updating NOT filter handling

Author: davidsbatista

integrations/faiss/src/haystack_integrations/document_stores/faiss/document_store.py

@@ -290,7 +290,11 @@ def _check_condition(self, doc: Document, condition: dict[str, Any]) -> bool:
             if "conditions" not in condition:
                 msg = "Missing 'conditions' for NOT operator"
                 raise FilterError(msg)
-            return not self._check_condition(doc, condition.get("conditions", [])[0])
+            conditions = condition.get("conditions")
+            if not isinstance(conditions, list) or not conditions:
+                msg = "NOT operator expects at least one condition"
+                raise FilterError(msg)
+            return not all(self._check_condition(doc, cond) for cond in conditions)
 
         # Leaf condition
         if "field" not in condition:

integrations/faiss/tests/test_document_store.py

@@ -4,6 +4,7 @@
 
 import pytest
 from haystack.dataclasses import Document
+from haystack.errors import FilterError
 from haystack.testing.document_store import (
     CountDocumentsTest,
     DeleteAllTest,
@@ -149,3 +150,9 @@ def test_count_unique_metadata_by_filter(self, document_store):
         )
         assert "meta.status" in counts
         assert counts["meta.status"] == 1  # Only "active" status for category A
+
+    def test_not_filter_with_empty_conditions_raises_filter_error(self, document_store):
+        document_store.write_documents([Document(content="test", meta={"category": "A"})])
+
+        with pytest.raises(FilterError, match="NOT operator expects at least one condition"):
+            document_store.filter_documents(filters={"operator": "NOT", "conditions": []})