Fix Windows symlink detection

core/src/main/java/hudson/Util.java

@@ -68,6 +68,8 @@ import java.util.logging.Logger;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import hudson.util.jna.Kernel32Utils;
+
 import static hudson.util.jna.GNUCLibrary.LIBC;
 
 /**
@@ -308,6 +310,9 @@ public class Util {
      */
     //Taken from http://svn.apache.org/viewvc/maven/shared/trunk/file-management/src/main/java/org/apache/maven/shared/model/fileset/util/FileSetManager.java?view=markup
     public static boolean isSymlink(File file) throws IOException {
+        if (Functions.isWindows()) {
+          return Kernel32Utils.isJunctionOrSymlink(file);
+        }
         String name = file.getName();
         if (name.equals(".") || name.equals(".."))
             return false;

core/src/main/java/hudson/util/jna/Kernel32.java

@@ -26,6 +26,7 @@ package hudson.util.jna;
 import com.sun.jna.Pointer;
 import com.sun.jna.ptr.IntByReference;
 import com.sun.jna.win32.StdCallLibrary;
+import com.sun.jna.WString;
 import com.sun.jna.Native;
 
 /**
@@ -47,8 +48,11 @@ public interface Kernel32 extends StdCallLibrary {
     int MOVEFILE_FAIL_IF_NOT_TRACKABLE = 32;
     int MOVEFILE_REPLACE_EXISTING = 1;
     int MOVEFILE_WRITE_THROUGH = 8;
+    
+    int FILE_ATTRIBUTE_REPARSE_POINT = 0x400;
 
     int WaitForSingleObject(Pointer handle, int milliseconds);
+    int GetFileAttributesW(WString lpFileName);
     boolean GetExitCodeProcess(Pointer handle, IntByReference r);
 
     int STILL_ACTIVE = 259;

core/src/main/java/hudson/util/jna/Kernel32Utils.java

@@ -23,8 +23,11 @@
  */
 package hudson.util.jna;
 
+import java.io.*;
+
 import com.sun.jna.Pointer;
 import com.sun.jna.ptr.IntByReference;
+import com.sun.jna.WString;
 
 /**
  *
@@ -50,4 +53,12 @@ public class Kernel32Utils {
             }
         }
     }
+
+    public static int getWin32FileAttributes(File file) throws IOException {
+      return Kernel32.INSTANCE.GetFileAttributesW(new WString(file.getCanonicalPath()));
+    }
+
+    public static boolean isJunctionOrSymlink(File file) throws IOException {
+      return (file.exists() && (Kernel32.INSTANCE.FILE_ATTRIBUTE_REPARSE_POINT & getWin32FileAttributes(file)) != 0);
+    }
 }