Fix: prevent infinity bug on agent (#4876)

* Fix error handling and logging in build_flow function

* Refactor: Update serialize_field function in utils.py

This commit refactors the serialize_field function in utils.py to handle additional data types. It now properly serializes BaseModel objects and dictionaries by recursively calling the serialize_field function on their values. Additionally, it ensures that all other data types are converted to strings before returning.

#4873

* update serialize

src/backend/base/langflow/api/v1/chat.py

@@ -409,6 +409,10 @@ async def build_flow(
             for task in tasks:
                 task.cancel()
             return
+        except Exception as e:
+            logger.error(f"Error building vertices: {e}")
+            event_manager.on_error(data={"error": str(e)})
+            raise
         event_manager.on_end(data={})
         await event_manager.queue.put((None, None, time.time))
 

src/backend/base/langflow/graph/utils.py

@@ -79,14 +79,14 @@ def serialize_field(value):
     if isinstance(value, Document):
         return value.to_json()
     if isinstance(value, BaseModel):
-        return value.model_dump()
+        return serialize_field(value.model_dump())
+    if isinstance(value, dict):
+        return {k: serialize_field(v) for k, v in value.items()}
     if isinstance(value, V1BaseModel):
         if hasattr(value, "to_json"):
             return value.to_json()
         return value.dict()
-    if isinstance(value, str):
-        return {"result": value}
-    return value
+    return str(value)
 
 
 def get_artifact_type(value, build_result) -> str: