From 5da5ec3b6d764870046912b71bbae3b265b0ae4e Mon Sep 17 00:00:00 2001
From: dragonmacher <48328597+dragonmacher@users.noreply.github.com>
Date: Tue, 24 Jan 2023 13:30:35 -0500
Subject: [PATCH] GP-3047 - fixed potential npe due to a timing issue

---
 .../graph/VisualGraphComponentProvider.java   | 22 +++++++++++--------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/Ghidra/Framework/Graph/src/main/java/ghidra/graph/VisualGraphComponentProvider.java b/Ghidra/Framework/Graph/src/main/java/ghidra/graph/VisualGraphComponentProvider.java
index b99aa03264..f15ff79a87 100644
--- a/Ghidra/Framework/Graph/src/main/java/ghidra/graph/VisualGraphComponentProvider.java
+++ b/Ghidra/Framework/Graph/src/main/java/ghidra/graph/VisualGraphComponentProvider.java
@@ -33,11 +33,11 @@ import ghidra.graph.viewer.event.mouse.VertexMouseInfo;
  * A base component provider for displaying {@link VisualGraph}s
  * 
  * <p>This class will provide many optional sub-features, enabled as desired by calling the
- * various <code>addXyzFeature()</code> methods.  
+ * various <code>addXyzFeature()</code> methods.
  * 
  * <p>Implementation Notes:   to get full functionality, you must:
  * <ul>
- *  <li>Have your plugin call {@link #readConfigState(SaveState)} and 
+ *  <li>Have your plugin call {@link #readConfigState(SaveState)} and
  *  {@link #writeConfigState(SaveState)} to save user settings.
  *  </li>
  *  <li>Enable features you desire after calling your {@link #addToTool()} method.
@@ -49,9 +49,9 @@ import ghidra.graph.viewer.event.mouse.VertexMouseInfo;
  * @param <G> the graph type
  */
 //@formatter:off
-public abstract class VisualGraphComponentProvider<V extends VisualVertex, 
-												   E extends VisualEdge<V>, 
-												   G extends VisualGraph<V, E>> 
+public abstract class VisualGraphComponentProvider<V extends VisualVertex,
+												   E extends VisualEdge<V>,
+												   G extends VisualGraph<V, E>>
 	extends ComponentProvider {
 //@formatter:on
 
@@ -104,6 +104,10 @@ public abstract class VisualGraphComponentProvider<V extends VisualVertex,
 	public Set<V> getSelectedVertices() {
 		VisualGraphView<V, E, G> view = getView();
 		VisualizationViewer<V, E> viewer = view.getPrimaryGraphViewer();
+		if (viewer == null) {
+			// we have seen this happen on some systems; timing issue?
+			return Collections.emptySet();
+		}
 		PickedState<V> pickedState = viewer.getPickedVertexState();
 		return pickedState.getPicked();
 	}
@@ -127,7 +131,7 @@ public abstract class VisualGraphComponentProvider<V extends VisualVertex,
 
 //==================================================================================================
 // Featurette Methods
-//==================================================================================================	
+//==================================================================================================
 
 	/**
 	 * Adds the satellite viewer functionality to this provider
@@ -164,14 +168,14 @@ public abstract class VisualGraphComponentProvider<V extends VisualVertex,
 			
 		Undo/redo for graph operations (delete; group/ungroup; move)
 			-rapid pressing will shortcut items
-			-undo/redo allows us to prune nodes 
-				--how to maintain old nodes/edges?  (FilteringVisualGraph)	
+			-undo/redo allows us to prune nodes
+				--how to maintain old nodes/edges?  (FilteringVisualGraph)
 	
 	*/
 
 //==================================================================================================
 // Provider Methods
-//==================================================================================================	
+//==================================================================================================
 
 	/**
 	 * To be called at the end of this provider's lifecycle