GP-2737 - Function Graph - Added support for rendering Area Markers. Added support for a breakpoint margin area in each vertex.

Ghidra/Debug/Debugger/build.gradle

@@ -30,6 +30,7 @@ dependencies {
 	api project(':Base')
 	api project(':ByteViewer')
 	api project(':Decompiler')
+	api project(':FunctionGraph')
 	api project(':ProposedUtils')
 
 	testImplementation project(path: ':Generic', configuration: 'testArtifacts')

Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/gui/breakpoint/DebuggerBreakpointMarkerPlugin.java

@@ -41,6 +41,9 @@ import ghidra.app.plugin.core.debug.event.TraceOpenedPluginEvent;
 import ghidra.app.plugin.core.debug.gui.DebuggerResources;
 import ghidra.app.plugin.core.debug.gui.DebuggerResources.*;
 import ghidra.app.plugin.core.decompile.DecompilerActionContext;
+import ghidra.app.plugin.core.functiongraph.FunctionGraphMarginService;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
+import ghidra.app.plugin.core.marker.MarkerMarginProvider;
 import ghidra.app.services.*;
 import ghidra.app.util.viewer.listingpanel.MarkerClickedListener;
 import ghidra.async.AsyncDebouncer;
@@ -501,6 +504,16 @@ public class DebuggerBreakpointMarkerPlugin extends Plugin
 		}
 	}
 
+	private class DefaultMarginProviderSupplier implements MarginProviderSupplier {
+		@Override
+		public MarkerMarginProvider createMarginProvider() {
+			if (markerService != null) {
+				return markerService.createMarginProvider();
+			}
+			return null;
+		}
+	}
+	
 	protected static State computeState(LogicalBreakpoint breakpoint, Program programOrView) {
 		if (programOrView instanceof TraceProgramView view) {
 			return breakpoint.computeStateForTrace(view.getTrace());
@@ -735,6 +748,8 @@ public class DebuggerBreakpointMarkerPlugin extends Plugin
 	private DebuggerControlService controlService;
 	// @AutoServiceConsumed via method
 	DecompilerMarginService decompilerMarginService;
+	// @AutoServiceConsumed via method
+	private FunctionGraphMarginService functionGraphMarginService;
 	@SuppressWarnings("unused")
 	private final AutoService.Wiring autoServiceWiring;
 
@@ -793,6 +808,8 @@ public class DebuggerBreakpointMarkerPlugin extends Plugin
 	DebuggerPlaceBreakpointDialog placeBreakpointDialog = new DebuggerPlaceBreakpointDialog();
 
 	BreakpointsDecompilerMarginProvider decompilerMarginProvider;
+	private MarginProviderSupplier functionGraphMarginSupplier =
+			new DefaultMarginProviderSupplier();
 
 	public DebuggerBreakpointMarkerPlugin(PluginTool tool) {
 		super(tool);
@@ -1038,6 +1055,21 @@ public class DebuggerBreakpointMarkerPlugin extends Plugin
 		}
 	}
 
+	@AutoServiceConsumed
+	private void setFunctionGraphMarginService(
+			FunctionGraphMarginService functionGraphMarginService) {
+
+		if (this.functionGraphMarginService != null) {
+			this.functionGraphMarginService
+					.removeMarkerProviderSupplier(functionGraphMarginSupplier);
+		}
+
+		this.functionGraphMarginService = functionGraphMarginService;
+		if (this.functionGraphMarginService != null) {
+			this.functionGraphMarginService.addMarkerProviderSupplier(functionGraphMarginSupplier);
+		}
+	}
+	
 	protected void createActions() {
 		actionSetSoftwareBreakpoint =
 			new SetBreakpointAction(Set.of(TraceBreakpointKind.SW_EXECUTE));

Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarginProviderSupplier.java

@@ -0,0 +1,28 @@
+/* ###
+ * 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.marker;
+
+/**
+ * Supplies {@link MarkerMarginProvider}s.
+ */
+public interface MarginProviderSupplier {
+
+	/**
+	 * Creates a new marker margin provider.
+	 * @return the provider.
+	 */
+	public MarkerMarginProvider createMarginProvider();
+}

Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/marker/MarkerManagerPlugin.java

@@ -25,9 +25,7 @@ import ghidra.framework.plugintool.*;
 import ghidra.framework.plugintool.util.PluginStatus;
 import ghidra.util.HelpLocation;
 
-/**
- * Plugin to manage marker and navigation panels.
- */
+//@formatter:off
 @PluginInfo(
 	status = PluginStatus.RELEASED,
 	packageName = CorePluginPackage.NAME,
@@ -43,15 +41,17 @@ import ghidra.util.HelpLocation;
 		"as bookmarks.",
 	servicesRequired = { CodeViewerService.class, GoToService.class },
 	servicesProvided = { MarkerService.class },
-	eventsConsumed = {})
+	eventsConsumed = {}
+)
+//@formatter:on
+/**
+ * Plugin to manage marker and navigation panels.
+ */
 public class MarkerManagerPlugin extends Plugin {
 
 	private CodeViewerService codeViewerService;
 	private MarkerManager markerManager;
 
-	/**
-	 * @param tool
-	 */
 	public MarkerManagerPlugin(PluginTool tool) {
 		super(tool);
 		markerManager = new MarkerManager(this);

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

@@ -32,6 +32,7 @@ import ghidra.app.plugin.core.functiongraph.graph.*;
 import ghidra.app.plugin.core.functiongraph.graph.vertex.FGVertex;
 import ghidra.app.plugin.core.functiongraph.graph.vertex.GroupedFunctionGraphVertex;
 import ghidra.app.plugin.core.functiongraph.mvc.*;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
 import ghidra.app.services.*;
 import ghidra.app.util.ListingHighlightProvider;
 import ghidra.framework.model.*;
@@ -129,8 +130,6 @@ public class FGProvider extends VisualGraphComponentProvider<FGVertex, FGEdge, F
 			new SwingUpdateManager(250, 750, () -> setPendingLocationFromUpdateManager());
 
 		clipboardProvider = new FGClipboardProvider(tool, controller);
-		ClipboardService service = tool.getService(ClipboardService.class);
-		setClipboardService(service);
 	}
 
 	@Override
@@ -139,7 +138,7 @@ public class FGProvider extends VisualGraphComponentProvider<FGVertex, FGEdge, F
 		return !isConnected();
 	}
 
-	public void setClipboardService(ClipboardService service) {
+	void setClipboardService(ClipboardService service) {
 		clipboardService = service;
 		if (clipboardService != null) {
 			clipboardService.registerClipboardContentProvider(clipboardProvider);
@@ -1136,6 +1135,16 @@ public class FGProvider extends VisualGraphComponentProvider<FGVertex, FGEdge, F
 		controller.setGraphPerspective(info);
 	}
 
+	void addMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		controller.addMarkerProviderSupplier(supplier);
+		refreshAndKeepPerspective();
+	}
+
+	void removeMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		controller.removeMarkerProviderSupplier(supplier);
+		refreshAndKeepPerspective();
+	}
+
 //==================================================================================================
 // Navigatable interface methods
 //==================================================================================================
@@ -1298,7 +1307,8 @@ public class FGProvider extends VisualGraphComponentProvider<FGVertex, FGEdge, F
 	}
 
 	@Override
-	public void removeHighlightProvider(ListingHighlightProvider highlightProvider, Program program) {
+	public void removeHighlightProvider(ListingHighlightProvider highlightProvider,
+			Program program) {
 		// currently unsupported
 	}
 

Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/FunctionGraphMarginService.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;
+
+import ghidra.app.plugin.core.functiongraph.graph.FunctionGraph;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
+import ghidra.framework.plugintool.ServiceInfo;
+
+/**
+ * A service that allows clients to add custom margins in the {@link FunctionGraph} UI.
+ */
+@ServiceInfo(defaultProvider = FunctionGraphPlugin.class)
+public interface FunctionGraphMarginService {
+
+	/**
+	 * Add a marker margin supplier to Function Graph's primary window.  The supplier will be called
+	 * for each node in the graph.
+	 *
+	 * @param supplier the supplier.
+	 */
+	public void addMarkerProviderSupplier(MarginProviderSupplier supplier);
+
+	/**
+	 * Removes the given margin supplier from the Function Graph's UI.
+	 *
+	 * @param supplier the supplier.
+	 */
+	public void removeMarkerProviderSupplier(MarginProviderSupplier supplier);
+}

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

@@ -33,6 +33,7 @@ import ghidra.app.plugin.core.colorizer.ColorizingService;
 import ghidra.app.plugin.core.functiongraph.graph.layout.FGLayoutOptions;
 import ghidra.app.plugin.core.functiongraph.graph.layout.FGLayoutProvider;
 import ghidra.app.plugin.core.functiongraph.mvc.FunctionGraphOptions;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
 import ghidra.app.services.*;
 import ghidra.app.util.viewer.format.FormatManager;
 import ghidra.framework.model.DomainFile;
@@ -53,10 +54,13 @@ import ghidra.util.exception.AssertException;
 	category = PluginCategoryNames.GRAPH,
 	shortDescription = FunctionGraphPlugin.FUNCTION_GRAPH_NAME,
 	description = "Plugin for show a graphical representation of the code blocks of a function",
-	servicesRequired = { GoToService.class, BlockModelService.class, CodeViewerService.class, ProgramManager.class }
+	servicesRequired = { GoToService.class, BlockModelService.class, CodeViewerService.class, ProgramManager.class },
+	servicesProvided = { FunctionGraphMarginService.class }
 )
 //@formatter:on
-public class FunctionGraphPlugin extends ProgramPlugin implements OptionsChangeListener {
+public class FunctionGraphPlugin extends ProgramPlugin
+		implements OptionsChangeListener, FunctionGraphMarginService {
+
 	static final String FUNCTION_GRAPH_NAME = "Function Graph";
 	static final String OPTIONS_NAME_PATH =
 		ToolConstants.GRAPH_OPTIONS + Options.DELIMITER + FUNCTION_GRAPH_NAME;
@@ -111,20 +115,32 @@ public class FunctionGraphPlugin extends ProgramPlugin implements OptionsChangeL
 			colorProvider = new ToolBasedColorProvider(this, (ColorizingService) service);
 			connectedProvider.refreshAndKeepPerspective();
 		}
+		else if (interfaceClass == MarkerService.class) {
+			for (FGProvider disconnectedProvider : disconnectedProviders) {
+				disconnectedProvider.refreshAndKeepPerspective();
+			}
+			connectedProvider.refreshAndKeepPerspective();
+		}
 	}
 
 	@Override
 	public void serviceRemoved(Class<?> interfaceClass, Object service) {
 		if (interfaceClass == ClipboardService.class) {
-			connectedProvider.setClipboardService((ClipboardService) service);
+			connectedProvider.setClipboardService(null);
 			for (FGProvider disconnectedProvider : disconnectedProviders) {
-				disconnectedProvider.setClipboardService((ClipboardService) service);
+				disconnectedProvider.setClipboardService(null);
 			}
 		}
 		else if (interfaceClass == ColorizingService.class) {
 			colorProvider = new IndependentColorProvider(tool);
 			connectedProvider.refreshAndKeepPerspective();
 		}
+		else if (interfaceClass == MarkerService.class) {
+			for (FGProvider disconnectedProvider : disconnectedProviders) {
+				disconnectedProvider.refreshAndKeepPerspective();
+			}
+			connectedProvider.refreshAndKeepPerspective();
+		}
 	}
 
 	private List<FGLayoutProvider> loadLayoutProviders() {
@@ -194,6 +210,22 @@ public class FunctionGraphPlugin extends ProgramPlugin implements OptionsChangeL
 		}
 	}
 
