Structured BuilderProblem pipeline for DiagnosticCollector

impl/maven-cli/src/main/java/org/apache/maven/cling/invoker/LookupInvoker.java

@@ -76,6 +76,7 @@
 import org.apache.maven.eventspy.internal.EventSpyDispatcher;
 import org.apache.maven.execution.MavenExecutionRequest;
 import org.apache.maven.impl.SettingsUtilsV4;
+import org.apache.maven.internal.build.DefaultDiagnosticCollector;
 import org.apache.maven.jline.FastTerminal;
 import org.apache.maven.jline.MessageUtils;
 import org.apache.maven.logging.AsyncDrainWriter;
@@ -757,6 +758,13 @@ protected Runnable settings(C context, boolean emitSettingsWarnings, SettingsBui
                 }
             }
             context.logger.info("");
+
+            // Pipe structured problems directly to DiagnosticCollector so that
+            // key, suggestion, documentationUrl, and source location are preserved
+            // in the build report (instead of being lost to plain-text logging).
+            // This runs before SessionStarted, so the SLF4J auto-collection hook
+            // is not active yet — no double-counting risk.
+            pipeSettingsProblems(context, settingsResult);
         }
         return () -> {
             context.installationSettingsPath = null;
@@ -768,6 +776,20 @@ protected Runnable settings(C context, boolean emitSettingsWarnings, SettingsBui
         };
     }
 
+    /**
+     * Pipes structured settings validation problems to the DiagnosticCollector.
+     * This preserves key, suggestion, documentationUrl, and source location
+     * that would otherwise be lost when problems are logged as plain text.
+     */
+    private void pipeSettingsProblems(C context, SettingsBuilderResult settingsResult) {
+        context.lookup.lookupOptional(DefaultDiagnosticCollector.class).ifPresent(collector -> {
+            for (BuilderProblem problem :
+                    settingsResult.getProblems().problems().toList()) {
+                collector.report(problem);
+            }
+        });
+    }
+
     protected void customizeSettingsRequest(C context, SettingsBuilderRequest settingsBuilderRequest)
             throws Exception {}
 

impl/maven-cli/src/main/java/org/apache/maven/cling/invoker/mvn/MavenInvoker.java

@@ -69,6 +69,7 @@
 import org.apache.maven.execution.MavenExecutionResult;
 import org.apache.maven.execution.ProfileActivation;
 import org.apache.maven.execution.ProjectActivation;
+import org.apache.maven.internal.build.DefaultDiagnosticCollector;
 import org.apache.maven.jline.MessageUtils;
 import org.apache.maven.lifecycle.LifecycleExecutionException;
 import org.apache.maven.logging.BuildEventListener;
@@ -220,6 +221,17 @@ protected void toolchains(MavenContext context, MavenExecutionRequest request) t
             }
 
             context.logger.info("");
+
+            // Pipe structured problems directly to DiagnosticCollector so that
+            // key, suggestion, documentationUrl, and source location are preserved
+            // in the build report. This runs before SessionStarted, so the SLF4J
+            // auto-collection hook is not active yet — no double-counting risk.
+            context.lookup.lookupOptional(DefaultDiagnosticCollector.class).ifPresent(collector -> {
+                for (BuilderProblem problem :
+                        toolchainsResult.getProblems().problems().toList()) {
+                    collector.report(problem);
+                }
+            });
         }
     }
 

impl/maven-core/pom.xml

@@ -396,6 +396,8 @@ under the License.
               <exclude>org.apache.maven.toolchain.ToolchainManagerPrivate</exclude>
               <exclude>org.apache.maven.toolchain.ToolchainPrivate</exclude>
               <exclude>org.apache.maven.toolchain.ToolchainsBuilder</exclude>
+              <!-- PluginValidationManager: String issue → BuilderProblem problem (4.1.0) -->
+              <exclude>org.apache.maven.plugin.PluginValidationManager</exclude>
             </excludes>
           </parameter>
         </configuration>

