merge from 3.1

diff --cc Lib/test/test_tarfile.py
index 68e094d5dbc872199b252f6570a923d93792c5f7,487f28f6223687343ae617641efd03ff9360e9ab..e3e140e59e4891b838ea0845a867275b27dcd597
--- 1/Lib/test/test_tarfile.py
--- 2/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@@ -950,83 -678,34 +950,111 @@@ class WriteTest(WriteTestBase)
          finally:
              shutil.rmtree(tempdir)
  
 +    # Guarantee that stored pathnames are not modified. Don't
 +    # remove ./ or ../ or double slashes. Still make absolute
 +    # pathnames relative.
 +    # For details see bug #6054.
 +    def _test_pathname(self, path, cmp_path=None, dir=False):
 +        # Create a tarfile with an empty member named path
 +        # and compare the stored name with the original.
 +        foo = os.path.join(TEMPDIR, "foo")
 +        if not dir:
 +            open(foo, "w").close()
 +        else:
 +            os.mkdir(foo)
 +
 +        tar = tarfile.open(tmpname, self.mode)
 +        try:
 +            tar.add(foo, arcname=path)
 +        finally:
 +            tar.close()
 +
 +        tar = tarfile.open(tmpname, "r")
 +        try:
 +            t = tar.next()
 +        finally:
 +            tar.close()
 +
 +        if not dir:
 +            os.remove(foo)
 +        else:
 +            os.rmdir(foo)
 +
 +        self.assertEqual(t.name, cmp_path or path.replace(os.sep, "/"))
 +
+     def test_extractall_symlinks(self):
+         # Test if extractall works properly when tarfile contains symlinks
+         tempdir = os.path.join(TEMPDIR, "testsymlinks")
+         temparchive = os.path.join(TEMPDIR, "testsymlinks.tar")
+         os.mkdir(tempdir)
+         try:
+             source_file = os.path.join(tempdir,'source')
+             target_file = os.path.join(tempdir,'symlink')
+             with open(source_file,'w') as f:
+                 f.write('something\n')
+             os.symlink(source_file, target_file)
+             tar = tarfile.open(temparchive,'w')
+             tar.add(source_file)
+             tar.add(target_file)
+             tar.close()
+             # Let's extract it to the location which contains the symlink
+             tar = tarfile.open(temparchive,'r')
+             # this should not raise OSError: [Errno 17] File exists
+             try:
+                 tar.extractall(path=tempdir)
+             except OSError:
+                 self.fail("extractall failed with symlinked files")
+             finally:
+                 tar.close()
+         finally:
+             os.unlink(temparchive)
+             shutil.rmtree(tempdir)
+ 
 +    def test_pathnames(self):
 +        self._test_pathname("foo")
 +        self._test_pathname(os.path.join("foo", ".", "bar"))
 +        self._test_pathname(os.path.join("foo", "..", "bar"))
 +        self._test_pathname(os.path.join(".", "foo"))
 +        self._test_pathname(os.path.join(".", "foo", "."))
 +        self._test_pathname(os.path.join(".", "foo", ".", "bar"))
 +        self._test_pathname(os.path.join(".", "foo", "..", "bar"))
 +        self._test_pathname(os.path.join(".", "foo", "..", "bar"))
 +        self._test_pathname(os.path.join("..", "foo"))
 +        self._test_pathname(os.path.join("..", "foo", ".."))
 +        self._test_pathname(os.path.join("..", "foo", ".", "bar"))
 +        self._test_pathname(os.path.join("..", "foo", "..", "bar"))
 +
 +        self._test_pathname("foo" + os.sep + os.sep + "bar")
 +        self._test_pathname("foo" + os.sep + os.sep, "foo", dir=True)
 +
 +    def test_abs_pathnames(self):
 +        if sys.platform == "win32":
 +            self._test_pathname("C:\\foo", "foo")
 +        else:
 +            self._test_pathname("/foo", "foo")
 +            self._test_pathname("///foo", "foo")
 +
 +    def test_cwd(self):
 +        # Test adding the current working directory.
 +        cwd = os.getcwd()
 +        os.chdir(TEMPDIR)
 +        try:
 +            tar = tarfile.open(tmpname, self.mode)
 +            try:
 +                tar.add(".")
 +            finally:
 +                tar.close()
 +
 +            tar = tarfile.open(tmpname, "r")
 +            try:
 +                for t in tar:
 +                    self.assertTrue(t.name == "." or t.name.startswith("./"))
 +            finally:
 +                tar.close()
 +        finally:
 +            os.chdir(cwd)
 +
 +
  class StreamWriteTest(WriteTestBase):
  
      mode = "w|"