Fix dataset filters matching datasets that never declare the filtered axis

pyrit/datasets/seed_datasets/seed_dataset_provider.py

@@ -222,9 +222,18 @@ def _match_single_criterion(
             filter_vals = getattr(criterion, field.name)
             meta_vals = getattr(metadata, field.name)
 
-            if filter_vals is None or meta_vals is None:
+            if filter_vals is None:
                 continue
 
+            # `meta_vals is None` means the dataset never declared this axis, which
+            # is not the same as declaring it and matching. Skipping here dropped
+            # the filtered axis entirely, so every dataset silent on that axis came
+            # back as a match. It also disagreed with get_all_dataset_names_async,
+            # which excludes datasets carrying no metadata at all - a dataset with
+            # partial metadata was treated as better qualified than one with none.
+            if meta_vals is None:
+                return False
+
             if strict_match:
                 if filter_vals - meta_vals:
                     return False

tests/unit/datasets/test_seed_dataset_provider.py

@@ -371,6 +371,39 @@ def test_modalities(self):
             dataset_filter=SeedDatasetFilter(modalities={"audio"}),
         )
 
+    def test_undeclared_axis_does_not_match(self):
+        """A dataset silent on a filtered axis does not satisfy that axis."""
+        metadata = SeedDatasetMetadata(tags={"safety"}, size={"small"}, source_type={"local"})
+        assert not SeedDatasetProvider._match_filter_to_metadata(
+            metadata=metadata,
+            dataset_filter=SeedDatasetFilter(modalities={"audio"}),
+        )
+        assert not SeedDatasetProvider._match_filter_to_metadata(
+            metadata=metadata,
+            dataset_filter=SeedDatasetFilter(harm_categories={"violence"}),
+        )
+        # An axis the dataset does declare is still matched normally.
+        assert SeedDatasetProvider._match_filter_to_metadata(
+            metadata=metadata,
+            dataset_filter=SeedDatasetFilter(tags={"safety"}),
+        )
+
+    def test_undeclared_axis_does_not_match_strict(self):
+        """strict_match also rejects a dataset silent on the filtered axis."""
+        metadata = SeedDatasetMetadata(tags={"safety"}, size={"small"}, source_type={"local"})
+        assert not SeedDatasetProvider._match_filter_to_metadata(
+            metadata=metadata,
+            dataset_filter=SeedDatasetFilter(modalities={"audio"}, strict_match=True),
+        )
+
+    def test_undeclared_axis_does_not_mask_a_declared_mismatch(self):
+        """Two filtered axes, one declared and mismatching: still no match."""
+        metadata = SeedDatasetMetadata(modalities={"text"})
+        assert not SeedDatasetProvider._match_filter_to_metadata(
+            metadata=metadata,
+            dataset_filter=SeedDatasetFilter(modalities={"text"}, harm_categories={"violence"}),
+        )
+
     def test_sources(self):
         """Source filter checks membership."""
         metadata = SeedDatasetMetadata(source_type={"remote"})