Fix issue with portability of PickledDB objects

Signed-off-by: Fabrice Normandin <[email protected]>

src/orion/core/io/database/pickleddb.py

@@ -101,6 +101,9 @@ def __init__(self, host="", timeout=60, *args, **kwargs):
             host = DEFAULT_HOST
         super().__init__(host)
 
+        # NOTE: Save the original value of `host`, so this object can be pickled and unpickled on
+        # different machines more easily if it's a relative path.
+        self.original_host = host
         self.host = os.path.abspath(host)
 
         self.timeout = timeout
@@ -255,6 +258,17 @@ def get_defaults(cls):
         """
         return {"host": DEFAULT_HOST}
 
+    def __getstate__(self):
+        """Return state to be pickled."""
+        return self.__dict__.copy()
+
+    def __setstate__(self, state: dict) -> None:
+        """Restore state from pickled object."""
+        self.__dict__.update(state)
+        # NOTE: `original_host` might not be present when unpickling old databases.
+        self.original_host = state.setdefault("original_host", self.host)
+        self.host = os.path.abspath(self.original_host)
+
 
 local_file_systems = ["ext2", "ext3", "ext4", "ntfs"]