[MNG-7893] Allow versioning the superpom according to the model version

api/maven-api-core/src/main/java/org/apache/maven/api/services/SuperPomProvider.java

@@ -20,6 +20,7 @@
 
 import org.apache.maven.api.Service;
 import org.apache.maven.api.annotations.Experimental;
+import org.apache.maven.api.annotations.Nonnull;
 import org.apache.maven.api.model.Model;
 
 /**
@@ -33,7 +34,8 @@ public interface SuperPomProvider extends Service {
      *
      * @param version The model version to retrieve the super POM for (e.g. "4.0.0"), must not be {@code null}.
      * @return The super POM, never {@code null}.
-     * @throws IllegalStateException if the super POM could not be retrieved
+     * @throws SuperPomProviderException if the super POM could not be retrieved
      */
-    Model getSuperPom(String version);
+    @Nonnull
+    Model getSuperPom(@Nonnull String version);
 }

api/maven-api-core/src/main/java/org/apache/maven/api/services/SuperPomProviderException.java

@@ -0,0 +1,43 @@
+/*
+ * 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.
+ */
+package org.apache.maven.api.services;
+
+/**
+ * Exceptions thrown by the {@link SuperPomProvider} service.
+ *
+ * @since 4.0.0
+ */
+public class SuperPomProviderException extends MavenException {
+
+    public SuperPomProviderException() {
+        super();
+    }
+
+    public SuperPomProviderException(String message) {
+        super(message);
+    }
+
+    public SuperPomProviderException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public SuperPomProviderException(Throwable cause) {
+        super(cause);
+    }
+}

maven-core/src/main/java/org/apache/maven/DefaultMaven.java

@@ -495,6 +495,7 @@ private void validatePrerequisitesForNonMavenPluginProjects(List<MavenProject> p
      * @return A {@link Set} of profile identifiers, never {@code null}.
      */
     private Set<String> getAllProfiles(MavenSession session) {
+        // TODO: which version of super pom should we use here ?
         final Model superPomModel = superPomProvider.getSuperModel("4.0.0").getDelegate();
         final Set<MavenProject> projectsIncludingParents = new HashSet<>();
         for (MavenProject project : session.getProjects()) {

maven-core/src/main/java/org/apache/maven/internal/impl/DefaultSuperPomProvider.java

@@ -24,6 +24,7 @@
 
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.services.SuperPomProvider;
+import org.apache.maven.api.services.SuperPomProviderException;
 
 @Named
 @Singleton
@@ -38,6 +39,10 @@ public DefaultSuperPomProvider(org.apache.maven.model.superpom.SuperPomProvider
 
     @Override
     public Model getSuperPom(String version) {
-        return provider.getSuperModel(version).getDelegate();
+        try {
+            return provider.getSuperModel(version).getDelegate();
+        } catch (IllegalStateException e) {
+            throw new SuperPomProviderException("Could not retrieve super pom " + version, e);
+        }
     }
 }

maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuilder.java

@@ -746,7 +746,8 @@ private Model readEffectiveModel(
         problems.setRootModel(inputModel);
 
         ModelData resultData = new ModelData(request.getModelSource(), inputModel);
-        ModelData superData = new ModelData(null, getSuperModel());
+        String superModelVersion = inputModel.getModelVersion() != null ? inputModel.getModelVersion() : "4.0.0";
+        ModelData superData = new ModelData(null, getSuperModel(superModelVersion));
 
         // profile activation
         DefaultProfileActivationContext profileActivationContext = getProfileActivationContext(request);
@@ -1605,8 +1606,8 @@ private ModelData readParentExternally(
                 modelSource, parentModel, parent.getGroupId(), parent.getArtifactId(), parent.getVersion());
     }
 
