Fix NPE when opening quick type hierarchy twice #2002

[fedejeanne]

Fixes #2002

Changes

• Introduce private method runWithVisited
• Override expandToLevel(Object, int, boolean) and let it use runWithVisited

[fedejeanne]

cc @jukzi

[jukzi]

Maybe it would be less error prone to set and reset visited only in internalExpandToLevel if and only if visited==null when entered

[fedejeanne]

Maybe it would be less error prone to set and reset visited only in internalExpandToLevel if and only if visited==null when entered

Something like

@Override
protected void internalExpandToLevel(Widget node, int level) {
	boolean reset = false;
	if (visited == null) {
		reset = true;
		visited = new HashSet<>();
	}
	if (!shouldExpand(node))
		return;

	super.internalExpandToLevel(node, level);
	if (reset) {
		visited = null;
	}
}

?

[fedejeanne]

Maybe it would be less error prone to set and reset visited only in internalExpandToLevel if and only if visited==null when entered

See #2006

[fedejeanne]

replaced by #2006