Fix false parent cycle detection with flatten-maven-plugin (fixes #11399) (#11400) (#11403)

When using flatten-maven-plugin with updatePomFile=true and parent expansion,
Maven incorrectly detected a parent cycle during the install phase. The error
occurred because the consumer POM builder was using Path instead of ModelSource
when reading the flattened POM.

This change updates the PomArtifactTransformer API to use ModelSource instead
of Path. ModelSource includes the necessary context (base directory, ModelLocator)
to properly resolve parent POMs and avoid false cycle detection.

Changes:
- Updated PomArtifactTransformer.transform() to accept ModelSource instead of Path
- Modified ConsumerPomArtifactTransformer to create ModelSource with proper resolution context
- Updated DefaultConsumerPomBuilder and related classes to work with ModelSource
- Added integration test to verify the fix

Fixes #11399

(cherry picked from commit 5ec059c)

Author: gnodet

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

@@ -24,6 +24,7 @@
 import java.nio.file.Path;
 
 import org.apache.maven.api.services.ModelBuilderException;
+import org.apache.maven.api.services.ModelSource;
 import org.apache.maven.project.MavenProject;
 import org.eclipse.aether.RepositorySystemSession;
 import org.eclipse.aether.deployment.DeployRequest;
@@ -41,6 +42,6 @@ public interface PomArtifactTransformer {
 
     void injectTransformedArtifacts(RepositorySystemSession session, MavenProject currentProject) throws IOException;
 
-    void transform(MavenProject project, RepositorySystemSession session, Path src, Path tgt)
+    void transform(MavenProject project, RepositorySystemSession session, ModelSource src, Path tgt)
             throws ModelBuilderException, XMLStreamException, IOException;
 }

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

@@ -23,7 +23,9 @@
 import javax.inject.Singleton;
 import javax.xml.stream.XMLStreamException;
 
+import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -36,6 +38,9 @@
 import org.apache.maven.api.feature.Features;
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.services.ModelBuilderException;
+import org.apache.maven.api.services.ModelSource;
+import org.apache.maven.api.services.Source;
+import org.apache.maven.api.services.Sources;
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.project.artifact.ProjectArtifact;
 import org.eclipse.aether.RepositorySystemSession;
@@ -93,19 +98,53 @@ public void injectTransformedArtifacts(RepositorySystemSession session, MavenPro
 
     TransformedArtifact createConsumerPomArtifact(
             MavenProject project, Path consumer, RepositorySystemSession session) {
+        Path actual = project.getFile().toPath();
+        Path parent = project.getBaseDirectory();
+        ModelSource source = new ModelSource() {
+            @Override
+            public Path getPath() {
+                return actual;
+            }
+
+            @Override
+            public InputStream openStream() throws IOException {
+                return Files.newInputStream(actual);
+            }
+
+            @Override
+            public String getLocation() {
+                return actual.toString();
+            }
+
+            @Override
+            public Source resolve(String relative) {
+                return Sources.buildSource(actual.resolve(relative));
+            }
+
+            @Override
+            public ModelSource resolve(ModelLocator modelLocator, String relative) {
+                String norm = relative.replace('\\', File.separatorChar).replace('/', File.separatorChar);
+                Path path = parent.resolve(norm);
+                Path relatedPom = modelLocator.locateExistingPom(path);
+                if (relatedPom != null) {
+                    return Sources.buildSource(relatedPom);
+                }
+                return null;
+            }
+        };
         return new TransformedArtifact(
                 this,
                 project,
                 consumer,
                 session,
                 new ProjectArtifact(project),
-                () -> project.getFile().toPath(),
+                () -> source,
                 CONSUMER_POM_CLASSIFIER,
                 "pom");
     }
 
     @Override
-    public void transform(MavenProject project, RepositorySystemSession session, Path src, Path tgt)
+    public void transform(MavenProject project, RepositorySystemSession session, ModelSource src, Path tgt)
             throws ModelBuilderException, XMLStreamException, IOException {
         Model model = builder.build(session, project, src);
         write(model, tgt);

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

@@ -21,7 +21,6 @@
 import javax.inject.Inject;
 import javax.inject.Named;
 
