Index: lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(revision 1292983)
+++ lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(working copy)
@@ -3134,7 +3134,7 @@
       return false;
     }
 
-    final ReadersAndLiveDocs mergedDeletes = commitMergedDeletes(merge);
+    final ReadersAndLiveDocs mergedDeletes =  merge.info.docCount == 0 ? null : commitMergedDeletes(merge);
 
     assert mergedDeletes == null || mergedDeletes.pendingDeleteCount != 0;