+	@Override
+	public void addMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		for (FGProvider disconnectedProvider : disconnectedProviders) {
+			disconnectedProvider.addMarkerProviderSupplier(supplier);
+		}
+		connectedProvider.addMarkerProviderSupplier(supplier);
+	}
+
+	@Override
+	public void removeMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		for (FGProvider disconnectedProvider : disconnectedProviders) {
+			disconnectedProvider.removeMarkerProviderSupplier(supplier);
+		}
+		connectedProvider.removeMarkerProviderSupplier(supplier);
+	}
+
 	@Override
 	protected void programActivated(Program program) {
 		if (connectedProvider == null) {
@@ -431,6 +463,10 @@ public class FunctionGraphPlugin extends ProgramPlugin implements OptionsChangeL
 		return colorProvider;
 	}
 
+	public <T> T getService(Class<T> serviceClass) {
+		return tool.getService(serviceClass);
+	}
+
 	public FunctionGraphOptions getFunctionGraphOptions() {
 		return functionGraphOptions;
 	}

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

@@ -39,9 +39,9 @@ public class FGVertexListingPanel extends ListingPanel {
 			//
 			// Unusual Code Alert!: when the data of the listing changes its preferred size
 			// 						may also change.  If we don't invalidate the containing
-			//                      Java component, then the cached preferred size will be 
+			//                      Java component, then the cached preferred size will be
 			//                      invalid.
-			// 
+			//
 			getFieldPanel().invalidate();
 			controller.repaint();
 		}
@@ -73,10 +73,9 @@ public class FGVertexListingPanel extends ListingPanel {
 		Color color = options.getDefaultVertexBackgroundColor();
 		setTextBackgroundColor(color);
 
+		// Custom colors are in use when the ColorizingService is not installed.
 		FGColorProvider colorProvider = controller.getColorProvider();
-		if (!colorProvider.isUsingCustomColors()) {
-			enablePropertyBasedColorModel(true); // turn on user colors in the graph
-		}
+		enablePropertyBasedColorModel(!colorProvider.isUsingCustomColors());
 	}
 
 	@Override
@@ -94,8 +93,8 @@ public class FGVertexListingPanel extends ListingPanel {
 	 * Overridden to set the view before the parent class notifies the listeners.  This prevents
 	 * our methods that calculate preferred size from going 'out to lunch' when attempting to
 	 * examine the entire program instead of just the given view.
-	 * 
-	 * @param model The listing model needed by the layout model	 * 
+	 *
+	 * @param model The listing model needed by the layout model
 	 * @return the new model adapter
 	 */
 	@Override

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

@@ -23,10 +23,12 @@ import java.awt.event.*;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 
 import javax.swing.*;
 import javax.swing.border.BevelBorder;
 import javax.swing.border.Border;
+import javax.swing.event.ChangeListener;
 
 import docking.ActionContext;
 import docking.GenericHeader;
@@ -41,16 +43,19 @@ import generic.theme.GColor;
 import generic.theme.GIcon;
 import generic.theme.GThemeDefaults.Colors;
 import generic.theme.GThemeDefaults.Colors.Tooltips;
+import ghidra.app.plugin.core.codebrowser.MarkerServiceBackgroundColorModel;
 import ghidra.app.plugin.core.codebrowser.hover.ListingHoverService;
 import ghidra.app.plugin.core.functiongraph.FunctionGraphPlugin;
 import ghidra.app.plugin.core.functiongraph.graph.FGEdge;
 import ghidra.app.plugin.core.functiongraph.mvc.FGController;
 import ghidra.app.plugin.core.functiongraph.mvc.FunctionGraphOptions;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
+import ghidra.app.plugin.core.marker.MarkerMarginProvider;
 import ghidra.app.services.HoverService;
+import ghidra.app.services.MarkerService;
 import ghidra.app.util.AddEditDialog;
 import ghidra.app.util.viewer.format.FormatManager;
-import ghidra.app.util.viewer.listingpanel.ListingHoverProvider;
-import ghidra.app.util.viewer.listingpanel.ListingModel;
+import ghidra.app.util.viewer.listingpanel.*;
 import ghidra.app.util.viewer.util.AddressIndexMap;
 import ghidra.app.util.viewer.util.FieldNavigator;
 import ghidra.framework.plugintool.PluginTool;
@@ -105,6 +110,12 @@ public class ListingGraphComponentPanel extends AbstractGraphComponentPanel {
 		}
 	};
 