-import java.nio.file.Path;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -45,7 +44,7 @@
 import org.apache.maven.api.services.ModelBuilderException;
 import org.apache.maven.api.services.ModelBuilderRequest;
 import org.apache.maven.api.services.ModelBuilderResult;
-import org.apache.maven.api.services.Sources;
+import org.apache.maven.api.services.ModelSource;
 import org.apache.maven.api.services.model.LifecycleBindingsInjector;
 import org.apache.maven.impl.InternalSession;
 import org.apache.maven.model.v4.MavenModelVersion;
@@ -71,7 +70,8 @@ class DefaultConsumerPomBuilder implements PomBuilder {
     }
 
     @Override
-    public Model build(RepositorySystemSession session, MavenProject project, Path src) throws ModelBuilderException {
+    public Model build(RepositorySystemSession session, MavenProject project, ModelSource src)
+            throws ModelBuilderException {
         Model model = project.getModel().getDelegate();
         boolean flattenEnabled = Features.consumerPomFlatten(session.getConfigProperties());
 
@@ -95,27 +95,27 @@ public Model build(RepositorySystemSession session, MavenProject project, Path s
         }
     }
 
-    protected Model buildPom(RepositorySystemSession session, MavenProject project, Path src)
+    protected Model buildPom(RepositorySystemSession session, MavenProject project, ModelSource src)
             throws ModelBuilderException {
         ModelBuilderResult result = buildModel(session, src);
         Model model = result.getRawModel();
         return transformPom(model, project);
     }
 
-    protected Model buildBom(RepositorySystemSession session, MavenProject project, Path src)
+    protected Model buildBom(RepositorySystemSession session, MavenProject project, ModelSource src)
             throws ModelBuilderException {
         ModelBuilderResult result = buildModel(session, src);
         Model model = result.getEffectiveModel();
         return transformBom(model, project);
     }
 
-    protected Model buildNonPom(RepositorySystemSession session, MavenProject project, Path src)
+    protected Model buildNonPom(RepositorySystemSession session, MavenProject project, ModelSource src)
             throws ModelBuilderException {
         Model model = buildEffectiveModel(session, src);
         return transformNonPom(model, project);
     }
 
-    private Model buildEffectiveModel(RepositorySystemSession session, Path src) throws ModelBuilderException {
+    private Model buildEffectiveModel(RepositorySystemSession session, ModelSource src) throws ModelBuilderException {
         InternalSession iSession = InternalSession.from(session);
         ModelBuilderResult result = buildModel(session, src);
         Model model = result.getEffectiveModel();
@@ -222,12 +222,13 @@ private static String getDependencyKey(Dependency dependency) {
                 + (dependency.getClassifier() != null ? dependency.getClassifier() : "");
     }
 
-    private ModelBuilderResult buildModel(RepositorySystemSession session, Path src) throws ModelBuilderException {
+    private ModelBuilderResult buildModel(RepositorySystemSession session, ModelSource src)
+            throws ModelBuilderException {
         InternalSession iSession = InternalSession.from(session);
         ModelBuilderRequest.ModelBuilderRequestBuilder request = ModelBuilderRequest.builder();
         request.requestType(ModelBuilderRequest.RequestType.BUILD_CONSUMER);
         request.session(iSession);
-        request.source(Sources.buildSource(src));
+        request.source(src);
         request.locationTracking(false);
         request.systemProperties(session.getSystemProperties());
         request.userProperties(session.getUserProperties());

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

@@ -21,10 +21,10 @@
 import javax.xml.stream.XMLStreamException;
 
 import java.io.IOException;
-import java.nio.file.Path;
 
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.services.ModelBuilderException;
+import org.apache.maven.api.services.ModelSource;
 import org.apache.maven.project.MavenProject;
 import org.eclipse.aether.RepositorySystemSession;
 
@@ -33,6 +33,6 @@
  * of {@link ConsumerPomArtifactTransformer}.
  */
 interface PomBuilder {
-    Model build(RepositorySystemSession session, MavenProject project, Path src)
+    Model build(RepositorySystemSession session, MavenProject project, ModelSource src)
             throws ModelBuilderException, IOException, XMLStreamException;
 }

