diff --git a/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexModule.java b/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexModule.java
index b1bb7b1..c18b965 100644
--- a/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexModule.java
+++ b/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexModule.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.elasticsearch;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.index.project.ProjectIndex;
 import com.google.gerrit.server.ModuleImpl;
@@ -25,7 +26,6 @@
 import com.google.gerrit.server.index.group.GroupIndex;
 import com.google.gerrit.server.index.options.AutoFlush;
 import com.google.inject.Inject;
-import java.util.Map;
 
 @ModuleImpl(name = AbstractIndexModule.INDEX_MODULE)
 public class ElasticIndexModule extends AbstractIndexModule {
@@ -35,12 +35,12 @@
 
   @VisibleForTesting
   public static ElasticIndexModule singleVersionWithExplicitVersions(
-      Map<String, Integer> versions, int threads, boolean slave) {
+      ImmutableMap<String, Integer> versions, int threads, boolean slave) {
     return new ElasticIndexModule(versions, threads, slave, AutoFlush.ENABLED);
   }
 
   public static ElasticIndexModule singleVersionWithExplicitVersions(
-      Map<String, Integer> versions, int threads, boolean slave, AutoFlush autoFlush) {
+      ImmutableMap<String, Integer> versions, int threads, boolean slave, AutoFlush autoFlush) {
     return new ElasticIndexModule(versions, threads, slave, autoFlush);
   }
 
@@ -50,7 +50,10 @@
   }
 
   protected ElasticIndexModule(
-      Map<String, Integer> singleVersions, int threads, boolean slave, AutoFlush autoFlush) {
+      ImmutableMap<String, Integer> singleVersions,
+      int threads,
+      boolean slave,
+      AutoFlush autoFlush) {
     super(singleVersions, threads, slave);
     this.autoFlush = autoFlush;
   }
diff --git a/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexVersionManager.java b/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexVersionManager.java
index b9d86d5..f39a604 100644
--- a/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexVersionManager.java
+++ b/src/main/java/com/google/gerrit/elasticsearch/ElasticIndexVersionManager.java
@@ -48,7 +48,12 @@
       PluginSetContext<OnlineUpgradeListener> listeners,
       Collection<IndexDefinition<?, ?, ?>> defs,
       ElasticIndexVersionDiscovery versionDiscovery) {
-    super(sitePaths, listeners, defs, VersionManager.getOnlineUpgrade(cfg));
+    super(
+        sitePaths,
+        listeners,
+        defs,
+        VersionManager.getOnlineUpgrade(cfg),
+        cfg.getBoolean("index", "reuseExistingDocuments", false));
     this.versionDiscovery = versionDiscovery;
     prefix = Strings.nullToEmpty(cfg.getString("elasticsearch", null, "prefix"));
   }
diff --git a/src/test/java/com/google/gerrit/elasticsearch/ElasticAbstractQueryChangesTest.java b/src/test/java/com/google/gerrit/elasticsearch/ElasticAbstractQueryChangesTest.java
index d5c60ad..2fa004e 100644
--- a/src/test/java/com/google/gerrit/elasticsearch/ElasticAbstractQueryChangesTest.java
+++ b/src/test/java/com/google/gerrit/elasticsearch/ElasticAbstractQueryChangesTest.java
@@ -18,6 +18,7 @@
 import static com.google.gerrit.testing.GerritJUnit.assertThrows;
 
 import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.Project;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.server.query.change.AbstractQueryChangesTest;
 import com.google.gerrit.testing.ConfigSuite;
@@ -83,9 +84,9 @@
 
   @Test
   public void testErrorResponseFromChangeIndex() throws Exception {
-    String repository = "repo";
-    TestRepository<Repository> repo = createAndOpenProject(repository);
-    Change c = insert(repository, newChangeWithStatus(repo, Change.Status.NEW));
+    Project.NameKey project = Project.nameKey("repo");
+    TestRepository<Repository> repo = createAndOpenProject(project);
+    Change c = insert(project, newChangeWithStatus(repo, Change.Status.NEW));
     gApi.changes().id(c.getChangeId()).index();
 
     ElasticTestUtils.closeIndex(client, container, testName);