Fixing possible NPE. Tests added.

java/maven/src/org/netbeans/modules/maven/NbMavenProjectImpl.java

@@ -1386,10 +1386,10 @@ protected List<File> getParents() {
             while(true) {
                 try {
                     MavenProject parent = loadParentOf(getEmbedder(), project);
-                    if (NbMavenProject.isErrorPlaceholder(parent)) {
+                    if (parent == null || NbMavenProject.isErrorPlaceholder(parent)) {
                         break;
                     }
-                    File parentFile = parent != null ? parent.getFile() : null;
+                    File parentFile = parent.getFile();
                     if(parentFile != null) {
                         ret.add(parentFile);
                         project = parent;

java/maven/src/org/netbeans/modules/maven/execute/MavenCommandLineExecutor.java

@@ -173,9 +173,14 @@ public static ExecutorTask executeMaven(final RunConfig config, InputOutput io,
      * Hooks for tests to mock the Maven execution.
      */
     public static class ExecuteMaven {
+        // tests only
+        MavenExecutor createCommandLineExecutor(RunConfig config, InputOutput io, TabContext tc) {
+            return new MavenCommandLineExecutor(config, io, tc);
+        }
+
         public ExecutorTask execute(RunConfig config, InputOutput io, TabContext tc) {
             LifecycleManager.getDefault().saveAll();
-            MavenExecutor exec = new MavenCommandLineExecutor(config, io, tc);
+            MavenExecutor exec = createCommandLineExecutor(config, io, tc);
             ExecutorTask task = ExecutionEngine.getDefault().execute(config.getTaskDisplayName(), exec, new ProxyNonSelectableInputOutput(exec.getInputOutput()));
             exec.setTask(task);
             task.addTaskListener(new TaskListener() {
@@ -628,7 +633,8 @@ private static String quote2apos(String s) {
         return sb.toString();
     }
 
-    private ProcessBuilder constructBuilder(final RunConfig clonedConfig, InputOutput ioput) {
+    // tests only
+    ProcessBuilder constructBuilder(final RunConfig clonedConfig, InputOutput ioput) {
         File javaHome = null;
         Map<String, String> envMap = new LinkedHashMap<String, String>();
         for (Map.Entry<? extends String,? extends String> entry : clonedConfig.getProperties().entrySet()) {

java/maven/test/unit/src/org/netbeans/modules/maven/NbMavenProjectImplTest2.java

@@ -45,6 +45,8 @@
 import org.netbeans.modules.maven.api.NbMavenProject;
 import org.netbeans.modules.maven.debug.MavenJPDAStart;
 import org.netbeans.modules.maven.embedder.EmbedderFactory;
+import org.netbeans.modules.maven.execute.MavenExecMonitor;
+import org.netbeans.modules.maven.execute.MockMavenExec;
 import org.netbeans.modules.maven.modelcache.MavenProjectCache;
 import org.netbeans.modules.projectapi.nb.TimedWeakReference;
 import org.netbeans.spi.project.ActionProgress;
@@ -57,6 +59,7 @@
 import org.openide.modules.DummyInstalledFileLocator;
 import org.openide.util.Lookup;
 import org.openide.util.lookup.Lookups;
+import org.openide.util.test.MockLookup;
 import org.openide.windows.IOProvider;
 
 public class NbMavenProjectImplTest2 extends NbTestCase {
@@ -145,6 +148,11 @@ public void finished(boolean success) {
         primeLatch.await(300, TimeUnit.SECONDS);
     }
 
+    MavenExecMonitor mme;
+
+    /**
+     * Checks that subproject reload after the subproject primes.
+     */
     public void testSubprojectsReloadAfterPriming() throws Exception {
         cleanMavenRepository();
         clearWorkDir();
@@ -161,7 +169,6 @@ public void testSubprojectsReloadAfterPriming() throws Exception {
         assertNotNull(sub);
 
