Remove several uses of 6.x version constants (#41162)

This commit removes many conditionals in serialization, as well as tests
which no longer need to be compatible with 6.x now that master is 8.0.
Additionally, many tests are changed to not depend on a fixed version,
but instead use new helper methods for getting the range of index
compatible versions with the current version, which will make the tests
not need changes in the future when version constants are removed.

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolateQueryBuilder.java

@@ -57,7 +57,6 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
-import org.elasticsearch.common.xcontent.XContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentHelper;
@@ -90,8 +89,6 @@ import java.util.List;
 import java.util.Objects;
 import java.util.function.Supplier;
 
-import static org.elasticsearch.percolator.PercolatorFieldMapper.parseQuery;
-
 public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBuilder> {
     public static final String NAME = "percolate";
 
@@ -247,14 +244,8 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
     PercolateQueryBuilder(StreamInput in) throws IOException {
         super(in);
         field = in.readString();
-        if (in.getVersion().onOrAfter(Version.V_6_1_0)) {
-            name = in.readOptionalString();
-        }
-        if (in.getVersion().before(Version.V_6_0_0_beta1)) {
-            documentType = in.readString();
-        } else {
-            documentType = in.readOptionalString();
-        }
+        name = in.readOptionalString();
+        documentType = in.readOptionalString();
         indexedDocumentIndex = in.readOptionalString();
         indexedDocumentType = in.readOptionalString();
         indexedDocumentId = in.readOptionalString();
@@ -265,12 +256,7 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
         } else {
             indexedDocumentVersion = null;
         }
-        if (in.getVersion().onOrAfter(Version.V_6_1_0)) {
-            documents = in.readList(StreamInput::readBytesReference);
-        } else {
-            BytesReference document = in.readOptionalBytesReference();
-            documents = document != null ? Collections.singletonList(document) : Collections.emptyList();
-        }
+        documents = in.readList(StreamInput::readBytesReference);
         if (documents.isEmpty() == false) {
             documentXContentType = in.readEnum(XContentType.class);
         } else {
@@ -294,14 +280,8 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
             throw new IllegalStateException("supplier must be null, can't serialize suppliers, missing a rewriteAndFetch?");
         }
         out.writeString(field);
-        if (out.getVersion().onOrAfter(Version.V_6_1_0)) {
-            out.writeOptionalString(name);
-        }
-        if (out.getVersion().before(Version.V_6_0_0_beta1)) {
-            out.writeString(documentType);
-        } else {
-            out.writeOptionalString(documentType);
-        }
+        out.writeOptionalString(name);
+        out.writeOptionalString(documentType);
         out.writeOptionalString(indexedDocumentIndex);
         out.writeOptionalString(indexedDocumentType);
         out.writeOptionalString(indexedDocumentId);
@@ -685,50 +665,30 @@ public class PercolateQueryBuilder extends AbstractQueryBuilder<PercolateQueryBu
             if (binaryDocValues == null) {
                 return docId -> null;
             }
-            if (indexVersion.onOrAfter(Version.V_6_0_0_beta2)) {
-                return docId -> {
-                    if (binaryDocValues.advanceExact(docId)) {
-                        BytesRef qbSource = binaryDocValues.binaryValue();
-                        try (InputStream in = new ByteArrayInputStream(qbSource.bytes, qbSource.offset, qbSource.length)) {
-                            try (StreamInput input = new NamedWriteableAwareStreamInput(
-                                    new InputStreamStreamInput(in, qbSource.length), registry)) {
-                                input.setVersion(indexVersion);
-                                // Query builder's content is stored via BinaryFieldMapper, which has a custom encoding
-                                // to encode multiple binary values into a single binary doc values field.
-                                // This is the reason we need to first need to read the number of values and
-                                // then the length of the field value in bytes.
-                                int numValues = input.readVInt();
-                                assert numValues == 1;
-                                int valueLength = input.readVInt();
-                                assert valueLength > 0;
-                                QueryBuilder queryBuilder = input.readNamedWriteable(QueryBuilder.class);
-                                assert in.read() == -1;
-                                return PercolatorFieldMapper.toQuery(context, mapUnmappedFieldsAsString, queryBuilder);
-                            }
+            return docId -> {
+                if (binaryDocValues.advanceExact(docId)) {
+                    BytesRef qbSource = binaryDocValues.binaryValue();
+                    try (InputStream in = new ByteArrayInputStream(qbSource.bytes, qbSource.offset, qbSource.length)) {
+                        try (StreamInput input = new NamedWriteableAwareStreamInput(
+                                new InputStreamStreamInput(in, qbSource.length), registry)) {
+                            input.setVersion(indexVersion);
+                            // Query builder's content is stored via BinaryFieldMapper, which has a custom encoding
+                            // to encode multiple binary values into a single binary doc values field.
+                            // This is the reason we need to first need to read the number of values and
+                            // then the length of the field value in bytes.
+                            int numValues = input.readVInt();
+                            assert numValues == 1;
+                            int valueLength = input.readVInt();
+                            assert valueLength > 0;
+                            QueryBuilder queryBuilder = input.readNamedWriteable(QueryBuilder.class);
+                            assert in.read() == -1;
+                            return PercolatorFieldMapper.toQuery(context, mapUnmappedFieldsAsString, queryBuilder);
                         }
-                    } else {
-                        return null;
                     }
-                };
-            } else {
-                return docId -> {
-                    if (binaryDocValues.advanceExact(docId)) {
-                        BytesRef qbSource = binaryDocValues.binaryValue();
-                        if (qbSource.length > 0) {
-                            XContent xContent = PercolatorFieldMapper.QUERY_BUILDER_CONTENT_TYPE.xContent();
-                            try (XContentParser sourceParser = xContent
-                                    .createParser(context.getXContentRegistry(), LoggingDeprecationHandler.INSTANCE,
-                                        qbSource.bytes, qbSource.offset, qbSource.length)) {
-                                return parseQuery(context, mapUnmappedFieldsAsString, sourceParser);
-                            }
-                        } else {
-                            return null;
-                        }
-                    } else {
-                        return null;
-                    }
-                };
-            }
+                } else {
+                    return null;
+                }
+            };
         };
     }
 

