Tar: preserve symlinks from <tarfileset> sources

src/etc/testcases/taskdefs/tar.xml

@@ -203,4 +203,12 @@
     <untar src="${output}/testout/test.tar" dest="${output}/untar"/>
   </target>
 
+  <target name="testTarFilesetWithSymlinks">
+    <gunzip src="../testtarwithsymlinks.tar.gz" dest="${output}/source.tar"/>
+    <tar destfile="${output}/result.tar">
+      <tarfileset prefix="pre" src="${output}/source.tar"/>
+    </tar>
+    <echo message="asd ${output}"/>
+  </target>
+
 </project>

src/main/org/apache/tools/ant/taskdefs/Tar.java

@@ -459,6 +459,14 @@ public class Tar extends MatchingTask {
                 te.setUserId(tr.getLongUid());
                 te.setGroupName(tr.getGroup());
                 te.setGroupId(tr.getLongGid());
+                String linkName = tr.getLinkName();
+                byte linkFlag = tr.getLinkFlag();
+                if (linkFlag == TarConstants.LF_LINK &&
+                    linkName != null && linkName.length() > 0 && !linkName.startsWith("/")) {
+                    linkName = getCanonicalPrefix(tarFileSet, this.getProject()) + linkName;
+                }
+                te.setLinkName(linkName);
+                te.setLinkFlag(linkFlag);
             }
         }
 

src/tests/junit/org/apache/tools/ant/taskdefs/TarTest.java

@@ -19,16 +19,21 @@
 package org.apache.tools.ant.taskdefs;
 
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.BuildFileRule;
 import org.apache.tools.ant.FileUtilities;
+import org.apache.tools.tar.TarEntry;
+import org.apache.tools.tar.TarInputStream;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 public class TarTest {
@@ -186,4 +191,27 @@ public class TarTest {
     public void testtestTarFilesetWithReference() {
         buildRule.executeTarget("testTarFilesetWithReference");
     }
+
+    @Test
+    public void testTarFilesetWithSymlinks() throws IOException {
+        buildRule.executeTarget("testTarFilesetWithSymlinks");
+        final File f = new File(buildRule.getProject().getProperty("output"), "result.tar");
+        final TarInputStream tis = new TarInputStream(new FileInputStream(f));
+        try {
+            final TarEntry e1 = tis.getNextEntry();
+            assertEquals("pre/dir/file", e1.getName());
+            assertEquals("", e1.getLinkName());
+            assertEquals(48, e1.getLinkFlag());
+
+            final TarEntry e2 = tis.getNextEntry();
+            assertEquals("pre/sub/file", e2.getName());
+            assertEquals("../dir/file", e2.getLinkName());
+            assertEquals(50, e2.getLinkFlag());
+
+            assertNull(tis.getNextEntry());
+        }
+        finally {
+            tis.close();
+        }
+    }
 }