diff --git a/src/java/org/apache/lucene/index/IndexWriter.java b/src/java/org/apache/lucene/index/IndexWriter.java
index 528a48bbe3c..56a5e7ac09b 100644
--- a/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/src/java/org/apache/lucene/index/IndexWriter.java
@@ -3583,7 +3583,7 @@ public class IndexWriter {
           info = segmentInfos.info(i);
           if (info.dir != directory) {
             done = false;
-            final MergePolicy.OneMerge newMerge = new MergePolicy.OneMerge(segmentInfos.range(i, 1+i), info.getUseCompoundFile());
+            final MergePolicy.OneMerge newMerge = new MergePolicy.OneMerge(segmentInfos.range(i, 1+i), mergePolicy instanceof LogMergePolicy && getUseCompoundFile());
 
             // Returns true if no running merge conflicts
             // with this one (and, records this merge as
diff --git a/src/test/org/apache/lucene/index/TestAddIndexesNoOptimize.java b/src/test/org/apache/lucene/index/TestAddIndexesNoOptimize.java
index d61dcebcd05..a9354a1db40 100755
--- a/src/test/org/apache/lucene/index/TestAddIndexesNoOptimize.java
+++ b/src/test/org/apache/lucene/index/TestAddIndexesNoOptimize.java
@@ -537,4 +537,21 @@ public class TestAddIndexesNoOptimize extends LuceneTestCase {
     dir.close();
     dir2.close();
   }
+
+  // LUCENE-1642: make sure CFS of destination indexwriter
+  // is respected when copying tail segments
+  public void testTargetCFS() throws IOException {
+    Directory dir = new RAMDirectory();
+    IndexWriter writer = newWriter(dir, true);
+    writer.setUseCompoundFile(false);
+    addDocs(writer, 1);
+    writer.close();
+
+    Directory other = new RAMDirectory();
+    writer = newWriter(other, true);
+    writer.setUseCompoundFile(true);
+    writer.addIndexesNoOptimize(new Directory[] {dir});
+    assertTrue(writer.newestSegment().getUseCompoundFile());
+    writer.close();
+  }
 }