[CI] Handle git snapshot BWC versions correctly when calculating jdk fallback

In elastic#135300 we introduced a fallback to
use adoptopenjdk17 when running bwc tests with older distributions.
This fix handles the calculation of overriding requirement by taken 0.0.0 version into account
which is used to represent versions representing git snapshots.

Author: breskeby

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java

@@ -113,6 +113,9 @@ private void registerInternalDistributionResolutions(List<DistributionResolution
             String versionProperty = System.getProperty("tests.bwc.main.version");
             // We use this phony version as a placeholder for the real version
             if (distribution.getVersion().equals("0.0.0")) {
+                if (versionProperty == null) {
+                    throw new GradleException("System property 'tests.bwc.main.version' expected for building bwc version.");
+                }
                 BwcVersions.UnreleasedVersionInfo unreleasedVersionInfo = new BwcVersions.UnreleasedVersionInfo(
                     Version.fromString(versionProperty),
                     "main",

build-tools/src/integTest/groovy/org/elasticsearch/gradle/TestClustersPluginFuncTest.groovy

@@ -250,7 +250,7 @@ class TestClustersPluginFuncTest extends AbstractGradleFuncTest {
 
         buildFile << """
             testClusters {
-              myCluster {
+              myCluster1 {
                 testDistribution = 'default'
                 version = '8.10.4'
               }

build-tools/src/main/java/org/elasticsearch/gradle/util/OsUtils.java

@@ -38,7 +38,7 @@ private OsUtils() {}
       * This method returns true if the given version of the JDK is known to be incompatible
       */
     public static boolean jdkIsIncompatibleWithOS(Version version) {
-        return version.onOrBefore("8.10.4") && isUbuntu2404OrLater();
+        return version.after("0.0.0") && version.onOrBefore("8.10.4") && isUbuntu2404OrLater();
     }
 
     private static boolean isUbuntu2404OrLater() {

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalClusterFactory.java

@@ -82,7 +82,7 @@ public abstract class AbstractLocalClusterFactory<S extends LocalClusterSpec, H
     private static final String ENABLE_DEBUG_JVM_ARGS = "-agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=";
     private static final String ENTITLEMENT_POLICY_YAML = "entitlement-policy.yaml";
     private static final String PLUGIN_DESCRIPTOR_PROPERTIES = "plugin-descriptor.properties";
-    public static final String DISTRO_WITH_JDK_LOWER_21 = "8.11.0";
+    public static final String FIRST_DISTRO_WITH_JDK_21 = "8.11.0";
 
     private final DistributionResolver distributionResolver;
 
@@ -869,7 +869,7 @@ private void startElasticsearch() {
         private Map<String, String> getEnvironmentVariables() {
             Map<String, String> environment = new HashMap<>(spec.resolveEnvironment());
             String esFallbackJavaHome = System.getenv("ES_FALLBACK_JAVA_HOME");
-            if (spec.getVersion().before(DISTRO_WITH_JDK_LOWER_21) && esFallbackJavaHome != null && esFallbackJavaHome.isEmpty() == false) {
+            if (jdkIsIncompatible(spec.getVersion()) && esFallbackJavaHome != null && esFallbackJavaHome.isEmpty() == false) {
                 environment.put("ES_JAVA_HOME", esFallbackJavaHome);
             }
             environment.put("ES_PATH_CONF", configDir.toString());
@@ -922,6 +922,10 @@ private Map<String, String> getEnvironmentVariables() {
             return environment;
         }
 
+        private boolean jdkIsIncompatible(Version version) {
+            return version.after("0.0.0") && version.before(FIRST_DISTRO_WITH_JDK_21);
+        }
+
         private record ReplacementKey(String key, String fallback) {
             ReplacementKey {
                 assert fallback == null || fallback.isEmpty() == false; // no empty fallback, which would match anything