bug: Langchain Python Dataset run has null trace I/O

[nimbusaeta]

Describe the bug

In the VUI, in the Dataset run view, the inputs of each view appear as null, but in the Dataset Item view, the input is populated with the expected text.

To reproduce

The run was created following the Datasets Cookbook (the Langchain application part).

Additional information

No response

[marcklingen]

Thanks for creating this issue. We'll try to push a fix soon.

More context:

• item.get_langchain_handler() creates a trace under the hood
• if the handler is then passed to a langchain agent/chain, it does not update the trace (this is generally the desired behavior as multiple runs could be grouped into the same trace).