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

@@ -30,6 +30,7 @@
 import java.util.function.Supplier;
 
 import org.apache.maven.api.services.ModelBuilderException;
+import org.apache.maven.api.services.ModelSource;
 import org.apache.maven.artifact.DefaultArtifact;
 import org.apache.maven.internal.transformation.PomArtifactTransformer;
 import org.apache.maven.internal.transformation.TransformationFailedException;
@@ -48,7 +49,7 @@ class TransformedArtifact extends DefaultArtifact {
     private static final int SHA1_BUFFER_SIZE = 8192;
     private final PomArtifactTransformer pomArtifactTransformer;
     private final MavenProject project;
-    private final Supplier<Path> sourcePathProvider;
+    private final Supplier<ModelSource> sourcePathProvider;
     private final Path target;
     private final RepositorySystemSession session;
     private final AtomicReference<String> sourceState;
@@ -60,7 +61,7 @@ class TransformedArtifact extends DefaultArtifact {
             Path target,
             RepositorySystemSession session,
             org.apache.maven.artifact.Artifact source,
-            Supplier<Path> sourcePathProvider,
+            Supplier<ModelSource> sourcePathProvider,
             String classifier,
             String extension) {
         super(
@@ -105,20 +106,21 @@ public synchronized File getFile() {
 
     private String mayUpdate() throws IOException, XMLStreamException, ModelBuilderException {
         String result;
-        Path src = sourcePathProvider.get();
+        ModelSource src = sourcePathProvider.get();
         if (src == null) {
             Files.deleteIfExists(target);
             result = null;
-        } else if (!Files.exists(src)) {
+        } else if (!Files.exists(src.getPath())) {
             Files.deleteIfExists(target);
             result = "";
         } else {
-            String current = ChecksumAlgorithmHelper.calculate(src, List.of(new Sha1ChecksumAlgorithmFactory()))
+            String current = ChecksumAlgorithmHelper.calculate(
+                            src.getPath(), List.of(new Sha1ChecksumAlgorithmFactory()))
                     .get(Sha1ChecksumAlgorithmFactory.NAME);
             String existing = sourceState.get();
             if (!Files.exists(target) || !Objects.equals(current, existing)) {
                 pomArtifactTransformer.transform(project, session, src, target);
-                Files.setLastModifiedTime(target, Files.getLastModifiedTime(src));
+                Files.setLastModifiedTime(target, Files.getLastModifiedTime(src.getPath()));
             }
             result = current;
         }

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

@@ -28,6 +28,7 @@
 
 import org.apache.maven.api.model.Model;
 import org.apache.maven.api.services.ModelBuilderException;
+import org.apache.maven.api.services.ModelSource;
 import org.apache.maven.internal.transformation.PomArtifactTransformer;
 import org.apache.maven.model.v4.MavenStaxReader;
 import org.apache.maven.model.v4.MavenStaxWriter;
@@ -58,7 +59,7 @@ public DeployRequest remapDeployArtifacts(RepositorySystemSession session, Deplo
     public void injectTransformedArtifacts(RepositorySystemSession session, MavenProject project) throws IOException {}
 
     @Override
-    public void transform(MavenProject project, RepositorySystemSession session, Path src, Path tgt)
+    public void transform(MavenProject project, RepositorySystemSession session, ModelSource src, Path tgt)
             throws ModelBuilderException, XMLStreamException, IOException {
         throw new IllegalStateException("This transformer does not use this call.");
     }

impl/maven-core/src/test/java/org/apache/maven/internal/transformation/impl/ConsumerPomArtifactTransformerTest.java

@@ -28,6 +28,7 @@
 import java.util.Map;
 
 import org.apache.maven.api.Constants;
+import org.apache.maven.api.services.Sources;
 import org.apache.maven.model.Model;
 import org.apache.maven.model.v4.MavenStaxReader;
 import org.apache.maven.project.MavenProject;
@@ -66,12 +67,12 @@ void transform() throws Exception {
             MavenProject project = new MavenProject(model);
             project.setOriginalModel(model);
             ConsumerPomArtifactTransformer t = new ConsumerPomArtifactTransformer((s, p, f) -> {
-                try (InputStream is = Files.newInputStream(f)) {
+                try (InputStream is = f.openStream()) {
                     return DefaultConsumerPomBuilder.transformPom(new MavenStaxReader().read(is), project);
                 }
             });
 
