Some Cleanup in o.e.i.engine (#42278) (#42566)

* Some Cleanup in o.e.i.engine

* Remove dead code and parameters
* Reduce visibility in some obvious spots
* Add missing `assert`s (not that important here since the methods
themselves will probably be dead-code eliminated) but still

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

@@ -911,7 +911,7 @@ public abstract class Engine implements Closeable {
             map.put(extension, length);
         }
 
-        if (useCompoundFile && directory != null) {
+        if (useCompoundFile) {
             try {
                 directory.close();
             } catch (IOException e) {
@@ -954,8 +954,7 @@ public abstract class Engine implements Closeable {
 
         // now, correlate or add the committed ones...
         if (lastCommittedSegmentInfos != null) {
-            SegmentInfos infos = lastCommittedSegmentInfos;
+            for (SegmentCommitInfo info : lastCommittedSegmentInfos) {
-            for (SegmentCommitInfo info : infos) {
                 Segment segment = segments.get(info.info.name);
                 if (segment == null) {
                     segment = new Segment(info.info.name);
@@ -1783,11 +1782,8 @@ public abstract class Engine implements Closeable {
 
             CommitId commitId = (CommitId) o;
 
-            if (!Arrays.equals(id, commitId.id)) {
+            return Arrays.equals(id, commitId.id);
-                return false;
-            }
 
-            return true;
         }
 
         @Override

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

@@ -563,7 +563,7 @@ public class InternalEngine extends Engine {
     /**
      * Reads the current stored history ID from the IW commit data.
      */
-    private String loadHistoryUUID(final IndexWriter writer) throws IOException {
+    private String loadHistoryUUID(final IndexWriter writer) {
         final String uuid = commitDataAsMap(writer).get(HISTORY_UUID_KEY);
         if (uuid == null) {
             throw new IllegalStateException("commit doesn't contain history uuid");
@@ -635,9 +635,8 @@ public class InternalEngine extends Engine {
                                 if (operation != null) {
                                     // in the case of a already pruned translog generation we might get null here - yet very unlikely
                                     final Translog.Index index = (Translog.Index) operation;
-                                    TranslogLeafReader reader = new TranslogLeafReader(index, engineConfig
+                                    TranslogLeafReader reader = new TranslogLeafReader(index);
-                                        .getIndexSettings().getIndexVersionCreated());
+                                    return new GetResult(new Searcher("realtime_get", new IndexSearcher(reader), reader),
-                                    return new GetResult(new Searcher("realtime_get", new IndexSearcher(reader), reader::close),
                                         new VersionsAndSeqNoResolver.DocIdAndVersion(0, index.version(), index.seqNo(), index.primaryTerm(),
                                             reader, 0));
                                 }
@@ -756,7 +755,7 @@ public class InternalEngine extends Engine {
                 + index.getAutoGeneratedIdTimestamp();
             switch (index.origin()) {
                 case PRIMARY:
-                    assertPrimaryCanOptimizeAddDocument(index);
+                    assert assertPrimaryCanOptimizeAddDocument(index);
                     return true;
                 case PEER_RECOVERY:
                 case REPLICA:
@@ -782,7 +781,7 @@ public class InternalEngine extends Engine {
 
     private boolean assertIncomingSequenceNumber(final Engine.Operation.Origin origin, final long seqNo) {
         if (origin == Operation.Origin.PRIMARY) {
-            assertPrimaryIncomingSequenceNumber(origin, seqNo);
+            assert assertPrimaryIncomingSequenceNumber(origin, seqNo);
         } else {
             // sequence number should be set when operation origin is not primary
             assert seqNo >= 0 : "recovery or replica ops should have an assigned seq no.; origin: " + origin;
@@ -923,7 +922,7 @@ public class InternalEngine extends Engine {
     }
 
     protected final IndexingStrategy planIndexingAsNonPrimary(Index index) throws IOException {
-        assertNonPrimaryOrigin(index);
+        assert assertNonPrimaryOrigin(index);
         final IndexingStrategy plan;
         final boolean appendOnlyRequest = canOptimizeAddDocument(index);
         if (appendOnlyRequest && mayHaveBeenIndexedBefore(index) == false && index.seqNo() > maxSeqNoOfNonAppendOnlyOperations.get()) {
@@ -978,13 +977,13 @@ public class InternalEngine extends Engine {
         }
     }
 
