[MNG-6797] Remember if Maven model problems were encountered in Maven 4

api/maven-api-core/src/main/java/org/apache/maven/api/Session.java

@@ -32,6 +32,8 @@
 import org.apache.maven.api.model.Repository;
 import org.apache.maven.api.services.ArtifactCoordinatesFactory;
 import org.apache.maven.api.services.DependencyCoordinatesFactory;
+import org.apache.maven.api.services.ModelProblem;
+import org.apache.maven.api.services.ProblemCollector;
 import org.apache.maven.api.services.VersionResolverException;
 import org.apache.maven.api.settings.Settings;
 import org.apache.maven.api.toolchain.ToolchainModel;
@@ -93,6 +95,25 @@ public interface Session extends ProtoSession {
     @Nonnull
     SessionData getData();
 
+    /**
+     * Returns the model problems encountered while discovering the projects in this session's reactor.
+     *
+     * @return the session model problem collector, never {@code null}
+     */
+    @Nonnull
+    default ProblemCollector<ModelProblem> getModelProblemCollector() {
+        return SessionModelProblems.getProblemCollector(this);
+    }
+
+    /**
+     * Returns whether model problems were encountered while discovering the projects in this session's reactor.
+     *
+     * @return {@code true} if at least one model problem was encountered
+     */
+    default boolean hasModelProblems() {
+        return getModelProblemCollector().hasWarningProblems();
+    }
+
     /**
      * Default implementation at {@link ProtoSession} level, as the notion of project
      * does not exist there.

api/maven-api-core/src/main/java/org/apache/maven/api/SessionModelProblems.java

@@ -0,0 +1,44 @@
+/*
+ * 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;
+
+import org.apache.maven.api.services.ModelProblem;
+import org.apache.maven.api.services.ProblemCollector;
+
+final class SessionModelProblems {
+
+    private static final SessionData.Key<State> KEY = SessionData.key(State.class, SessionModelProblems.class);
+
+    private SessionModelProblems() {}
+
+    static ProblemCollector<ModelProblem> getProblemCollector(Session session) {
+        return session.getData()
+                .computeIfAbsent(KEY, () -> new State(ProblemCollector.create(session)))
+                .problemCollector;
+    }
+
+    private static final class State {
+
+        private final ProblemCollector<ModelProblem> problemCollector;
+
+        private State(ProblemCollector<ModelProblem> problemCollector) {
+            this.problemCollector = problemCollector;
+        }
+    }
+}

impl/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java

@@ -34,6 +34,7 @@
 import org.apache.maven.artifact.repository.ArtifactRepository;
 import org.apache.maven.artifact.repository.RepositoryCache;
 import org.apache.maven.impl.SettingsUtilsV4;
+import org.apache.maven.internal.impl.SessionModelProblemsBridge;
 import org.apache.maven.model.Profile;
 import org.apache.maven.monitor.event.EventDispatcher;
 import org.apache.maven.plugin.descriptor.PluginDescriptor;
@@ -295,6 +296,8 @@ public void setAllProjects(List<MavenProject> allProjects) {
 
     private Session session;
 
+    private boolean modelProblems;
+
     @Deprecated
     /** @deprecated This appears not to be used anywhere within Maven itself. */
     public Map<String, MavenProject> getProjectMap() {
@@ -496,8 +499,34 @@ public Session getSession() {
         return session;
     }
 
+    /**
+     * Returns whether the reactor projects had model problems.
+     *
+     * @return {@code true} if model problems were encountered
+     * @since 3.10.0
+     */
+    public boolean hasModelProblems() {
+        return modelProblems || (session != null && session.hasModelProblems());
+    }
+
+    /**
+     * Sets whether the reactor projects had model problems.
+     *
+     * @param modelProblems whether model problems were encountered
+     * @since 3.10.0
+     */
+    public void setModelProblems(boolean modelProblems) {
+        this.modelProblems = modelProblems;
+        if (session != null) {
+            SessionModelProblemsBridge.setLegacyFlag(session, modelProblems);
+        }
+    }
+
     public void setSession(Session session) {
         this.session = session;
+        if (session != null) {
+            SessionModelProblemsBridge.setLegacyFlag(session, modelProblems);
+        }
     }
     /*end[MAVEN4]*/
 }

impl/maven-core/src/main/java/org/apache/maven/graph/DefaultGraphBuilder.java

@@ -31,6 +31,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Consumer;
 
 import org.apache.maven.MavenExecutionException;
 import org.apache.maven.ProjectCycleException;
@@ -349,22 +350,48 @@ private String formatProjects(List<MavenProject> projects) {
     private List<MavenProject> getProjectsForMavenReactor(MavenSession session) throws ProjectBuildingException {
         MavenExecutionRequest request = session.getRequest();
         request.getProjectBuildingRequest().setRepositorySession(session.getRepositorySession());
+        Consumer<org.apache.maven.model.building.ModelProblem> modelProblemConsumer = getModelProblemConsumer(session);
 