modules/percolator/src/main/java/org/elasticsearch/percolator/PercolatorFieldMapper.java

@@ -53,8 +53,6 @@ import org.elasticsearch.common.io.stream.OutputStreamStreamOutput;
 import org.elasticsearch.common.lucene.search.Queries;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentLocation;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.common.xcontent.XContentType;
@@ -84,7 +82,6 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -423,21 +420,12 @@ public class PercolatorFieldMapper extends FieldMapper {
 
     static void createQueryBuilderField(Version indexVersion, BinaryFieldMapper qbField,
                                         QueryBuilder queryBuilder, ParseContext context) throws IOException {
-        if (indexVersion.onOrAfter(Version.V_6_0_0_beta2)) {
-            try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
-                try (OutputStreamStreamOutput out  = new OutputStreamStreamOutput(stream)) {
-                    out.setVersion(indexVersion);
-                    out.writeNamedWriteable(queryBuilder);
-                    byte[] queryBuilderAsBytes = stream.toByteArray();
-                    qbField.parse(context.createExternalValueContext(queryBuilderAsBytes));
-                }
-            }
-        } else {
-            try (XContentBuilder builder = XContentFactory.contentBuilder(QUERY_BUILDER_CONTENT_TYPE)) {
-                queryBuilder.toXContent(builder, new MapParams(Collections.emptyMap()));
-                builder.flush();
-                byte[] queryBuilderAsBytes = BytesReference.toBytes(BytesReference.bytes(builder));
-                context.doc().add(new Field(qbField.name(), queryBuilderAsBytes, qbField.fieldType()));
+        try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
+            try (OutputStreamStreamOutput out  = new OutputStreamStreamOutput(stream)) {
+                out.setVersion(indexVersion);
+                out.writeNamedWriteable(queryBuilder);
+                byte[] queryBuilderAsBytes = stream.toByteArray();
+                qbField.parse(context.createExternalValueContext(queryBuilderAsBytes));
             }
         }
     }

modules/percolator/src/test/java/org/elasticsearch/percolator/QueryBuilderStoreTests.java

@@ -74,7 +74,7 @@ public class QueryBuilderStoreTests extends ESTestCase {
             BinaryFieldMapper fieldMapper = PercolatorFieldMapper.Builder.createQueryBuilderFieldBuilder(
                 new Mapper.BuilderContext(settings, new ContentPath(0)));
 