-    protected final IndexingStrategy planIndexingAsPrimary(Index index) throws IOException {
+    private IndexingStrategy planIndexingAsPrimary(Index index) throws IOException {
         assert index.origin() == Operation.Origin.PRIMARY : "planing as primary but origin isn't. got " + index.origin();
         final IndexingStrategy plan;
         // resolve an external operation into an internal one which is safe to replay
         if (canOptimizeAddDocument(index)) {
             if (mayHaveBeenIndexedBefore(index)) {
-                plan = IndexingStrategy.overrideExistingAsIfNotThere(1L);
+                plan = IndexingStrategy.overrideExistingAsIfNotThere();
                 versionMap.enforceSafeAccess();
             } else {
                 plan = IndexingStrategy.optimizedAppendOnly(1L);
@@ -1006,7 +1005,7 @@ public class InternalEngine extends Engine {
             if (index.getIfSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO && versionValue == null) {
                 final VersionConflictEngineException e = new VersionConflictEngineException(shardId, index.id(),
                     index.getIfSeqNo(), index.getIfPrimaryTerm(), SequenceNumbers.UNASSIGNED_SEQ_NO, 0);
-                plan = IndexingStrategy.skipDueToVersionConflict(e, currentNotFoundOrDeleted, currentVersion, getPrimaryTerm());
+                plan = IndexingStrategy.skipDueToVersionConflict(e, true, currentVersion, getPrimaryTerm());
             } else if (index.getIfSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO && (
                 versionValue.seqNo != index.getIfSeqNo() || versionValue.term != index.getIfPrimaryTerm()
             )) {
@@ -1164,9 +1163,9 @@ public class InternalEngine extends Engine {
                 true, false, versionForIndexing, null);
         }
 
-        static IndexingStrategy overrideExistingAsIfNotThere(long versionForIndexing) {
+        static IndexingStrategy overrideExistingAsIfNotThere() {
             return new IndexingStrategy(true, true, true,
-                false, versionForIndexing, null);
+                false, 1L, null);
         }
 
         public static IndexingStrategy processButSkipLucene(boolean currentNotFoundOrDeleted, long versionForIndexing) {
@@ -1285,7 +1284,7 @@ public class InternalEngine extends Engine {
     }
 
     protected final DeletionStrategy planDeletionAsNonPrimary(Delete delete) throws IOException {
-        assertNonPrimaryOrigin(delete);
+        assert assertNonPrimaryOrigin(delete);
         maxSeqNoOfNonAppendOnlyOperations.updateAndGet(curr -> Math.max(delete.seqNo(), curr));
         assert maxSeqNoOfNonAppendOnlyOperations.get() >= delete.seqNo() : "max_seqno of non-append-only was not updated;" +
             "max_seqno non-append-only [" + maxSeqNoOfNonAppendOnlyOperations.get() + "], seqno of delete [" + delete.seqNo() + "]";
@@ -1305,7 +1304,7 @@ public class InternalEngine extends Engine {
         } else {
             final OpVsLuceneDocStatus opVsLucene = compareOpToLuceneDocBasedOnSeqNo(delete);
             if (opVsLucene == OpVsLuceneDocStatus.OP_STALE_OR_EQUAL) {
-                plan = DeletionStrategy.processAsStaleOp(softDeleteEnabled, false, delete.version());
+                plan = DeletionStrategy.processAsStaleOp(softDeleteEnabled, delete.version());
             } else {
                 plan = DeletionStrategy.processNormally(opVsLucene == OpVsLuceneDocStatus.LUCENE_DOC_NOT_FOUND, delete.version());
             }
@@ -1318,7 +1317,7 @@ public class InternalEngine extends Engine {
         return true;
     }
 
