chore: Weaviate - remove legacy filter support (#1070)

* Remove legacy filter support

* Linting

* Remove outdated test

* Improve error message

* Error msg fmt

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

@@ -12,7 +12,6 @@
 from haystack.dataclasses.document import Document
 from haystack.document_stores.errors import DocumentStoreError, DuplicateDocumentError
 from haystack.document_stores.types.policy import DuplicatePolicy
-from haystack.utils.filters import convert
 
 import weaviate
 from weaviate.collections.classes.data import DataObject
@@ -388,7 +387,8 @@ def filter_documents(self, filters: Optional[Dict[str, Any]] = None) -> List[Doc
         :returns: A list of Documents that match the given filters.
         """
         if filters and "operator" not in filters and "conditions" not in filters:
-            filters = convert(filters)
+            msg = "Invalid filter syntax. See https://docs.haystack.deepset.ai/docs/metadata-filtering for details."
+            raise ValueError(msg)
 
         result = []
         if filters:

integrations/weaviate/tests/test_document_store.py

@@ -660,15 +660,6 @@ def test_embedding_retrieval_with_distance_and_certainty(self, document_store):
         with pytest.raises(ValueError):
             document_store._embedding_retrieval(query_embedding=[], distance=0.1, certainty=0.1)
 
-    def test_filter_documents_with_legacy_filters(self, document_store):
-        docs = []
-        for index in range(10):
-            docs.append(Document(content="This is some content", meta={"index": index}))
-        document_store.write_documents(docs)
-        result = document_store.filter_documents({"content": {"$eq": "This is some content"}})
-
-        assert len(result) == 10
-
     def test_filter_documents_below_default_limit(self, document_store):
         docs = []
         for index in range(9998):