Introduce yamlRestCompatTest task and plugin.

buildSrc/src/main/java/org/elasticsearch/gradle/test/rest/CopyRestApiTask.java

@@ -58,8 +58,10 @@ public class CopyRestApiTask extends DefaultTask {
     final ListProperty<String> includeCore = getProject().getObjects().listProperty(String.class);
     final ListProperty<String> includeXpack = getProject().getObjects().listProperty(String.class);
     String sourceSetName;
+    boolean skipHasRestTestCheck;
     Configuration coreConfig;
     Configuration xpackConfig;
+    Configuration additionalConfig;
 
     private final PatternFilterable corePatternSet;
     private final PatternFilterable xpackPatternSet;
@@ -89,6 +91,11 @@ String getSourceSetName() {
         return sourceSetName;
     }
 
+    @Input
+    public boolean isSkipHasRestTestCheck() {
+        return skipHasRestTestCheck;
+    }
+
     @SkipWhenEmpty
     @InputFiles
     public FileTree getInputDir() {
@@ -98,7 +105,7 @@ public FileTree getInputDir() {
             xpackPatternSet.setIncludes(includeXpack.get().stream().map(prefix -> prefix + "*/**").collect(Collectors.toList()));
             xpackFileTree = xpackConfig.getAsFileTree().matching(xpackPatternSet);
         }
-        boolean projectHasYamlRestTests = projectHasYamlRestTests();
+        boolean projectHasYamlRestTests = skipHasRestTestCheck || projectHasYamlRestTests();
         if (includeCore.get().isEmpty() == false || projectHasYamlRestTests) {
             if (BuildParams.isInternal()) {
                 corePatternSet.setIncludes(includeCore.get().stream().map(prefix -> prefix + "*/**").collect(Collectors.toList()));
@@ -107,7 +114,10 @@ public FileTree getInputDir() {
                 coreFileTree = coreConfig.getAsFileTree(); // jar file
             }
         }
-        ConfigurableFileCollection fileCollection = getProject().files(coreFileTree, xpackFileTree);
+
+        ConfigurableFileCollection fileCollection = additionalConfig == null
+            ? getProject().files(coreFileTree, xpackFileTree)
+            : getProject().files(coreFileTree, xpackFileTree, additionalConfig.getAsFileTree());
 
         // if project has rest tests or the includes are explicitly configured execute the task, else NO-SOURCE due to the null input
         return projectHasYamlRestTests || includeCore.get().isEmpty() == false || includeXpack.get().isEmpty() == false
@@ -132,7 +142,7 @@ void copy() {
         if (BuildParams.isInternal()) {
             getLogger().debug("Rest specs for project [{}] will be copied to the test resources.", project.getPath());
             project.copy(c -> {
-                c.from(coreConfig.getSingleFile());
+                c.from(coreConfig.getAsFileTree());
                 c.into(getOutputDir());
                 c.include(corePatternSet.getIncludes());
             });
@@ -164,6 +174,14 @@ void copy() {
                 c.include(xpackPatternSet.getIncludes());
             });
         }
+        // TODO: once https://github.com/elastic/elasticsearch/pull/62968 lands ensure that this uses `getFileSystemOperations()`
+        // copy any additional config
+        if (additionalConfig != null) {
+            project.copy(c -> {
+                c.from(additionalConfig.getAsFileTree());
+                c.into(getOutputDir());
+            });
+        }
     }
 
     /**

buildSrc/src/main/java/org/elasticsearch/gradle/test/rest/CopyRestTestsTask.java

@@ -58,6 +58,7 @@ public class CopyRestTestsTask extends DefaultTask {
     String sourceSetName;
     Configuration coreConfig;
     Configuration xpackConfig;
+    Configuration additionalConfig;
 
     private final PatternFilterable corePatternSet;
     private final PatternFilterable xpackPatternSet;
@@ -104,10 +105,14 @@ public FileTree getInputDir() {
                 coreFileTree = coreConfig.getAsFileTree(); // jar file
             }
         }
-        ConfigurableFileCollection fileCollection = getProject().files(coreFileTree, xpackFileTree);
+        ConfigurableFileCollection fileCollection = additionalConfig == null
+            ? getProject().files(coreFileTree, xpackFileTree)
+            : getProject().files(coreFileTree, xpackFileTree, additionalConfig.getAsFileTree());
 
         // copy tests only if explicitly requested
-        return includeCore.get().isEmpty() == false || includeXpack.get().isEmpty() == false ? fileCollection.getAsFileTree() : null;
+        return includeCore.get().isEmpty() == false || includeXpack.get().isEmpty() == false || additionalConfig != null
+            ? fileCollection.getAsFileTree()
+            : null;
     }
 
