[DLM]Use default lifecycle instance instead of default constructor (elastic#126461)

When creating the an empty lifecycle we used to use the default
constructor. This is not just for efficiency but it will allow us to
separate the default data and failures lifecycle in the future.

(cherry picked from commit 060a9b7)

# Conflicts:
#	server/src/test/java/org/elasticsearch/cluster/metadata/DataStreamLifecycleWithRetentionWarningsTests.java
#	server/src/test/java/org/elasticsearch/cluster/metadata/MetadataCreateDataStreamServiceTests.java
#	server/src/test/java/org/elasticsearch/cluster/metadata/MetadataIndexTemplateServiceTests.java

Author: gmarouli

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/lifecycle/DataStreamLifecycleServiceIT.java

@@ -146,7 +146,7 @@ public void cleanup() {
 
     public void testRolloverLifecycle() throws Exception {
         // empty lifecycle contains the default rollover
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         putComposableIndexTemplate("id1", null, List.of("metrics-foo*"), null, null, lifecycle, false);
         String dataStreamName = "metrics-foo";
@@ -393,7 +393,7 @@ public void testOriginationDate() throws Exception {
     }
 
     public void testUpdatingLifecycleAppliesToAllBackingIndices() throws Exception {
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         putComposableIndexTemplate("id1", null, List.of("metrics-foo*"), null, null, lifecycle, false);
 
@@ -437,7 +437,7 @@ public void testAutomaticForceMerge() throws Exception {
          * because all necessary merging has already happened automatically. So in order to detect whether forcemerge has been called, we
          * use a SendRequestBehavior in the MockTransportService to detect it.
          */
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
         disableDataStreamLifecycle();
         String dataStreamName = "metrics-foo";
         putComposableIndexTemplate(
@@ -539,7 +539,7 @@ private static void disableDataStreamLifecycle() {
 
     public void testErrorRecordingOnRollover() throws Exception {
         // empty lifecycle contains the default rollover
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
         /*
          * We set index.auto_expand_replicas to 0-1 so that if we get a single-node cluster it is not yellow. The cluster being yellow
          * could result in data stream lifecycle's automatic forcemerge failing, which would result in an unexpected error in the error
@@ -697,7 +697,7 @@ public void testErrorRecordingOnRollover() throws Exception {
     public void testErrorRecordingOnRetention() throws Exception {
         // starting with a lifecycle without retention so we can rollover the data stream and manipulate the second generation index such
         // that its retention execution fails
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         /*
          * We set index.auto_expand_replicas to 0-1 so that if we get a single-node cluster it is not yellow. The cluster being yellow
@@ -871,7 +871,7 @@ public void testErrorRecordingOnRetention() throws Exception {
     }
 
     public void testDataLifecycleServiceConfiguresTheMergePolicy() throws Exception {
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         putComposableIndexTemplate(
             "id1",

modules/data-streams/src/internalClusterTest/java/org/elasticsearch/datastreams/lifecycle/ExplainDataStreamLifecycleIT.java

@@ -92,7 +92,7 @@ public void cleanup() {
 
     public void testExplainLifecycle() throws Exception {
         // empty lifecycle contains the default rollover
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         putComposableIndexTemplate("id1", null, List.of("metrics-foo*"), null, null, lifecycle);
         String dataStreamName = "metrics-foo";
@@ -264,7 +264,7 @@ public void testExplainFailuresLifecycle() throws Exception {
             List.of("metrics-foo*"),
             null,
             null,
-            DataStreamLifecycle.Template.DEFAULT,
+            DataStreamLifecycle.Template.DATA_DEFAULT,
             new DataStreamOptions.Template(new DataStreamFailureStore.Template(true))
         );
         String dataStreamName = "metrics-foo";
@@ -381,7 +381,7 @@ public void testExplainFailuresLifecycle() throws Exception {
 
     public void testExplainLifecycleForIndicesWithErrors() throws Exception {
         // empty lifecycle contains the default rollover
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
 
         putComposableIndexTemplate(
             "id1",

modules/data-streams/src/test/java/org/elasticsearch/datastreams/MetadataIndexTemplateServiceTests.java

