Generate automatically a marker file for a maven profile depending on java level to use

src/it/ensure-java-level-marker-11-migration/invoker.properties

@@ -0,0 +1,20 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF 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.
+#
+
+invoker.goals=-ntp validate

src/it/ensure-java-level-marker-11-migration/pom.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.jenkins-ci.plugins</groupId>
+    <artifactId>plugin</artifactId>
+    <version>4.77</version>
+    <relativePath />
+  </parent>
+  <groupId>org.jenkins-ci.tools.hpi.its</groupId>
+  <artifactId>ensure-java-level-marker-11-migration</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>hpi</packaging>
+  <name>MyNewPlugin</name>
+  <properties>
+    <jenkins.version>2.361.4</jenkins.version>
+    <hpi-plugin.version>@project.version@</hpi-plugin.version>
+    <spotless.check.skip>false</spotless.check.skip>
+  </properties>
+</project>

src/it/ensure-java-level-marker-11-migration/verify.groovy

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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.
+ */
+
+assert new File(basedir, 'target/java-level').list().length == 1
+assert new File(basedir, 'target/java-level/11').exists()
+assert new File(basedir, 'build.log').getText('UTF-8').contains("Removing old marker file")
+
+return true

src/it/ensure-java-level-marker-11/invoker.properties

@@ -0,0 +1,20 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF 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.
+#
+
+invoker.goals=-ntp validate

src/it/ensure-java-level-marker-11/pom.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.jenkins-ci.plugins</groupId>
+    <artifactId>plugin</artifactId>
+    <version>4.77</version>
+    <relativePath />
+  </parent>
+  <groupId>org.jenkins-ci.tools.hpi.its</groupId>
+  <artifactId>ensure-java-level-marker-11</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>hpi</packaging>
+  <name>MyNewPlugin</name>
+  <properties>
+    <jenkins.version>2.361.4</jenkins.version>
+    <hpi-plugin.version>@project.version@</hpi-plugin.version>
+    <spotless.check.skip>false</spotless.check.skip>
+  </properties>
+</project>

src/it/ensure-java-level-marker-11/verify.groovy

@@ -0,0 +1,23 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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.
+ */
+
+assert new File(basedir, 'target/java-level').list().length == 1
+assert new File(basedir, 'target/java-level/11').exists()
+
+return true

src/main/java/org/jenkinsci/maven/plugins/hpi/InitializeMojo.java

@@ -0,0 +1,73 @@
+package org.jenkinsci.maven.plugins.hpi;
+
+import hudson.util.VersionNumber;
+import io.jenkins.lib.versionnumber.JavaSpecificationVersion;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+
+/**
+ * Configure Maven for the desired version of Java.
+ *
+ * @author Basil Crow
+ */
+@Mojo(name = "initialize", defaultPhase = LifecyclePhase.INITIALIZE)
+public class InitializeMojo extends AbstractJenkinsMojo {
+
+    @Override
+    public void execute() throws MojoExecutionException {
+        setCompilerProperties();
+    }
+
+    private void setCompilerProperties() throws MojoExecutionException {
+        if (!project.getProperties().containsKey("maven.compiler.source")
+                && !project.getProperties().containsKey("maven.compiler.release")) {
+            // On an older plugin parent POM that predates the setting of these values as Maven properties.
+            return;
+        }
+
+        JavaSpecificationVersion javaVersion = getMinimumJavaVersion();
+        if (JavaSpecificationVersion.forCurrentJVM().isOlderThan(new VersionNumber("9"))) {
+            // Should always be set already, but just in case...
+            setProperty("maven.compiler.source", javaVersion.toString());
+            setProperty("maven.compiler.target", javaVersion.toString());
+            setProperty("maven.compiler.testSource", javaVersion.toString());
+            setProperty("maven.compiler.testTarget", javaVersion.toString());
+            // Should never be set already, but just in case...
+            unsetProperty("maven.compiler.release");
+            unsetProperty("maven.compiler.testRelease");
+        } else {
+            /*
+             * When compiling with a Java 9+ compiler, we always rely on "release" in favor of "source" and "target",
+             * even when compiling to Java 8 bytecode.
+             */
+            setProperty("maven.compiler.release", Integer.toString(javaVersion.toReleaseVersion()));
+            setProperty("maven.compiler.testRelease", Integer.toString(javaVersion.toReleaseVersion()));
+
+            /*
+             * While it does not hurt to have these set to the Java specification version, it is also not needed when
+             * "release" is in use.
+             */
+            unsetProperty("maven.compiler.source");
+            unsetProperty("maven.compiler.target");
+            unsetProperty("maven.compiler.testSource");
+            unsetProperty("maven.compiler.testTarget");
+        }
+    }
+
+    private void setProperty(String key, String value) {
+        String currentValue = project.getProperties().getProperty(key);
+        if (currentValue == null || !currentValue.equals(value)) {
+            getLog().info("Setting " + key + " to " + value);
+            project.getProperties().setProperty(key, value);
+        }
+    }
+
+    private void unsetProperty(String key) {
+        String currentValue = project.getProperties().getProperty(key);
+        if (currentValue != null && !currentValue.isEmpty()) {
+            getLog().info("Unsetting " + key);
+            project.getProperties().remove(key);
+        }
+    }
+}