-    protected final DeletionStrategy planDeletionAsPrimary(Delete delete) throws IOException {
+    private DeletionStrategy planDeletionAsPrimary(Delete delete) throws IOException {
         assert delete.origin() == Operation.Origin.PRIMARY : "planing as primary but got " + delete.origin();
         // resolve operation from external to internal
         final VersionValue versionValue = resolveDocVersion(delete, delete.getIfSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO);
@@ -1336,7 +1335,7 @@ public class InternalEngine extends Engine {
         if (delete.getIfSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO && versionValue == null) {
             final VersionConflictEngineException e = new VersionConflictEngineException(shardId, delete.id(),
                 delete.getIfSeqNo(), delete.getIfPrimaryTerm(), SequenceNumbers.UNASSIGNED_SEQ_NO, 0);
-            plan = DeletionStrategy.skipDueToVersionConflict(e, currentVersion, getPrimaryTerm(), currentlyDeleted);
+            plan = DeletionStrategy.skipDueToVersionConflict(e, currentVersion, getPrimaryTerm(), true);
         } else if (delete.getIfSeqNo() != SequenceNumbers.UNASSIGNED_SEQ_NO && (
             versionValue.seqNo != delete.getIfSeqNo() || versionValue.term != delete.getIfPrimaryTerm()
         )) {
@@ -1428,8 +1427,8 @@ public class InternalEngine extends Engine {
             return new DeletionStrategy(false, false, currentlyDeleted, versionOfDeletion, null);
         }
 
-        static DeletionStrategy processAsStaleOp(boolean addStaleOpToLucene, boolean currentlyDeleted, long versionOfDeletion) {
+        static DeletionStrategy processAsStaleOp(boolean addStaleOpToLucene, long versionOfDeletion) {
-            return new DeletionStrategy(false, addStaleOpToLucene, currentlyDeleted, versionOfDeletion, null);
+            return new DeletionStrategy(false, addStaleOpToLucene, false, versionOfDeletion, null);
         }
     }
 

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

@@ -234,7 +234,7 @@ final class LiveVersionMap implements ReferenceManager.RefreshListener, Accounta
     /**
      * Tracks bytes used by tombstones (deletes)
      */
-    final AtomicLong ramBytesUsedTombstones = new AtomicLong();
+    private final AtomicLong ramBytesUsedTombstones = new AtomicLong();
 
     @Override
     public void beforeRefresh() throws IOException {

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

@@ -188,8 +188,7 @@ final class LuceneChangesSnapshot implements Translog.Snapshot {
             int readerIndex = 0;
             CombinedDocValues combinedDocValues = null;
             LeafReaderContext leaf = null;
-            for (int i = 0; i < scoreDocs.length; i++) {
+            for (ScoreDoc scoreDoc : scoreDocs) {
-                ScoreDoc scoreDoc = scoreDocs[i];
                 if (scoreDoc.doc >= docBase + maxDoc) {
                     do {
                         leaf = leaves.get(readerIndex++);

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

@@ -457,8 +457,8 @@ public class ReadOnlyEngine extends Engine {
 
     }
 
-    protected void processReaders(IndexReader reader, IndexReader previousReader) {
+    protected void processReader(IndexReader reader) {
-        searcherFactory.processReaders(reader, previousReader);
+        searcherFactory.processReaders(reader, null);
     }
 
     @Override

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

@@ -1,65 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.elasticsearch.index.engine;
-
-import org.elasticsearch.common.lease.Releasable;
-import org.elasticsearch.index.store.Store;
-
-import java.util.concurrent.atomic.AtomicInteger;
-
-/**
- * RecoveryCounter keeps tracks of the number of ongoing recoveries for a
- * particular {@link Store}
- */
-public class RecoveryCounter implements Releasable {
-
-    private final Store store;
-
-    RecoveryCounter(Store store) {
-        this.store = store;
-    }
-
-    private final AtomicInteger onGoingRecoveries = new AtomicInteger();
-
-    void startRecovery() {
-        store.incRef();
-        onGoingRecoveries.incrementAndGet();
-    }
-
-    public int get() {
-        return onGoingRecoveries.get();
-    }
-
-    /**
-     * End the recovery counter by decrementing the store's ref and the ongoing recovery counter
-     * @return number of ongoing recoveries remaining
-     */
-    int endRecovery() {
-        store.decRef();
-        int left = onGoingRecoveries.decrementAndGet();
-        assert onGoingRecoveries.get() >= 0 : "ongoingRecoveries must be >= 0 but was: " + onGoingRecoveries.get();
-        return left;
-    }
-
-    @Override
-    public void close() {
-        endRecovery();
-    }
-}