-            Version version = Version.V_6_0_0_beta2;
+            Version version = Version.CURRENT;
             try (IndexWriter indexWriter = new IndexWriter(directory, config)) {
                 for (int i = 0; i < queryBuilders.length; i++) {
                     queryBuilders[i] = new TermQueryBuilder(randomAlphaOfLength(4), randomAlphaOfLength(8));

server/src/main/java/org/elasticsearch/action/index/IndexRequest.java

@@ -603,12 +603,7 @@ public class IndexRequest extends ReplicatedWriteRequest<IndexRequest> implement
             assert ifSeqNo == UNASSIGNED_SEQ_NO;
             assert ifPrimaryTerm == UNASSIGNED_PRIMARY_TERM;
             autoGeneratedTimestamp = Math.max(0, System.currentTimeMillis()); // extra paranoia
-            String uid;
-            if (indexCreatedVersion.onOrAfter(Version.V_6_0_0_beta1)) {
-                uid = UUIDs.base64UUID();
-            } else {
-                uid = UUIDs.legacyBase64UUID();
-            }
+            String uid = UUIDs.base64UUID();
             id(uid);
         }
     }

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

@@ -161,14 +161,9 @@ 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];
-                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);
-            }
+            BytesRef bytesRef = Uid.encodeId(operation.id());
+            final byte[] id = new byte[bytesRef.length];
+            System.arraycopy(bytesRef.bytes, bytesRef.offset, id, 0, bytesRef.length);
             visitor.stringField(FAKE_ID_FIELD, id);
         }
     }

server/src/main/java/org/elasticsearch/indices/recovery/RecoverySourceHandler.java

@@ -253,9 +253,8 @@ public class RecoverySourceHandler {
 
     private boolean isTargetSameHistory() {
         final String targetHistoryUUID = request.metadataSnapshot().getHistoryUUID();
-        assert targetHistoryUUID != null || shard.indexSettings().getIndexVersionCreated().before(Version.V_6_0_0_rc1) :
-            "incoming target history N/A but index was created after or on 6.0.0-rc1";
-        return targetHistoryUUID != null && targetHistoryUUID.equals(shard.getHistoryUUID());
+        assert targetHistoryUUID != null : "incoming target history missing";
+        return targetHistoryUUID.equals(shard.getHistoryUUID());
     }
 
     static void runUnderPrimaryPermit(CancellableThreads.Interruptible runnable, String reason,

server/src/main/java/org/elasticsearch/indices/recovery/RecoveryTarget.java

@@ -395,9 +395,6 @@ public class RecoveryTarget extends AbstractRefCounted implements RecoveryTarget
         store.incRef();
         try {
             store.cleanupAndVerify("recovery CleanFilesRequestHandler", sourceMetaData);
-            if (indexShard.indexSettings().getIndexVersionCreated().before(Version.V_6_0_0_rc1)) {
-                store.ensureIndexHasHistoryUUID();
-            }
             assert globalCheckpoint >= Long.parseLong(sourceMetaData.getCommitUserData().get(SequenceNumbers.MAX_SEQ_NO))
                 || indexShard.indexSettings().getIndexVersionCreated().before(Version.V_7_1_0) :
                 "invalid global checkpoint[" + globalCheckpoint + "] source_meta_data [" + sourceMetaData.getCommitUserData() + "]";

server/src/main/java/org/elasticsearch/plugins/PluginInfo.java

@@ -196,10 +196,6 @@ public class PluginInfo implements Writeable, ToXContentObject {
             }
         }
 
-        if (esVersion.before(Version.V_6_3_0) && esVersion.onOrAfter(Version.V_6_0_0_beta2)) {
-            propsMap.remove("requires.keystore");
-        }
-
         if (propsMap.isEmpty() == false) {
             throw new IllegalArgumentException("Unknown properties in plugin descriptor: " + propsMap.keySet());
         }

server/src/test/java/org/elasticsearch/ExceptionSerializationTests.java

@@ -878,7 +878,7 @@ public class ExceptionSerializationTests extends ESTestCase {
     public void testShardLockObtainFailedException() throws IOException {
         ShardId shardId = new ShardId("foo", "_na_", 1);
         ShardLockObtainFailedException orig = new ShardLockObtainFailedException(shardId, "boom");
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         ShardLockObtainFailedException ex = serialize(orig, version);
         assertEquals(orig.getMessage(), ex.getMessage());
         assertEquals(orig.getShardId(), ex.getShardId());

server/src/test/java/org/elasticsearch/VersionTests.java

@@ -101,8 +101,7 @@ public class VersionTests extends ESTestCase {
     }
 
     public void testMinimumIndexCompatibilityVersion() {
-        assertEquals(Version.fromId(5000099), Version.V_6_0_0_beta1.minimumIndexCompatibilityVersion());
-        assertEquals(Version.fromId(2000099), Version.fromId(5000099).minimumIndexCompatibilityVersion());
+        assertEquals(Version.fromId(5000099), Version.fromId(6000099).minimumIndexCompatibilityVersion());
         assertEquals(Version.fromId(2000099),
                 Version.fromId(5010000).minimumIndexCompatibilityVersion());
         assertEquals(Version.fromId(2000099),
@@ -161,7 +160,7 @@ public class VersionTests extends ESTestCase {
 
     public void testIndexCreatedVersion() {
         // an actual index has a IndexMetaData.SETTING_INDEX_UUID
-        final Version version = Version.V_6_0_0_beta1;
+        final Version version = VersionUtils.randomVersion(random());
         assertEquals(version, Version.indexCreated(
             Settings.builder()
                 .put(IndexMetaData.SETTING_INDEX_UUID, "foo")

server/src/test/java/org/elasticsearch/action/admin/cluster/shards/ClusterSearchShardsRequestTests.java

@@ -54,7 +54,7 @@ public class ClusterSearchShardsRequestTests extends ESTestCase {
             request.routing(routings);
         }
 
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         try (BytesStreamOutput out = new BytesStreamOutput()) {
             out.setVersion(version);
             request.writeTo(out);

server/src/test/java/org/elasticsearch/action/admin/cluster/shards/ClusterSearchShardsResponseTests.java

@@ -77,7 +77,7 @@ public class ClusterSearchShardsResponseTests extends ESTestCase {
         List<NamedWriteableRegistry.Entry> entries = new ArrayList<>();
         entries.addAll(searchModule.getNamedWriteables());
         NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(entries);
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         try(BytesStreamOutput out = new BytesStreamOutput()) {
             out.setVersion(version);
             clusterSearchShardsResponse.writeTo(out);

server/src/test/java/org/elasticsearch/common/geo/GeoJsonShapeParserTests.java

@@ -291,7 +291,7 @@ public class GeoJsonShapeParserTests extends BaseGeoParsingTestCase {
         shellCoordinates.add(new Coordinate(100, 0, 10));
         Coordinate[] coordinates = shellCoordinates.toArray(new Coordinate[shellCoordinates.size()]);
 
-        Version randomVersion = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version randomVersion = VersionUtils.randomIndexCompatibleVersion(random());
         Settings indexSettings = Settings.builder()
             .put(IndexMetaData.SETTING_VERSION_CREATED, randomVersion)
             .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0)

server/src/test/java/org/elasticsearch/index/mapper/ExternalFieldMapperTests.java

@@ -63,8 +63,7 @@ public class ExternalFieldMapperTests extends ESSingleNodeTestCase {
     }
 
     public void testExternalValues() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         IndexService indexService = createIndex("test", settings);
         MapperRegistry mapperRegistry = new MapperRegistry(

server/src/test/java/org/elasticsearch/index/mapper/TypeFieldTypeTests.java

@@ -39,7 +39,7 @@ public class TypeFieldTypeTests extends FieldTypeTestCase {
 
     public void testTermsQuery() throws Exception {
         QueryShardContext context = Mockito.mock(QueryShardContext.class);
-        Version indexVersionCreated = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version indexVersionCreated = VersionUtils.randomIndexCompatibleVersion(random());
         Settings indexSettings = Settings.builder()
                 .put(IndexMetaData.SETTING_VERSION_CREATED, indexVersionCreated)
                 .put(IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 0)

server/src/test/java/org/elasticsearch/indices/IndicesServiceTests.java

@@ -524,7 +524,7 @@ public class IndicesServiceTests extends ESSingleNodeTestCase {
 
     public void testIsMetaDataField() {
         IndicesService indicesService = getIndicesService();
-        final Version randVersion = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        final Version randVersion = VersionUtils.randomIndexCompatibleVersion(random());
         assertFalse(indicesService.isMetaDataField(randVersion, randomAlphaOfLengthBetween(10, 15)));
         for (String builtIn : IndicesModule.getBuiltInMetaDataFields()) {
             assertTrue(indicesService.isMetaDataField(randVersion, builtIn));

server/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java

@@ -133,10 +133,11 @@ public class AnalysisModuleTests extends ESTestCase {
 
     public void testVersionedAnalyzers() throws Exception {
         String yaml = "/org/elasticsearch/index/analysis/test1.yml";
+        Version version = VersionUtils.randomVersion(random());
         Settings settings2 = Settings.builder()
                 .loadFromStream(yaml, getClass().getResourceAsStream(yaml), false)
                 .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
-                .put(IndexMetaData.SETTING_VERSION_CREATED, Version.V_6_0_0)
+                .put(IndexMetaData.SETTING_VERSION_CREATED, version)
                 .build();
         AnalysisRegistry newRegistry = getNewRegistry(settings2);
         IndexAnalyzers indexAnalyzers = getIndexAnalyzers(newRegistry, settings2);
@@ -149,9 +150,9 @@ public class AnalysisModuleTests extends ESTestCase {
 