+	private final ChangeListener markerChangeListener = e -> {
+		if (controller != null) {
+			controller.repaint();
+		}
+	};
+
 	ListingGraphComponentPanel(final FGVertex vertex, final FGController controller,
 			PluginTool tool, Program program, AddressSetView addressSet) {
 		super(controller, vertex);
@@ -122,6 +133,21 @@ public class ListingGraphComponentPanel extends AbstractGraphComponentPanel {
 				.addButtonPressedListener(controller.getSharedHighlighterButtonPressedListener());
 		listingPanel.setStringSelectionListener(controller.getSharedStringSelectionListener());
 
+		MarkerService markerService = controller.getService(MarkerService.class);
+		if (markerService != null) {
+			ListingBackgroundColorModel colorModel = new MarkerServiceBackgroundColorModel(
+				markerService, listingPanel.getAddressIndexMap());
+			listingPanel.setBackgroundColorModel(colorModel);
+			markerService.addChangeListener(markerChangeListener);
+		}
+
+		// The margin providers may be installed by services other than the MarkerService
+		Set<MarginProviderSupplier> marginProviders = controller.getMarginProviderSuppliers();
+		for (MarginProviderSupplier supplier : marginProviders) {
+			MarkerMarginProvider marginProvider = supplier.createMarginProvider();
+			listingPanel.addMarginProvider(marginProvider);
+		}
+
 		fieldPanel = listingPanel.getFieldPanel();
 		fieldPanel.setCursorOn(false);
 
@@ -676,6 +702,11 @@ public class ListingGraphComponentPanel extends AbstractGraphComponentPanel {
 		// references and removing the data from Jung's graph
 		//
 
+		MarkerService markerService = controller.getService(MarkerService.class);
+		if (markerService != null) {
+			markerService.removeChangeListener(markerChangeListener);
+		}
+
 		removeAll();
 
 		listingPanel.setStringSelectionListener(null);

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

@@ -18,9 +18,8 @@ package ghidra.app.plugin.core.functiongraph.mvc;
 import java.awt.*;
 import java.awt.event.MouseEvent;
 import java.awt.geom.Point2D;
-import java.util.ArrayList;
+import java.util.*;
 import java.util.List;
-import java.util.Set;
 import java.util.function.BiConsumer;
 
 import javax.swing.JComponent;
@@ -40,6 +39,7 @@ import ghidra.app.plugin.core.functiongraph.graph.FGEdge;
 import ghidra.app.plugin.core.functiongraph.graph.FunctionGraph;
 import ghidra.app.plugin.core.functiongraph.graph.layout.FGLayoutProvider;
 import ghidra.app.plugin.core.functiongraph.graph.vertex.*;
+import ghidra.app.plugin.core.marker.MarginProviderSupplier;
 import ghidra.app.services.ButtonPressedListener;
 import ghidra.app.services.CodeViewerService;
 import ghidra.app.util.ListingHighlightProvider;
@@ -58,6 +58,8 @@ import ghidra.program.model.symbol.*;
 import ghidra.program.util.ProgramLocation;
 import ghidra.program.util.ProgramSelection;
 import ghidra.util.SystemUtilities;
+import ghidra.util.datastruct.WeakDataStructureFactory;
+import ghidra.util.datastruct.WeakSet;
 
 public class FGController implements ProgramLocationListener, ProgramSelectionListener {
 
@@ -90,6 +92,9 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 		// dummy
 	};
 
