From 4623d59206e88132432b6db74945a717057b2f8a Mon Sep 17 00:00:00 2001
From: Fabian Dill <Berserker66@users.noreply.github.com>
Date: Mon, 7 Jul 2025 15:51:39 +0200
Subject: [PATCH] Core: ensure slot_data and er_hint_info are only base data
 types (#5144)

---------

Co-authored-by: Doug Hoskisson <beauxq@users.noreply.github.com>
---
 Main.py                          |  4 ++++
 NetUtils.py                      | 21 +++++++++++++++++++++
 test/general/test_implemented.py |  4 ++--
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/Main.py b/Main.py
index 442c2ff4..456820a4 100644
--- a/Main.py
+++ b/Main.py
@@ -12,6 +12,7 @@ import worlds
 from BaseClasses import CollectionState, Item, Location, LocationProgressType, MultiWorld
 from Fill import FillError, balance_multiworld_progression, distribute_items_restrictive, flood_items, \
     parse_planned_blocks, distribute_planned_blocks, resolve_early_locations_for_planned
+from NetUtils import convert_to_base_types
 from Options import StartInventoryPool
 from Utils import __version__, output_path, version_tuple
 from settings import get_settings
@@ -334,6 +335,9 @@ def main(args, seed=None, baked_server_options: dict[str, object] | None = None)
                 }
                 AutoWorld.call_all(multiworld, "modify_multidata", multidata)
 
+                for key in ("slot_data", "er_hint_data"):
+                    multidata[key] = convert_to_base_types(multidata[key])
+
                 multidata = zlib.compress(pickle.dumps(multidata), 9)
 
                 with open(os.path.join(temp_dir, f'{outfilebase}.archipelago'), 'wb') as f:
diff --git a/NetUtils.py b/NetUtils.py
index f2ae2a63..cc6e917c 100644
--- a/NetUtils.py
+++ b/NetUtils.py
@@ -106,6 +106,27 @@ def _scan_for_TypedTuples(obj: typing.Any) -> typing.Any:
     return obj
 
 
+_base_types = str | int | bool | float | None | tuple["_base_types", ...] | dict["_base_types", "base_types"]
+
+
+def convert_to_base_types(obj: typing.Any) -> _base_types:
+    if isinstance(obj, (tuple, list, set, frozenset)):
+        return tuple(convert_to_base_types(o) for o in obj)
+    elif isinstance(obj, dict):
+        return {convert_to_base_types(key): convert_to_base_types(value) for key, value in obj.items()}
+    elif obj is None or type(obj) in (str, int, float, bool):
+        return obj
+    # unwrap simple types to their base, such as StrEnum
+    elif isinstance(obj, str):
+        return str(obj)
+    elif isinstance(obj, int):
+        return int(obj)
+    elif isinstance(obj, float):
+        return float(obj)
+    else:
+        raise Exception(f"Cannot handle {type(obj)}")
+
+
 _encode = JSONEncoder(
     ensure_ascii=False,
     check_circular=False,
diff --git a/test/general/test_implemented.py b/test/general/test_implemented.py
index b74f82b7..cf0624a2 100644
--- a/test/general/test_implemented.py
+++ b/test/general/test_implemented.py
@@ -1,7 +1,7 @@
 import unittest
 
 from Fill import distribute_items_restrictive
-from NetUtils import encode
+from NetUtils import convert_to_base_types
 from worlds.AutoWorld import AutoWorldRegister, call_all
 from worlds import failed_world_loads
 from . import setup_solo_multiworld
@@ -47,7 +47,7 @@ class TestImplemented(unittest.TestCase):
                 call_all(multiworld, "post_fill")
                 for key, data in multiworld.worlds[1].fill_slot_data().items():
                     self.assertIsInstance(key, str, "keys in slot data must be a string")
-                    self.assertIsInstance(encode(data), str, f"object {type(data).__name__} not serializable.")
+                    convert_to_base_types(data)  # only put base data types into slot data
 
     def test_no_failed_world_loads(self):
         if failed_world_loads: