Remove Support for VERSION_CHECKPOINTS Translogs (elastic#42782)

* Closes elastic#42699

server/src/main/java/org/elasticsearch/index/translog/TranslogHeader.java

@@ -34,8 +34,6 @@
 import java.nio.channels.FileChannel;
 import java.nio.file.Path;
 
-import static org.elasticsearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
-
 /**
  * Each translog file is started with a translog header then followed by translog operations.
  */
@@ -123,6 +121,9 @@ static TranslogHeader read(final String translogUUID, final Path path, final Fil
         if (version == VERSION_CHECKSUMS) {
             throw new IllegalStateException("pre-2.0 translog found [" + path + "]");
         }
+        if (version == VERSION_CHECKPOINTS) {
+            throw new IllegalStateException("pre-6.3 translog found [" + path + "]");
+        }
         // Read the translogUUID
         final int uuidLen = in.readInt();
         if (uuidLen > channel.size()) {
@@ -141,17 +142,10 @@ static TranslogHeader read(final String translogUUID, final Path path, final Fil
                             " this translog file belongs to a different translog");
         }
         // Read the primary term
-        final long primaryTerm;
-        if (version == VERSION_PRIMARY_TERM) {
-            primaryTerm = in.readLong();
-        } else {
-            assert version == VERSION_CHECKPOINTS : "Unknown header version [" + version + "]";
-            primaryTerm = UNASSIGNED_PRIMARY_TERM;
-        }
+        assert version == VERSION_PRIMARY_TERM;
+        final long primaryTerm = in.readLong();
         // Verify the checksum
-        if (version >= VERSION_PRIMARY_TERM) {
-            Translog.verifyChecksum(in);
-        }
+        Translog.verifyChecksum(in);
         assert primaryTerm >= 0 : "Primary term must be non-negative [" + primaryTerm + "]; translog path [" + path + "]";
 
         final int headerSizeInBytes = headerSizeInBytes(version, uuid.length);

server/src/test/java/org/elasticsearch/index/translog/TranslogHeaderTests.java

@@ -19,24 +19,17 @@
 
 package org.elasticsearch.index.translog;
 
-import org.apache.lucene.codecs.CodecUtil;
-import org.apache.lucene.store.OutputStreamDataOutput;
-import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.UUIDs;
-import org.elasticsearch.common.io.stream.OutputStreamStreamOutput;
 import org.elasticsearch.index.seqno.SequenceNumbers;
 import org.elasticsearch.test.ESTestCase;
 
-import java.io.IOException;
-import java.nio.channels.Channels;
 import java.nio.channels.FileChannel;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.lessThan;
 
 public class TranslogHeaderTests extends ESTestCase {
 
@@ -72,40 +65,10 @@ public void testCurrentHeaderVersion() throws Exception {
         });
     }
 
-    public void testHeaderWithoutPrimaryTerm() throws Exception {
-        final String translogUUID = UUIDs.randomBase64UUID();
-        final long generation = randomNonNegativeLong();
-        final Path translogFile = createTempDir().resolve(Translog.getFilename(generation));
-        try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE)) {
-            writeHeaderWithoutTerm(channel, translogUUID);
-            assertThat((int)channel.position(), lessThan(TranslogHeader.headerSizeInBytes(translogUUID)));
-        }
-        try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
-            final TranslogHeader inHeader = TranslogHeader.read(translogUUID, translogFile, channel);
-            assertThat(inHeader.getTranslogUUID(), equalTo(translogUUID));
-            assertThat(inHeader.getPrimaryTerm(), equalTo(SequenceNumbers.UNASSIGNED_PRIMARY_TERM));
-            assertThat(inHeader.sizeInBytes(), equalTo((int)channel.position()));
-        }
-        expectThrows(TranslogCorruptedException.class, () -> {
-            try (FileChannel channel = FileChannel.open(translogFile, StandardOpenOption.READ)) {
-                TranslogHeader.read(UUIDs.randomBase64UUID(), translogFile, channel);
-            }
-        });
-    }
-
-    static void writeHeaderWithoutTerm(FileChannel channel, String translogUUID) throws IOException {
-        final OutputStreamStreamOutput out = new OutputStreamStreamOutput(Channels.newOutputStream(channel));
-        CodecUtil.writeHeader(new OutputStreamDataOutput(out), TranslogHeader.TRANSLOG_CODEC, TranslogHeader.VERSION_CHECKPOINTS);
-        final BytesRef uuid = new BytesRef(translogUUID);
-        out.writeInt(uuid.length);
-        out.writeBytes(uuid.bytes, uuid.offset, uuid.length);
-        channel.force(true);
-        assertThat(channel.position(), equalTo(43L));
-    }
-
-    public void testLegacyTranslogVersions() throws Exception {
+    public void testLegacyTranslogVersions() {
         checkFailsToOpen("/org/elasticsearch/index/translog/translog-v0.binary", IllegalStateException.class, "pre-1.4 translog");
         checkFailsToOpen("/org/elasticsearch/index/translog/translog-v1.binary", IllegalStateException.class, "pre-2.0 translog");
+        checkFailsToOpen("/org/elasticsearch/index/translog/translog-v2.binary", IllegalStateException.class, "pre-6.3 translog");
         checkFailsToOpen("/org/elasticsearch/index/translog/translog-v1-truncated.binary", IllegalStateException.class, "pre-2.0 translog");
         checkFailsToOpen("/org/elasticsearch/index/translog/translog-v1-corrupted-magic.binary",
             TranslogCorruptedException.class, "translog looks like version 1 or later, but has corrupted header");