fix(torrent): improve get_files() fields handling

This commit fixes the following issues with `Torrent.get_files()`:

If Client.get_torrent() was called with "files" not in `arguments`, then
`get_files()` returns an empty list. This is surprising - it should
raise an error instead.

If Client.get_torrent() was called with arguments=["files"], get_files()
fails because it expects to find `properties` and `wanted`, which were
not requested. For efficiency we should not force users to request
fields they don't need, so leave these unset in this case.

tests/test_torrent.py

@@ -45,7 +45,8 @@ def test_attributes():
 
     with pytest.raises(KeyError):
         torrent.format_eta()
-    assert not torrent.get_files()
+    with pytest.raises(KeyError):
+        torrent.get_files()
 
     data = {
         "id": 1,

transmission_rpc/torrent.py

@@ -429,25 +429,21 @@ def get_files(self) -> list[File]:
                 print(file.id)
 
         """
-        result: list[File] = []
-        if "files" in self.fields:
-            files = self.fields["files"]
-            indices = range(len(files))
-            priorities = self.fields["priorities"]
-            wanted = self.fields["wanted"]
-            result.extend(
-                File(
-                    selected=bool(raw_selected),
-                    priority=Priority(raw_priority),
-                    size=file["length"],
-                    name=file["name"],
-                    completed=file["bytesCompleted"],
-                    id=id,
-                )
-                for id, file, raw_priority, raw_selected in zip(indices, files, priorities, wanted)
+        files = self.fields["files"]
+        indices = range(len(files))
+        priorities = self.fields.get("priorities", [None] * len(files))
+        wanted = self.fields.get("wanted", [None] * len(files))
+        return [
+            File(
+                selected=bool(raw_selected) if raw_selected is not None else None,
+                priority=Priority(raw_priority) if raw_priority is not None else None,
+                size=file["length"],
+                name=file["name"],
+                completed=file["bytesCompleted"],
+                id=id,
             )
-
-        return result
+            for id, file, raw_priority, raw_selected in zip(indices, files, priorities, wanted)
+        ]
 
     @property
     def file_stats(self) -> list[FileStat]:

transmission_rpc/types.py

@@ -30,10 +30,10 @@ class File(NamedTuple):
     completed: int
     """bytes completed"""
 
-    priority: Priority
+    priority: Priority | None
     """download priority"""
 
-    selected: bool
+    selected: bool | None
     """if selected for download"""
 
     id: int