Verify that lib store exists when loading

Author: malmeloo

anisette/_anisette.py

@@ -24,15 +24,20 @@ def __init__(self, fs_collection: FSCollection, default_device_config: AnisetteD
 
     @classmethod
     def load(cls, *files: BinaryIO, default_device_config: AnisetteDeviceConfig | None = None) -> Self:
-        return cls(FSCollection.load(*files), default_device_config)
+        provider = cls(FSCollection.load(*files), default_device_config)
+        assert provider.library_store is not None  # verify that library store exists
+        return provider
 
     def save(self, file: BinaryIO, include: list[str] | None = None, exclude: list[str] | None = None) -> None:
         return self._fs_collection.save(file, include, exclude)
 
     @property
     def library_store(self) -> LibraryStore:
         if self._lib_store is None:
-            lib_fs = self._fs_collection.get("libs")
+            lib_fs = self._fs_collection.get("libs", False)
+            if lib_fs is None:
+                msg = "Library filesystem missing"
+                raise RuntimeError(msg)
             self._lib_store = LibraryStore.from_virtfs(lib_fs)
         return self._lib_store
 

anisette/_fs.py

@@ -7,7 +7,7 @@
 from contextlib import ExitStack
 from dataclasses import dataclass
 from pathlib import Path
-from typing import IO, TYPE_CHECKING, BinaryIO, Union
+from typing import IO, TYPE_CHECKING, BinaryIO, Literal, Union, overload
 
 from fs import open_fs
 from fs.copy import copy_dir, copy_file, copy_fs
@@ -185,11 +185,23 @@ def save(self, file: BinaryIO, include: list[str] | None = None, exclude: list[s
 
             tar_fs.writetext("fs.json", json.dumps(fs_index))
 
-    def get(self, fs_name: str) -> VirtualFileSystem:
+    @overload
+    def get(self, fs_name: str) -> VirtualFileSystem: ...
+
+    @overload
+    def get(self, fs_name: str, create_if_missing: Literal[True]) -> VirtualFileSystem: ...
+
+    @overload
+    def get(self, fs_name: str, create_if_missing: Literal[False]) -> VirtualFileSystem | None: ...
+
+    def get(self, fs_name: str, create_if_missing: bool = True) -> VirtualFileSystem | None:
         if fs_name in self._filesystems:
             logging.debug("Get FS from collection: %s", fs_name)
             return self._filesystems[fs_name]
 
+        if not create_if_missing:
+            return None
+
         logging.debug("Create new VFS: %s", fs_name)
         fs = VirtualFileSystem()
         self._filesystems[fs_name] = fs