version_info gate for is_relative_to

jupyter_server/utils.py

@@ -378,12 +378,17 @@ def filefind(filename: str, path_dirs: Sequence[str]) -> str:
         # os.path.abspath resolves '..', but Path.absolute() doesn't
         # Path.resolve() does, but traverses symlinks, which we don't want
         test_path = Path(os.path.abspath(test_path))
-        try:
-            # can use is_relative_to when we require Python 3.9
-            test_path.relative_to(path)
-        except ValueError:
-            # points outside root, e.g. via `filename='../foo'`
-            continue
+        if sys.version_info >= (3, 9):
+            if not test_path.is_relative_to(path):
+                # points outside root, e.g. via `filename='../foo'`
+                continue
+        else:
+            # is_relative_to is new in 3.9
+            try:
+                test_path.relative_to(path)
+            except ValueError:
+                # points outside root, e.g. via `filename='../foo'`
+                continue
         # make sure we don't call is_file before we know it's a file within a prefix
         # GHSA-hrw6-wg82-cm62 - can leak password hash on windows.
         if test_path.is_file():