+	private WeakSet<MarginProviderSupplier> marginProviders =
+		WeakDataStructureFactory.createSingleThreadAccessWeakSet();
+
 	public FGController(FGProvider provider, FunctionGraphPlugin plugin) {
 		this.provider = provider;
 		this.plugin = plugin;
@@ -421,7 +426,7 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 //==================================================================================================
 
 //==================================================================================================
-//  Methods call by the providers
+//  Methods called by the providers
 //==================================================================================================
 
 	public void programClosed(Program program) {
@@ -830,8 +835,16 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 		}
 	}
 
+	public void addMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		marginProviders.add(supplier);
+	}
+
+	public void removeMarkerProviderSupplier(MarginProviderSupplier supplier) {
+		marginProviders.add(supplier);
+	}
+
 //==================================================================================================
-//  Methods call by the model
+//  Methods called by the model
 //==================================================================================================
 
 	public void setFunctionGraphData(FGData data) {
@@ -916,7 +929,7 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 	}
 
 //==================================================================================================
-//  Methods call by the vertices (actions and such)
+//  Methods called by the vertices (actions and such)
 //==================================================================================================
 
 	/** Zooms so that the graph will fit completely into the size of the primary viewer */
@@ -1007,6 +1020,10 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 		return plugin.getColorProvider();
 	}
 
+	public <T> T getService(Class<T> serviceClass) {
+		return plugin.getService(serviceClass);
+	}
+
 	/**
 	 * Update the graph's notion of the current location based upon that of the Tool. This method is
 	 * meant to be called from internal mutative operations.
@@ -1063,6 +1080,10 @@ public class FGController implements ProgramLocationListener, ProgramSelectionLi
 		};
 	}
 
+	public Set<MarginProviderSupplier> getMarginProviderSuppliers() {
+		return Collections.unmodifiableSet(marginProviders);
+	}
+
 //==================================================================================================
 // Inner Classes
 //==================================================================================================

Ghidra/Framework/Project/src/main/java/ghidra/framework/plugintool/mgr/ServiceManager.java

@@ -28,7 +28,7 @@ import ghidra.util.exception.AssertException;
  * it may depend on a service. The ServiceManager maintains a list of
  * service names and plugins that provide those services. A plugin may
  * dynamically add and remove services from the service registry. As services
- * are added and removed, all the plugins (ServiceListener) 
+ * are added and removed, all the plugins (ServiceListener)
  * in the tool are notified.
  */
 
@@ -93,20 +93,24 @@ public class ServiceManager {
 	/**
 	 * Add the service to the tool. Notify the service listeners if the
 	 * notification indicator is true; otherwise, add the service to a list
-	 * that will be used to notify listeners when notifications are 
+	 * that will be used to notify listeners when notifications are
 	 * turned on again.
 	 * @param interfaceClass class of the service interface being added
 	 * @param service implementation of the service; it may be a plugin or
 	 * may be some object created by the plugin
-	 * 
-	 * @see #setServiceAddedNotificationsOn(boolean) 
+	 *
+	 * @see #setServiceAddedNotificationsOn(boolean)
 	 */
 	public synchronized <T> void addService(Class<? extends T> interfaceClass, T service) {
 		List<Object> list =
 			servicesByInterface.computeIfAbsent(interfaceClass, (k) -> new ArrayList<>());
 		if (list.contains(service)) {
+			// Note: this can happen if a plugin implements a service it declares and also calls
+			// Plugin.registerServiceProvided(), which is a mistake, since the plugin will get
+			// auto-wired when it implements the service interface.
 			throw new AssertException(
-				"Same Service implementation cannot be " + "added more than once");
+				"The same Service implementation cannot be added more than once.  Interface: " +
+					interfaceClass + ". Service: " + service);
 		}
 
 		list.add(service);
@@ -120,6 +124,8 @@ public class ServiceManager {
 
 	/**
 	 * Remove the service from the tool.
+	 * @param interfaceClass the service interface
+	 * @param service the service implementation
 	 */
 	public void removeService(Class<?> interfaceClass, Object service) {
 		List<Object> list = servicesByInterface.get(interfaceClass);