[MINVOKER-335] Preserve symlinks for copied files

src/it/MINVOKER-335-symlinks-in-source/invoker.properties

@@ -0,0 +1,19 @@
+# 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.
+
+# NOTE: Don't clean here to be able to detect test failures
+invoker.goals = initialize

src/it/MINVOKER-335-symlinks-in-source/pom.xml

@@ -0,0 +1,65 @@
+<?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.
+-->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.plugins.invoker</groupId>
+  <artifactId>clone-clean-invocation</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <packaging>pom</packaging>
+
+  <description>Test to check for copping symlinks from source to target</description>
+  <url>https://issues.apache.org/jira/browse/MINVOKER-335</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-invoker-plugin</artifactId>
+        <version>@project.version@</version>
+        <configuration>
+          <cloneProjectsTo>${project.build.directory}/it</cloneProjectsTo>
+          <pomIncludes>
+            <pomInclude>*/pom.xml</pomInclude>
+          </pomIncludes>
+          <goals>
+            <goal>validate</goal>
+          </goals>
+        </configuration>
+        <executions>
+          <execution>
+            <id>integration-test</id>
+            <phase>initialize</phase>
+            <goals>
+              <goal>run</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

src/it/MINVOKER-335-symlinks-in-source/setup.groovy

@@ -0,0 +1,34 @@
+/*
+ * 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.nio.file.Files
+import java.nio.file.Paths
+
+def projectPath = new File(basedir, 'src/it/clone-symlinks').toPath()
+
+def testDir = projectPath.resolve('testDir');
+def testFile = projectPath.resolve('test.txt')
+
+Files.createDirectory(testDir)
+Files.createFile(testFile)
+
+Files.createSymbolicLink(projectPath.resolve('testDirLink'), Paths.get('testDir'))
+Files.createSymbolicLink(projectPath.resolve('testLink.txt'), Paths.get('test.txt'))
+
+true

src/it/MINVOKER-335-symlinks-in-source/src/it/clone-symlinks/pom.xml

@@ -0,0 +1,32 @@
+<?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.
+-->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>test</groupId>
+  <artifactId>clone-symlnks</artifactId>
+  <version>0.1-SNAPSHOT</version>
+  <packaging>pom</packaging>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+</project>

src/it/MINVOKER-335-symlinks-in-source/verify.groovy

@@ -0,0 +1,26 @@
+/*
+ * 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.nio.file.Files
+import java.nio.file.Paths
+
+def projectPath = new File(basedir, 'target/it/clone-symlinks').toPath()
+
+assert Files.readSymbolicLink(projectPath.resolve('testDirLink')) == Paths.get('testDir')
+assert Files.readSymbolicLink(projectPath.resolve('testLink.txt')) == Paths.get('test.txt')

src/main/java/org/apache/maven/plugins/invoker/AbstractInvokerMojo.java

@@ -92,6 +92,7 @@
 import org.codehaus.plexus.util.FileUtils;
 import org.codehaus.plexus.util.IOUtil;
 import org.codehaus.plexus.util.InterpolationFilterReader;
+import org.codehaus.plexus.util.NioFiles;
 import org.codehaus.plexus.util.ReflectionUtils;
 import org.codehaus.plexus.util.cli.CommandLineException;
 import org.codehaus.plexus.util.cli.CommandLineUtils;
@@ -1178,14 +1179,18 @@ private void copyDirectoryStructure(File sourceDir, File destDir) throws IOExcep
         /*
          * NOTE: Make sure the destination directory is always there (even if empty) to support POM-less ITs.
          */
-        destDir.mkdirs();
+        Files.createDirectories(destDir.toPath());
         // Create all the directories, including any symlinks present in source
         FileUtils.mkDirs(sourceDir, scanner.getIncludedDirectories(), destDir);
 
         for (String includedFile : scanner.getIncludedFiles()) {
             File sourceFile = new File(sourceDir, includedFile);
             File destFile = new File(destDir, includedFile);
-            FileUtils.copyFile(sourceFile, destFile);
+            if (NioFiles.isSymbolicLink(sourceFile)) {
+                NioFiles.createSymbolicLink(destFile, NioFiles.readSymbolicLink(sourceFile));
+            } else {
+                FileUtils.copyFile(sourceFile, destFile);
+            }
 
             // ensure clone project must be writable for additional changes
             destFile.setWritable(true);