         // analysis service has the expected version
         assertThat(indexAnalyzers.get("standard").analyzer(), is(instanceOf(StandardAnalyzer.class)));
-        assertEquals(Version.V_6_0_0.luceneVersion,
+        assertEquals(version.luceneVersion,
                 indexAnalyzers.get("standard").analyzer().getVersion());
-        assertEquals(Version.V_6_0_0.luceneVersion,
+        assertEquals(version.luceneVersion,
                 indexAnalyzers.get("stop").analyzer().getVersion());
 
         assertThat(indexAnalyzers.get("custom7").analyzer(), is(instanceOf(StandardAnalyzer.class)));

server/src/test/java/org/elasticsearch/plugins/PluginsServiceTests.java

@@ -601,7 +601,7 @@ public class PluginsServiceTests extends ESTestCase {
     }
 
     public void testIncompatibleElasticsearchVersion() throws Exception {
-        PluginInfo info = new PluginInfo("my_plugin", "desc", "1.0", Version.V_6_0_0,
+        PluginInfo info = new PluginInfo("my_plugin", "desc", "1.0", Version.fromId(6000099),
             "1.8", "FakePlugin", Collections.emptyList(), false);
         IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> PluginsService.verifyCompatibility(info));
         assertThat(e.getMessage(), containsString("was built for Elasticsearch version 6.0.0"));

server/src/test/java/org/elasticsearch/search/aggregations/bucket/GeoDistanceIT.java

@@ -64,7 +64,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
         return false;
     }
 
-    private Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+    private Version version = VersionUtils.randomIndexCompatibleVersion(random());
 
     private IndexRequestBuilder indexCity(String idx, String name, String... latLons) throws Exception {
         XContentBuilder source = jsonBuilder().startObject().field("city", name);

server/src/test/java/org/elasticsearch/search/aggregations/bucket/GeoHashGridIT.java

@@ -61,8 +61,7 @@ public class GeoHashGridIT extends ESIntegTestCase {
         return false;
     }
 
-    private Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-            Version.CURRENT);
+    private Version version = VersionUtils.randomIndexCompatibleVersion(random());
 
     static ObjectIntMap<String> expectedDocCountsForGeoHash = null;
     static ObjectIntMap<String> multiValuedExpectedDocCountsForGeoHash = null;

server/src/test/java/org/elasticsearch/search/functionscore/DecayFunctionScoreIT.java

@@ -610,7 +610,7 @@ public class DecayFunctionScoreIT extends ESIntegTestCase {
     }
 
     public void testManyDocsLin() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = jsonBuilder().startObject().startObject("type").startObject("properties")
                 .startObject("test").field("type", "text").endObject().startObject("date").field("type", "date")

server/src/test/java/org/elasticsearch/search/geo/GeoBoundingBoxIT.java

@@ -47,8 +47,7 @@ public class GeoBoundingBoxIT extends ESIntegTestCase {
     }
 
     public void testSimpleBoundingBoxTest() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1")
                 .startObject("properties").startObject("location").field("type", "geo_point");
@@ -119,8 +118,7 @@ public class GeoBoundingBoxIT extends ESIntegTestCase {
     }
 
     public void testLimit2BoundingBox() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1")
                 .startObject("properties").startObject("location").field("type", "geo_point");
@@ -174,8 +172,7 @@ public class GeoBoundingBoxIT extends ESIntegTestCase {
     }
 
     public void testCompleteLonRange() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1")
                 .startObject("properties").startObject("location").field("type", "geo_point");

server/src/test/java/org/elasticsearch/search/geo/GeoDistanceIT.java

@@ -104,8 +104,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
 
     @Before
     public void setupTestIndex() throws IOException {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1")
                 .startObject("properties").startObject("location").field("type", "geo_point");

server/src/test/java/org/elasticsearch/search/geo/GeoFilterIT.java

@@ -367,8 +367,7 @@ public class GeoFilterIT extends ESIntegTestCase {
 
     public void testBulk() throws Exception {
         byte[] bulkAction = unZipData("/org/elasticsearch/search/geo/gzippedmap.gz");
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder()
                 .startObject()

server/src/test/java/org/elasticsearch/search/geo/GeoPolygonIT.java

@@ -49,8 +49,7 @@ public class GeoPolygonIT extends ESIntegTestCase {
 
     @Override
     protected void setupSuiteScopeCluster() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
 
         assertAcked(prepareCreate("test").setSettings(settings).addMapping("type1", "location",

server/src/test/java/org/elasticsearch/search/sort/GeoDistanceIT.java

@@ -55,8 +55,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
     }
 
     public void testDistanceSortingMVFields() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1").startObject("properties")
                 .startObject("locations").field("type", "geo_point");
@@ -182,8 +181,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
     // Regression bug:
     // https://github.com/elastic/elasticsearch/issues/2851
     public void testDistanceSortingWithMissingGeoPoint() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("type1").startObject("properties")
                 .startObject("locations").field("type", "geo_point");
@@ -225,8 +223,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
     }
 
     public void testDistanceSortingNestedFields() throws Exception {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("company").startObject("properties")
                 .startObject("name").field("type", "text").endObject().startObject("branches").field("type", "nested")
@@ -374,8 +371,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
      * Issue 3073
      */
     public void testGeoDistanceFilter() throws IOException {
-        Version version = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-                Version.CURRENT);
+        Version version = VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         double lat = 40.720611;
         double lon = -73.998776;

server/src/test/java/org/elasticsearch/search/sort/GeoDistanceSortBuilderIT.java

@@ -69,7 +69,7 @@ public class GeoDistanceSortBuilderIT extends ESIntegTestCase {
          * 1   2   3   4   5   6   7
          */
         Version version = randomBoolean() ? Version.CURRENT
-                : VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+                : VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         assertAcked(prepareCreate("index").setSettings(settings).addMapping("type", LOCATION_FIELD, "type=geo_point"));
         XContentBuilder d1Builder = jsonBuilder();
@@ -143,7 +143,7 @@ public class GeoDistanceSortBuilderIT extends ESIntegTestCase {
          * d2 = (0, 1), (0, 5), (0, 6); so avg. distance is 4, median distance is 5
          */
         Version version = randomBoolean() ? Version.CURRENT
-                : VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+                : VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         assertAcked(prepareCreate("index").setSettings(settings).addMapping("type", LOCATION_FIELD, "type=geo_point"));
         XContentBuilder d1Builder = jsonBuilder();
@@ -208,7 +208,7 @@ public class GeoDistanceSortBuilderIT extends ESIntegTestCase {
          * 1   2   3   4   5   6
          */
         Version version = randomBoolean() ? Version.CURRENT
-                : VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+                : VersionUtils.randomIndexCompatibleVersion(random());
         Settings settings = Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, version).build();
         assertAcked(prepareCreate("index").setSettings(settings).addMapping("type", LOCATION_FIELD, "type=geo_point"));
         XContentBuilder d1Builder = jsonBuilder();

test/framework/src/main/java/org/elasticsearch/test/AbstractBuilderTestCase.java

@@ -179,8 +179,7 @@ public abstract class AbstractBuilderTestCase extends ESTestCase {
 
     protected Settings createTestIndexSettings() {
         // we have to prefer CURRENT since with the range of versions we support it's rather unlikely to get the current actually.
-        Version indexVersionCreated = randomBoolean() ? Version.CURRENT
-                : VersionUtils.randomVersionBetween(random(), Version.V_6_0_0, Version.CURRENT);
+        Version indexVersionCreated = randomBoolean() ? Version.CURRENT : VersionUtils.randomIndexCompatibleVersion(random());
         return Settings.builder()
             .put(IndexMetaData.SETTING_VERSION_CREATED, indexVersionCreated)
             .build();

test/framework/src/main/java/org/elasticsearch/test/VersionUtils.java

@@ -248,4 +248,11 @@ public class VersionUtils {
         assert compatible.size() > 0;
         return compatible.get(compatible.size() - 1);
     }
+
+    /**
+     * Returns a random version index compatible with the current version.
+     */
+    public static Version randomIndexCompatibleVersion(Random random) {
+        return randomVersionBetween(random, Version.CURRENT.minimumIndexCompatibilityVersion(), Version.CURRENT);
+    }
 }