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

@@ -58,8 +58,7 @@ final class RecoverySourcePruneMergePolicy extends OneMergeWrappingMergePolicy {
         });
     }
 
-    // pkg private for testing
+    private static CodecReader wrapReader(String recoverySourceField, CodecReader reader, Supplier<Query> retainSourceQuerySupplier)
-    static CodecReader wrapReader(String recoverySourceField, CodecReader reader, Supplier<Query> retainSourceQuerySupplier)
         throws IOException {
         NumericDocValues recoverySource = reader.getNumericDocValues(recoverySourceField);
         if (recoverySource == null || recoverySource.nextDoc() == DocIdSetIterator.NO_MORE_DOCS) {

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

@@ -40,6 +40,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class Segment implements Streamable {
 
@@ -94,10 +95,6 @@ public class Segment implements Streamable {
         return new ByteSizeValue(sizeInBytes);
     }
 
-    public long getSizeInBytes() {
-        return this.sizeInBytes;
-    }
-
     public org.apache.lucene.util.Version getVersion() {
         return version;
     }
@@ -145,9 +142,8 @@ public class Segment implements Streamable {
 
         Segment segment = (Segment) o;
 
-        if (name != null ? !name.equals(segment.name) : segment.name != null) return false;
+        return Objects.equals(name, segment.name);
 
-        return true;
     }
 
     @Override
@@ -220,7 +216,7 @@ public class Segment implements Streamable {
         }
     }
 
-    Sort readSegmentSort(StreamInput in) throws IOException {
+    private Sort readSegmentSort(StreamInput in) throws IOException {
         int size = in.readVInt();
         if (size == 0) {
             return null;
@@ -271,7 +267,7 @@ public class Segment implements Streamable {
         return new Sort(fields);
     }
 
-    void writeSegmentSort(StreamOutput out, Sort sort) throws IOException {
+    private void writeSegmentSort(StreamOutput out, Sort sort) throws IOException {
         if (sort == null) {
             out.writeVInt(0);
             return;
@@ -311,14 +307,14 @@ public class Segment implements Streamable {
         }
     }
 
-    Accountable readRamTree(StreamInput in) throws IOException {
+    private Accountable readRamTree(StreamInput in) throws IOException {
         final String name = in.readString();
         final long bytes = in.readVLong();
         int numChildren = in.readVInt();
         if (numChildren == 0) {
             return Accountables.namedAccountable(name, bytes);
         }
-        List<Accountable> children = new ArrayList(numChildren);
+        List<Accountable> children = new ArrayList<>(numChildren);
         while (numChildren-- > 0) {
             children.add(readRamTree(in));
         }
@@ -326,7 +322,7 @@ public class Segment implements Streamable {
     }
 
     // the ram tree is written recursively since the depth is fairly low (5 or 6)
-    void writeRamTree(StreamOutput out, Accountable tree) throws IOException {
+    private void writeRamTree(StreamOutput out, Accountable tree) throws IOException {
         out.writeString(tree.toString());
         out.writeVLong(tree.ramBytesUsed());
         Collection<Accountable> children = tree.getChildResources();

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

@@ -30,7 +30,6 @@ import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
-import java.util.Iterator;
 
 public class SegmentsStats implements Streamable, Writeable, ToXContentFragment {
 
