[MNG-5913] Allow defining aliases for existing server configurations in settings.xml

maven-settings-builder/pom.xml

@@ -63,6 +63,13 @@ under the License.
       <groupId>org.codehaus.plexus</groupId>
       <artifactId>plexus-sec-dispatcher</artifactId>
     </dependency>
+
+    <dependency>
+      <groupId>org.assertj</groupId>
+      <artifactId>assertj-core</artifactId>
+      <version>3.27.3</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>

maven-settings-builder/src/main/java/org/apache/maven/settings/building/DefaultSettingsBuilder.java

@@ -29,9 +29,12 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.apache.maven.building.FileSource;
 import org.apache.maven.building.Source;
+import org.apache.maven.settings.Server;
 import org.apache.maven.settings.Settings;
 import org.apache.maven.settings.TrackableBase;
 import org.apache.maven.settings.io.SettingsParseException;
@@ -91,10 +94,10 @@ public SettingsBuildingResult build(SettingsBuildingRequest request) throws Sett
 
         Source globalSettingsSource =
                 getSettingsSource(request.getGlobalSettingsFile(), request.getGlobalSettingsSource());
-        Settings globalSettings = readSettings(globalSettingsSource, request, problems);
+        Settings globalSettings = readSettings(globalSettingsSource, problems);
 
         Source userSettingsSource = getSettingsSource(request.getUserSettingsFile(), request.getUserSettingsSource());
-        Settings userSettings = readSettings(userSettingsSource, request, problems);
+        Settings userSettings = readSettings(userSettingsSource, problems);
 
         settingsMerger.merge(userSettings, globalSettings, TrackableBase.GLOBAL_LEVEL);
 
@@ -139,8 +142,7 @@ private Source getSettingsSource(File settingsFile, Source settingsSource) {
         return null;
     }
 
-    private Settings readSettings(
-            Source settingsSource, SettingsBuildingRequest request, DefaultSettingsProblemCollector problems) {
+    private Settings readSettings(Source settingsSource, DefaultSettingsProblemCollector problems) {
         if (settingsSource == null) {
             return new Settings();
         }
@@ -180,11 +182,26 @@ private Settings readSettings(
             return new Settings();
         }
 
+        settings.setServers(serversByIds(settings.getServers()));
         settingsValidator.validate(settings, problems);
 
         return settings;
     }
 
+    private List<Server> serversByIds(List<Server> servers) {
+        return servers.stream()
+                .flatMap(server -> Stream.concat(
+                        Stream.of(server), server.getIds().stream().map(id -> serverAlias(server, id))))
+                .collect(Collectors.toList());
+    }
+
+    private Server serverAlias(Server server, String id) {
+        Server serverClone = server.clone();
+        serverClone.setId(id);
+        serverClone.setIds(Collections.emptyList());
+        return serverClone;
+    }
+
     private Settings interpolate(
             Settings settings, SettingsBuildingRequest request, SettingsProblemCollector problems) {
         StringWriter writer = new StringWriter(1024 * 4);

maven-settings-builder/src/test/java/org/apache/maven/settings/building/DefaultSettingsBuilderFactoryTest.java

@@ -19,28 +19,105 @@
 package org.apache.maven.settings.building;
 
 import java.io.File;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
 
-import junit.framework.TestCase;
+import org.apache.maven.settings.Server;
+import org.apache.maven.settings.Settings;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author Benjamin Bentmann
  */
-public class DefaultSettingsBuilderFactoryTest extends TestCase {
+public class DefaultSettingsBuilderFactoryTest {
 
     private File getSettings(String name) {
         return new File("src/test/resources/settings/factory/" + name + ".xml").getAbsoluteFile();
     }
 
-    public void testCompleteWiring() throws Exception {
+    private SettingsBuildingResult execute(String settingsName) throws Exception {
+        Properties properties = new Properties();
+        properties.setProperty("user.home", "/home/user");
+
         SettingsBuilder builder = new DefaultSettingsBuilderFactory().newInstance();
-        assertNotNull(builder);
+        assertThat(builder).isNotNull();
 
         DefaultSettingsBuildingRequest request = new DefaultSettingsBuildingRequest();
-        request.setSystemProperties(System.getProperties());
-        request.setUserSettingsFile(getSettings("simple"));
+        request.setSystemProperties(properties);
+        request.setUserSettingsFile(getSettings(settingsName));
 