@@ -157,7 +157,7 @@ public void testLifecycleComposition() {
         // Enabled is always true unless it's explicitly set to false
         {
             DataStreamLifecycle.Template lifecycle = new DataStreamLifecycle.Template(false, randomPositiveTimeValue(), randomRounds());
-            List<DataStreamLifecycle.Template> lifecycles = List.of(lifecycle, DataStreamLifecycle.Template.DEFAULT);
+            List<DataStreamLifecycle.Template> lifecycles = List.of(lifecycle, DataStreamLifecycle.Template.DATA_DEFAULT);
             DataStreamLifecycle result = composeDataLifecycles(lifecycles).build();
             assertThat(result.enabled(), equalTo(true));
             assertThat(result.dataRetention(), equalTo(lifecycle.dataRetention().get()));

modules/data-streams/src/test/java/org/elasticsearch/datastreams/action/GetDataStreamsResponseTests.java

@@ -83,7 +83,7 @@ public void testResponseIlmAndDataStreamLifecycleRepresentation() throws Excepti
                 .setGeneration(3)
                 .setAllowCustomRouting(true)
                 .setIndexMode(IndexMode.STANDARD)
-                .setLifecycle(new DataStreamLifecycle())
+                .setLifecycle(DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE)
                 .setDataStreamOptions(DataStreamOptions.FAILURE_STORE_ENABLED)
                 .setFailureIndices(DataStream.DataStreamIndices.failureIndicesBuilder(failureStores).build())
                 .build();

modules/data-streams/src/test/java/org/elasticsearch/datastreams/lifecycle/DataStreamLifecycleServiceTests.java

@@ -254,7 +254,7 @@ public void testRetentionNotConfigured() {
             dataStreamName,
             numBackingIndices,
             settings(IndexVersion.current()),
-            new DataStreamLifecycle(),
+            DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE,
             now
         );
         builder.put(dataStream);
@@ -498,7 +498,7 @@ public void testDeletedIndicesAreRemovedFromTheErrorStore() throws IOException {
             dataStreamName,
             numBackingIndices,
             Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, IndexVersion.current()),
-            new DataStreamLifecycle(),
+            DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE,
             now
         );
         builder.put(dataStream);
@@ -1496,7 +1496,7 @@ public void testTargetIndices() {
             numBackingIndices,
             numFailureIndices,
             settings(IndexVersion.current()),
-            new DataStreamLifecycle(),
+            DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE,
             now
         ).copy().setDataStreamOptions(dataStreamOptions).build(); // failure store is managed even when disabled
         builder.put(dataStream);

server/src/main/java/org/elasticsearch/action/admin/indices/template/post/TransportSimulateIndexTemplateAction.java

@@ -346,7 +346,7 @@ public static Template resolveTemplate(
         DataStreamLifecycle.Builder lifecycleBuilder = resolveLifecycle(simulatedState.metadata(), matchingTemplate);
         DataStreamLifecycle.Template lifecycle = lifecycleBuilder == null ? null : lifecycleBuilder.buildTemplate();
         if (template.getDataStreamTemplate() != null && lifecycle == null && isDslOnlyMode) {
-            lifecycle = DataStreamLifecycle.Template.DEFAULT;
+            lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
         }
         DataStreamOptions.Builder optionsBuilder = resolveDataStreamOptions(simulatedState.metadata(), matchingTemplate);
         return new Template(

server/src/main/java/org/elasticsearch/cluster/metadata/DataStreamLifecycle.java

@@ -86,7 +86,7 @@ public static boolean isDataStreamsLifecycleOnlyMode(final Settings settings) {
         Setting.Property.NodeScope
     );
 
-    public static final DataStreamLifecycle DEFAULT = new DataStreamLifecycle();
+    public static final DataStreamLifecycle DEFAULT_DATA_LIFECYCLE = new DataStreamLifecycle(null, null, null);
 
     public static final String DATA_STREAM_LIFECYCLE_ORIGIN = "data_stream_lifecycle";
 
