improve error message for prototype datasets without options (#5224)

* improve error message for prototype datasets without options

* remove early exit

* add test

Author: pmeier

test/test_prototype_datasets_api.py

@@ -126,13 +126,16 @@ def test_default_config(self, info):
         assert info.default_config == default_config
 
     @pytest.mark.parametrize(
-        ("options", "expected_error_msg"),
+        ("valid_options", "options", "expected_error_msg"),
         [
-            pytest.param(dict(unknown_option=None), "Unknown option 'unknown_option'", id="unknown_option"),
-            pytest.param(dict(split="unknown_split"), "Invalid argument 'unknown_split'", id="invalid_argument"),
+            (dict(), dict(any_option=None), "does not take any options"),
+            (dict(split="train"), dict(unknown_option=None), "Unknown option 'unknown_option'"),
+            (dict(split="train"), dict(split="invalid_argument"), "Invalid argument 'invalid_argument'"),
         ],
     )
-    def test_make_config_invalid_inputs(self, info, options, expected_error_msg):
+    def test_make_config_invalid_inputs(self, info, valid_options, options, expected_error_msg):
+        info = make_minimal_dataset_info(valid_options=valid_options)
+
         with pytest.raises(ValueError, match=expected_error_msg):
             info.make_config(**options)
 

torchvision/prototype/datasets/utils/_dataset.py

@@ -78,6 +78,12 @@ def read_categories_file(path: pathlib.Path) -> List[List[str]]:
             return [row for row in csv.reader(file)]
 
     def make_config(self, **options: Any) -> DatasetConfig:
+        if not self._valid_options and options:
+            raise ValueError(
+                f"Dataset {self.name} does not take any options, "
+                f"but got {sequence_to_str(list(options), separate_last=' and')}."
+            )
+
         for name, arg in options.items():
             if name not in self._valid_options:
                 raise ValueError(