@@ -54,7 +53,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
      * Ideally this should be in sync to what the current version of Lucene is using, but it's harmless to leave extensions out,
      * they'll just miss a proper description in the stats
      */
-    private static ImmutableOpenMap<String, String> fileDescriptions = ImmutableOpenMap.<String, String>builder()
+    private static final ImmutableOpenMap<String, String> FILE_DESCRIPTIONS = ImmutableOpenMap.<String, String>builder()
             .fPut("si", "Segment Info")
             .fPut("fnm", "Fields")
             .fPut("fdx", "Field Index")
@@ -150,8 +149,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
     public void addFileSizes(ImmutableOpenMap<String, Long> fileSizes) {
         ImmutableOpenMap.Builder<String, Long> map = ImmutableOpenMap.builder(this.fileSizes);
 
-        for (Iterator<ObjectObjectCursor<String, Long>> it = fileSizes.iterator(); it.hasNext();) {
+        for (ObjectObjectCursor<String, Long> entry : fileSizes) {
-            ObjectObjectCursor<String, Long> entry = it.next();
             if (map.containsKey(entry.key)) {
                 Long oldValue = map.get(entry.key);
                 map.put(entry.key, oldValue + entry.value);
@@ -206,7 +204,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.termsMemoryInBytes;
     }
 
-    public ByteSizeValue getTermsMemory() {
+    private ByteSizeValue getTermsMemory() {
         return new ByteSizeValue(termsMemoryInBytes);
     }
 
@@ -217,7 +215,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.storedFieldsMemoryInBytes;
     }
 
-    public ByteSizeValue getStoredFieldsMemory() {
+    private ByteSizeValue getStoredFieldsMemory() {
         return new ByteSizeValue(storedFieldsMemoryInBytes);
     }
 
@@ -228,7 +226,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.termVectorsMemoryInBytes;
     }
 
-    public ByteSizeValue getTermVectorsMemory() {
+    private ByteSizeValue getTermVectorsMemory() {
         return new ByteSizeValue(termVectorsMemoryInBytes);
     }
 
@@ -239,7 +237,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.normsMemoryInBytes;
     }
 
-    public ByteSizeValue getNormsMemory() {
+    private ByteSizeValue getNormsMemory() {
         return new ByteSizeValue(normsMemoryInBytes);
     }
 
@@ -250,7 +248,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.pointsMemoryInBytes;
     }
 
-    public ByteSizeValue getPointsMemory() {
+    private ByteSizeValue getPointsMemory() {
         return new ByteSizeValue(pointsMemoryInBytes);
     }
 
@@ -261,7 +259,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         return this.docValuesMemoryInBytes;
     }
 
-    public ByteSizeValue getDocValuesMemory() {
+    private ByteSizeValue getDocValuesMemory() {
         return new ByteSizeValue(docValuesMemoryInBytes);
     }
 
@@ -326,11 +324,10 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         builder.humanReadableField(Fields.FIXED_BIT_SET_MEMORY_IN_BYTES, Fields.FIXED_BIT_SET, getBitsetMemory());
         builder.field(Fields.MAX_UNSAFE_AUTO_ID_TIMESTAMP, maxUnsafeAutoIdTimestamp);
         builder.startObject(Fields.FILE_SIZES);
-        for (Iterator<ObjectObjectCursor<String, Long>> it = fileSizes.iterator(); it.hasNext();) {
+        for (ObjectObjectCursor<String, Long> entry : fileSizes) {
-            ObjectObjectCursor<String, Long> entry = it.next();
             builder.startObject(entry.key);
             builder.humanReadableField(Fields.SIZE_IN_BYTES, Fields.SIZE, new ByteSizeValue(entry.value));
-            builder.field(Fields.DESCRIPTION, fileDescriptions.getOrDefault(entry.key, "Others"));
+            builder.field(Fields.DESCRIPTION, FILE_DESCRIPTIONS.getOrDefault(entry.key, "Others"));
             builder.endObject();
         }
         builder.endObject();
@@ -391,7 +388,7 @@ public class SegmentsStats implements Streamable, Writeable, ToXContentFragment
         out.writeVInt(fileSizes.size());
         for (ObjectObjectCursor<String, Long> entry : fileSizes) {
             out.writeString(entry.key);
-            out.writeLong(entry.value.longValue());
+            out.writeLong(entry.value);
         }
     }
 

