fix: ElasticSearch - Fallback to default filter policy when deseria…

…lizing retrievers without the init parameter (#898)

* Add defensive check for filter_policy deserialization

* Add defensive check for filter_policy deserialization

* Add unit test

* Revert change in chroma

* Linter fix

integrations/elasticsearch/src/haystack_integrations/components/retrievers/elasticsearch/bm25_retriever.py

@@ -108,7 +108,10 @@ def from_dict(cls, data: Dict[str, Any]) -> "ElasticsearchBM25Retriever":
         data["init_parameters"]["document_store"] = ElasticsearchDocumentStore.from_dict(
             data["init_parameters"]["document_store"]
         )
-        data["init_parameters"]["filter_policy"] = FilterPolicy.from_str(data["init_parameters"]["filter_policy"])
+        # Pipelines serialized with old versions of the component might not
+        # have the filter_policy field.
+        if filter_policy := data["init_parameters"].get("filter_policy"):
+            data["init_parameters"]["filter_policy"] = FilterPolicy.from_str(filter_policy)
         return default_from_dict(cls, data)
 
     @component.output_types(documents=List[Document])

integrations/elasticsearch/src/haystack_integrations/components/retrievers/elasticsearch/embedding_retriever.py

@@ -106,7 +106,10 @@ def from_dict(cls, data: Dict[str, Any]) -> "ElasticsearchEmbeddingRetriever":
         data["init_parameters"]["document_store"] = ElasticsearchDocumentStore.from_dict(
             data["init_parameters"]["document_store"]
         )
-        data["init_parameters"]["filter_policy"] = FilterPolicy.from_str(data["init_parameters"]["filter_policy"])
+        # Pipelines serialized with old versions of the component might not
+        # have the filter_policy field.
+        if filter_policy := data["init_parameters"].get("filter_policy"):
+            data["init_parameters"]["filter_policy"] = FilterPolicy.from_str(filter_policy)
         return default_from_dict(cls, data)
 
     @component.output_types(documents=List[Document])

integrations/elasticsearch/tests/test_bm25_retriever.py

@@ -77,6 +77,30 @@ def test_from_dict(_mock_elasticsearch_client):
     assert retriever._filter_policy == FilterPolicy.REPLACE
 
 
+@patch("haystack_integrations.document_stores.elasticsearch.document_store.Elasticsearch")
+def test_from_dict_no_filter_policy(_mock_elasticsearch_client):
+    data = {
+        "type": "haystack_integrations.components.retrievers.elasticsearch.bm25_retriever.ElasticsearchBM25Retriever",
+        "init_parameters": {
+            "document_store": {
+                "init_parameters": {"hosts": "some fake host", "index": "default"},
+                "type": "haystack_integrations.document_stores.elasticsearch.document_store.ElasticsearchDocumentStore",
+            },
+            "filters": {},
+            "fuzziness": "AUTO",
+            "top_k": 10,
+            "scale_score": True,
+        },
+    }
+    retriever = ElasticsearchBM25Retriever.from_dict(data)
+    assert retriever._document_store
+    assert retriever._filters == {}
+    assert retriever._fuzziness == "AUTO"
+    assert retriever._top_k == 10
+    assert retriever._scale_score
+    assert retriever._filter_policy == FilterPolicy.REPLACE  # defaults to REPLACE
+
+
 def test_run():
     mock_store = Mock(spec=ElasticsearchDocumentStore)
     mock_store._bm25_retrieval.return_value = [Document(content="Test doc")]

integrations/elasticsearch/tests/test_embedding_retriever.py

@@ -74,6 +74,29 @@ def test_from_dict(_mock_elasticsearch_client):
     assert retriever._num_candidates is None
 
 
+@patch("haystack_integrations.document_stores.elasticsearch.document_store.Elasticsearch")
+def test_from_dict_no_filter_policy(_mock_elasticsearch_client):
+    t = "haystack_integrations.components.retrievers.elasticsearch.embedding_retriever.ElasticsearchEmbeddingRetriever"
+    data = {
+        "type": t,
+        "init_parameters": {
+            "document_store": {
+                "init_parameters": {"hosts": "some fake host", "index": "default"},
+                "type": "haystack_integrations.document_stores.elasticsearch.document_store.ElasticsearchDocumentStore",
+            },
+            "filters": {},
+            "top_k": 10,
+            "num_candidates": None,
+        },
+    }
+    retriever = ElasticsearchEmbeddingRetriever.from_dict(data)
+    assert retriever._document_store
+    assert retriever._filters == {}
+    assert retriever._top_k == 10
+    assert retriever._num_candidates is None
+    assert retriever._filter_policy == FilterPolicy.REPLACE  # defaults to REPLACE
+
+
 def test_run():
     mock_store = Mock(spec=ElasticsearchDocumentStore)
     mock_store._embedding_retrieval.return_value = [Document(content="Test doc", embedding=[0.1, 0.2])]