Bug 163357 [Viewers] NullPointerException on AbstractTreeViewer.remove(path, index)
I20061102-1715 It's possible to get an NPE when removing an element from a tree viewer. The remove API accepts a "parent path" and "child index". It is possible to specify an empty tree path for the parent to indicate the root element. However, the remove code eventually trys to find the widget associated with the "last segment" of the parent path. This results in null, and an NPE: Caused by: java.lang.NullPointerException at org.eclipse.jface.viewers.CustomHashtable.hashCode(CustomHashtable.java:265) at org.eclipse.jface.viewers.CustomHashtable.get(CustomHashtable.java:237) at org.eclipse.jface.viewers.StructuredViewer.findItems(StructuredViewer.java:769) at org.eclipse.jface.viewers.AbstractTreeViewer.internalFindItem(AbstractTreeViewer.java:173) at org.eclipse.jface.viewers.AbstractTreeViewer.internalFindItems(AbstractTreeViewer.java:153) at org.eclipse.jface.viewers.TreeViewer$8.run(TreeViewer.java:1017) at org.eclipse.jface.viewers.StructuredViewer.preservingSelection(StructuredViewer.java:1326) at org.eclipse.jface.viewers.TreeViewer.remove(TreeViewer.java:1005) at org.eclipse.debug.internal.ui.viewers.model.ChildrenUpdate.performUpdate(ChildrenUpdate.java:62) at org.eclipse.debug.internal.ui.viewers.model.ViewerUpdateMonitor$1.runInUIThread(ViewerUpdateMonitor.java:43) at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:94) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:123) ... 20 more
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
if (columns.length == 0)
			getTree().setData(ViewerColumn.COLUMN_VIEWER_KEY, null);
		else {
			for (int i = 0; i < columns.length; i++) {
				columns[i].setData(ViewerColumn.COLUMN_VIEWER_KEY, null);
			}
		}
	}
	/*
	 * (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected void setSelection(List items) {
		Item[] current = getSelection(getTree());
		
		if (isSameSelection(items, current)) {
			return;
		}
		TreeItem[] newItems = new TreeItem[items.size()];
		items.toArray(newItems);
		getTree().setSelection(newItems);
	}
	/**
	 * Returns <code>true</code> if the given list and array of items refer to
	 * the same model elements. Order is unimportant.
	 * 
	 * @param items
	 *            the list of items
	 * @param current
	 *            the array of items
	 * @return <code>true</code> if the refer to the same elements,