Bug 540243 - Bad selection when opening Debug View on breakpointY20181212-2200I20181212-1800

When the Debug View is not open and a breakpoint is hit, a preference
dictates whether the Debug View is opened. If this preference is used,
it is possible to observe a bad selection in the Debug View. E.g. a
thread is selected and not a stack frame, or a stack frame and a thread
are selected.

The problem is seen for Java debug targets, when owned monitors are
displayed in the Debug View. When the Debug View debug target element is
created, DebugTargetProxy.doInstalled() is called. This will retrieve
the first suspended thread and expand it,  if such a thread is
available. The expand delta contains also the top stack frame at which
the thread is suspended. This stack frame is added to the delta with
index 0. Unfortunately, owned monitors are displayed before stack frames
in the list of thread children. So as soon as the children of the thread
are updated for the tree view, a thread owned monitor will replace the
selected stack frame. This results in an invalid selection handling,
which in turn breaks the selection.

This change allows classes which extend DebugTargetProxy to override
computation of indices for the launch, debug target and suspended stack
frame. A follow-up change in JDT debug will ensure the correct index is
computed for the suspended stack frame, one which takes the thread owned
monitors into account.

Change-Id: Ic8ca2f06a7ea9e47c0322e5d3a62775a0c816652
Signed-off-by: Simeon Andreev <simeon.danailov.andreev@gmail.com>

3 files changed, 47 insertions, 9 deletions

diff --git a/org.eclipse.debug.ui/META-INF/MANIFEST.MF b/org.eclipse.debug.ui/META-INF/MANIFEST.MF
index a6f49a4db..d49a0a101 100644
--- a/org.eclipse.debug.ui/META-INF/MANIFEST.MF
+++ b/org.eclipse.debug.ui/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.debug.ui; singleton:=true
-Bundle-Version: 3.13.200.qualifier
+Bundle-Version: 3.13.300.qualifier
 Bundle-Activator: org.eclipse.debug.internal.ui.DebugUIPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
diff --git a/org.eclipse.debug.ui/pom.xml b/org.eclipse.debug.ui/pom.xml
index 00343310b..49a95e7ee 100644
--- a/org.eclipse.debug.ui/pom.xml
+++ b/org.eclipse.debug.ui/pom.xml
@@ -18,7 +18,7 @@
   </parent>
   <groupId>org.eclipse.debug</groupId>
   <artifactId>org.eclipse.debug.ui</artifactId>
-  <version>3.13.200-SNAPSHOT</version>
+  <version>3.13.300-SNAPSHOT</version>
   <packaging>eclipse-plugin</packaging>
   <properties>
     <code.ignoredWarnings>-warn:+resource,-deprecation,unavoidableGenericProblems</code.ignoredWarnings>
diff --git a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/update/DebugTargetProxy.java b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/update/DebugTargetProxy.java
index cb71acf5a..e97ef177f 100644
--- a/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/update/DebugTargetProxy.java
+++ b/org.eclipse.debug.ui/ui/org/eclipse/debug/internal/ui/viewers/update/DebugTargetProxy.java
@@ -88,8 +88,8 @@ public class DebugTargetProxy extends EventHandlerModelProxy {
                 try {
                     ILaunchManager manager = DebugPlugin.getDefault().getLaunchManager();
                     ILaunch launch = target.getLaunch();
-                    int launchIndex = indexOf(manager.getLaunches(), target.getLaunch());
-                    int targetIndex = indexOf(target.getLaunch().getChildren(), target);
+                    int launchIndex = getLaunchIndex(launch);
+                    int targetIndex = getTargetIndex(target);
                     delta = new ModelDelta(manager, IModelDelta.NO_CHANGE);
                     ModelDelta node = delta.addNode(launch, launchIndex, IModelDelta.NO_CHANGE, target.getLaunch().getChildren().length);
                     node = node.addNode(target, targetIndex, IModelDelta.EXPAND | IModelDelta.SELECT, target.getThreads().length);
@@ -108,10 +108,6 @@ public class DebugTargetProxy extends EventHandlerModelProxy {
         if (target != null) {
             try {
                 IThread[] threads = target.getThreads();
-                ILaunchManager manager = DebugPlugin.getDefault().getLaunchManager();
-                ILaunch launch = target.getLaunch();
-                int launchIndex = indexOf(manager.getLaunches(), target.getLaunch());
-                int targetIndex = indexOf(target.getLaunch().getChildren(), target);
                 IThread chosen = null;
                 int threadIndex = -1;
                 // select the first thread with a breakpoint, or the first suspended thread
@@ -140,11 +136,16 @@ public class DebugTargetProxy extends EventHandlerModelProxy {
                 if (chosen != null) {
                     IStackFrame frame = chosen.getTopStackFrame();
                     if (frame != null) {
+                        ILaunchManager manager = DebugPlugin.getDefault().getLaunchManager();
+                        ILaunch launch = target.getLaunch();
+                        int launchIndex = getLaunchIndex(launch);
+                        int targetIndex = getTargetIndex(target);
+                        int stackFrameIndex = getStackFrameIndex(frame);
                         ModelDelta delta = new ModelDelta(manager, IModelDelta.NO_CHANGE);
                         ModelDelta node = delta.addNode(launch, launchIndex, IModelDelta.NO_CHANGE, target.getLaunch().getChildren().length);
                         node = node.addNode(target, targetIndex, IModelDelta.NO_CHANGE, threads.length);
                         node = node.addNode(chosen, threadIndex, IModelDelta.NO_CHANGE | IModelDelta.EXPAND, chosen.getStackFrames().length);
-                        node = node.addNode(frame, 0, IModelDelta.NO_CHANGE | IModelDelta.SELECT, 0);
+                        node = node.addNode(frame, stackFrameIndex, IModelDelta.NO_CHANGE | IModelDelta.SELECT, 0);
                         return delta;
                     }
                 }
@@ -154,4 +155,41 @@ public class DebugTargetProxy extends EventHandlerModelProxy {
         return null;
     }
 
+	/**
+	 * Computes the index of a launch at top level in the {@code Debug View} tree.
+	 *
+	 * @param launch The launch for which to compute the index.
+	 *
+	 * @return The index of the specified launch at top level in the
+	 *         {@code Debug View}.
+	 */
+	protected int getLaunchIndex(ILaunch launch) {
+		ILaunchManager manager = DebugPlugin.getDefault().getLaunchManager();
+		return indexOf(manager.getLaunches(), launch);
+	}
+
+	/**
+	 * Computes the index of a debug target in its parent launch. The debug target
+	 * index corresponds to the index in {@code Debug View} tree.
+	 *
+	 * @param target The debug target for which to compute the index.
+	 *
+	 * @return The index of the specified debug target in its launch.
+	 */
+	protected int getTargetIndex(IDebugTarget target) {
+		return indexOf(target.getLaunch().getChildren(), target);
+	}
+
+	/**
+	 * Computes the index of a stack frame in the thread suspended at that stack
+	 * frame. The stack frame index corresponds to the index in {@code Debug View}
+	 * tree.
+	 *
+	 * @param stackFrame The stack frame for which to compute the index.
+	 *
+	 * @return The index of the specified stack frame in its parent thread.
+	 */
+	protected int getStackFrameIndex(IStackFrame stackFrame) {
+		return 0;
+	}
 }