-            t.transform(project, systemSessionMock, beforePomFile, tempFile);
+            t.transform(project, systemSessionMock, Sources.buildSource(beforePomFile), tempFile);
         }
         Diff diff = DiffBuilder.compare(afterPomFile.toFile())
                 .withTest(tempFile.toFile())
@@ -98,12 +99,12 @@ void transformJarConsumerPom() throws Exception {
             MavenProject project = new MavenProject(model);
             project.setOriginalModel(model);
             ConsumerPomArtifactTransformer t = new ConsumerPomArtifactTransformer((s, p, f) -> {
-                try (InputStream is = Files.newInputStream(f)) {
+                try (InputStream is = f.openStream()) {
                     return DefaultConsumerPomBuilder.transformNonPom(new MavenStaxReader().read(is), project);
                 }
             });
 
-            t.transform(project, systemSessionMock, beforePomFile, tempFile);
+            t.transform(project, systemSessionMock, Sources.buildSource(beforePomFile), tempFile);
         }
         Diff diff = DiffBuilder.compare(afterPomFile.toFile())
                 .withTest(tempFile.toFile())

impl/maven-core/src/test/java/org/apache/maven/internal/transformation/impl/ConsumerPomBuilderTest.java

@@ -108,7 +108,7 @@ void testTrivialConsumer() throws Exception {
 
         MavenProject project = new MavenProject(orgModel);
         project.setOriginalModel(new org.apache.maven.model.Model(orgModel));
-        Model model = builder.build(session, project, file);
+        Model model = builder.build(session, project, Sources.buildSource(file));
 
         assertNotNull(model);
     }
@@ -135,7 +135,7 @@ void testSimpleConsumer() throws Exception {
         MavenProject project = new MavenProject(orgModel);
         project.setOriginalModel(new org.apache.maven.model.Model(orgModel));
         request.setRootDirectory(Paths.get("src/test/resources/consumer/simple"));
-        Model model = builder.build(session, project, file);
+        Model model = builder.build(session, project, Sources.buildSource(file));
 
         assertNotNull(model);
         assertTrue(model.getProfiles().isEmpty());

its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh11399FlattenPluginParentCycleTest.java

@@ -0,0 +1,61 @@
+/*
+ * 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.it;
+
+import java.io.File;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * This is a test set for <a href="https://github.com/apache/maven/issues/11399">GH-11399</a>.
+ *
+ * Verifies that using flatten-maven-plugin with updatePomFile=true does not cause a false
+ * parent cycle detection error during install phase. The issue occurred when the plugin
+ * updated the POM file reference, causing the consumer POM builder to incorrectly detect
+ * a cycle between the project and its parent.
+ *
+ * @see <a href="https://github.com/mojohaus/flatten-maven-plugin">flatten-maven-plugin</a>
+ */
+class MavenITgh11399FlattenPluginParentCycleTest extends AbstractMavenIntegrationTestCase {
+
+    /**
+     * Verify that flatten-maven-plugin with updatePomFile=true and parent expansion
+     * does not cause a false parent cycle detection error during install.
+     *
+     * The error was:
+     * "The parents form a cycle: org.apache:apache:35 -> /path/to/pom.xml -> org.apache:apache:35"
+     *
+     * @throws Exception in case of failure
+     */
+    @Test
+    void testFlattenPluginWithParentExpansionDoesNotCauseCycle() throws Exception {
+        File testDir = extractResources("/gh-11399-flatten-plugin-parent-cycle");
+
+        Verifier verifier = newVerifier(testDir.getAbsolutePath());
+        verifier.setAutoclean(false);
+        verifier.deleteArtifacts("org.apache.maven.its.mng8750");
+        verifier.addCliArgument("install");
+        verifier.execute();
+        verifier.verifyErrorFreeLog();
+
+        // Verify that the flattened POM was created
+        verifier.verifyFilePresent("target/.flattened-pom.xml");
+    }
+}
+