TypeError: metaclass conflict when importing dspy LangChainPredict about dspy

[atursunov]

I had similar issue. Can someone on DSPy side please fix this?

[drmwilke]

Hi,

experienced the same issue today. I don't have a proper solution but it might unblock you:

In the file \lib\site-packages\dspy\predict\langchain.py:L40
You can change the metaclass information:

class LangChainPredictMetaClass(type(Predict), type(Runnable)):
    pass

class LangChainPredict(Predict, Runnable, metaclass=LangChainPredictMetaClass): #, RunnableBinding):

I tried downgrading pydantic and dspy to random versions but it didn't work out with other packages that I need to use. So I did not follow that approach further. Adding the metaclass obviously breaks as soon as this file is updated by pip but it's a workaround till there is an actual solution.

[aishwaryap]

It turns out that downgrading to dspy_ai==2.1.4 also works. However, I think the issue should remain open so that the authors can integrate the correction from @drmwilke 's response to retain support for LangChain.

[rhamnett]

@CShorten any ideas on this pls?

[rhamnett]

Looks like this will fix it:

# Define a common metaclass
class CombinedMeta(type(Predict), type(Runnable)):
    pass


class LangChainPredict(Predict, Runnable, metaclass=CombinedMeta):