use _sync_open

Author: TomNicholas

src/zarr/storage/_zip.py

@@ -92,13 +92,15 @@ def __init__(
 
     def with_read_only(self, read_only: bool = False) -> ZipStore:
         # docstring inherited
-        return type(self)(
+        store = type(self)(
             path=self.path,
             mode='r',
             read_only=read_only,
             compression=self.compression,
             allowZip64=self.allowZip64,
         )
+        store._sync_open()
+        return store
 
     def _sync_open(self) -> None:
         if self._is_open: