Noisy warning if restart is required

core/src/main/java/hudson/PluginManager.java

@@ -119,6 +119,8 @@ import org.xml.sax.helpers.DefaultHandler;
 import static hudson.init.InitMilestone.*;
 import hudson.model.DownloadService;
 import hudson.util.FormValidation;
+
+import static java.util.logging.Level.SEVERE;
 import static java.util.logging.Level.WARNING;
 import org.kohsuke.accmod.Restricted;
 import org.kohsuke.accmod.restrictions.NoExternalUse;
@@ -803,6 +805,7 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
      */
     public void doInstall(StaplerRequest req, StaplerResponse rsp) throws IOException, ServletException {
         boolean dynamicLoad = req.getParameter("dynamicLoad")!=null;
+        final List<Future<UpdateCenter.UpdateCenterJob>> deployJobs = new ArrayList<>();
 
         Enumeration<String> en = req.getParameterNames();
         while (en.hasMoreElements()) {
@@ -835,9 +838,36 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
                 if (p == null) {
                     throw new Failure("No such plugin: " + n);
                 }
-                p.deploy(dynamicLoad);
+                
+                deployJobs.add(p.deploy(dynamicLoad));
             }
         }
+        
+        // Fire a one-off thread to wait for the plugins to be deployed and then
+        // refresh the dependant plugins list.
+        new Thread() {
+            @Override
+            public void run() {
+                INSTALLING: while (true) {
+                    for (Future<UpdateCenter.UpdateCenterJob> deployJob : deployJobs) {
+                        try {
+                            Thread.sleep(500);
+                        } catch (InterruptedException e) {
+                            LOGGER.log(SEVERE, "Unexpected error while waiting for some plugins to install. Plugin Manager state may be invalid. Please restart Jenkins ASAP.", e);
+                        }
+                        if (!deployJob.isCancelled() && !deployJob.isDone()) {
+                            // One of the plugins is not installing/canceled, so
+                            // go back to sleep and try again in a while.
+                            continue INSTALLING;
+                        }
+                    }
+                    // All the plugins are installed. It's now safe to refresh.
+                    resolveDependantPlugins();
+                    break;
+                }
+            }
+        }.start();
+        
         rsp.sendRedirect("../updateCenter/");
     }
 

core/src/main/resources/hudson/PluginManager/installed.jelly

@@ -35,6 +35,11 @@ THE SOFTWARE.
             ${%Filter}:
             <input type="text" id="filter-box"/>
         </div>
+
+      <j:if test="${app.updateCenter.isRestartRequiredForCompletion()}">
+        <div class="alert alert-warning"><strong>${%Warning}</strong>: ${%requires.restart}</div>
+      </j:if>
+        
       <local:tabBar page="installed" xmlns:local="/hudson/PluginManager" />
 
       <div class="pane-frame">

core/src/main/resources/hudson/PluginManager/installed.properties

@@ -20,4 +20,5 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 wiki.url=http://wiki.jenkins-ci.org/display/JENKINS/Pinned+Plugins
-downgradeTo=Downgrade to {0}
\ No newline at end of file
+downgradeTo=Downgrade to {0}
+requires.restart=This Jenkins instance requires a restart. Changing the state of plugins at this time is strongly discouraged. Restart Jenkins before proceeding.
\ No newline at end of file

war/src/main/webapp/css/style.css

@@ -1773,4 +1773,17 @@ table#legend-table td {
 
 .i18n {
     display: none;
+}
+
+.alert {
+    padding: 15px;
+    margin-bottom: 20px;
+    border: 1px solid transparent;
+    border-radius: 4px;
+}
+
+.alert-warning {
+    color: #8a6d3b;
+    background-color: #fcf8e3;
+    border-color: #faebcc;
 }
\ No newline at end of file