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/job/results/ModelPlot.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.xpack.core.ml.job.results;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -112,18 +111,9 @@ public class ModelPlot implements ToXContentObject, Writeable {
         modelLower = in.readDouble();
         modelUpper = in.readDouble();
         modelMedian = in.readDouble();
-        if (in.getVersion().before(Version.V_6_0_0_rc1)) {
-            actual = in.readDouble();
-        } else {
-            actual = in.readOptionalDouble();
-        }
+        actual = in.readOptionalDouble();
         bucketSpan = in.readLong();
-        if (in.getVersion().onOrAfter(Version.V_6_1_0)) {
-            detectorIndex = in.readInt();
-        } else {
-            // default to -1 as marker for no detector index
-            detectorIndex = -1;
-        }
+        detectorIndex = in.readInt();
     }
 
     @Override
@@ -140,21 +130,9 @@ public class ModelPlot implements ToXContentObject, Writeable {
         out.writeDouble(modelLower);
         out.writeDouble(modelUpper);
         out.writeDouble(modelMedian);
-        if (out.getVersion().before(Version.V_6_0_0_rc1)) {
-            if (actual == null) {
-                // older versions cannot accommodate null, so we have no choice but to propagate the bug of
-                // https://github.com/elastic/x-pack-elasticsearch/issues/2528
-                out.writeDouble(0.0);
-            } else {
-                out.writeDouble(actual);
-            }
-        } else {
-            out.writeOptionalDouble(actual);
-        }
+        out.writeOptionalDouble(actual);
         out.writeLong(bucketSpan);
-        if (out.getVersion().onOrAfter(Version.V_6_1_0)) {
-            out.writeInt(detectorIndex);
-        }
+        out.writeInt(detectorIndex);
     }
 
     @Override

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/monitoring/action/MonitoringBulkDoc.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.xpack.core.monitoring.action;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesArray;
@@ -15,8 +14,6 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.xpack.core.monitoring.MonitoredSystem;
-import org.elasticsearch.xpack.core.monitoring.exporter.MonitoringDoc;
-import org.elasticsearch.xpack.core.monitoring.exporter.MonitoringTemplateUtils;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -54,52 +51,29 @@ public class MonitoringBulkDoc implements Writeable {
      */
     public static MonitoringBulkDoc readFrom(StreamInput in) throws IOException {
         final MonitoredSystem system = MonitoredSystem.fromSystem(in.readOptionalString());
-
-        if (in.getVersion().before(Version.V_6_0_0_rc1)) {
-            in.readOptionalString(); // Monitoring version, removed in 6.0 rc1
-            in.readOptionalString(); // Cluster UUID, removed in 6.0 rc1
-        }
-
         final long timestamp = in.readVLong();
 
-        if (in.getVersion().before(Version.V_6_0_0_rc1)) {
-            in.readOptionalWriteable(MonitoringDoc.Node::new);// Source node, removed in 6.0 rc1
-            MonitoringIndex.readFrom(in);// Monitoring index, removed in 6.0 rc1
-        }
-
         final String type = in.readOptionalString();
         final String id = in.readOptionalString();
         final BytesReference source = in.readBytesReference();
         final XContentType xContentType = (source != BytesArray.EMPTY) ? in.readEnum(XContentType.class) : XContentType.JSON;
+        long interval = in.readVLong();
 
-        long interval = 0L;
-        if (in.getVersion().onOrAfter(Version.V_6_0_0_rc1)) {
-            interval = in.readVLong();
-        }
         return new MonitoringBulkDoc(system, type, id, timestamp, interval, source, xContentType);
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalString(system.getSystem());
-        if (out.getVersion().before(Version.V_6_0_0_rc1)) {
-            out.writeOptionalString(MonitoringTemplateUtils.TEMPLATE_VERSION);
-            out.writeOptionalString(null);
-        }
         out.writeVLong(timestamp);
-        if (out.getVersion().before(Version.V_6_0_0_rc1)) {
-            out.writeOptionalWriteable(null);
-            MonitoringIndex.IGNORED_DATA.writeTo(out);
-        }
         out.writeOptionalString(type);
         out.writeOptionalString(id);
         out.writeBytesReference(source);
         if (source != BytesArray.EMPTY) {
             out.writeEnum(xContentType);
         }
-        if (out.getVersion().onOrAfter(Version.V_6_0_0_rc1)) {
-            out.writeVLong(intervalMillis);
-        }
+        out.writeVLong(intervalMillis);
+
     }
 
     public MonitoredSystem getSystem() {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/monitoring/exporter/MonitoringDoc.java

