[MNG-8746] Preserve property insertion order in WrapperProperties (#2404)

* Fix MNG-8746: Preserve property insertion order in WrapperProperties

This commit implements order preservation for properties in the Maven compat
layer's WrapperProperties class, ensuring that properties maintain their
insertion order when accessed through the Properties API.

Key changes:

1. Enhanced WrapperProperties template (src/mdo/java/WrapperProperties.java):
   - Added internal OrderedProperties class that maintains insertion order
   - Implemented caching mechanism to preserve order across read/write operations
   - Modified all read operations to use the ordered cache
   - Simplified write operations to work directly with the ordered properties

2. OrderedProperties implementation:
   - Uses ArrayList to track key insertion order
   - Overrides put/setProperty/remove to maintain order
   - Custom KeySet and EntrySet implementations that iterate in insertion order
   - Removed unnecessary synchronized wrappers that interfered with ordering

3. Updated model-v3.vm template:
   - Ensured LinkedHashMap is used when converting properties to v4 API
   - This preserves order when properties are synced between compat and v4 layers

4. Added comprehensive tests:
   - PropertiesOrderTest: Tests v4 API model order preservation
   - WrapperPropertiesOrderTest: Tests compat layer order preservation
   - Covers various scenarios including modification and initial properties

The implementation ensures that properties accessed through model.getProperties()
maintain their insertion order, which is important for consistent behavior
and reproducible builds.

Fixes: MNG-8746

* Update src/mdo/java/WrapperProperties.java

Co-authored-by: Pankraz76 <[email protected]>

* Update src/mdo/java/WrapperProperties.java

Co-authored-by: Pankraz76 <[email protected]>

---------

Co-authored-by: Pankraz76 <[email protected]>

Author: gnodet

impl/maven-core/src/test/java/org/apache/maven/model/PropertiesOrderTest.java

@@ -0,0 +1,97 @@
+/*
+ * 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.model;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+/**
+ * Test for MNG-8746: Properties order is preserved in model
+ */
+public class PropertiesOrderTest {
+
+    @Test
+    public void testPropertiesOrderPreservedInImmutableModel() {
+        // Create properties with specific insertion order using LinkedHashMap
+        Map<String, String> orderedMap = new LinkedHashMap<>();
+        orderedMap.put("third", "3");
+        orderedMap.put("first", "1");
+        orderedMap.put("second", "2");
+
+        // Create model and set properties
+        Model model = new Model();
+        Properties props = model.getProperties();
+
+        // Create properties and populate from map to maintain order
+        orderedMap.forEach(props::setProperty);
+
+        // Get the immutable delegate (v4 API model is already immutable)
+        org.apache.maven.api.model.Model immutable = model.getDelegate();
+
+        // Verify order is preserved
+        Map<String, String> resultProps = immutable.getProperties();
+        assertNotNull(resultProps);
+
+        // Check order by collecting keys in iteration order
+        List<String> keys = new ArrayList<>(resultProps.keySet());
+
+        // Verify the original insertion order is maintained
+        assertEquals(3, keys.size());
+        assertEquals("third", keys.get(0));
+        assertEquals("first", keys.get(1));
+        assertEquals("second", keys.get(2));
+    }
+
+    @Test
+    public void testPropertiesOrderPreservedInMutableModel() {
+        // Create ordered map to simulate properties with specific order
+        Map<String, String> orderedMap = new LinkedHashMap<>();
+        orderedMap.put("z-property", "z");
+        orderedMap.put("a-property", "a");
+        orderedMap.put("m-property", "m");
+
+        // Create and populate model
+        Model model = new Model();
+        Properties props = model.getProperties();
+
+        // Create properties and populate from map to maintain order
+        orderedMap.forEach(props::setProperty);
+
+        // Get properties back and verify order
+        Properties resultProps = model.getProperties();
+
+        // Check order by collecting keys in iteration order
+        List<String> keys = new ArrayList<>();
+        resultProps.keySet().forEach(k -> keys.add(k.toString()));
+
+        // Verify the original insertion order is maintained
+        assertEquals(3, keys.size());
+        assertEquals("z-property", keys.get(0));
+        assertEquals("a-property", keys.get(1));
+        assertEquals("m-property", keys.get(2));
+    }
+}

impl/maven-core/src/test/java/org/apache/maven/model/WrapperPropertiesOrderTest.java

@@ -0,0 +1,63 @@
+/*
+ * 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.model;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Test for order preservation in WrapperProperties used by Model
+ */
+public class WrapperPropertiesOrderTest {
+
+    @Test
+    public void testOrderPreservationAfterModification() {
+        // Create a model with properties
+        Model model = new Model();
+        Properties modelProps = model.getProperties();
+
+        // Add properties in specific order
+        modelProps.setProperty("first", "1");
+        modelProps.setProperty("second", "2");
+
+        // Modify existing property
+        modelProps.setProperty("first", "modified");
+
+        // Add new property
+        modelProps.setProperty("third", "3");
+
+        // Collect keys in iteration order
+        List<String> keys = new ArrayList<>();
+        modelProps.keySet().forEach(k -> keys.add(k.toString()));
+
+        // Verify order is preserved (first should still be first since it was modified, not re-added)
+        assertEquals(3, keys.size());
+        assertEquals("first", keys.get(0));
+        assertEquals("second", keys.get(1));
+        assertEquals("third", keys.get(2));
+
+        // Verify value was updated
+        assertEquals("modified", modelProps.getProperty("first"));
+    }
+}