Merge branch 'master' of github.com:jenkinsci/jenkins

Conflicts:
	changelog.html

core/src/main/java/hudson/PluginWrapper.java

@@ -28,6 +28,7 @@ import com.google.common.collect.ImmutableSet;
 import hudson.PluginManager.PluginInstanceStore;
 import hudson.model.Api;
 import hudson.model.ModelObject;
+import jenkins.MissingDependencyException;
 import jenkins.YesNoMaybe;
 import jenkins.model.Jenkins;
 import hudson.model.UpdateCenter;
@@ -441,6 +442,10 @@ public class PluginWrapper implements Comparable<PluginWrapper>, ModelObject {
      * Enables this plugin next time Jenkins runs.
      */
     public void enable() throws IOException {
+        if (!disableFile.exists()) {
+            LOGGER.log(Level.FINEST, "Plugin {0} has been already enabled. Skipping the enable() operation", getShortName());
+            return;
+        }
         if(!disableFile.delete())
             throw new IOException("Failed to delete "+disableFile);
     }
@@ -514,14 +519,14 @@ public class PluginWrapper implements Comparable<PluginWrapper>, ModelObject {
      *             thrown if one or several mandatory dependencies doesn't exists.
      */
     /*package*/ void resolvePluginDependencies() throws IOException {
-        List<String> missingDependencies = new ArrayList<String>();
+        List<Dependency> missingDependencies = new ArrayList<>();
         // make sure dependencies exist
         for (Dependency d : dependencies) {
             if (parent.getPlugin(d.shortName) == null)
-                missingDependencies.add(d.toString());
+                missingDependencies.add(d);
         }
         if (!missingDependencies.isEmpty())
-            throw new IOException("Dependency "+Util.join(missingDependencies, ", ")+" doesn't exist");
+            throw new MissingDependencyException(this.shortName, missingDependencies);
 
         // add the optional dependencies that exists
         for (Dependency d : optionalDependencies) {