Revert "Ensure FrozenEngine always applies engine-level wrapper (#76100)"

This reverts commit 6f31abc.

Author: ywelsch

server/src/main/java/org/elasticsearch/index/engine/ReadOnlyEngine.java

@@ -76,7 +76,6 @@ public class ReadOnlyEngine extends Engine {
 
     protected volatile TranslogStats translogStats;
     private final String commitId;
-    private final Function<DirectoryReader, DirectoryReader> readerWrapperFunction;
 
     /**
      * Creates a new ReadOnlyEngine. This ctor can also be used to open a read-only engine on top of an already opened
@@ -117,8 +116,7 @@ public ReadOnlyEngine(EngineConfig config, SeqNoStats seqNoStats, TranslogStats
                 this.seqNoStats = seqNoStats;
                 this.indexCommit = Lucene.getIndexCommit(lastCommittedSegmentInfos, directory);
                 this.lazilyLoadSoftDeletes = lazilyLoadSoftDeletes;
-                this.readerWrapperFunction = readerWrapperFunction;
-                reader = wrapReader(open(indexCommit));
+                reader = wrapReader(open(indexCommit), readerWrapperFunction);
                 readerManager = new ElasticsearchReaderManager(reader);
                 assert translogStats != null || obtainLock : "mutiple translogs instances should not be opened at the same time";
                 this.translogStats = translogStats != null ? translogStats : translogStats(config, lastCommittedSegmentInfos);
@@ -194,7 +192,8 @@ public void verifyEngineBeforeIndexClosing() throws IllegalStateException {
         // reopened as an internal engine, which would be the path to fix the issue.
     }
 
-    protected final ElasticsearchDirectoryReader wrapReader(DirectoryReader reader) throws IOException {
+    protected final ElasticsearchDirectoryReader wrapReader(DirectoryReader reader,
+                                                    Function<DirectoryReader, DirectoryReader> readerWrapperFunction) throws IOException {
         reader = readerWrapperFunction.apply(reader);
         return ElasticsearchDirectoryReader.wrap(reader, engineConfig.getShardId());
     }

x-pack/plugin/core/src/main/java/org/elasticsearch/index/engine/frozen/FrozenEngine.java

@@ -161,7 +161,7 @@ private synchronized ElasticsearchDirectoryReader getOrOpenReader() throws IOExc
                     listeners.beforeRefresh();
                 }
                 final DirectoryReader dirReader = openDirectory(engineConfig.getStore().directory());
-                reader = lastOpenedReader = wrapReader(dirReader);
+                reader = lastOpenedReader = wrapReader(dirReader, Function.identity());
                 reader.getReaderCacheHelper().addClosedListener(this::onReaderClosed);
                 for (ReferenceManager.RefreshListener listeners : config().getInternalRefreshListener()) {
                     listeners.afterRefresh(true);

x-pack/plugin/searchable-snapshots/src/test/java/org/elasticsearch/xpack/searchablesnapshots/AbstractSearchableSnapshotsRestTestCase.java

@@ -21,12 +21,10 @@
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
-import org.elasticsearch.index.mapper.SeqNoFieldMapper;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.builder.SearchSourceBuilder;
-import org.elasticsearch.search.sort.SortOrder;
 import org.elasticsearch.test.rest.ESRestTestCase;
 
 import java.io.IOException;
@@ -470,12 +468,7 @@ protected static Number count(String index) throws IOException {
 
     protected static Map<String, Object> search(String index, QueryBuilder query, Boolean ignoreThrottled) throws IOException {
         final Request request = new Request(HttpPost.METHOD_NAME, '/' + index + "/_search");
-        final SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder().trackTotalHits(true).query(query);
-        if (randomBoolean()) {
-            // ensures we can always access sequence numbers, even on source-only mounted snapshots
-            searchSourceBuilder.sort(SeqNoFieldMapper.NAME, SortOrder.ASC);
-        }
-        request.setJsonEntity(searchSourceBuilder.toString());
+        request.setJsonEntity(new SearchSourceBuilder().trackTotalHits(true).query(query).toString());
         if (ignoreThrottled != null) {
             request.addParameter("ignore_throttled", ignoreThrottled.toString());
         }