         SettingsBuildingResult result = builder.build(request);
-        assertNotNull(result);
-        assertNotNull(result.getEffectiveSettings());
+        return assertThat(result).isNotNull().actual();
+    }
+
+    @Test
+    public void testCompleteWiring() throws Exception {
+        Settings settings = assertThat(execute("simple"))
+                .extracting(SettingsBuildingResult::getEffectiveSettings)
+                .actual();
+
+        assertThat(settings.getLocalRepository())
+                .satisfiesAnyOf(
+                        repo -> assertThat(repo).isEqualTo("/home/user/.m2/repository"),
+                        repo -> assertThat(repo).endsWith("\\home\\user\\.m2\\repository"));
+    }
+
+    @Test
+    public void testSettingsWithServers() throws Exception {
+        Settings settings = assertThat(execute("settings-servers-1"))
+                .extracting(SettingsBuildingResult::getEffectiveSettings)
+                .actual();
+
+        assertThat(settings.getServers())
+                .hasSize(2)
+                .usingRecursiveFieldByFieldElementComparator()
+                .containsExactlyInAnyOrder(
+                        aServer("server-1", "username1", "password1"), aServer("server-2", "username2", "password2"));
+    }
+
+    @Test
+    public void testSettingsWithServersAndAliases() throws Exception {
+        Settings settings = assertThat(execute("settings-servers-2"))
+                .extracting(SettingsBuildingResult::getEffectiveSettings)
+                .actual();
+
+        assertThat(settings.getServers())
+                .hasSize(6)
+                .usingRecursiveFieldByFieldElementComparator()
+                .containsExactlyInAnyOrder(
+                        aServer("server-1", "username1", "password1", Arrays.asList("server-11", "server-12")),
+                        aServer("server-11", "username1", "password1"),
+                        aServer("server-12", "username1", "password1"),
+                        aServer("server-2", "username2", "password2", Collections.singletonList("server-21")),
+                        aServer("server-21", "username2", "password2"),
+                        aServer("server-3", "username3", "password3"));
+    }
+
+    private Server aServer(String id, String username, String password) {
+        Server server = new Server();
+        server.setId(id);
+        server.setUsername(username);
+        server.setPassword(password);
+        return server;
+    }
+
+    private Server aServer(String id, String username, String password, List<String> ids) {
+        Server server = aServer(id, username, password);
+        server.setIds(ids);
+        return server;
+    }
+
+    @Test
+    public void testSettingsWithDuplicateServersIds() throws Exception {
+        SettingsBuildingResult result = execute("settings-servers-3");
+
+        assertThat(result.getProblems())
+                .hasSize(1)
+                .extracting(SettingsProblem::getMessage)
+                .containsExactly("'servers.server.id' must be unique but found duplicate server with id server-2");
     }
 }

maven-settings-builder/src/test/resources/settings/factory/settings-servers-1.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+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.
+-->
+
+<settings>
+  <localRepository>${user.home}/.m2/repository</localRepository>
+  <servers>
+    <server>
+      <id>server-1</id>
+      <username>username1</username>
+      <password>password1</password>
+    </server>
+    <server>
+      <id>server-2</id>
+      <username>username2</username>
+      <password>password2</password>
+    </server>
+  </servers>
+
+</settings>

maven-settings-builder/src/test/resources/settings/factory/settings-servers-2.xml

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+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.
+-->
+
+<settings>
+  <localRepository>${user.home}/.m2/repository</localRepository>
+  <servers>
+    <server>
+      <id>server-1</id>
+      <ids>
+        <id>server-11</id>
+        <id>server-12</id>
+      </ids>
+      <username>username1</username>
+      <password>password1</password>
+    </server>
+    <server>
+      <id>server-2</id>
+      <ids>
+        <id>server-21</id>
+      </ids>
+      <username>username2</username>
+      <password>password2</password>
+    </server>
+    <server>
+      <id>server-3</id>
+      <username>username3</username>
+      <password>password3</password>
+    </server>
+  </servers>
+
+</settings>

maven-settings-builder/src/test/resources/settings/factory/settings-servers-3.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+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.
+-->
+
+<settings>
+  <localRepository>${user.home}/.m2/repository</localRepository>
+  <servers>
+    <server>
+      <id>server-1</id>
+      <ids>
+        <id>server-2</id>
+      </ids>
+      <username>username1</username>
+      <password>password1</password>
+    </server>
+    <server>
+      <id>server-2</id>
+      <username>username2</username>
+      <password>password2</password>
+    </server>
+  </servers>
+
+</settings>

maven-settings/pom.xml

@@ -44,7 +44,7 @@ under the License.
         <groupId>org.codehaus.modello</groupId>
         <artifactId>modello-maven-plugin</artifactId>
         <configuration>
-          <version>1.2.0</version>
+          <version>1.3.0</version>
           <models>
             <model>src/main/mdo/settings.mdo</model>
           </models>

maven-settings/src/main/mdo/settings.mdo

@@ -581,7 +581,18 @@
             ]]>
           </description>
         </field>
-      </fields>
+        <field>
+          <name>ids</name>
+          <version>1.3.0+</version>
+          <description>
+            List of additional ids for server.
+          </description>
+          <association>
+            <type>String</type>
+            <multiplicity>*</multiplicity>
+          </association>
+        </field>
+    </fields>
     </class>
     <class>
       <name>Mirror</name>