diff --git a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
index 267e1eb..e14700e 100644
--- a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
@@ -2935,7 +2935,12 @@
     commitInternal();
   }
 
-  /** Returns true if there are changes that have not been committed */
+  /** Returns true if there are changes that have not been
+   *  committed.  Note that if a merge kicked off as a
+   *  result of flushing a new segment during {@link
+   *  #commit}, or a concurrent merged finished,
+   *  this method may return true right after you
+   *  had just called {@link #commit}. */
   public final boolean hasUncommittedChanges() {
     return changeCount != lastCommitChangeCount || docWriter.anyChanges() || bufferedDeletesStream.any();
   }
diff --git a/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java b/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java
index ffd2007..e7e925a 100644
--- a/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java
+++ b/lucene/core/src/test/org/apache/lucene/index/TestIndexWriter.java
@@ -2303,6 +2303,11 @@
     doc.add(newTextField("myfield", "a b c", Field.Store.NO));
     writer.addDocument(doc);
     assertTrue(writer.hasUncommittedChanges());
+
+    // Must commit, waitForMerges, commit again, to be
+    // certain that hasUncommittedChanges returns false:
+    writer.commit();
+    writer.waitForMerges();
     writer.commit();
     assertFalse(writer.hasUncommittedChanges());
     writer.addDocument(doc);
@@ -2312,10 +2317,20 @@
     doc.add(newStringField("id", "xyz", Field.Store.YES));
     writer.addDocument(doc);
     assertTrue(writer.hasUncommittedChanges());
+
+    // Must commit, waitForMerges, commit again, to be
+    // certain that hasUncommittedChanges returns false:
+    writer.commit();
+    writer.waitForMerges();
     writer.commit();
     assertFalse(writer.hasUncommittedChanges());
     writer.deleteDocuments(new Term("id", "xyz"));
     assertTrue(writer.hasUncommittedChanges());
+
+    // Must commit, waitForMerges, commit again, to be
+    // certain that hasUncommittedChanges returns false:
+    writer.commit();
+    writer.waitForMerges();
     writer.commit();
     assertFalse(writer.hasUncommittedChanges());
     writer.close();