         // 1. Collect project for invocation without a POM.
         if (request.getPom() == null) {
-            return pomlessCollectionStrategy.collectProjects(request);
+            return pomlessCollectionStrategy.collectProjects(request, modelProblemConsumer);
         }
 
         // 2. Collect projects for all modules in the multi-module project.
         if (request.getMakeBehavior() != null || !request.getProjectActivation().isEmpty()) {
-            List<MavenProject> projects = multiModuleCollectionStrategy.collectProjects(request);
+            List<MavenProject> projects = multiModuleCollectionStrategy.collectProjects(request, modelProblemConsumer);
             if (!projects.isEmpty()) {
                 return projects;
             }
         }
 
         // 3. Collect projects for explicitly requested POM.
-        return requestPomCollectionStrategy.collectProjects(request);
+        return requestPomCollectionStrategy.collectProjects(request, modelProblemConsumer);
+    }
+
+    private Consumer<org.apache.maven.model.building.ModelProblem> getModelProblemConsumer(MavenSession session) {
+        org.apache.maven.api.Session apiSession = session.getSession();
+        if (apiSession == null) {
+            return problem -> session.setModelProblems(true);
+        }
+        return problem -> apiSession.getModelProblemCollector().reportProblem(toApiModelProblem(problem));
+    }
+
+    private org.apache.maven.api.services.ModelProblem toApiModelProblem(
+            org.apache.maven.model.building.ModelProblem problem) {
+        return new org.apache.maven.impl.model.DefaultModelProblem(
+                problem.getMessage(),
+                org.apache.maven.api.services.BuilderProblem.Severity.valueOf(
+                        problem.getSeverity().name()),
+                problem.getVersion() != null
+                        ? org.apache.maven.api.services.ModelProblem.Version.valueOf(
+                                problem.getVersion().name())
+                        : org.apache.maven.api.services.ModelProblem.Version.BASE,
+                problem.getSource(),
+                problem.getLineNumber(),
+                problem.getColumnNumber(),
+                problem.getModelId(),
+                problem.getException());
     }
 
     private void validateProjects(List<MavenProject> projects, MavenExecutionRequest request)

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

@@ -180,6 +180,11 @@ public List<Project> getProjects() {
         return getProjects(getMavenSession().getProjects());
     }
 
+    @Override
+    public boolean hasModelProblems() {
+        return SessionModelProblemsBridge.hasModelProblems(this);
+    }
+
     @Nonnull
     @Override
     public Map<String, Object> getPluginContext(Project project) {

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

@@ -0,0 +1,55 @@
+/*
+ * 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.internal.impl;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.apache.maven.api.Session;
+import org.apache.maven.api.SessionData;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * Stores the legacy model-problem flag in session data so that derived sessions see the same state.
+ */
+public final class SessionModelProblemsBridge {
+
+    private static final SessionData.Key<State> KEY = SessionData.key(State.class, SessionModelProblemsBridge.class);
+
+    private SessionModelProblemsBridge() {}
+
+    public static boolean hasModelProblems(Session session) {
+        return getState(session).legacyFlag.get()
+                || session.getModelProblemCollector().hasWarningProblems();
+    }
+
+    public static void setLegacyFlag(Session session, boolean value) {
+        getState(session).legacyFlag.set(value);
+    }
+
+    private static State getState(Session session) {
+        requireNonNull(session, "session");
+        return session.getData().computeIfAbsent(KEY, State::new);
+    }
+
+    private static final class State {
+
+        private final AtomicBoolean legacyFlag = new AtomicBoolean();
+    }
+}

impl/maven-core/src/main/java/org/apache/maven/project/collector/DefaultProjectsSelector.java

@@ -25,6 +25,7 @@
 import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.apache.maven.execution.MavenExecutionRequest;
 import org.apache.maven.model.building.ModelProblem;
@@ -54,6 +55,13 @@ public DefaultProjectsSelector(ProjectBuilder projectBuilder) {
     @Override
     public List<MavenProject> selectProjects(List<File> files, MavenExecutionRequest request)
             throws ProjectBuildingException {
+        return selectProjects(files, request, problem -> {});
+    }
+
+    @Override
+    public List<MavenProject> selectProjects(
+            List<File> files, MavenExecutionRequest request, Consumer<ModelProblem> problemConsumer)
+            throws ProjectBuildingException {
         ProjectBuildingRequest projectBuildingRequest = request.getProjectBuildingRequest();
 
         boolean hasProjectSelection = !request.getProjectActivation().isEmpty();
@@ -66,6 +74,7 @@ public List<MavenProject> selectProjects(List<File> files, MavenExecutionRequest
 
         for (ProjectBuildingResult result : results) {
             projects.add(result.getProject());
+            result.getProblems().forEach(problemConsumer);
 
             int problemsCount = result.getProblems().size();
             totalProblemsCount += problemsCount;

impl/maven-core/src/main/java/org/apache/maven/project/collector/MultiModuleCollectionStrategy.java

