GT-3101 - Function Graph - fixed exception when hovering on the root

node when it has incoming edges

Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/FGPrimaryViewer.java

@@ -50,6 +50,7 @@ public class FGPrimaryViewer extends GraphViewer<FGVertex, FGEdge> {
 
 		return new VisualGraphPathHighlighter<>(getVisualGraph(), listener) {
 
+			@Override
 			protected GDirectedGraph<FGVertex, FGEdge> getDominanceGraph(
 					VisualGraph<FGVertex, FGEdge> graph, boolean forward) {
 

Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/FunctionGraph.java

@@ -604,7 +604,7 @@ public class FunctionGraph extends GroupingVisualGraph<FGVertex, FGEdge> {
 		for (FGVertex entry : entries) {
 			AbstractFunctionGraphVertex abstractVertex = (AbstractFunctionGraphVertex) entry;
 			FGController controller = abstractVertex.getController();
-			ListingFunctionGraphVertex newEntry = new ListingFunctionGraphVertex(controller,
+			ListingFunctionGraphVertex newEntry = new DummyListingFGVertex(controller,
 				abstractVertex.getAddresses(), RefType.UNCONDITIONAL_JUMP, true);
 			newEntry.setVertexType(FGVertexType.ENTRY);
 			FGVertex groupVertex = getVertexForAddress(entry.getVertexAddress());

Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/vertex/DummyListingFGVertex.java

@@ -0,0 +1,42 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package ghidra.app.plugin.core.functiongraph.graph.vertex;
+
+import ghidra.app.plugin.core.functiongraph.mvc.FGController;
+import ghidra.program.model.address.AddressSetView;
+import ghidra.program.model.symbol.FlowType;
+
+/**
+ * A vertex that is used as a temporary placeholder for graph algorithms that require a 
+ * particular structure, such as having a source or sink
+ */
+public class DummyListingFGVertex extends ListingFunctionGraphVertex {
+
+	public DummyListingFGVertex(FGController controller, AddressSetView addressSet,
+			FlowType flowType, boolean isEntry) {
+		super(controller, addressSet, flowType, isEntry);
+	}
+
+	@Override
+	public String toString() {
+		return "Dummy " + super.toString();
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		return this == obj;
+	}
+}

Ghidra/Features/FunctionGraph/src/test/java/ghidra/app/plugin/core/functiongraph/FunctionGraphGroupVertices2Test.java

@@ -447,6 +447,36 @@ public class FunctionGraphGroupVertices2Test extends AbstractFunctionGraphTest {
 		assertHovered(edges);
 	}
 
+	@Test
+	public void testFindForwardScopedFlow_WithoutGroup_IncomingEdgeToRoot() {
+
+		//
+		// Test the case that an ungrouped graph does not throw an exception if the root node
+		// is hovered when it has incoming edges.
+		//
+
+		create12345GraphWithTransaction();
+
+		FGVertex entry = vertex("100415a");
+		FGVertex v2 = vertex("1004178");
+
+		FunctionGraph graph = getFunctionGraph();
+		FGEdgeImpl edge = new FGEdgeImpl(v2, entry, RefType.UNCONDITIONAL_JUMP, graph.getOptions());
+		graph.addEdge(edge);
+
+		FGComponent graphComponent = getGraphComponent();
+		VisualGraphPathHighlighter<FGVertex, FGEdge> pathHighlighter =
+			graphComponent.getPathHighlighter();
+		pathHighlighter.setHoveredVertex(entry);
+		waitForPathHighligter();
+
+		Collection<FGEdge> edges = graph.getEdges();
+		assertHovered(edges);
+
+		pathHighlighter.setHoveredVertex(null);
+		assertHovered(Collections.emptySet());
+	}
+
 //==================================================================================================
 // Private Methods
 //==================================================================================================