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

@@ -43,6 +43,7 @@
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.model.Prerequisites;
 import org.apache.maven.api.model.Profile;
+import org.apache.maven.api.services.BuilderProblem;
 import org.apache.maven.api.services.Lookup;
 import org.apache.maven.api.services.LookupException;
 import org.apache.maven.artifact.ArtifactUtils;
@@ -59,6 +60,7 @@
 import org.apache.maven.execution.ProjectDependencyGraph;
 import org.apache.maven.graph.GraphBuilder;
 import org.apache.maven.graph.ProjectSelector;
+import org.apache.maven.internal.build.DefaultDiagnosticCollector;
 import org.apache.maven.internal.impl.DefaultSessionFactory;
 import org.apache.maven.internal.impl.InternalMavenSession;
 import org.apache.maven.lifecycle.LifecycleExecutionException;
@@ -113,6 +115,8 @@ public class DefaultMaven implements Maven {
 
     private final ProjectSelector projectSelector;
 
+    private final DefaultDiagnosticCollector diagnosticCollector;
+
     @Inject
     @SuppressWarnings("checkstyle:ParameterNumber")
     public DefaultMaven(
@@ -126,7 +130,8 @@ public DefaultMaven(
             BuildResumptionDataRepository buildResumptionDataRepository,
             SuperPomProvider superPomProvider,
             DefaultSessionFactory defaultSessionFactory,
-            @Nullable @Named("ide") WorkspaceReader ideWorkspaceReader) {
+            @Nullable @Named("ide") WorkspaceReader ideWorkspaceReader,
+            DefaultDiagnosticCollector diagnosticCollector) {
         this.lookup = lookup;
         this.eventCatapult = eventCatapult;
         this.legacySupport = legacySupport;
@@ -138,6 +143,7 @@ public DefaultMaven(
         this.superPomProvider = superPomProvider;
         this.ideWorkspaceReader = ideWorkspaceReader;
         this.defaultSessionFactory = defaultSessionFactory;
+        this.diagnosticCollector = diagnosticCollector;
         this.projectSelector = new ProjectSelector(); // if necessary switch to DI
     }
 
@@ -650,6 +656,10 @@ private Result<? extends ProjectDependencyGraph> buildGraph(MavenSession session
             } else {
                 logger.error(problem.getMessage());
             }
+            // Pipe structured problem directly to DiagnosticCollector so that
+            // source location and severity are preserved in the build report.
+            // The SLF4J hook excludes this logger to avoid double-counting.
+            diagnosticCollector.report(toBuilderProblem(problem));
         }
 
         if (!graphResult.hasErrors()) {
@@ -662,6 +672,28 @@ private Result<? extends ProjectDependencyGraph> buildGraph(MavenSession session
         return graphResult;
     }
 
+    /**
+     * Converts a compat {@link ModelProblem} to the Maven 4 {@link BuilderProblem} API,
+     * preserving source, line, column, severity, and message.
+     */
+    private static BuilderProblem toBuilderProblem(ModelProblem problem) {
+        BuilderProblem.Severity severity =
+                switch (problem.getSeverity()) {
+                    case FATAL -> BuilderProblem.Severity.FATAL;
+                    case ERROR -> BuilderProblem.Severity.ERROR;
+                    default -> BuilderProblem.Severity.WARNING;
+                };
+        return BuilderProblem.builder()
+                .source(problem.getSource())
+                .lineNumber(problem.getLineNumber())
+                .columnNumber(problem.getColumnNumber())
+                .exception(problem.getException())
+                .message(problem.getMessage())
+                .severity(severity)
+                .key("model:" + problem.getMessage().hashCode())
+                .build();
+    }
+
     @Deprecated
     // 5 January 2014
     protected Logger getLogger() {

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

@@ -91,6 +91,19 @@ public final class BuildReportCollector extends AbstractEventSpy {
 
     private static final int MAX_STACKTRACE_LINES = 30;
 
