diff -r 2b54e25d6ecb Doc/library/os.rst
--- a/Doc/library/os.rst	Sun Jun 24 04:37:41 2012 +0200
+++ b/Doc/library/os.rst	Sat Jun 23 22:43:11 2012 -0700
@@ -2188,11 +2188,6 @@
 
    Create a symbolic link pointing to *source* named *link_name*.
 
-   On Windows, a symlink represents either a file or a directory, and does not
-   morph to the target dynamically.  If *target_is_directory* is set to ``True``,
-   the symlink will be created as a directory symlink, otherwise as a file symlink
-   (the default).  On non-Window platforms, *target_is_directory* is ignored.
-
    Symbolic link support was introduced in Windows 6.0 (Vista).  :func:`symlink`
    will raise a :exc:`NotImplementedError` on Windows versions earlier than 6.0.
 
@@ -2204,6 +2199,8 @@
    :data:`os.supports_dir_fd`.  If it is unavailable, using it will raise
    a :exc:`NotImplementedError`.
 
+   The *target_is_directory* argument is deprecated, and is always ignored.
+
    .. note::
 
       On Windows, the *SeCreateSymbolicLinkPrivilege* is required in order to
@@ -2221,8 +2218,8 @@
       Added support for Windows 6.0 (Vista) symbolic links.
 
    .. versionadded:: 3.3
-      Added the *dir_fd* argument, and now allow *target_is_directory*
-      on non-Windows platforms.
+      Added the *dir_fd* argument, and deprecated the *target_is_directory*
+      argument.
 
 
 .. function:: sync()
diff -r 2b54e25d6ecb Misc/NEWS
--- a/Misc/NEWS	Sun Jun 24 04:37:41 2012 +0200
+++ b/Misc/NEWS	Sat Jun 23 22:43:11 2012 -0700
@@ -47,6 +47,10 @@
 Library
 -------
 
+- Issue #14917: Deprecated the "target_is_directory" argument for
+  os.symlink.  On Windows os.symlink now determines automatically
+  whether or not the target is a directory.
+
 - Issue #15154: Add "dir_fd" parameter to os.rmdir, remove "rmdir"
   parameter from os.remove / os.unlink.
 
diff -r 2b54e25d6ecb Modules/posixmodule.c
--- a/Modules/posixmodule.c	Sun Jun 24 04:37:41 2012 +0200
+++ b/Modules/posixmodule.c	Sat Jun 23 22:43:11 2012 -0700
@@ -7161,15 +7161,13 @@
 PyDoc_STRVAR(posix_symlink__doc__,
 "symlink(src, dst, target_is_directory=False, *, dir_fd=None)\n\n\
 Create a symbolic link pointing to src named dst.\n\n\
-target_is_directory is required on Windows if the target is to be\n\
-  interpreted as a directory.  (On Windows, symlink requires\n\
-  Windows 6.0 or greater, and raises a NotImplementedError otherwise.)\n\
-  target_is_directory is ignored on non-Windows platforms.\n\
 \n\
 If dir_fd is not None, it should be a file descriptor open to a directory,\n\
   and path should be relative; path will then be relative to that directory.\n\
 dir_fd may not be implemented on your platform.\n\
-  If it is unavailable, using it will raise a NotImplementedError.");
+  If it is unavailable, using it will raise a NotImplementedError.\n\
+\n\
+The target_is_directory parameter is deprecated, and is always ignored.");
 
 #if defined(MS_WINDOWS)
 
@@ -7199,11 +7197,13 @@
     path_t src;
     path_t dst;
     int dir_fd = DEFAULT_DIR_FD;
-    int target_is_directory = 0;
+    int ignored;
     static char *keywords[] = {"src", "dst", "target_is_directory",
                                "dir_fd", NULL};
     PyObject *return_value;
 #ifdef MS_WINDOWS
+    int target_is_directory;
+    DWORD src_attr;
     DWORD result;
 #else
     int result;
@@ -7230,7 +7230,7 @@
             keywords,
             path_converter, &src,
             path_converter, &dst,
-            &target_is_directory,
+            &ignored,
 #ifdef HAVE_SYMLINKAT
             dir_fd_converter, &dir_fd
 #else
@@ -7248,6 +7248,12 @@
 
 #ifdef MS_WINDOWS
     Py_BEGIN_ALLOW_THREADS
+    if (src.wide)
+        src_attr = GetFileAttributesW(src.wide);
+    else
+        src_attr = GetFileAttributesA(src.narrow);
+    target_is_directory = (src_attr & FILE_ATTRIBUTE_DIRECTORY) ? 1 : 0;
+
     if (dst.wide)
         result = Py_CreateSymbolicLinkW(dst.wide, src.wide,
                                         target_is_directory);