Build: Move java home checks to pre-execution phase (#29548)

This commit moves the checks on JAVAX_HOME (where X is the java version
number) existing to the end of gradle's configuration phase, and based
on whether the tasks needing the java home are configured to execute.

relates #29519

buildSrc/src/main/groovy/org/elasticsearch/gradle/BuildPlugin.groovy

@@ -38,6 +38,7 @@ import org.gradle.api.artifacts.ModuleVersionIdentifier
 import org.gradle.api.artifacts.ProjectDependency
 import org.gradle.api.artifacts.ResolvedArtifact
 import org.gradle.api.artifacts.dsl.RepositoryHandler
+import org.gradle.api.execution.TaskExecutionGraph
 import org.gradle.api.plugins.JavaPlugin
 import org.gradle.api.publish.maven.MavenPublication
 import org.gradle.api.publish.maven.plugins.MavenPublishPlugin
@@ -221,21 +222,34 @@ class BuildPlugin implements Plugin<Project> {
         return System.getenv('JAVA' + version + '_HOME')
     }
 
-    /**
-     * Get Java home for the project for the specified version. If the specified version is not configured, an exception with the specified
-     * message is thrown.
-     *
-     * @param project the project
-     * @param version the version of Java home to obtain
-     * @param message the exception message if Java home for the specified version is not configured
-     * @return Java home for the specified version
-     * @throws GradleException if Java home for the specified version is not configured
-     */
-    static String getJavaHome(final Project project, final int version, final String message) {
-        if (project.javaVersions.get(version) == null) {
-            throw new GradleException(message)
+    /** Add a check before gradle execution phase which ensures java home for the given java version is set. */
+    static void requireJavaHome(Task task, int version) {
+        Project rootProject = task.project.rootProject // use root project for global accounting
+        if (rootProject.hasProperty('requiredJavaVersions') == false) {
+            rootProject.rootProject.ext.requiredJavaVersions = [:].withDefault{key -> return []}
+            rootProject.gradle.taskGraph.whenReady { TaskExecutionGraph taskGraph ->
+                List<String> messages = []
+                for (entry in rootProject.requiredJavaVersions) {
+                    if (rootProject.javaVersions.get(entry.key) != null) {
+                        continue
+                    }
+                    List<String> tasks = entry.value.findAll { taskGraph.hasTask(it) }.collect { "  ${it.path}" }
+                    if (tasks.isEmpty() == false) {
+                        messages.add("JAVA${entry.key}_HOME required to run tasks:\n${tasks.join('\n')}")
+                    }
+                }
+                if (messages.isEmpty() == false) {
+                    throw new GradleException(messages.join('\n'))
+                }
+            }
         }
-        return project.javaVersions.get(version)
+        rootProject.requiredJavaVersions.get(version).add(task)
+    }
+
+    /** A convenience method for getting java home for a version of java and requiring that version for the given task to execute */
+    static String getJavaHome(final Task task, final int version) {
+        requireJavaHome(task, version)
+        return task.project.javaVersions.get(version)
     }
 
     private static String findRuntimeJavaHome(final String compilerJavaHome) {

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

@@ -20,6 +20,7 @@ package org.elasticsearch.gradle.test
 
 import org.apache.tools.ant.DefaultLogger
 import org.apache.tools.ant.taskdefs.condition.Os
+import org.elasticsearch.gradle.BuildPlugin
 import org.elasticsearch.gradle.LoggedExec
 import org.elasticsearch.gradle.Version
 import org.elasticsearch.gradle.VersionProperties
@@ -611,6 +612,9 @@ class ClusterFormationTasks {
         }
 
         Task start = project.tasks.create(name: name, type: DefaultTask, dependsOn: setup)
+        if (node.javaVersion != null) {
+            BuildPlugin.requireJavaHome(start, node.javaVersion)
+        }
         start.doLast(elasticsearchRunner)
         return start
     }

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

@@ -36,6 +36,9 @@ import static org.elasticsearch.gradle.BuildPlugin.getJavaHome
  * A container for the files and configuration associated with a single node in a test cluster.
  */
 class NodeInfo {
+    /** Gradle project this node is part of */
+    Project project
+
     /** common configuration for all nodes, including this one */
     ClusterConfiguration config
 
@@ -84,6 +87,9 @@ class NodeInfo {
     /** directory to install plugins from */
     File pluginsTmpDir
 