+    /**
+     * Logger names excluded from SLF4J auto-collection because these classes
+     * already pipe structured {@link org.apache.maven.api.services.BuilderProblem}
+     * objects directly to the {@link DefaultDiagnosticCollector}. Without this
+     * exclusion, each problem would be counted twice: once from the direct pipe
+     * and once from the SLF4J WARN interception.
+     */
+    private static final Set<String> EXCLUDED_LOGGERS = Set.of(
+            BuildReportCollector.class.getName(),
+            "org.apache.maven.DefaultMaven",
+            "org.apache.maven.project.collector.DefaultProjectsSelector",
+            "org.apache.maven.plugin.internal.DefaultPluginValidationManager");
+
     private final DefaultDiagnosticCollector diagnosticCollector;
 
     @Inject
@@ -353,10 +366,12 @@ private void captureLogEvent(LogEvent event) {
 
         // Auto-collect WARN-level log events as build problems, giving Maven 3 plugins
         // automatic deduplication and summary at end of build without code changes.
-        // Skip our own logger to avoid feedback loops from problem summary printing.
+        // Skip loggers that already pipe structured BuilderProblems directly to the
+        // DiagnosticCollector (avoiding double-counting), and our own logger to avoid
+        // feedback loops from problem summary printing.
         if (event.level() == LogLevel.WARN
                 && event.message() != null
-                && !event.loggerName().equals(BuildReportCollector.class.getName())) {
+                && !EXCLUDED_LOGGERS.contains(event.loggerName())) {
             String syntheticKey = syntheticDiagnosticKey(event.loggerName(), event.message());
             diagnosticCollector.report(BuilderProblem.builder()
                     .source(event.loggerName())

impl/maven-core/src/main/java/org/apache/maven/plugin/PluginValidationManager.java

@@ -18,6 +18,7 @@
  */
 package org.apache.maven.plugin;
 
+import org.apache.maven.api.services.BuilderProblem;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.plugin.descriptor.MojoDescriptor;
 import org.eclipse.aether.RepositorySystemSession;
@@ -54,27 +55,94 @@ enum IssueLocality {
      * This method should be used in "early" phase of plugin execution, possibly even when plugin or mojo descriptor
      * does not exist yet. In turn, this method will not record extra information like plugin occurrence or declaration
      * location as those are not yet available.
+     *
+     * @since 4.1.0
      */
     void reportPluginValidationIssue(
-            IssueLocality locality, RepositorySystemSession session, Artifact pluginArtifact, String issue);
+            IssueLocality locality, RepositorySystemSession session, Artifact pluginArtifact, BuilderProblem problem);
 
     /**
      * Reports plugin issues applicable to the plugin as a whole.
      * <p>
      * This method will record extra information as well, like plugin occurrence or declaration location.
+     *
+     * @since 4.1.0
      */
     void reportPluginValidationIssue(
-            IssueLocality locality, MavenSession mavenSession, MojoDescriptor mojoDescriptor, String issue);
+            IssueLocality locality, MavenSession mavenSession, MojoDescriptor mojoDescriptor, BuilderProblem problem);
 
