fix(langchain): skip non-dict rows in format_recall_content

sdk/wren-langchain/src/wren_langchain/_format.py

@@ -110,10 +110,19 @@ def format_recall_content(rows: list[dict[str, Any]]) -> str:
         return "_No similar past queries found._"
 
     chunks = []
-    for i, row in enumerate(rows, start=1):
+    n = 0
+    for row in rows:
+        # Vector stores / serializers occasionally emit None or plain
+        # strings alongside dict hits. Calling ``.get`` on those aborted
+        # the entire recall content render.
+        if not isinstance(row, dict):
+            continue
         nl = row.get("nl_query") or row.get("nl") or ""
         sql = row.get("sql_query") or row.get("sql") or ""
-        chunks.append(f'{i}. "{nl}"\n   ```sql\n   {sql}\n   ```')
+        n += 1
+        chunks.append(f'{n}. "{nl}"\n   ```sql\n   {sql}\n   ```')
+    if not chunks:
+        return "_No similar past queries found._"
     return "\n".join(chunks)
 
 

sdk/wren-langchain/tests/unit/test_format_recall_content_guard.py

@@ -0,0 +1,21 @@
+import importlib.util
+from pathlib import Path
+
+_ROOT = Path(__file__).resolve().parents[2]
+_PATH = _ROOT / "src" / "wren_langchain" / "_format.py"
+_spec = importlib.util.spec_from_file_location("_fmt", _PATH)
+_mod = importlib.util.module_from_spec(_spec)
+_spec.loader.exec_module(_mod)
+
+
+def test_skips_non_dict_rows():
+    out = _mod.format_recall_content(
+        [None, "x", {"nl": "q1", "sql": "SELECT 1"}, {"nl_query": "q2", "sql_query": "SELECT 2"}]
+    )
+    assert "q1" in out and "SELECT 1" in out
+    assert "q2" in out
+    assert out.startswith('1. "')
+
+
+def test_all_invalid_returns_empty_message():
+    assert _mod.format_recall_content([None, 3]) == "_No similar past queries found._"