Bug 341259: [JFace] Add debug flag to find bad content providers that return multiple equal children

3 files changed, 39 insertions, 3 deletions

diff --git a/bundles/org.eclipse.jface/.options b/bundles/org.eclipse.jface/.options
index a96d27674d5..c4674c5a185 100644
--- a/bundles/org.eclipse.jface/.options
+++ b/bundles/org.eclipse.jface/.options
@@ -20,4 +20,4 @@ org.eclipse.jface/newlook/preferences/showNewLook=false
 org.eclipse.jface/trace/toolbarDisposal=false
 
 # Reports the time to run an action
-org.eclipse.jface/trace/actions=false
\ No newline at end of file
+org.eclipse.jface/trace/actions=false
diff --git a/bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java b/bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
index 96d05941ec4..b57935880ad 100644
--- a/bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
+++ b/bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
@@ -1412,6 +1412,41 @@ public abstract class AbstractTreeViewer extends ColumnViewer {
 	}
 	
 	/**
+	 * Asserts that the given array of elements is itself non- <code>null</code>
+	 * and contains no <code>null</code> elements.
+	 * 
+	 * @param parent
+	 *            the parent element
+	 * @param elements
+	 *            the array to check
+	 * 
+	 * @see #assertElementsNotNull(Object[])
+	 */
+	private void assertElementsNotNull(Object parent, Object[] elements) {
+		Assert.isNotNull(elements);
+		for (int i = 0, n = elements.length; i < n; ++i) {
+			Assert.isNotNull(elements[i]);
+		}
+		
+		if (InternalPolicy.DEBUG_LOG_EQUAL_VIEWER_ELEMENTS
+				&& elements.length > 1) {
+			CustomHashtable elementSet = newHashtable(elements.length * 2);
+			for (int i = 0; i < elements.length; i++) {
+				Object element = elements[i];
+				Object old = elementSet.put(element, element);
+				if (old != null) {
+					String message = "Sibling elements in viewer must not be equal:\n  " //$NON-NLS-1$
+							+ old + ",\n  " + element + ",\n  parent: " + parent; //$NON-NLS-1$ //$NON-NLS-2$
+					Policy.getLog().log(
+							new Status(IStatus.WARNING, Policy.JFACE, message,
+									new RuntimeException()));
+					return;
+				}
+			}
+		}
+	}
+	
+	/**
 	 * Returns all selected items for the given SWT control.
 	 *
 	 * @param control
diff --git a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/JFaceUtil.java b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/JFaceUtil.java
index 2848c79a453..c6ce5022097 100644
--- a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/JFaceUtil.java
+++ b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/JFaceUtil.java
@@ -16,8 +16,8 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
-import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences.NodeChangeEvent;
+import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.jface.internal.InternalPolicy;
 import org.eclipse.jface.preference.JFacePreferences;
 import org.eclipse.jface.util.ILogger;
@@ -72,11 +72,12 @@ final class JFaceUtil {
 		});
 
 		// Get all debug options from Platform
-		if ("true".equalsIgnoreCase(Platform.getDebugOption("/debug"))) { //$NON-NLS-1$ //$NON-NLS-2$
+		if ("true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/debug"))) { //$NON-NLS-1$ //$NON-NLS-2$
 			Policy.DEBUG_DIALOG_NO_PARENT = "true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/debug/dialog/noparent")); //$NON-NLS-1$ //$NON-NLS-2$
 			Policy.TRACE_ACTIONS = "true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/trace/actions")); //$NON-NLS-1$ //$NON-NLS-2$
 			Policy.TRACE_TOOLBAR = "true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/trace/toolbarDisposal")); //$NON-NLS-1$ //$NON-NLS-2$
 			InternalPolicy.DEBUG_LOG_REENTRANT_VIEWER_CALLS = "true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/debug/viewers/reentrantViewerCalls")); //$NON-NLS-1$ //$NON-NLS-2$
+			InternalPolicy.DEBUG_LOG_EQUAL_VIEWER_ELEMENTS = "true".equalsIgnoreCase(Platform.getDebugOption(Policy.JFACE + "/debug/viewers/equalElements")); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}