@@ -28,6 +28,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
 
 import org.apache.maven.api.services.model.ModelProcessor;
@@ -62,12 +63,19 @@ public MultiModuleCollectionStrategy(ModelProcessor modelProcessor, ProjectsSele
 
     @Override
     public List<MavenProject> collectProjects(MavenExecutionRequest request) throws ProjectBuildingException {
+        return collectProjects(request, problem -> {});
+    }
+
+    public List<MavenProject> collectProjects(MavenExecutionRequest request, Consumer<ModelProblem> problemConsumer)
+            throws ProjectBuildingException {
         File moduleProjectPomFile = getRootProject(request);
         List<File> files = Collections.singletonList(moduleProjectPomFile.getAbsoluteFile());
         try {
-            List<MavenProject> projects = projectsSelector.selectProjects(files, request);
+            List<ModelProblem> problems = new ArrayList<>();
+            List<MavenProject> projects = projectsSelector.selectProjects(files, request, problems::add);
             boolean isRequestedProjectCollected = isRequestedProjectCollected(request, projects);
             if (isRequestedProjectCollected) {
+                problems.forEach(problemConsumer);
                 return projects;
             } else {
                 LOGGER.debug(

impl/maven-core/src/main/java/org/apache/maven/project/collector/PomlessCollectionStrategy.java

@@ -24,15 +24,18 @@
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.apache.maven.DefaultMaven;
 import org.apache.maven.execution.MavenExecutionRequest;
+import org.apache.maven.model.building.ModelProblem;
 import org.apache.maven.model.building.ModelSource;
 import org.apache.maven.model.building.UrlModelSource;
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.project.ProjectBuilder;
 import org.apache.maven.project.ProjectBuildingException;
 import org.apache.maven.project.ProjectBuildingRequest;
+import org.apache.maven.project.ProjectBuildingResult;
 
 /**
  * Strategy to collect projects for building when the Maven invocation is not in a directory that contains a pom.xml.
@@ -49,10 +52,16 @@ public PomlessCollectionStrategy(ProjectBuilder projectBuilder) {
 
     @Override
     public List<MavenProject> collectProjects(final MavenExecutionRequest request) throws ProjectBuildingException {
+        return collectProjects(request, problem -> {});
+    }
+
+    public List<MavenProject> collectProjects(MavenExecutionRequest request, Consumer<ModelProblem> problemConsumer)
+            throws ProjectBuildingException {
         ProjectBuildingRequest buildingRequest = request.getProjectBuildingRequest();
         ModelSource modelSource = new UrlModelSource(DefaultMaven.class.getResource("project/standalone.xml"));
-        MavenProject project =
-                projectBuilder.build(modelSource, buildingRequest).getProject();
+        ProjectBuildingResult result = projectBuilder.build(modelSource, buildingRequest);
+        result.getProblems().forEach(problemConsumer);
+        MavenProject project = result.getProject();
         project.setExecutionRoot(true);
         request.setProjectPresent(false);
 

impl/maven-core/src/main/java/org/apache/maven/project/collector/ProjectsSelector.java

@@ -20,8 +20,10 @@
 
 import java.io.File;
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.apache.maven.execution.MavenExecutionRequest;
+import org.apache.maven.model.building.ModelProblem;
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.project.ProjectBuildingException;
 
@@ -37,4 +39,19 @@ public interface ProjectsSelector {
      * @throws ProjectBuildingException In case the POMs are not used.
      */
     List<MavenProject> selectProjects(List<File> files, MavenExecutionRequest request) throws ProjectBuildingException;
+
+    /**
+     * Select Maven projects from a list of POM files and report model problems encountered while building them.
+     *
+     * @param files List of POM files.
+     * @param request The {@link MavenExecutionRequest}
+     * @param problemConsumer Consumer for model problems encountered while building the selected projects.
+     * @return A list of projects that have been found in the specified POM files.
+     * @throws ProjectBuildingException In case the POMs are not used.
+     */
+    default List<MavenProject> selectProjects(
+            List<File> files, MavenExecutionRequest request, Consumer<ModelProblem> problemConsumer)
+            throws ProjectBuildingException {
+        return selectProjects(files, request);
+    }
 }