[FIXED JENKINS-9822] occasional NPE when running maven jobs

changelog.html

@@ -58,6 +58,9 @@ Upcoming changes</a>
   <li class=bug>
     Fixed a race condition in the fingerprint computation 
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-10346">issue 10346</a>)
+  <li class=bug>
+    Fixed an occasional NPE when running Maven jobs 
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-9822">issue 9822</a>)
 </ul>
 </div><!--=TRUNK-END=-->
 

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

@@ -540,7 +540,7 @@ public class MavenBuild extends AbstractMavenBuild<MavenModule,MavenBuild> {
         }
 
         /**
-         * Sends the accumuldated log in {@link SplittableBuildListener} to the log of this build.
+         * Sends the accumulated log in {@link SplittableBuildListener} to the log of this build.
          */
         public void appendLastLog() {
             try {
@@ -586,6 +586,11 @@ public class MavenBuild extends AbstractMavenBuild<MavenModule,MavenBuild> {
         private void rememberModulesToBuildAgainNextTime() {
             MavenModuleSetBuild moduleSetBuild = getModuleSetBuild();
             
+            if (moduleSetBuild == null) {
+                // ModuleSetBuild is gone, for whatever reason JENKINS-9822
+                return;
+            }
+            
             if(hasntStartedYet()) {
                 // record modules which have not been build though they should have - i.e. because they
                 // have SCM changes.