[MNG-6261] Relative parent POM resolution failing in 3.5.0 with complex multimodule builds

Using java File api to compare

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

@@ -852,10 +852,11 @@ public class DefaultModelBuilder
                 File pomFile = parentData.getModel().getPomFile();
                 if ( pomFile != null )
                 {
+                    FileModelSource pomSource = new FileModelSource( pomFile );
                     ModelSource expectedParentSource = getParentPomFile( childModel, childSource );
 
                     if ( expectedParentSource == null || ( expectedParentSource instanceof ModelSource2
-                        && !pomFile.toURI().equals( ( (ModelSource2) expectedParentSource ).getLocationURI() ) ) )
+                        && !pomSource.equals(  expectedParentSource ) ) )
                     {
                         parentData = readParentExternally( childModel, request, problems );
                     }

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

@@ -80,4 +80,27 @@ public class FileModelSource extends FileSource implements ModelSource2
     {
         return getFile().toURI();
     }
+
+    @Override
+    public boolean equals( Object obj ) 
+    {
+        if ( this == obj ) 
+        {
+            return true;
+        }
+        
+        if ( !( obj instanceof FileModelSource ) ) 
+        {
+            return false;
+        }
+        FileModelSource other = ( FileModelSource ) obj;
+        return getFile().equals( other.getFile() );
+    }
+
+    @Override
+    public int hashCode() 
+    {
+        return getFile().hashCode(); 
+    }
+
 }

maven-model-builder/src/test/java/org/apache/maven/model/building/FileModelSourceTest.java

@@ -0,0 +1,75 @@
+package org.apache.maven.model.building;
+
+/*
+ * 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.
+ */
+import java.io.File;
+import java.io.IOException;
+import static junit.framework.TestCase.assertFalse;
+import static junit.framework.TestCase.assertTrue;
+import org.apache.commons.lang3.SystemUtils;
+import static org.junit.Assume.assumeTrue;
+import org.junit.Test;
+
+/**
+ * Test that validate the solution of MNG-6261 issue
+ *
+ */
+public class FileModelSourceTest
+{
+
+    /**
+     * Test of equals method, of class FileModelSource.
+     */
+    @Test
+    public void testEquals()
+            throws Exception 
+    {
+        File tempFile = createTempFile( "pomTest" );
+        FileModelSource instance = new FileModelSource( tempFile );
+
+        assertFalse( instance.equals( null ) );
+        assertFalse( instance.equals( new Object() ) );
+        assertTrue( instance.equals( instance ) );
+        assertTrue( instance.equals( new FileModelSource( tempFile ) ) );
+    }
+
+    @Test
+    public void testWindowsPaths() 
+            throws Exception 
+    {
+        assumeTrue( SystemUtils.IS_OS_WINDOWS );
+
+        File upperCaseFile = createTempFile( "TESTE" );
+        String absolutePath = upperCaseFile.getAbsolutePath();
+        File lowerCaseFile = new File( absolutePath.toLowerCase() );
+        
+        FileModelSource upperCaseFileSouce = new FileModelSource( upperCaseFile );
+        FileModelSource lowerCaseFileSouce = new FileModelSource( lowerCaseFile );
+
+        assertTrue( upperCaseFileSouce.equals( lowerCaseFileSouce ) );        
+    }
+
+    private File createTempFile( String name ) throws IOException
+    {
+        File tempFile = File.createTempFile( name, ".xml" );
+        tempFile.deleteOnExit();
+        return tempFile;
+    }
+
+}

pom.xml

@@ -147,6 +147,9 @@ under the License.
     <contributor>
       <name>Joseph Walton (MNG-5297)</name>
     </contributor>
+    <contributor>
+      <name>Fabiano Cipriano de Oliveira (MNG-6261)</name>
+    </contributor>
   </contributors>
 
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