[ML] Simplify minimum supported snapshot version handling for Machine Learning jobs (#118549)

Since in 9.0 we don't need to support snapshots prior to 7.17, we can simplify the changes made in #81039 and re-introduce a single contant to manage the minimum supported snapshot version.

Author: valeriy42

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/MachineLearningField.java

@@ -64,12 +64,8 @@ public final class MachineLearningField {
         License.OperationMode.PLATINUM
     );
 
-    // Ideally this would be 7.0.0, but it has to be 6.4.0 because due to an oversight it's impossible
-    // for the Java code to distinguish the model states for versions 6.4.0 to 7.9.3 inclusive.
-    public static final MlConfigVersion MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION = MlConfigVersion.fromString("6.4.0");
-    // We tell the user we support model snapshots newer than 7.0.0 as that's the major version
-    // boundary, even though behind the scenes we have to support back to 6.4.0.
-    public static final MlConfigVersion MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION = MlConfigVersion.V_7_0_0;
+    // This is the last version when we changed the ML job snapshot format.
+    public static final MlConfigVersion MIN_SUPPORTED_SNAPSHOT_VERSION = MlConfigVersion.V_8_3_0;
 
     private MachineLearningField() {}
 

x-pack/plugin/deprecation/qa/rest/src/javaRestTest/java/org/elasticsearch/xpack/deprecation/MlDeprecationIT.java

@@ -63,7 +63,7 @@ public void testMlDeprecationChecks() throws Exception {
         indexDoc(
             ".ml-anomalies-.write-" + jobId,
             jobId + "_model_snapshot_2",
-            "{\"job_id\":\"deprecation_check_job\",\"snapshot_id\":\"2\",\"snapshot_doc_count\":1,\"min_version\":\"8.0.0\"}"
+            "{\"job_id\":\"deprecation_check_job\",\"snapshot_id\":\"2\",\"snapshot_doc_count\":1,\"min_version\":\"8.3.0\"}"
         );
         client().performRequest(new Request("POST", "/.ml-anomalies-*/_refresh"));
 

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/MlDeprecationChecker.java

@@ -26,8 +26,7 @@
 import java.util.Map;
 import java.util.Optional;
 
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION;
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION;
+import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_SUPPORTED_SNAPSHOT_VERSION;
 
 public class MlDeprecationChecker implements DeprecationChecker {
 
@@ -69,13 +68,13 @@ static Optional<DeprecationIssue> checkDataFeedAggregations(DatafeedConfig dataf
     }
 
     static Optional<DeprecationIssue> checkModelSnapshot(ModelSnapshot modelSnapshot) {
-        if (modelSnapshot.getMinVersion().before(MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION)) {
+        if (modelSnapshot.getMinVersion().before(MIN_SUPPORTED_SNAPSHOT_VERSION)) {
             StringBuilder details = new StringBuilder(
                 String.format(
                     Locale.ROOT,
                     "Delete model snapshot [%s] or update it to %s or greater.",
                     modelSnapshot.getSnapshotId(),
-                    MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION
+                    MIN_SUPPORTED_SNAPSHOT_VERSION
                 )
             );
             if (modelSnapshot.getLatestRecordTimeStamp() != null) {

x-pack/plugin/ml/src/internalClusterTest/java/org/elasticsearch/xpack/ml/integration/AnomalyJobCRUDIT.java

@@ -195,7 +195,7 @@ public void testOpenJobWithOldSnapshot() {
         assertThat(
             ex.getMessage(),
             containsString(
-                "[open-job-with-old-model-snapshot] job model snapshot [snap_1] has min version before [7.0.0], "
+                "[open-job-with-old-model-snapshot] job model snapshot [snap_1] has min version before [8.3.0], "
                     + "please revert to a newer model snapshot or reset the job"
             )
         );

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/action/TransportOpenJobAction.java

@@ -58,8 +58,7 @@
 
 import static org.elasticsearch.core.Strings.format;
 import static org.elasticsearch.xpack.core.ClientHelper.ML_ORIGIN;
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION;
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION;
+import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_SUPPORTED_SNAPSHOT_VERSION;
 import static org.elasticsearch.xpack.ml.job.task.OpenJobPersistentTasksExecutor.checkAssignmentState;
 
 /*
@@ -214,7 +213,7 @@ public void onFailure(Exception e) {
                             return;
                         }
                         assert modelSnapshot.getPage().results().size() == 1;
-                        if (modelSnapshot.getPage().results().get(0).getMinVersion().onOrAfter(MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION)) {
+                        if (modelSnapshot.getPage().results().get(0).getMinVersion().onOrAfter(MIN_SUPPORTED_SNAPSHOT_VERSION)) {
                             modelSnapshotValidationListener.onResponse(true);
                             return;
                         }
@@ -224,7 +223,7 @@ public void onFailure(Exception e) {
                                     + "please revert to a newer model snapshot or reset the job",
                                 jobParams.getJobId(),
                                 jobParams.getJob().getModelSnapshotId(),
-                                MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION.toString()
+                                MIN_SUPPORTED_SNAPSHOT_VERSION.toString()
                             )
                         );
                     }, failure -> {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/job/task/OpenJobPersistentTasksExecutor.java

@@ -73,8 +73,7 @@
 import static org.elasticsearch.core.Strings.format;
 import static org.elasticsearch.xpack.core.ClientHelper.ML_ORIGIN;
 import static org.elasticsearch.xpack.core.ClientHelper.executeAsyncWithOrigin;
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION;
-import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION;
+import static org.elasticsearch.xpack.core.ml.MachineLearningField.MIN_SUPPORTED_SNAPSHOT_VERSION;
 import static org.elasticsearch.xpack.core.ml.MlTasks.AWAITING_UPGRADE;
 import static org.elasticsearch.xpack.core.ml.MlTasks.PERSISTENT_TASK_MASTER_NODE_TIMEOUT;
 import static org.elasticsearch.xpack.ml.job.JobNodeSelector.AWAITING_LAZY_ASSIGNMENT;
@@ -436,7 +435,7 @@ private void verifyCurrentSnapshotVersion(String jobId, ActionListener<Boolean>
                     }
                     assert snapshot.getPage().results().size() == 1;
                     ModelSnapshot snapshotObj = snapshot.getPage().results().get(0);
-                    if (snapshotObj.getMinVersion().onOrAfter(MIN_CHECKED_SUPPORTED_SNAPSHOT_VERSION)) {
+                    if (snapshotObj.getMinVersion().onOrAfter(MIN_SUPPORTED_SNAPSHOT_VERSION)) {
                         listener.onResponse(true);
                         return;
                     }
@@ -446,7 +445,7 @@ private void verifyCurrentSnapshotVersion(String jobId, ActionListener<Boolean>
                                 + "please revert to a newer model snapshot or reset the job",
                             jobId,
                             jobSnapshotId,
-                            MIN_REPORTED_SUPPORTED_SNAPSHOT_VERSION.toString()
+                            MIN_SUPPORTED_SNAPSHOT_VERSION.toString()
                         )
                     );
                 }, snapshotFailure -> {