added a mechanism to filter out descriptors

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

@@ -30,6 +30,7 @@ import hudson.model.AbstractProject;
 import hudson.model.Action;
 import hudson.model.Describable;
 import hudson.model.Descriptor;
+import hudson.model.DescriptorVisibilityFilter;
 import hudson.model.Hudson;
 import hudson.model.Item;
 import hudson.model.ItemGroup;
@@ -1274,6 +1275,10 @@ public class Functions {
         return o.toString();
     }
 
+    public List filterDescriptors(Object context, Iterable descriptors) {
+        return DescriptorVisibilityFilter.apply(context,descriptors);
+    }
+    
     private static final Pattern SCHEME = Pattern.compile("[a-z]+://.+");
 
     /**

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

+package hudson.model;
+
+import hudson.ExtensionList;
+import hudson.ExtensionPoint;
+import hudson.scm.SCMDescriptor;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Hides {@link Descriptor}s from users.
+ *
+ * @author Kohsuke Kawaguchi
+ * @since 1.393
+ */
+public abstract class DescriptorVisibilityFilter implements ExtensionPoint {
+
+    /**
+     * Decides if the given descriptor should be visible to the user.
+     *
+     * @param context
+     *      The object that indicates where the visibility of a descriptor is evaluated.
+     *      For example, if Hudson is deciding whether a {@link FreeStyleProject} should gets a
+     *      {@link SCMDescriptor}, the context object will be the {@link FreeStyleProject}.
+     *      The caller can pass in null if there's no context.
+     * @param descriptor
+     *      Descriptor whose visibility is evaluated. Never null.
+     *
+     * @return
+     *      true to allow the descriptor to be visible. false to hide it.
+     *      If any of the installed {@link DescriptorVisibilityFilter} returns false,
+     *      the descriptor is not shown.
+     */
+    public abstract boolean filter(Object context, Descriptor descriptor);
+
+    public static ExtensionList<DescriptorVisibilityFilter> all() {
+        return Hudson.getInstance().getExtensionList(DescriptorVisibilityFilter.class);
+    }
+
+    public static <T extends Descriptor> List<T> apply(Object context, Iterable<T> source) {
+        ExtensionList<DescriptorVisibilityFilter> filters = all();
+        List<T> r = new ArrayList<T>();
+        
+        OUTER:
+        for (T d : source) {
+            for (DescriptorVisibilityFilter f : filters) {
+                if (!f.filter(context,d))
+                    continue OUTER; // veto-ed. not shown
+            }
+            r.add(d);
+        }
+        return r;
+    }
+}

core/src/main/resources/lib/hudson/newFromList/form.jelly

@@ -33,6 +33,8 @@ THE SOFTWARE.
     @checkUrl    : form field validation url
 -->
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:s="/lib/form">
+  <j:set var="descriptors" value="${h.filterDescriptors(it,attrs.descriptors)}" />
+
   <s:form method="post" action="createItem">
     <s:entry title="${attrs.nameTitle}">
       <s:textbox id="name" name="name" checkUrl="'${rootURL}/${attrs.checkUrl}?value='+encodeURIComponent(this.value)"
@@ -40,7 +42,7 @@ THE SOFTWARE.
       <script>$('name').focus();</script>
     </s:entry>
 
-    <j:forEach var="descriptor" items="${attrs.descriptors}">
+    <j:forEach var="descriptor" items="${descriptors}">
       <s:block>
         <input type="radio" name="mode" value="${descriptor.class.name}" onchange="updateOk(this.form)" onclick="updateOk(this.form)" />
         <st:nbsp/>