[builder][server] restore compatibility with python 3.7

1 files changed, 8 insertions, 6 deletions

diff --git a/src/hydrilla/builder/piggybacking.py b/src/hydrilla/builder/piggybacking.py
index 3e4084f..c152135 100644
--- a/src/hydrilla/builder/piggybacking.py
+++ b/src/hydrilla/builder/piggybacking.py
@@ -52,10 +52,10 @@ class Piggybacked:
     """
     def __init__(
             self,
-            archives:              dict[str, Path]     = {},
-            roots:                 dict[str, Path]     = {},
-            package_license_files: list[PurePosixPath] = [],
-            resource_must_depend:  list[dict]          = []
+            archives:              t.Dict[str, Path]     = {},
+            roots:                 t.Dict[str, Path]     = {},
+            package_license_files: t.List[PurePosixPath] = [],
+            resource_must_depend:  t.List[dict]          = []
     ) -> None:
         """
         Initialize this Piggybacked object.
@@ -106,13 +106,15 @@ class Piggybacked:
 
         path = path.resolve()
 
-        if not path.is_relative_to(root_path):
+        try:
+            path.relative_to(root_path)
+        except ValueError:
             raise FileReferenceError(_('loading_{}_outside_piggybacked_dir')
                                      .format(file_ref_name))
 
         return path
 
-    def archive_files(self) -> t.Iterator[tuple[PurePosixPath, Path]]:
+    def archive_files(self) -> t.Iterator[t.Tuple[PurePosixPath, Path]]:
         """
         Yield all archive files in use. Each yielded tuple holds file's desired
         path relative to the piggybacked archives directory to be created and