     /**
      * Reports plugin Mojo issues applicable to the Mojo itself.
      * <p>
      * This method will record extra information as well, like plugin occurrence or declaration location.
+     *
+     * @since 4.1.0
      */
     void reportPluginMojoValidationIssue(
             IssueLocality locality,
             MavenSession mavenSession,
             MojoDescriptor mojoDescriptor,
             Class<?> mojoClass,
-            String issue);
+            BuilderProblem problem);
+
+    // ---- Deprecated String-based adapters for external callers ----
+
+    /**
+     * @deprecated Use {@link #reportPluginValidationIssue(IssueLocality, RepositorySystemSession, Artifact,
+     *     BuilderProblem)} instead.
+     */
+    @Deprecated(since = "4.1.0", forRemoval = true)
+    default void reportPluginValidationIssue(
+            IssueLocality locality, RepositorySystemSession session, Artifact pluginArtifact, String issue) {
+        reportPluginValidationIssue(
+                locality,
+                session,
+                pluginArtifact,
+                BuilderProblem.builder()
+                        .message(issue)
+                        .severity(BuilderProblem.Severity.WARNING)
+                        .key("plugin-validation:" + issue.hashCode())
+                        .build());
+    }
+
+    /**
+     * @deprecated Use {@link #reportPluginValidationIssue(IssueLocality, MavenSession, MojoDescriptor,
+     *     BuilderProblem)} instead.
+     */
+    @Deprecated(since = "4.1.0", forRemoval = true)
+    default void reportPluginValidationIssue(
+            IssueLocality locality, MavenSession mavenSession, MojoDescriptor mojoDescriptor, String issue) {
+        reportPluginValidationIssue(
+                locality,
+                mavenSession,
+                mojoDescriptor,
+                BuilderProblem.builder()
+                        .message(issue)
+                        .severity(BuilderProblem.Severity.WARNING)
+                        .key("plugin-validation:" + issue.hashCode())
+                        .build());
+    }
+
+    /**
+     * @deprecated Use {@link #reportPluginMojoValidationIssue(IssueLocality, MavenSession, MojoDescriptor, Class,
+     *     BuilderProblem)} instead.
+     */
+    @Deprecated(since = "4.1.0", forRemoval = true)
+    default void reportPluginMojoValidationIssue(
+            IssueLocality locality,
+            MavenSession mavenSession,
+            MojoDescriptor mojoDescriptor,
+            Class<?> mojoClass,
+            String issue) {
+        reportPluginMojoValidationIssue(
+                locality,
+                mavenSession,
+                mojoDescriptor,
+                mojoClass,
+                BuilderProblem.builder()
+                        .message(issue)
+                        .severity(BuilderProblem.Severity.WARNING)
+                        .key("plugin-validation:" + issue.hashCode())
+                        .build());
+    }
 }

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

@@ -18,6 +18,7 @@
  */
 package org.apache.maven.plugin.internal;
 
+import org.apache.maven.api.services.BuilderProblem;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.plugin.PluginValidationManager;
 import org.apache.maven.plugin.descriptor.MojoDescriptor;
@@ -97,6 +98,11 @@ protected boolean isIgnoredProperty(String strValue) {
 
     protected abstract String getParameterLogReason(Parameter parameter);
 
+    /**
+     * Returns the validation key prefix for this validator (e.g. "deprecated-param", "readonly-param").
+     */
+    protected abstract String getValidationKeyPrefix();
+
     protected String formatParameter(Parameter parameter) {
         StringBuilder stringBuilder = new StringBuilder()
                 .append("Parameter '")
@@ -112,4 +118,12 @@ protected String formatParameter(Parameter parameter) {
 
         return stringBuilder.toString();
     }
+
+    protected BuilderProblem buildParameterProblem(Parameter parameter) {
+        return BuilderProblem.builder()
+                .message(formatParameter(parameter))
+                .severity(BuilderProblem.Severity.WARNING)
+                .key("plugin-validation:" + getValidationKeyPrefix() + ":" + parameter.getName())
+                .build();
+    }
 }

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

@@ -51,6 +51,7 @@
 import org.apache.maven.api.Service;
 import org.apache.maven.api.Session;
 import org.apache.maven.api.plugin.descriptor.Resolution;
+import org.apache.maven.api.services.BuilderProblem;
 import org.apache.maven.api.services.DependencyResolver;
 import org.apache.maven.api.services.DependencyResolverResult;
 import org.apache.maven.api.services.PathScopeRegistry;
@@ -752,7 +753,13 @@ private <T> T loadV3Mojo(
                     session,
                     mojoDescriptor,
                     mojo.getClass(),
-                    "Mojo implements `Contextualizable` interface from Plexus Container, which is EOL.");
+                    BuilderProblem.builder()
+                            .message(
+                                    "Mojo implements `Contextualizable` interface from Plexus Container, which is EOL.")
+                            .severity(BuilderProblem.Severity.WARNING)
+                            .key("plugin-validation:contextualizable")
+                            .suggestion("Migrate from Contextualizable to javax.inject dependency injection")
+                            .build());
         }
 
         XmlNode dom = mojoExecution.getConfiguration() != null