     @OutputDirectory
@@ -158,6 +163,14 @@ void copy() {
                 c.include(xpackPatternSet.getIncludes());
             });
         }
+        // TODO: once https://github.com/elastic/elasticsearch/pull/62968 lands ensure that this uses `getFileSystemOperations()`
+        // copy any additional config
+        if (additionalConfig != null) {
+            project.copy(c -> {
+                c.from(additionalConfig.getAsFileTree());
+                c.into(getOutputDir());
+            });
+        }
     }
 
     private Optional<SourceSet> getSourceSet() {

buildSrc/src/main/java/org/elasticsearch/gradle/test/rest/YamlRestCompatTestPlugin.java

@@ -0,0 +1,189 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.gradle.test.rest;
+
+import org.elasticsearch.gradle.ElasticsearchJavaPlugin;
+import org.elasticsearch.gradle.VersionProperties;
+import org.elasticsearch.gradle.test.RestIntegTestTask;
+import org.elasticsearch.gradle.test.RestTestBasePlugin;
+import org.elasticsearch.gradle.testclusters.ElasticsearchCluster;
+import org.elasticsearch.gradle.testclusters.TestClustersPlugin;
+import org.elasticsearch.gradle.testclusters.TestDistribution;
+import org.elasticsearch.gradle.util.GradleUtils;
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.plugins.JavaBasePlugin;
+import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.SourceSet;
+import org.gradle.api.tasks.SourceSetContainer;
+
+import java.io.File;
+import java.nio.file.Path;
+
+import static org.elasticsearch.gradle.test.rest.RestTestUtil.createTestCluster;
+import static org.elasticsearch.gradle.test.rest.RestTestUtil.setupDependencies;
+
+/**
+ * Apply this plugin to run the YAML based REST tests from a prior major version against this version's cluster.
+ */
+// TODO: support running tests against multiple prior versions in addition to bwc:minor. To achieve this we will need to create published
+// artifacts that include all of the REST tests for the latest 7.x.y releases
+public class YamlRestCompatTestPlugin implements Plugin<Project> {
+
+    public static final String SOURCE_SET_NAME = "yamlRestCompatTest";
+    private static final Path RELATIVE_API_PATH = Path.of("rest-api-spec/api");
+    private static final Path RELATIVE_TEST_PATH = Path.of("rest-api-spec/test");
+
+    @Override
+    public void apply(Project project) {
+
+        project.getPluginManager().apply(ElasticsearchJavaPlugin.class);
+        project.getPluginManager().apply(TestClustersPlugin.class);
+        project.getPluginManager().apply(RestTestBasePlugin.class);
+        project.getPluginManager().apply(RestResourcesPlugin.class);
+        project.getPluginManager().apply(YamlRestTestPlugin.class);
+
+        RestResourcesExtension extension = project.getExtensions().getByType(RestResourcesExtension.class);
+
+        // create source set
+        SourceSetContainer sourceSets = project.getExtensions().getByType(SourceSetContainer.class);
+        SourceSet yamlCompatTestSourceSet = sourceSets.create(SOURCE_SET_NAME);
+        SourceSet yamlTestSourceSet = sourceSets.getByName(YamlRestTestPlugin.SOURCE_SET_NAME);
+        GradleUtils.extendSourceSet(project, YamlRestTestPlugin.SOURCE_SET_NAME, SOURCE_SET_NAME);
+
+        // create the test cluster container, and always use the default distribution
+        ElasticsearchCluster testCluster = createTestCluster(project, yamlCompatTestSourceSet);
+        testCluster.setTestDistribution(TestDistribution.DEFAULT);
+
+        // TODO: once https://github.com/elastic/elasticsearch/pull/62473 lands refactor this to reference the checkoutDir as an artifact
+        int priorMajorVersion = VersionProperties.getElasticsearchVersion().getMajor() - 1;
+        final Path checkoutDir = project.findProject(":distribution:bwc:minor")
+            .getBuildDir()
+            .toPath()
+            .resolve("bwc")
+            .resolve("checkout-" + priorMajorVersion + ".x");
+
+        // copy compatible rest specs
+        Configuration compatSpec = project.getConfigurations().create("compatSpec");
+        Configuration xpackCompatSpec = project.getConfigurations().create("xpackCompatSpec");
+        Configuration additionalCompatSpec = project.getConfigurations().create("additionalCompatSpec");
+        Provider<CopyRestApiTask> copyCompatYamlSpecTask = project.getTasks()
+            .register("copyRestApiCompatSpecsTask", CopyRestApiTask.class, task -> {
+                task.includeCore.set(extension.restApi.getIncludeCore());
+                task.includeXpack.set(extension.restApi.getIncludeXpack());
+                task.sourceSetName = SOURCE_SET_NAME;
+                task.skipHasRestTestCheck = true;
+                task.coreConfig = compatSpec;
+                project.getDependencies()
+                    .add(
+                        task.coreConfig.getName(),
+                        project.files(checkoutDir.resolve("rest-api-spec/src/main/resources").resolve(RELATIVE_API_PATH))
+                    );
