diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index f90f9e3f8fd..1baeb7fa68e 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -129,6 +129,10 @@ Bug Fixes
 * LUCENE-8236: Filter duplicated points when creating GeoPath shapes to
   avoid creation of bogus planes. (Ignacio Vera)
 
+* LUCENE-8243: IndexWriter.addIndexes(Directory[]) did not properly preserve
+  index file names for updated doc values fields (Simon Willnauer,
+  Michael McCandless)
+
 Other
 
 * LUCENE-8228: removed obsolete IndexDeletionPolicy clone() requirements from
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 43051769cd6..8ba460d70b5 100644
--- a/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
+++ b/lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
@@ -3207,8 +3207,10 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
                                           info.info.getDiagnostics(), info.info.getId(), info.info.getAttributes(), info.info.getIndexSort());
     SegmentCommitInfo newInfoPerCommit = new SegmentCommitInfo(newInfo, info.getDelCount(), info.getDelGen(), 
                                                                info.getFieldInfosGen(), info.getDocValuesGen());
-    
-    newInfo.setFiles(info.files());
+
+    newInfo.setFiles(info.info.files());
+    newInfoPerCommit.setFieldInfosFiles(info.getFieldInfosFiles());
+    newInfoPerCommit.setDocValuesUpdatesFiles(info.getDocValuesUpdatesFiles());
 
     boolean success = false;
 
@@ -3228,7 +3230,7 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
       }
     }
 
-    assert copiedFiles.equals(newInfoPerCommit.files());
+    assert copiedFiles.equals(newInfoPerCommit.files()): "copiedFiles=" + copiedFiles + " vs " + newInfoPerCommit.files();
     
     return newInfoPerCommit;
   }
@@ -3569,6 +3571,7 @@ public class IndexWriter implements Closeable, TwoPhaseCommit, Accountable {
     return seqNo;
   }
 
+  @SuppressWarnings("try")
   private final void finishCommit() throws IOException {
 
     boolean commitCompleted = false;
diff --git a/lucene/core/src/test/org/apache/lucene/index/TestAddIndexes.java b/lucene/core/src/test/org/apache/lucene/index/TestAddIndexes.java
index 876328a4a42..48a28e2e791 100644
--- a/lucene/core/src/test/org/apache/lucene/index/TestAddIndexes.java
+++ b/lucene/core/src/test/org/apache/lucene/index/TestAddIndexes.java
@@ -1332,4 +1332,85 @@ public class TestAddIndexes extends LuceneTestCase {
     assertEquals("cannot change index sort from <int: \"foo\"> to <string: \"foo\">", message);
     IOUtils.close(r1, dir1, w2, dir2);
   }
+
+  public void testAddIndexesDVUpdateSameSegmentName() throws Exception {
+    Directory dir1 = newDirectory();
+    IndexWriterConfig iwc1 = newIndexWriterConfig(new MockAnalyzer(random()));
+    IndexWriter w1 = new IndexWriter(dir1, iwc1);
+    Document doc = new Document();
+    doc.add(new StringField("id", "1", Field.Store.YES));
+    doc.add(new StringField("version", "1", Field.Store.YES));
+    doc.add(new NumericDocValuesField("soft_delete", 1));
+    w1.addDocument(doc);
+    w1.flush();
+
+    w1.updateDocValues(new Term("id", "1"), new NumericDocValuesField("soft_delete", 1));
+    w1.commit();
+    w1.close();
+
+    IndexWriterConfig iwc2 = newIndexWriterConfig(new MockAnalyzer(random()));
+    Directory dir2 = newDirectory();
+    IndexWriter w2 = new IndexWriter(dir2, iwc2);
+    w2.addIndexes(dir1);
+    w2.commit();
+    w2.close();
+
+    if (VERBOSE) {
+      System.out.println("\nTEST: now open w3");
+    }
+    IndexWriterConfig iwc3 = newIndexWriterConfig(new MockAnalyzer(random()));
+    if (VERBOSE) {
+      iwc3.setInfoStream(System.out);
+    }        
+    IndexWriter w3 = new IndexWriter(dir2, iwc3);
+    w3.close();
+
+    iwc3 = newIndexWriterConfig(new MockAnalyzer(random()));
+    w3 = new IndexWriter(dir2, iwc3);
+    w3.close();
+    dir1.close();
+    dir2.close();
+  }
+
+  public void testAddIndexesDVUpdateNewSegmentName() throws Exception {
+    Directory dir1 = newDirectory();
+    IndexWriterConfig iwc1 = newIndexWriterConfig(new MockAnalyzer(random()));
+    IndexWriter w1 = new IndexWriter(dir1, iwc1);
+    Document doc = new Document();
+    doc.add(new StringField("id", "1", Field.Store.YES));
+    doc.add(new StringField("version", "1", Field.Store.YES));
+    doc.add(new NumericDocValuesField("soft_delete", 1));
+    w1.addDocument(doc);
+    w1.flush();
+
+    w1.updateDocValues(new Term("id", "1"), new NumericDocValuesField("soft_delete", 1));
+    w1.commit();
+    w1.close();
+
+    IndexWriterConfig iwc2 = newIndexWriterConfig(new MockAnalyzer(random()));
+    Directory dir2 = newDirectory();
+    IndexWriter w2 = new IndexWriter(dir2, iwc2);
+    w2.addDocument(new Document());
+    w2.commit();
+    
+    w2.addIndexes(dir1);
+    w2.commit();
+    w2.close();
+
+    if (VERBOSE) {
+      System.out.println("\nTEST: now open w3");
+    }
+    IndexWriterConfig iwc3 = newIndexWriterConfig(new MockAnalyzer(random()));
+    if (VERBOSE) {
+      iwc3.setInfoStream(System.out);
+    }        
+    IndexWriter w3 = new IndexWriter(dir2, iwc3);
+    w3.close();
+
+    iwc3 = newIndexWriterConfig(new MockAnalyzer(random()));
+    w3 = new IndexWriter(dir2, iwc3);
+    w3.close();
+    dir1.close();
+    dir2.close();
+  }
 }