added a callback to be notified when a child is removed

core/src/main/java/hudson/matrix/MatrixProject.java

@@ -467,6 +467,10 @@ public class MatrixProject extends AbstractProject<MatrixProject,MatrixBuild> im
         throw new UnsupportedOperationException();
     }
 
+    public void onDeleted(MatrixConfiguration item) throws IOException {
+        // noop
+    }
+
     public File getRootDirFor(Combination combination) {
         File f = getConfigurationsDir();
         for (Entry<String, String> e : combination.entrySet())

core/src/main/java/hudson/model/AbstractItem.java

@@ -412,12 +412,23 @@ public abstract class AbstractItem extends Actionable implements Item, HttpDelet
         checkPermission(DELETE);
         performDelete();
 
-        if(this instanceof TopLevelItem)
-            Hudson.getInstance().deleteJob((TopLevelItem)this);
+        try {
+            invokeOnDeleted();
+        } catch (AbstractMethodError e) {
+            // ignore
+        }
 
         Hudson.getInstance().rebuildDependencyGraph();
     }
 
+    /**
+     * A pointless function to work around what appears to be a HotSpot problem. See HUDSON-5756 and bug 6933067
+     * on BugParade for more details.
+     */
+    private void invokeOnDeleted() throws IOException {
+        getParent().onDeleted(this);
+    }
+
     /**
      * Does the real job of deleting the item.
      */

core/src/main/java/hudson/model/Hudson.java

@@ -2153,28 +2153,28 @@ public final class Hudson extends Node implements ItemGroup<TopLevelItem>, Stapl
     }
 
     /**
-     * Called in response to {@link Job#doDoDelete(StaplerRequest, StaplerResponse)}
+     * Called by {@link Job#renameTo(String)} to update relevant data structure.
+     * assumed to be synchronized on Hudson by the caller.
      */
-    /*package*/ void deleteJob(TopLevelItem item) throws IOException {
-        for (ItemListener l : ItemListener.all())
-            l.onDeleted(item);
+    public void onRenamed(TopLevelItem job, String oldName, String newName) throws IOException {
+        items.remove(oldName);
+        items.put(newName,job);
 
-        items.remove(item.getName());
         for (View v : views)
-            v.onJobRenamed(item, item.getName(), null);
+            v.onJobRenamed(job, oldName, newName);
         save();
     }
 
     /**
-     * Called by {@link Job#renameTo(String)} to update relevant data structure.
-     * assumed to be synchronized on Hudson by the caller.
+     * Called in response to {@link Job#doDoDelete(StaplerRequest, StaplerResponse)}
      */
-    public void onRenamed(TopLevelItem job, String oldName, String newName) throws IOException {
-        items.remove(oldName);
-        items.put(newName,job);
+    public void onDeleted(TopLevelItem item) throws IOException {
+        for (ItemListener l : ItemListener.all())
+            l.onDeleted(item);
 
+        items.remove(item.getName());
         for (View v : views)
-            v.onJobRenamed(job, oldName, newName);
+            v.onJobRenamed(item, item.getName(), null);
         save();
     }
 

core/src/main/java/hudson/model/ItemGroup.java

@@ -77,4 +77,9 @@ public interface ItemGroup<T extends Item> extends PersistenceRoot, ModelObject
      * Internal method. Called by {@link Item}s when they are renamed by users.
      */
     void onRenamed(T item, String oldName, String newName) throws IOException;
+
+    /**
+     * Internal method. Called by {@link Item}s when they are deleted by users.
+     */
+    void onDeleted(T item) throws IOException;
 }

maven-plugin/src/main/java/hudson/maven/MavenModuleSet.java

@@ -449,6 +449,10 @@ public final class MavenModuleSet extends AbstractMavenProject<MavenModuleSet,Ma
         throw new UnsupportedOperationException();
     }
 
+    public void onDeleted(MavenModule item) throws IOException {
+        // noop
+    }
+
     public Collection<Job> getAllJobs() {
         Set<Job> jobs = new HashSet<Job>(getItems());
         jobs.add(this);