Core: any platform is now None/missing key

worlds/AutoWorld.py

@@ -353,7 +353,7 @@ class World(metaclass=AutoWorldRegister):
     """path it was loaded from"""
     world_version: ClassVar[Version] = Version(0, 0, 0)
     """Optional world version loaded from archipelago.json"""
-    platforms: ClassVar[List[str]] = []
+    platforms: ClassVar[Optional[List[str]]] = None
     """Optional platforms loaded from archipelago.json"""
 
     def __init__(self, multiworld: "MultiWorld", player: int):

worlds/Files.py

@@ -197,7 +197,7 @@ class APWorldContainer(APContainer):
     world_version: "Version | None" = None
     minimum_ap_version: "Version | None" = None
     maximum_ap_version: "Version | None" = None
-    platforms: List[str] = []
+    platforms: Optional[List[str]] = None
 
     def read_contents(self, opened_zipfile: zipfile.ZipFile) -> Dict[str, Any]:
         from Utils import tuplize_version
@@ -206,7 +206,7 @@ class APWorldContainer(APContainer):
         for version_key in ("world_version", "minimum_ap_version", "maximum_ap_version"):
             if version_key in manifest:
                 setattr(self, version_key, tuplize_version(manifest[version_key]))
-        self.platforms = manifest.get("platforms", [])
+        self.platforms = manifest.get("platforms")
         return manifest
 
     def get_manifest(self) -> Dict[str, Any]:

worlds/__init__.py

@@ -118,7 +118,7 @@ for world_source in world_sources:
         game = manifest.get("game")
         if game in AutoWorldRegister.world_types:
             AutoWorldRegister.world_types[game].world_version = tuplize_version(manifest.get("world_version", "0.0.0"))
-            AutoWorldRegister.world_types[game].platforms = manifest.get("platforms", [])
+            AutoWorldRegister.world_types[game].platforms = manifest.get("platforms")
 
 if apworlds:
     # encapsulation for namespace / gc purposes