Bump TrialLicenseVersion to allow starting new trial on 9.0 (elastic#120198)

You are allowed to initiate a trial only if your cluster has not already
activated a trial for the current major product version. For example, if
you have already activated a trial for v6.0, you cannot start a new
trial until v7.0.

`LicensesMetadata` is a ClusterState custom that contains the license
information for a cluster. If the cluster has exercised a trial there is
a trial version field populated. During a major upgrade, we want to
allow users to run a new trial to test the features on the new major. 

This PR updates the trial version in the license to allow to start a new
trial on 9.0. 

When 9.0 is released we'll have no clusters that has already exercised
the trial so this PR also removes some of the BWC handling that was
added when [trial license version was decoupled from stack
version](elastic#100169).

Author: jfreden

docs/changelog/120198.yaml

@@ -0,0 +1,5 @@
+pr: 120198
+summary: Bump `TrialLicenseVersion` to allow starting new trial on 9.0
+area: License
+type: enhancement
+issues: []

x-pack/plugin/core/src/main/java/org/elasticsearch/license/internal/TrialLicenseVersion.java

@@ -27,11 +27,8 @@ public class TrialLicenseVersion implements ToXContentFragment, Writeable {
     // generic Elasticsearch version. While it's derived from the Elasticsearch version formula for BWC, it is independent of it going
     // forward. When we want users to be able to start a new trial, increment this number.
     // Pkg-private for testing only.
-    static final int TRIAL_VERSION_CUTOVER = 8_12_00_99;
-    public static final TrialLicenseVersion CURRENT = new TrialLicenseVersion(TRIAL_VERSION_CUTOVER);
-
-    // The most recently released major version when we cut over. Here for maintaining BWC behavior.
-    static final int TRIAL_VERSION_CUTOVER_MAJOR = 8;
+    static final int CURRENT_TRIAL_VERSION = 9_00_00_00;
+    public static final TrialLicenseVersion CURRENT = new TrialLicenseVersion(CURRENT_TRIAL_VERSION);
 
     private final int trialVersion;
 
@@ -84,10 +81,6 @@ int asInt() {
     public boolean ableToStartNewTrial() {
         assert trialVersion <= CURRENT.trialVersion
             : "trial version [" + trialVersion + "] cannot be greater than CURRENT [" + CURRENT.trialVersion + "]";
-        if (trialVersion < TRIAL_VERSION_CUTOVER) {
-            int sinceMajorVersion = trialVersion / 1_000_000; // integer division is intentional
-            return sinceMajorVersion < TRIAL_VERSION_CUTOVER_MAJOR;
-        }
         return trialVersion != CURRENT.trialVersion;
     }
 

x-pack/plugin/core/src/test/java/org/elasticsearch/license/internal/TrialLicenseVersionTests.java

@@ -11,22 +11,17 @@
 import org.elasticsearch.test.ESTestCase;
 
 import static org.elasticsearch.license.internal.TrialLicenseVersion.CURRENT;
-import static org.elasticsearch.license.internal.TrialLicenseVersion.TRIAL_VERSION_CUTOVER;
-import static org.elasticsearch.license.internal.TrialLicenseVersion.TRIAL_VERSION_CUTOVER_MAJOR;
+import static org.elasticsearch.license.internal.TrialLicenseVersion.CURRENT_TRIAL_VERSION;
 import static org.hamcrest.Matchers.equalTo;
 
 public class TrialLicenseVersionTests extends ESTestCase {
 
     public void testCanParseAllVersions() {
         for (var version : Version.getDeclaredVersions(Version.class)) {
             // Only consider versions before the cut-over; the comparison becomes meaningless after the cut-over point
-            if (version.onOrBefore(Version.fromId(TRIAL_VERSION_CUTOVER))) {
+            if (version.onOrBefore(Version.fromId(CURRENT_TRIAL_VERSION))) {
                 TrialLicenseVersion parsedVersion = TrialLicenseVersion.fromXContent(version.toString());
-                if (version.major < TRIAL_VERSION_CUTOVER_MAJOR) {
-                    assertTrue(parsedVersion.ableToStartNewTrial());
-                } else {
-                    assertFalse(parsedVersion.ableToStartNewTrial());
-                }
+                assertTrue(parsedVersion.ableToStartNewTrial());
             }
         }
     }
@@ -38,9 +33,10 @@ public void testRoundTripParsing() {
 
     public void testNewTrialAllowed() {
         assertTrue(new TrialLicenseVersion(randomIntBetween(7_00_00_00, 7_99_99_99)).ableToStartNewTrial());
+        assertTrue(new TrialLicenseVersion(randomIntBetween(8_00_00_00, 8_99_99_99)).ableToStartNewTrial());
         assertFalse(new TrialLicenseVersion(CURRENT.asInt()).ableToStartNewTrial());
-        assertFalse(new TrialLicenseVersion(randomIntBetween(8_00_00_00, TRIAL_VERSION_CUTOVER)).ableToStartNewTrial());
-        final int trialVersion = randomIntBetween(TRIAL_VERSION_CUTOVER, CURRENT.asInt());
+        assertFalse(new TrialLicenseVersion(randomIntBetween(9_00_00_00, CURRENT_TRIAL_VERSION)).ableToStartNewTrial());
+        final int trialVersion = randomIntBetween(CURRENT_TRIAL_VERSION, CURRENT.asInt());
         if (trialVersion < CURRENT.asInt()) {
             assertTrue(new TrialLicenseVersion(trialVersion).ableToStartNewTrial());
         } else {