Cache all rest tests tasks so long as they don't use shared clusters (#48161)

Author: mark-vieira

buildSrc/src/main/java/org/elasticsearch/gradle/testclusters/RestTestRunnerTask.java

@@ -5,10 +5,9 @@
 import org.gradle.api.tasks.testing.Test;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 
-import static org.elasticsearch.gradle.testclusters.TestDistribution.INTEG_TEST;
-
 /**
  * Customized version of Gradle {@link Test} task which tracks a collection of {@link ElasticsearchCluster} as a task input. We must do this
  * as a custom task type because the current {@link org.gradle.api.tasks.TaskInputs} runtime API does not have a way to register
@@ -20,9 +19,17 @@ public class RestTestRunnerTask extends Test implements TestClustersAware {
     private Collection<ElasticsearchCluster> clusters = new HashSet<>();
 
     public RestTestRunnerTask() {
-        super();
-        this.getOutputs().doNotCacheIf("Build cache is only enabled for tests against clusters using the 'integ-test' distribution",
-            task -> clusters.stream().flatMap(c -> c.getNodes().stream()).anyMatch(n -> n.getTestDistribution() != INTEG_TEST));
+        this.getOutputs().doNotCacheIf("Caching disabled for this task since it uses a cluster shared by other tasks",
+            /*
+             * Look for any other tasks which use the same cluster as this task. Since tests often have side effects for the cluster they
+             * execute against, this state can cause issues when trying to cache tests results of tasks that share a cluster. To avoid any
+             * undesired behavior we simply disable the cache if we detect that this task uses a cluster shared between multiple tasks.
+             */
+            t -> getProject().getTasks().withType(RestTestRunnerTask.class)
+                .stream()
+                .filter(task -> task != this)
+                .anyMatch(task -> Collections.disjoint(task.getClusters(), getClusters()) == false)
+        );
     }
 
     @Override