ShadowMenu: give details on duplicates

In particular, it helps to know which JAR file each entry came from.

Author: ctrueden

src/main/java/org/scijava/menu/ShadowMenu.java

@@ -549,13 +549,13 @@ else if (existingChild != null) {
 				if (childInfo != null && info.getPriority() == childInfo.getPriority())
 				{
 					log.warn("ShadowMenu: menu item already exists:\n" + //
-						"\texisting: " + childInfo + "\n" + //
-						"\t ignored: " + info);
+						"\texisting: " + details(childInfo) + "\n" + //
+						"\t ignored: " + details(info));
 				}
 				else {
 					log.debug("ShadowMenu: higher-priority menu item already exists:\n" +
-						"\texisting: " + childInfo + "\n" + //
-						"\t ignored: " + info);
+						"\texisting: " + details(childInfo) + "\n" + //
+						"\t ignored: " + details(info));
 				}
 			}
 		}
@@ -566,6 +566,21 @@ private boolean isLeaf(final int depth, final MenuPath path) {
 		return depth == path.size() - 1;
 	}
 
+	private String details(final ModuleInfo info) {
+		if (info == null) return "<null>";
+		String className, classLocation;
+		try {
+			final Class<?> c = info.loadDelegateClass();
+			className = c.getName();
+			classLocation = ClassUtils.getLocation(c).toString();
+		}
+		catch (final ClassNotFoundException exc) {
+			className = info.getDelegateClassName();
+			classLocation = "<invalid>";
+		}
+		return info.getMenuPath() + " : " + className + " [" + classLocation + "]";
+	}
+
 	private ShadowMenu getMenu(final MenuPath menuPath, final int index) {
 		final MenuEntry entry = menuPath.get(index);