03

[Wooza]

The CommonViewerSorter has been deprecated in favor of CommonViewerComparator in #3621.

The above PR added additional cases for TreePathViewerComparator in most locations, but here, the existing check for TreePathViewerSorter was replaced with TreePathViewerComparator.

eclipse.platform.ui/bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java

Lines 665 to 691 in 9b991c8

	@Override
	protected Object[] getSortedChildren(Object parentElementOrTreePath) {
	Object[] result = null;
	ViewerComparator comparator = getComparator();
	if (parentElementOrTreePath != null
	&& comparator instanceof TreePathViewerComparator tpvs) {
	result = getFilteredChildren(parentElementOrTreePath);
	// be sure we're not modifying the original array from the model
	result = result.clone();
	TreePath path = null;
	if (parentElementOrTreePath instanceof TreePath) {
	path = (TreePath) parentElementOrTreePath;
	} else {
	Object parent = parentElementOrTreePath;
	Widget w = internalGetWidgetToSelect(parent);
	if (w != null) {
	path = internalGetSorterParentPath(w, comparator);
	}
	}
	tpvs.sort(this, path, result);
	result = applyItemsLimit(parentElementOrTreePath, result);
	} else {
	return super.getSortedChildren(parentElementOrTreePath);
	}
	return result;
	}

So when using CommonViewerSorter, the above code falls trough to the else case where some default sorting is applied. I think instead of replacing the case for TreePathViewerSorter, the case should have been duplicated for TreePathViewerComparator.

This surfaced as a test-failure in LSP4E (see eclipse-lsp4e/lsp4e#1512), where it was solved by using the new CommonViewerComparator. However, other Plugins still using CommonViewerSorter will be broken on 2026-03+

FYI: @iloveeclipse @akurtakov

Edit: Sorry, meant to post this with my work account (@FlorianKroiss)

[akurtakov]

I would appreciate a PR doing that as you seem to have figured what is needed.

[iloveeclipse]

Thanks @FlorianKroiss !