src/main/java/org/jenkinsci/maven/plugins/hpi/ValidateMojo.java

@@ -2,12 +2,16 @@
 
 import hudson.util.VersionNumber;
 import io.jenkins.lib.versionnumber.JavaSpecificationVersion;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Properties;
 import org.apache.maven.model.Scm;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.project.MavenProject;
+import org.codehaus.plexus.util.FileUtils;
 
 /**
  * Make sure that we are running in the right environment.
@@ -37,6 +41,7 @@ public void execute() throws MojoExecutionException {
         if (JavaSpecificationVersion.forCurrentJVM().isOlderThan(javaVersion)) {
             throw new MojoExecutionException("Java " + javaVersion + " or later is necessary to build this plugin.");
         }
+        writeProfileMarker(javaVersion);
 
         if (new VersionNumber(findJenkinsVersion()).compareTo(new VersionNumber("2.361")) < 0) {
             throw new MojoExecutionException("This version of maven-hpi-plugin requires Jenkins 2.361 or later");
@@ -94,6 +99,56 @@ public void execute() throws MojoExecutionException {
         }
     }
 
+    private void writeProfileMarker(JavaSpecificationVersion javaVersion) throws MojoExecutionException {
+        var path = Path.of(project.getBuild().getDirectory(), "java-level");
+        if (!Files.exists(path)) {
+            try {
+                Files.createDirectories(path);
+            } catch (IOException e) {
+                throw new MojoExecutionException("Failed to create " + path, e);
+            }
+        }
+        var versionPath = path.resolve(Integer.toString(javaVersion.toReleaseVersion()));
+        boolean found = false;
+        try (var walk = Files.walk(path)) {
+            for (var it = walk.iterator(); it.hasNext(); ) {
+                var p = it.next();
+                if (p.equals(path)) {
+                    continue;
+                }
+                if (!p.equals(versionPath)) {
+                    getLog().info("Removing old marker file " + p);
+                    delete(p);
+                } else {
+                    found = true;
+                }
+            }
+        } catch (IOException e) {
+            throw new MojoExecutionException("Failed to walk " + path, e);
+        }
+        if (!found) {
+            try {
+                Files.createFile(versionPath);
+                getLog().info("Created marker file " + versionPath);
+            } catch (IOException e) {
+                throw new MojoExecutionException("Failed to create file " + versionPath, e);
+            }
+        }
+    }
+
+    private static void delete(Path p) throws MojoExecutionException {
+        try {
+            if (Files.isRegularFile(p)) {
+                Files.delete(p);
+            } else if (Files.isDirectory(p)) {
+                // In case someone manually created a subdirectory, delete it recursively
+                FileUtils.deleteDirectory(p.toFile());
+            }
+        } catch (IOException e) {
+            throw new MojoExecutionException("Failed to delete " + p, e);
+        }
+    }
+
     private void check(String tag, String value, String badStart, String goodStart, String reason) {
         if (value.startsWith(badStart)) {
             String goodValue = goodStart + value.substring(badStart.length());

src/main/java/org/jenkinsci/maven/plugins/hpi/extensions/HpiLifecycleMappingProvider.java

@@ -26,6 +26,7 @@ static Map<String, LifecyclePhase> getBindings() {
                 "validate",
                 new LifecyclePhase(
                         "org.jenkins-ci.tools:maven-hpi-plugin:validate,org.jenkins-ci.tools:maven-hpi-plugin:validate-hpi"));
+        bindings.put("initialize", new LifecyclePhase("org.jenkins-ci.tools:maven-hpi-plugin:initialize"));
         bindings.put(
                 "process-resources",
                 new LifecyclePhase("org.apache.maven.plugins:maven-resources-plugin:2.6:resources"));