TST: disable symlinks sdist test on Python 3.15 on Windows

Python 3.15 tarfile module translates POSIX paths to Windows paths
when extracting tar archives on Windows, but does not implement the
inverse normalization when creating archives. This results in invalid
tar archives and breaks this test.

Author: dnicolodi

tests/test_sdist.py

@@ -222,6 +222,11 @@ def test_reproducible(package_pure, tmp_path):
 # containing symbolic links to absolute paths on Python 3.14.
 # See https://github.com/mesonbuild/meson/issues/15142
 @pytest.mark.skipif(sys.version_info >= (3, 14) and MESON_VERSION < (1, 9, 2), reason='incompatible Python version')
+# Python 3.15 tarfile module translates POSIX paths to Windows paths
+# when extracting tar archives on Windows, but does not implement the
+# inverse when creating archives. This results in invalid tar archives
+# and breaks this test. See https://github.com/python/cpython/pull/151671
+@pytest.mark.xfail(sys.version_info >= (3, 15) and sys.platform == 'win32', reason='Python 3.15 tarfile module bug')
 @pytest.mark.filterwarnings('ignore:symbolic link')
 def test_symlinks(tmp_path, sdist_symlinks):
     with tarfile.open(sdist_symlinks, 'r:gz') as sdist: