SOLR-5494: CoreContainer#remove throws NPE rather than returning null when a SolrCore does not exist in core discovery mode.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1544844 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -103,6 +103,9 @@ New Features
   This is intended to eventually replace the Suggester support through the
   SpellCheckComponent. (Areek Zillur, Varun Thacker via shalin)
 
+* SOLR-5494: CoreContainer#remove throws NPE rather than returning null when
+  a SolrCore does not exist in core discovery mode. (Mark Miller)
+
 Bug Fixes
 ----------------------
 

solr/core/src/java/org/apache/solr/core/CorePropertiesLocator.java

@@ -91,7 +91,11 @@ public class CorePropertiesLocator implements CoresLocator {
 
   @Override
   public void delete(CoreContainer cc, CoreDescriptor... coreDescriptors) {
+    if (coreDescriptors == null) {
+      return;
+    }
     for (CoreDescriptor cd : coreDescriptors) {
+      if (cd == null) continue;
       File instanceDir = new File(cd.getInstanceDir());
       File propertiesFile = new File(instanceDir, PROPERTIES_FILENAME);
       propertiesFile.renameTo(new File(instanceDir, PROPERTIES_FILENAME + ".unloaded"));

solr/core/src/test/org/apache/solr/core/TestCoreContainer.java

@@ -149,7 +149,10 @@ public class TestCoreContainer extends SolrTestCaseJ4 {
     //create solrHome
     File solrHomeDirectory = new File(TEMP_DIR, this.getClass().getName()
         + "_noCores");
-    SetUpHome(solrHomeDirectory, EMPTY_SOLR_XML);
+    
+    boolean oldSolrXml = random().nextBoolean();
+    
+    SetUpHome(solrHomeDirectory, oldSolrXml ? EMPTY_SOLR_XML : EMPTY_SOLR_XML2);
     CoreContainer cores = new CoreContainer(solrHomeDirectory.getAbsolutePath());
     cores.load();
     try {
@@ -166,14 +169,19 @@ public class TestCoreContainer extends SolrTestCaseJ4 {
 
       assertEquals("There core registered", 1, cores.getCores().size());
 
-
+      if (oldSolrXml) {
         assertXmlFile(new File(solrHomeDirectory, "solr.xml"),
             "/solr/cores[@transientCacheSize='32']");
+      }
 
       newCore.close();
       cores.remove("core1");
       //assert cero cores
       assertEquals("There should not be cores", 0, cores.getCores().size());
+      
+      // try and remove a core that does not exist
+      SolrCore ret = cores.remove("non_existent_core");
+      assertNull(ret);
     } finally {
       cores.shutdown();
       FileUtils.deleteDirectory(solrHomeDirectory);
@@ -275,4 +283,8 @@ public class TestCoreContainer extends SolrTestCaseJ4 {
       "  <cores adminPath=\"/admin/cores\" transientCacheSize=\"32\" >\n" +
       "  </cores>\n" +
       "</solr>";
+  
+  private static final String EMPTY_SOLR_XML2 ="<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n" +
+      "<solr>\n" +
+      "</solr>";
 }