@@ -5,7 +5,6 @@
  */
 package org.elasticsearch.xpack.core.monitoring.exporter;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -163,17 +162,7 @@ public abstract class MonitoringDoc implements ToXContentObject {
             transportAddress = in.readOptionalString();
             ip = in.readOptionalString();
             name = in.readOptionalString();
-            if (in.getVersion().onOrAfter(Version.V_6_0_0_rc1)) {
-                timestamp = in.readVLong();
-            } else {
-                // Read the node attributes (removed in 6.0 rc1)
-                int size = in.readVInt();
-                for (int i = 0; i < size; i++) {
-                    in.readString();
-                    in.readString();
-                }
-                timestamp = 0L;
-            }
+            timestamp = in.readVLong();
         }
 
         @Override
@@ -183,12 +172,7 @@ public abstract class MonitoringDoc implements ToXContentObject {
             out.writeOptionalString(transportAddress);
             out.writeOptionalString(ip);
             out.writeOptionalString(name);
-            if (out.getVersion().onOrAfter(Version.V_6_0_0_rc1)) {
-                out.writeVLong(timestamp);
-            } else {
-                // Write an empty map of node attributes (removed in 6.0 rc1)
-                out.writeVInt(0);
-            }
+            out.writeVLong(timestamp);
         }
 
         public String getUUID() {

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/SecurityFeatureSetUsage.java

@@ -49,10 +49,6 @@ public class SecurityFeatureSetUsage extends XPackFeatureSet.Usage {
         }
         auditUsage = in.readMap();
         ipFilterUsage = in.readMap();
-        if (in.getVersion().before(Version.V_6_0_0_beta1)) {
-            // system key has been removed but older send its usage, so read the map and ignore
-            in.readMap();
-        }
         anonymousUsage = in.readMap();
         roleMappingStoreUsage = in.readMap();
     }
@@ -86,10 +82,6 @@ public class SecurityFeatureSetUsage extends XPackFeatureSet.Usage {
         }
         out.writeMap(auditUsage);
         out.writeMap(ipFilterUsage);
-        if (out.getVersion().before(Version.V_6_0_0_beta1)) {
-            // system key has been removed but older versions still expected it so send a empty map
-            out.writeMap(Collections.emptyMap());
-        }
         out.writeMap(anonymousUsage);
         out.writeMap(roleMappingStoreUsage);
     }

x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/cluster/ClusterStatsMonitoringDocTests.java

@@ -202,7 +202,7 @@ public class ClusterStatsMonitoringDocTests extends BaseMonitoringDocTestCase<Cl
                                                                 transportAddress,
                                                                 singletonMap("attr", "value"),
                                                                 singleton(DiscoveryNode.Role.MASTER),
-                                                                Version.V_6_0_0_beta1);
+                                                                Version.CURRENT);
 
         final ClusterState clusterState = ClusterState.builder(clusterName)
                                                         .metaData(MetaData.builder()

x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/indices/IndexRecoveryMonitoringDocTests.java

@@ -79,7 +79,7 @@ public class IndexRecoveryMonitoringDocTests extends BaseMonitoringDocTestCase<I
                                                                     new TransportAddress(TransportAddress.META_ADDRESS, 9300),
                                                                     singletonMap("attr", "value_0"),
                                                                     singleton(DiscoveryNode.Role.MASTER),
-                                                                    Version.V_6_0_0_beta1);
+                                                                    Version.CURRENT);
 
         final DiscoveryNode discoveryNodeOne = new DiscoveryNode("_node_1",
                                                                     "_node_id_1",

x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/ml/JobStatsMonitoringDocTests.java

@@ -86,7 +86,7 @@ public class JobStatsMonitoringDocTests extends BaseMonitoringDocTestCase<JobSta
                                                              new TransportAddress(TransportAddress.META_ADDRESS, 9300),
                                                              singletonMap("attr", "value"),
                                                              singleton(DiscoveryNode.Role.MASTER),
-                                                             Version.V_6_0_0_beta1);
+                                                             Version.CURRENT);
 
         final ModelSizeStats modelStats = new ModelSizeStats.Builder("_model")
                                                             .setModelBytes(100L)

x-pack/plugin/monitoring/src/test/java/org/elasticsearch/xpack/monitoring/collector/node/NodeStatsMonitoringDocTests.java

@@ -364,7 +364,7 @@ public class NodeStatsMonitoringDocTests extends BaseFilteredMonitoringDocTestCa
                                                                 new TransportAddress(TransportAddress.META_ADDRESS, 1234),
                                                                 emptyMap(),
                                                                 emptySet(),
-                                                                Version.V_6_0_0_beta1);
+                                                                Version.CURRENT);
 
         return new NodeStats(discoveryNode, no, indices, os, process, jvm, threadPool, fs, null, null, null, null, null, null, null);
     }