Prevent NPE for nested include files with no featureManager element

src/main/java/io/openliberty/tools/common/plugins/util/ServerFeatureUtil.java

@@ -612,7 +612,7 @@ private FeaturesPlatforms handleOnConflict(FeaturesPlatforms origResult, String
  } else {
  // anything else counts as "merge", even if the onConflict value is invalid
  if ((fp != null) && (!fp.getFeatures().isEmpty() || !fp.getPlatforms().isEmpty())) {
- if (result.getFeatures().isEmpty() && result.getPlatforms().isEmpty()) {
+ if ((result == null) || (result.getFeatures().isEmpty() && result.getPlatforms().isEmpty())) {
  result = fp;
  } else {
  result.getFeatures().addAll(fp.getFeatures());

src/test/java/io/openliberty/tools/common/plugins/util/InstallFeatureUtilGetServerFeaturesTest.java

@@ -156,6 +156,24 @@ public void testMergeServerXML() throws Exception{
  verifyServerFeatures(expected);
  }
 
+ /**
+ * Tests server.xml with MERGE function with nested include files, one of which contains no featureManager
+ * 
+ * @throws Exception
+ */
+ @Test
+ public void testNestedMergeServerXML() throws Exception{
+ copyAsName("server_merge_nested.xml", "server.xml");
+ copy("extraFeatures.xml");
+ copy("noList_nested_features.xml");
+
+ Set<String> expected = new HashSet<String>();
+ expected.add("orig");
+ expected.add("extra");
+
+ verifyServerFeatures(expected);
+ }
+
  /**
  * Tests server.xml with REPLACE function
  * 

src/test/resources/servers/noList_nested_features.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<server description="new server">
+ <include location="extraFeatures.xml" onConflict="MERGE"/>
+</server>

src/test/resources/servers/server_merge_nested.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<server description="new server">
+ <featureManager>
+ <feature>orig</feature>
+ </featureManager>
+ <include location="noList_nested_features.xml" onConflict="MERGE"/>
+</server>