         // check the project's validity:
-        NbMavenProject parentMaven = p.getLookup().lookup(NbMavenProject.class);
         NbMavenProject subMaven = sub.getLookup().lookup(NbMavenProject.class);
         assertTrue("Fallback parent project is expected on unpopulated repository", NbMavenProject.isErrorPlaceholder(subMaven.getMavenProject()));
         assertTrue("Fallback subproject project is expected on unpopulated repository", NbMavenProject.isErrorPlaceholder(subMaven.getMavenProject()));
@@ -170,6 +177,48 @@ public void testSubprojectsReloadAfterPriming() throws Exception {
         assertFalse("Subproject must recover after priming itself", NbMavenProject.isIncomplete(subMaven.getMavenProject()));
     }
 
+    /**
+     * Checks that Priming action on a subproject actually runs on a reactor with --auto-make to build the subproject.
+     * @throws Exception 
+     */
+    public void testSubprojectPrimeRunsReactor() throws Exception {
+        cleanMavenRepository();
+        clearWorkDir();
+
+        mme = new MavenExecMonitor();
+        MockLookup.setLayersAndInstances(mme);
+
+        FileUtil.toFileObject(getWorkDir()).refresh();
+
+        FileObject testApp = dataFO.getFileObject("projects/multiproject/democa");
+        FileObject prjCopy = FileUtil.copyFile(testApp, FileUtil.toFileObject(getWorkDir()), "simpleProject");
+
+        Project p = ProjectManager.getDefault().findProject(prjCopy);
+        assertNotNull(p);
+
+        Project sub = ProjectManager.getDefault().findProject(prjCopy.getFileObject("lib"));
+        assertNotNull(sub);
+
+        // check the project's validity:
+        NbMavenProject subMaven = sub.getLookup().lookup(NbMavenProject.class);
+        assertTrue("Fallback parent project is expected on unpopulated repository", NbMavenProject.isErrorPlaceholder(subMaven.getMavenProject()));
+        assertTrue("Fallback subproject project is expected on unpopulated repository", NbMavenProject.isErrorPlaceholder(subMaven.getMavenProject()));
+
+        primeProject(sub);
+
+        assertEquals("Just single maven executed:", 1, mme.builders.size());
+
+        ProcessBuilder b = mme.builders.getFirst();
+        assertEquals("Runs in root project's dir", FileUtil.toFile(prjCopy),  b.directory());
+        assertTrue("Specifies also-make", b.command().indexOf("--also-make") > 0);
+        int idx = b.command().indexOf("--projects");
+        assertTrue("Specifies projects", idx > 0);
+        assertEquals("Runs up to the lib subprojectsd", "lib", b.command().get(idx + 1));
+    }
+
+    /**
+     * Checks that subproject reload after its parent project primes.
+     */
     public void testSubprojectsReloadAfterParentPriming() throws Exception {
         cleanMavenRepository();
         clearWorkDir();

java/maven/test/unit/src/org/netbeans/modules/maven/execute/MavenExecMonitor.java

@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.netbeans.modules.maven.execute;
+
+import java.util.concurrent.ConcurrentLinkedDeque;
+import org.netbeans.modules.maven.api.execute.RunConfig;
+import org.openide.windows.InputOutput;
+
+/**
+ *
+ * @author sdedic
+ */
+public class MavenExecMonitor extends MavenCommandLineExecutor.ExecuteMaven {
+    public ConcurrentLinkedDeque<ProcessBuilder>    builders = new ConcurrentLinkedDeque<>();
+
+    @Override
+    MavenExecutor createCommandLineExecutor(RunConfig config, InputOutput io, AbstractMavenExecutor.TabContext tc) {
+        return new CmdlineExecutor(config, io, tc);
+    }
+
+    class CmdlineExecutor extends MavenCommandLineExecutor {
+
+        public CmdlineExecutor(RunConfig conf, InputOutput io, TabContext tc) {
+            super(conf, io, tc);
+        }
+
+        @Override
+        ProcessBuilder constructBuilder(RunConfig clonedConfig, InputOutput ioput) {
+            ProcessBuilder b = super.constructBuilder(clonedConfig, ioput);
+            builders.add(b);
+            return b;
+        }
+    }
+}