@@ -132,10 +132,6 @@ public static boolean isDataStreamsLifecycleOnlyMode(final Settings settings) {
     @Nullable
     private final List<DownsamplingRound> downsampling;
 
-    public DataStreamLifecycle() {
-        this(null, null, null);
-    }
-
     public DataStreamLifecycle(
         @Nullable Boolean enabled,
         @Nullable TimeValue dataRetention,
@@ -562,7 +558,7 @@ public Template(boolean enabled, TimeValue dataRetention, List<DataStreamLifecyc
             }
         }
 
-        public static final DataStreamLifecycle.Template DEFAULT = new DataStreamLifecycle.Template(
+        public static final DataStreamLifecycle.Template DATA_DEFAULT = new DataStreamLifecycle.Template(
             true,
             ResettableValue.undefined(),
             ResettableValue.undefined()

server/src/main/java/org/elasticsearch/cluster/metadata/MetadataCreateDataStreamService.java

@@ -329,7 +329,7 @@ static ClusterState createDataStream(
             System::currentTimeMillis,
             template.getDataStreamTemplate().isAllowCustomRouting(),
             indexMode,
-            lifecycle == null && isDslOnlyMode ? DataStreamLifecycle.DEFAULT : lifecycle,
+            lifecycle == null && isDslOnlyMode ? DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE : lifecycle,
             dataStreamOptions,
             new DataStream.DataStreamIndices(DataStream.BACKING_INDEX_PREFIX, dsBackingIndices, false, null),
             // If the failure store shouldn't be initialized on data stream creation, we're marking it for "lazy rollover", which will

server/src/test/java/org/elasticsearch/action/admin/indices/template/get/GetComponentTemplateResponseTests.java

@@ -66,7 +66,7 @@ public void testXContentSerializationWithRolloverAndEffectiveRetention() throws
         Settings settings = null;
         CompressedXContent mappings = null;
         Map<String, AliasMetadata> aliases = null;
-        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DEFAULT;
+        DataStreamLifecycle.Template lifecycle = DataStreamLifecycle.Template.DATA_DEFAULT;
         ResettableValue<DataStreamOptions.Template> dataStreamOptions = ResettableValue.undefined();
         if (randomBoolean()) {
             settings = randomSettings();

server/src/test/java/org/elasticsearch/action/datastreams/lifecycle/ExplainDataStreamLifecycleResponseTests.java

@@ -63,7 +63,7 @@ protected NamedWriteableRegistry getNamedWriteableRegistry() {
     @SuppressWarnings("unchecked")
     public void testToXContent() throws IOException {
         long now = System.currentTimeMillis();
-        DataStreamLifecycle lifecycle = new DataStreamLifecycle();
+        DataStreamLifecycle lifecycle = DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE;
         ExplainIndexDataStreamLifecycle explainIndex = createRandomIndexDataStreamLifecycleExplanation(now, lifecycle);
         explainIndex.setNowSupplier(() -> now);
         {
@@ -241,7 +241,7 @@ public void testToXContent() throws IOException {
 
     public void testChunkCount() {
         long now = System.currentTimeMillis();
-        DataStreamLifecycle lifecycle = new DataStreamLifecycle();
+        DataStreamLifecycle lifecycle = DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE;
         Response response = new Response(
             List.of(
                 createRandomIndexDataStreamLifecycleExplanation(now, lifecycle),
@@ -298,7 +298,12 @@ protected Response mutateInstance(Response instance) {
 
     private Response randomResponse() {
         return new Response(
-            List.of(createRandomIndexDataStreamLifecycleExplanation(System.nanoTime(), randomBoolean() ? new DataStreamLifecycle() : null)),
+            List.of(
+                createRandomIndexDataStreamLifecycleExplanation(
+                    System.nanoTime(),
+                    randomBoolean() ? DataStreamLifecycle.DEFAULT_DATA_LIFECYCLE : null
+                )
+            ),
             randomBoolean()
                 ? new RolloverConfiguration(
                     new RolloverConditions(