+                task.xpackConfig = xpackCompatSpec;
+                project.getDependencies()
+                    .add(
+                        task.xpackConfig.getName(),
+                        project.files(checkoutDir.resolve("x-pack/plugin/src/test/resources").resolve(RELATIVE_API_PATH))
+                    );
+                task.additionalConfig = additionalCompatSpec;
+                // per project can define custom specifications
+                project.getDependencies()
+                    .add(
+                        task.additionalConfig.getName(),
+                        project.files(
+                            getCompatProjectPath(project, checkoutDir).resolve("src/yamlRestTest/resources").resolve(RELATIVE_API_PATH)
+                        )
+                    );
+                task.dependsOn(task.coreConfig);
+                task.dependsOn(task.xpackConfig);
+                task.dependsOn(task.additionalConfig);
+                task.dependsOn(":distribution:bwc:minor:checkoutBwcBranch");
+            });
+
+        // copy compatible rest tests
+        Configuration compatTest = project.getConfigurations().create("compatTest");
+        Configuration xpackCompatTest = project.getConfigurations().create("xpackCompatTest");
+        Configuration additionalCompatTest = project.getConfigurations().create("additionalCompatTest");
+        Provider<CopyRestTestsTask> copyCompatYamlTestTask = project.getTasks()
+            .register("copyRestApiCompatTestTask", CopyRestTestsTask.class, task -> {
+                task.includeCore.set(extension.restTests.getIncludeCore());
+                task.includeXpack.set(extension.restTests.getIncludeXpack());
+                task.sourceSetName = SOURCE_SET_NAME;
+                task.coreConfig = compatTest;
+                project.getDependencies()
+                    .add(
+                        task.coreConfig.getName(),
+                        project.files(checkoutDir.resolve("rest-api-spec/src/main/resources").resolve(RELATIVE_TEST_PATH))
+                    );
+                task.xpackConfig = xpackCompatTest;
+                project.getDependencies()
+                    .add(
+                        task.xpackConfig.getName(),
+                        project.files(checkoutDir.resolve("x-pack/plugin/src/test/resources").resolve(RELATIVE_TEST_PATH))
+                    );
+                task.additionalConfig = additionalCompatTest;
+                project.getDependencies()
+                    .add(
+                        task.additionalConfig.getName(),
+                        project.files(
+                            getCompatProjectPath(project, checkoutDir).resolve("src/yamlRestTest/resources").resolve(RELATIVE_TEST_PATH)
+                        )
+                    );
+                task.dependsOn(task.coreConfig);
+                task.dependsOn(task.xpackConfig);
+                task.dependsOn(task.additionalConfig);
+                task.dependsOn(":distribution:bwc:minor:checkoutBwcBranch");
+                task.dependsOn(copyCompatYamlSpecTask);
+            });
+
+        // setup the yamlRestTest task
+        Provider<RestIntegTestTask> yamlRestCompatTestTask = RestTestUtil.registerTask(project, yamlCompatTestSourceSet);
+        project.getTasks().withType(RestIntegTestTask.class).named(SOURCE_SET_NAME).configure(testTask -> {
+            // Use test runner and classpath from "normal" yaml source set
+            testTask.setTestClassesDirs(yamlTestSourceSet.getOutput().getClassesDirs());
+            testTask.setClasspath(
+                yamlTestSourceSet.getRuntimeClasspath()
+                    // remove the "normal" api and tests
+                    .minus(project.files(yamlTestSourceSet.getOutput().getResourcesDir()))
+                    // add any additional classes/resources from the compatible source set
+                    // the api and tests are copied to the compatible source set
+                    .plus(yamlCompatTestSourceSet.getRuntimeClasspath())
+            );
+            // run compatibility tests after "normal" tests
+            testTask.mustRunAfter(project.getTasks().named(YamlRestTestPlugin.SOURCE_SET_NAME));
+            testTask.dependsOn(copyCompatYamlTestTask);
+        });
+
+        // setup the dependencies
+        setupDependencies(project, yamlCompatTestSourceSet);
+
+        // setup IDE
+        GradleUtils.setupIdeForTestSourceSet(project, yamlCompatTestSourceSet);
+
+        // wire this task into check
+        project.getTasks().named(JavaBasePlugin.CHECK_TASK_NAME).configure(check -> check.dependsOn(yamlRestCompatTestTask));
+    }
+
+    // TODO: implement custom extension that allows us move around of the projects between major versions and still find them
+    private Path getCompatProjectPath(Project project, Path checkoutDir) {
+        return checkoutDir.resolve(project.getPath().replaceFirst(":", "").replace(":", File.separator));
+    }
+}