+    /** Major version of java this node runs with, or {@code null} if using the runtime java version */
+    Integer javaVersion
+
     /** environment variables to start the node with */
     Map<String, String> env
 
@@ -109,6 +115,7 @@ class NodeInfo {
     NodeInfo(ClusterConfiguration config, int nodeNum, Project project, String prefix, Version nodeVersion, File sharedDir) {
         this.config = config
         this.nodeNum = nodeNum
+        this.project = project
         this.sharedDir = sharedDir
         if (config.clusterName != null) {
             clusterName = config.clusterName
@@ -165,12 +172,11 @@ class NodeInfo {
             args.add("${esScript}")
         }
 
+
         if (nodeVersion.before("6.2.0")) {
-            env = ['JAVA_HOME': "${-> getJavaHome(project, 8, "JAVA8_HOME must be set to run BWC tests against [" + nodeVersion + "]")}"]
+            javaVersion = 8
         } else if (nodeVersion.onOrAfter("6.2.0") && nodeVersion.before("6.3.0")) {
-            env = ['JAVA_HOME': "${-> getJavaHome(project, 9, "JAVA9_HOME must be set to run BWC tests against [" + nodeVersion + "]")}"]
-        } else {
-            env = ['JAVA_HOME': (String) project.runtimeJavaHome]
+            javaVersion = 9
         }
 
         args.addAll("-E", "node.portsfile=true")
@@ -182,7 +188,7 @@ class NodeInfo {
             // in the cluster-specific options
             esJavaOpts = String.join(" ", "-ea", "-esa", esJavaOpts)
         }
-        env.put('ES_JAVA_OPTS', esJavaOpts)
+        env = ['ES_JAVA_OPTS': esJavaOpts]
         for (Map.Entry<String, String> property : System.properties.entrySet()) {
             if (property.key.startsWith('tests.es.')) {
                 args.add("-E")
@@ -253,13 +259,19 @@ class NodeInfo {
         return Native.toString(shortPath).substring(4)
     }
 
+    /** Return the java home used by this node. */
+    String getJavaHome() {
+        return javaVersion == null ? project.runtimeJavaHome : project.javaVersions.get(javaVersion)
+    }
+
     /** Returns debug string for the command that started this node. */
     String getCommandString() {
         String esCommandString = "\nNode ${nodeNum} configuration:\n"
         esCommandString += "|-----------------------------------------\n"
         esCommandString += "|  cwd: ${cwd}\n"
         esCommandString += "|  command: ${executable} ${args.join(' ')}\n"
         esCommandString += '|  environment:\n'
+        esCommandString += "|    JAVA_HOME: ${javaHome}\n"
         env.each { k, v -> esCommandString += "|    ${k}: ${v}\n" }
         if (config.daemonize) {
             esCommandString += "|\n|  [${wrapperScript.name}]\n"

distribution/bwc/build.gradle

@@ -147,9 +147,9 @@ subprojects {
     workingDir = checkoutDir
     if (["5.6", "6.0", "6.1"].contains(bwcBranch)) {
       // we are building branches that are officially built with JDK 8, push JAVA8_HOME to JAVA_HOME for these builds
-      environment('JAVA_HOME', "${-> getJavaHome(project, 8, "JAVA8_HOME is required to build BWC versions for BWC branch [" + bwcBranch + "]")}")
+      environment('JAVA_HOME', getJavaHome(it, 8))
     } else if ("6.2".equals(bwcBranch)) {
-      environment('JAVA_HOME', "${-> getJavaHome(project, 9, "JAVA9_HOME is required to build BWC versions for BWC branch [" + bwcBranch + "]")}")
+      environment('JAVA_HOME', getJavaHome(it, 9))
     } else {
       environment('JAVA_HOME', project.compilerJavaHome)
     }

qa/reindex-from-old/build.gradle

@@ -77,7 +77,7 @@ if (Os.isFamily(Os.FAMILY_WINDOWS)) {
       dependsOn unzip
       executable = new File(project.runtimeJavaHome, 'bin/java')
       env 'CLASSPATH', "${ -> project.configurations.oldesFixture.asPath }"
-      env 'JAVA_HOME', "${-> getJavaHome(project, 7, "JAVA7_HOME must be set to run reindex-from-old")}"
+      env 'JAVA_HOME', getJavaHome(it, 7)
       args 'oldes.OldElasticsearch',
            baseDir,
            unzip.temporaryDir,