-    private Model getSuperModel() {
-        return superPomProvider.getSuperModel("4.0.0");
+    private Model getSuperModel(String modelVersion) {
+        return superPomProvider.getSuperModel(modelVersion);
     }
 
     private void importDependencyManagement(

maven-model-builder/src/main/java/org/apache/maven/model/superpom/DefaultSuperPomProvider.java

@@ -26,6 +26,8 @@
 import java.io.InputStream;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.maven.api.model.InputSource;
 import org.apache.maven.model.Model;
@@ -44,7 +46,7 @@ public class DefaultSuperPomProvider implements SuperPomProvider {
     /**
      * The cached super POM, lazily created.
      */
-    private Model superModel;
+    private static final Map<String, Model> SUPER_MODELS = new ConcurrentHashMap<>();
 
     @Inject
     public DefaultSuperPomProvider(ModelProcessor modelProcessor) {
@@ -53,8 +55,8 @@ public DefaultSuperPomProvider(ModelProcessor modelProcessor) {
 
     @Override
     public Model getSuperModel(String version) {
-        if (superModel == null) {
-            String resource = "/org/apache/maven/model/pom-" + version + ".xml";
+        return SUPER_MODELS.computeIfAbsent(Objects.requireNonNull(version), v -> {
+            String resource = "/org/apache/maven/model/pom-" + v + ".xml";
 
             InputStream is = getClass().getResourceAsStream(resource);
 
@@ -65,23 +67,21 @@ public Model getSuperModel(String version) {
 
             try {
                 Map<String, Object> options = new HashMap<>(2);
-                options.put("xml:4.0.0", "xml:4.0.0");
+                options.put("xml:" + version, "xml:" + version);
 
-                String modelId = "org.apache.maven:maven-model-builder:"
+                String modelId = "org.apache.maven:maven-model-builder:" + version + "-"
                         + this.getClass().getPackage().getImplementationVersion() + ":super-pom";
                 InputSource inputSource = new InputSource(
                         modelId, getClass().getResource(resource).toExternalForm());
                 options.put(ModelProcessor.INPUT_SOURCE, new org.apache.maven.model.InputSource(inputSource));
 
-                superModel = modelProcessor.read(is, options);
+                return modelProcessor.read(is, options);
             } catch (IOException e) {
                 throw new IllegalStateException(
                         "The super POM " + resource + " is damaged"
                                 + ", please verify the integrity of your Maven installation",
                         e);
             }
-        }
-
-        return superModel;
+        });
     }
 }

maven-model-builder/src/main/resources/org/apache/maven/model/pom-4.1.0.xml

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+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.
+-->
+
+<!-- START SNIPPET: superpom -->
+<project>
+  <modelVersion>4.0.0</modelVersion>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+  </properties>
+
+  <build>
+    <directory>${project.basedir}/target</directory>
+    <outputDirectory>${project.build.directory}/classes</outputDirectory>
+    <finalName>${project.artifactId}-${project.version}</finalName>
+    <testOutputDirectory>${project.build.directory}/test-classes</testOutputDirectory>
+    <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory>
+    <scriptSourceDirectory>${project.basedir}/src/main/scripts</scriptSourceDirectory>
+    <testSourceDirectory>${project.basedir}/src/test/java</testSourceDirectory>
+    <resources>
+      <resource>
+        <directory>${project.basedir}/src/main/resources</directory>
+      </resource>
+      <resource>
+        <directory>${project.basedir}/src/main/resources-filtered</directory>
+        <filtering>true</filtering>
+      </resource>
+    </resources>
+    <testResources>
+      <testResource>
+        <directory>${project.basedir}/src/test/resources</directory>
+      </testResource>
+      <testResource>
+        <directory>${project.basedir}/src/test/resources-filtered</directory>
+        <filtering>true</filtering>
+      </testResource>
+    </testResources>
+  </build>
+
+  <reporting>
+    <outputDirectory>${project.build.directory}/site</outputDirectory>
+  </reporting>
+
+</project>
+<!-- END SNIPPET: superpom -->