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

@@ -20,16 +20,11 @@
 package org.elasticsearch.index.engine;
 
 import org.elasticsearch.common.io.stream.StreamInput;
-import org.elasticsearch.index.shard.ShardId;
 
 import java.io.IOException;
 
 public class SnapshotFailedEngineException extends EngineException {
 
-    public SnapshotFailedEngineException(ShardId shardId, Throwable cause) {
-        super(shardId, "Snapshot failed", cause);
-    }
-
     public SnapshotFailedEngineException(StreamInput in) throws IOException{
         super(in);
     }

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

@@ -35,7 +35,6 @@ import org.apache.lucene.index.StoredFieldVisitor;
 import org.apache.lucene.index.Terms;
 import org.apache.lucene.util.Bits;
 import org.apache.lucene.util.BytesRef;
-import org.elasticsearch.Version;
 import org.elasticsearch.index.mapper.IdFieldMapper;
 import org.elasticsearch.index.mapper.RoutingFieldMapper;
 import org.elasticsearch.index.mapper.SourceFieldMapper;
@@ -61,11 +60,9 @@ final class TranslogLeafReader extends LeafReader {
     private static final FieldInfo FAKE_ID_FIELD
         = new FieldInfo(IdFieldMapper.NAME, 3, false, false, false, IndexOptions.NONE, DocValuesType.NONE, -1, Collections.emptyMap(),
         0, 0, 0, false);
-    private final Version indexVersionCreated;
 
-    TranslogLeafReader(Translog.Index operation, Version indexVersionCreated) {
+    TranslogLeafReader(Translog.Index operation) {
         this.operation = operation;
-        this.indexVersionCreated = indexVersionCreated;
     }
     @Override
     public CacheHelper getCoreCacheHelper() {
@@ -161,14 +158,9 @@ final class TranslogLeafReader extends LeafReader {
             visitor.stringField(FAKE_ROUTING_FIELD, operation.routing().getBytes(StandardCharsets.UTF_8));
         }
         if (visitor.needsField(FAKE_ID_FIELD) == StoredFieldVisitor.Status.YES) {
-            final byte[] id;
-            if (indexVersionCreated.onOrAfter(Version.V_6_0_0)) {
             BytesRef bytesRef = Uid.encodeId(operation.id());
-                id = new byte[bytesRef.length];
+            final byte[] id = new byte[bytesRef.length];
             System.arraycopy(bytesRef.bytes, bytesRef.offset, id, 0, bytesRef.length);
-            } else { // TODO this can go away in 7.0 after backport
-                id = operation.id().getBytes(StandardCharsets.UTF_8);
-            }
             visitor.stringField(FAKE_ID_FIELD, id);
         }
     }

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

@@ -42,11 +42,7 @@ public class VersionConflictEngineException extends EngineException {
     }
 
     public VersionConflictEngineException(ShardId shardId, String id, String explanation) {
-        this(shardId, null, id, explanation);
+        this(shardId, "[{}]: version conflict, {}", null, id, explanation);
-    }
-
-    public VersionConflictEngineException(ShardId shardId, Throwable cause, String id, String explanation) {
-        this(shardId, "[{}]: version conflict, {}", cause, id, explanation);
     }
 
     public VersionConflictEngineException(ShardId shardId, String msg, Throwable cause, Object... params) {

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

@@ -169,7 +169,7 @@ public final class FrozenEngine extends ReadOnlyEngine {
                     listeners.beforeRefresh();
                 }
                 reader = DirectoryReader.open(engineConfig.getStore().directory());
-                processReaders(reader, null);
+                processReader(reader);
                 reader = lastOpenedReader = wrapReader(reader, Function.identity());
                 reader.getReaderCacheHelper().addClosedListener(this::onReaderClosed);
                 for (ReferenceManager.RefreshListener listeners : config ().getInternalRefreshListener()) {