LUCENE-845: fixed a case that was allowing same segment name to be used twice when a concurrent merge was aborted in between

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@576934 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/lucene/index/IndexWriter.java

@@ -1472,6 +1472,12 @@ public class IndexWriter {
     // Cannot synchronize on IndexWriter because that causes
     // deadlock
     synchronized(segmentInfos) {
+      // Important to set commitPending so that the
+      // segmentInfos is written on close.  Otherwise we
+      // could close, re-open and re-return the same segment
+      // name that was previously returned which can cause
+      // problems at least with ConcurrentMergeScheduler.
+      commitPending = true;
       return "_" + Integer.toString(segmentInfos.counter++, Character.MAX_RADIX);
     }
   }
@@ -1906,6 +1912,7 @@ public class IndexWriter {
   private synchronized void checkpoint() throws IOException {
     if (autoCommit) {
       segmentInfos.write(directory);
+      commitPending = false;
       if (infoStream != null)
         message("checkpoint: wrote segments file \"" + segmentInfos.getCurrentSegmentFileName() + "\"");
     } else {

src/test/org/apache/lucene/index/TestIndexWriterDelete.java

@@ -698,6 +698,7 @@ public class TestIndexWriterDelete extends TestCase {
         }
         public void eval(MockRAMDirectory dir)  throws IOException {
           if (!failed) {
+            failed = true;
             throw new IOException("fail in add doc");
           }
         }