Prevent 404 in .../contextMenu link when there's no context menu

core/src/main/java/hudson/Functions.java

@@ -58,6 +58,7 @@ import hudson.views.ViewsTabBar;
 import hudson.widgets.RenderOnDemandClosure;
 import jenkins.model.GlobalConfiguration;
 import jenkins.model.Jenkins;
+import jenkins.model.ModelObjectWithContextMenu;
 import org.acegisecurity.providers.anonymous.AnonymousAuthenticationToken;
 import org.apache.commons.jelly.JellyContext;
 import org.apache.commons.jelly.JellyTagException;
@@ -146,6 +147,10 @@ public class Functions {
         return o instanceof ModelObject;
     }
 
+    public static boolean isModelWithContextMenu(Object o) {
+        return o instanceof ModelObjectWithContextMenu;
+    }
+
     public static String xsDate(Calendar cal) {
         return Util.XS_DATETIME_FORMATTER.format(cal.getTime());
     }

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

@@ -24,6 +24,7 @@
 package hudson.matrix;
 
 import hudson.Util;
+import hudson.remoting.LocalChannel;
 import hudson.util.AlternativeUiTextProvider;
 import hudson.util.DescribableList;
 import hudson.model.AbstractBuild;
@@ -31,6 +32,7 @@ import hudson.model.Cause;
 import hudson.model.CauseAction;
 import hudson.model.DependencyGraph;
 import hudson.model.Descriptor;
+import hudson.util.RemotingDiagnostics;
 import jenkins.model.Jenkins;
 import hudson.model.Item;
 import hudson.model.ItemGroup;
@@ -46,8 +48,11 @@ import hudson.tasks.BuildWrapper;
 import hudson.tasks.Builder;
 import hudson.tasks.LogRotator;
 import hudson.tasks.Publisher;
+import jenkins.model.Jenkins.MasterComputer;
 
 import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.util.List;
 import java.util.Map;
 

core/src/main/java/jenkins/model/ModelObjectWithContextMenu.java

@@ -163,6 +163,12 @@ public interface ModelObjectWithContextMenu extends ModelObject {
         @Exported
         public String icon;
 
+        /**
+         * If this is a submenu, definition of subitems.
+         */
+        @Exported(inline=true)
+        public ContextMenu subMenu;
+
         public MenuItem(String url, String icon, String displayName) {
             this.url = URI.create(Stapler.getCurrentRequest().getRequestURI()).resolve(url).toString();
             this.icon = icon;

core/src/main/resources/lib/layout/breadcrumbBar.jelly

@@ -58,7 +58,7 @@ THE SOFTWARE.
           <ul id="breadcrumbs">
             <j:forEach var="anc" items="${request.ancestors}">
               <j:if test="${h.isModel(anc.object) and anc.prev.url!=anc.url}">
-                <li>
+                <li class="${h.isModelWithContextMenu(anc.object)}?null:'no-context-menu'}">
                   <a href="${anc.url}/">
                     ${anc.object.displayName}
                   </a>

core/src/main/resources/lib/layout/breadcrumbs.js

@@ -116,7 +116,9 @@ var breadcrumbs = (function() {
 
     jenkinsRules["#breadcrumbs LI"] = function (e) {
         // when the mouse hovers over LI, activate the menu
-        $(e).observe("mouseover", function () { handleHover(e.firstChild,0) });
+        e = $(e);
+        if (e.hasClassName("no-context-menu"))  return;
+        e.observe("mouseover", function () { handleHover(e.firstChild,0) });
     };
 
     jenkinsRules["A.model-link"] = function (a) {