Bug 45356 [typing] IndentAction: Pressing Tab at document begin gives IAE
Build 200310150800: Having a multi-line comment starting at document offset 0, the caret as well at offset 0 and pressing tab, the indent action gives an IAE. Reason: The constructor of status called at IndentAction#run() requires a non- null message parameter. The exception that was triggered in the first place results from a taking the previous line of the first one.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/actions/IndentAction.java
*/
	private final boolean fIsTabAction;
	
	/**
	 * Creates a new instance.
	 * 
	 * @param bundle the resource bundle
	 * @param prefix the prefix to use for keys in <code>bundle</code>
	 * @param editor the text editor
	 */
	public IndentAction(ResourceBundle bundle, String prefix, ITextEditor editor, boolean isTabAction) {
		super(bundle, prefix, editor);
		fIsTabAction= isTabAction;
	}
	
	/*
	 * @see org.eclipse.jface.action.Action#run()
	 */
	public void run() {
		
		if (!isEnabled() || !validateEditorInputState())
			return;
		
		ITextSelection selection= getSelection();
		final IDocument document= getDocument();
		
		if (document != null) {
			
			final int offset= selection.getOffset();
			final int length= selection.getLength();