Ensure rest api specs are always copied before using test classpath (#46514)

(cherry picked from commit 45202903b4fea3a43f62594fd357ab3c98c3dd15)

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/RestIntegTestTask.groovy

@@ -22,10 +22,12 @@ import org.elasticsearch.gradle.VersionProperties
 import org.elasticsearch.gradle.testclusters.ElasticsearchCluster
 import org.elasticsearch.gradle.testclusters.RestTestRunnerTask
 import org.elasticsearch.gradle.testclusters.TestClustersPlugin
+import org.elasticsearch.gradle.tool.Boilerplate
 import org.elasticsearch.gradle.tool.ClasspathUtils
 import org.gradle.api.DefaultTask
 import org.gradle.api.Task
 import org.gradle.api.execution.TaskExecutionAdapter
+import org.gradle.api.file.FileCopyDetails
 import org.gradle.api.logging.Logger
 import org.gradle.api.logging.Logging
 import org.gradle.api.tasks.Copy
@@ -39,6 +41,7 @@ import org.gradle.process.CommandLineArgumentProvider
 import java.nio.charset.StandardCharsets
 import java.nio.file.Files
 import java.util.stream.Stream
+
 /**
  * A wrapper task around setting up a cluster and running rest tests.
  */
@@ -121,9 +124,9 @@ class RestIntegTestTask extends DefaultTask {
             runner.systemProperty('test.cluster', System.getProperty("tests.cluster"))
         }
 
-        // copy the rest spec/tests into the test resources
-        Task copyRestSpec = createCopyRestSpecTask()
-        runner.dependsOn(copyRestSpec)
+        // copy the rest spec/tests onto the test classpath
+        Copy copyRestSpec = createCopyRestSpecTask()
+        project.sourceSets.test.output.builtBy(copyRestSpec)
 
         // this must run after all projects have been configured, so we know any project
         // references can be accessed as a fully configured
@@ -222,40 +225,28 @@ class RestIntegTestTask extends DefaultTask {
 
     }
 
-    /**
-     * Creates a task (if necessary) to copy the rest spec files.
-     *
-     * @param project The project to add the copy task to
-     * @param includePackagedTests true if the packaged tests should be copied, false otherwise
-     */
-    Task createCopyRestSpecTask() {
-        project.configurations {
-            restSpec
-        }
-        project.dependencies {
-            restSpec ClasspathUtils.isElasticsearchProject() ? project.project(':rest-api-spec') :
+    Copy createCopyRestSpecTask() {
+        Boilerplate.maybeCreate(project.configurations, 'restSpec') {
+            project.dependencies.add(
+                    'restSpec',
+                    ClasspathUtils.isElasticsearchProject() ? project.project(':rest-api-spec') :
                             "org.elasticsearch:rest-api-spec:${VersionProperties.elasticsearch}"
+            )
         }
-        Task copyRestSpec = project.tasks.findByName('copyRestSpec')
-        if (copyRestSpec != null) {
-            return copyRestSpec
-        }
-        Map copyRestSpecProps = [
-                name     : 'copyRestSpec',
-                type     : Copy,
-                dependsOn: [project.configurations.restSpec, 'processTestResources']
-        ]
-        copyRestSpec = project.tasks.create(copyRestSpecProps) {
-            into project.sourceSets.test.output.resourcesDir
-        }
-        project.afterEvaluate {
-            copyRestSpec.from({ project.zipTree(project.configurations.restSpec.singleFile) }) {
-                include 'rest-api-spec/api/**'
-                if (includePackaged) {
-                    include 'rest-api-spec/test/**'
+
+        return Boilerplate.maybeCreate(project.tasks, 'copyRestSpec', Copy) { Copy copy ->
+            copy.dependsOn project.configurations.restSpec
+            copy.into(project.sourceSets.test.output.resourcesDir)
+            copy.from({ project.zipTree(project.configurations.restSpec.singleFile) }) {
+                includeEmptyDirs = false
+                include 'rest-api-spec/**'
+                filesMatching('rest-api-spec/test/**') { FileCopyDetails details ->
+                    if (includePackaged == false) {
+                        details.exclude()
                     }
                 }
             }
+
             if (project.plugins.hasPlugin(IdeaPlugin)) {
                 project.idea {
                     module {
@@ -265,7 +256,6 @@ class RestIntegTestTask extends DefaultTask {
                     }
                 }
             }
-        return copyRestSpec
         }
-
+    }
 }

buildSrc/src/main/java/org/elasticsearch/gradle/tool/Boilerplate.java

@@ -20,6 +20,7 @@ package org.elasticsearch.gradle.tool;
 
 import org.gradle.api.Action;
 import org.gradle.api.NamedDomainObjectContainer;
+import org.gradle.api.PolymorphicDomainObjectContainer;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.UnknownTaskException;
@@ -52,6 +53,16 @@ public abstract class Boilerplate {
 
     }
 
+    public static <T> T maybeCreate(PolymorphicDomainObjectContainer<T> collection, String name, Class<T> type, Action<T> action) {
+        return Optional.ofNullable(collection.findByName(name))
+            .orElseGet(() -> {
+                T result = collection.create(name, type);
+                action.execute(result);
+                return result;
+            });
+
+    }
+
     public static <T extends Task> TaskProvider<T> maybeRegister(TaskContainer tasks, String name, Class<T> clazz, Action<T> action) {
         try {
             return tasks.named(name, clazz);