fix(message-history): fall back within the requested session in get_relevant()

redisvl/extensions/message_history/semantic_history.py

@@ -330,7 +330,13 @@ def get_relevant(
 
         # if we don't find semantic matches fallback to returning recent context
         if not messages and fall_back:
-            return self.get_recent(as_text=as_text, top_k=top_k, raw=raw, role=role)
+            return self.get_recent(
+                as_text=as_text,
+                top_k=top_k,
+                raw=raw,
+                session_tag=session_tag,
+                role=role,
+            )
         if raw:
             return messages
         return self._format_context(messages, as_text)

tests/integration/test_message_history.py

@@ -411,6 +411,22 @@ def test_semantic_scope(semantic_history):
     assert no_context == []
 
 
+@pytest.mark.requires_hf
+def test_semantic_get_relevant_falls_back_within_the_requested_session(
+    semantic_history,
+):
+    semantic_history.store("default prompt", "default response")
+    semantic_history.store("other prompt", "other response", session_tag="other")
+
+    context = semantic_history.get_relevant(
+        "unrelated", session_tag="other", fall_back=True, distance_threshold=0
+    )
+    assert context == [
+        {"role": "user", "content": "other prompt"},
+        {"role": "llm", "content": "other response"},
+    ]
+
+
 @pytest.mark.requires_hf
 def test_semantic_store_and_get_recent(semantic_history):
     context = semantic_history.get_recent()