Don't use endianness reverse util for writing metadata state file

server/src/main/java/org/elasticsearch/gateway/MetadataStateFormat.java

@@ -10,7 +10,6 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
-import org.apache.lucene.backward_codecs.store.EndiannessReverserUtil;
 import org.apache.lucene.codecs.CodecUtil;
 import org.apache.lucene.index.CorruptIndexException;
 import org.apache.lucene.index.IndexFormatTooNewException;
@@ -56,8 +55,11 @@ public abstract class MetadataStateFormat<T> {
     public static final String STATE_FILE_EXTENSION = ".st";
 
     private static final String STATE_FILE_CODEC = "state";
+    // original version format
     private static final int MIN_COMPATIBLE_STATE_FILE_VERSION = 1;
-    private static final int STATE_FILE_VERSION = 1;
+    // Lucene directory API changed to LE, ES 8.0
+    private static final int LE_VERSION = 2;
+    private static final int CURRENT_VERSION = LE_VERSION;
     private final String prefix;
     private final Pattern stateFilePattern;
 
@@ -92,8 +94,8 @@ private void writeStateToFirstLocation(final T state, Path stateLocation, Direct
             throws WriteStateException {
         try {
             deleteFileIfExists(stateLocation, stateDir, tmpFileName);
-            try (IndexOutput out = EndiannessReverserUtil.createOutput(stateDir, tmpFileName, IOContext.DEFAULT)) {
-                CodecUtil.writeHeader(out, STATE_FILE_CODEC, STATE_FILE_VERSION);
+            try (IndexOutput out = stateDir.createOutput(tmpFileName, IOContext.DEFAULT)) {
+                CodecUtil.writeHeader(out, STATE_FILE_CODEC, CURRENT_VERSION);
                 out.writeInt(FORMAT.index());
                 try (XContentBuilder builder = newXContentBuilder(FORMAT, new IndexOutputOutputStream(out) {
                     @Override
@@ -268,11 +270,17 @@ protected XContentBuilder newXContentBuilder(XContentType type, OutputStream str
      */
     public final T read(NamedXContentRegistry namedXContentRegistry, Path file) throws IOException {
         try (Directory dir = newDirectory(file.getParent())) {
-            try (IndexInput indexInput = EndiannessReverserUtil.openInput(dir, file.getFileName().toString(), IOContext.DEFAULT)) {
+            try (IndexInput indexInput = dir.openInput(file.getFileName().toString(), IOContext.DEFAULT)) {
                 // We checksum the entire file before we even go and parse it. If it's corrupted we barf right here.
                 CodecUtil.checksumEntireFile(indexInput);
-                CodecUtil.checkHeader(indexInput, STATE_FILE_CODEC, MIN_COMPATIBLE_STATE_FILE_VERSION, STATE_FILE_VERSION);
-                final XContentType xContentType = XContentType.values()[indexInput.readInt()];
+                final int format =
+                    CodecUtil.checkHeader(indexInput, STATE_FILE_CODEC, MIN_COMPATIBLE_STATE_FILE_VERSION, CURRENT_VERSION);
+                final XContentType xContentType;
+                if (format < LE_VERSION) {
+                    xContentType = XContentType.values()[Integer.reverseBytes(indexInput.readInt())];
+                } else {
+                    xContentType = XContentType.values()[indexInput.readInt()];
+                }
                 if (xContentType != FORMAT) {
                     throw new IllegalStateException("expected state in " + file + " to be " + FORMAT + " format but was " + xContentType);
                 }

server/src/test/java/org/elasticsearch/gateway/MetadataStateFormatTests.java

@@ -42,14 +42,23 @@
 
 @LuceneTestCase.SuppressFileSystems("ExtrasFS") // TODO: fix test to work with ExtrasFS
 public class MetadataStateFormatTests extends ESTestCase {
+
+    public void testReadClusterStateV1() throws IOException {
+        assertReadClusterState("global-3-V1.st");
+    }
+
+    public void testReadClusterStateV2() throws IOException {
+        assertReadClusterState("global-3-V2.st");
+    }
+
     /**
      * Ensure we can read a pre-generated cluster state.
      */
-    public void testReadClusterState() throws IOException {
+    private void assertReadClusterState(String clusterState) throws IOException {
         final MetadataStateFormat<Metadata> format = new MetadataStateFormat<Metadata>("global-") {
 
             @Override
-            public void toXContent(XContentBuilder builder, Metadata state) {
+            public void toXContent(XContentBuilder builder, Metadata state) throws IOException {
                 fail("this test doesn't write");
             }
 
@@ -59,9 +68,9 @@ public Metadata fromXContent(XContentParser parser) throws IOException {
             }
         };
         Path tmp = createTempDir();
-        final InputStream resource = this.getClass().getResourceAsStream("global-3.st");
+        final InputStream resource = this.getClass().getResourceAsStream(clusterState);
         assertThat(resource, notNullValue());
-        Path dst = tmp.resolve("global-3.st");
+        Path dst = tmp.resolve(clusterState);
         Files.copy(resource, dst);
         Metadata read = format.read(xContentRegistry(), dst);
         assertThat(read, notNullValue());