{"record":{"id":"399291b1aba5c8c9","repo":"langchain-ai/langgraph","slug":"unsupported-callback-types-type-base-type-ne","errorCode":null,"errorMessage":"Unsupported callback types: {type(base)}, {type(new)}","messagePattern":"Unsupported callback types: (.+?), (.+?)","errorType":"exception","errorClass":"NotImplementedError","httpStatus":null,"severity":"error","filePath":"libs/langgraph/langgraph/_internal/_config.py","lineNumber":144,"sourceCode":"    if base is None:\n        return new.copy() if isinstance(new, (list, BaseCallbackManager)) else new\n    if isinstance(new, list):\n        if isinstance(base, list):\n            return base + new\n        if isinstance(base, BaseCallbackManager):\n            mngr = base.copy()\n            for cb in new:\n                mngr.add_handler(cb, inherit=True)\n            return mngr\n    elif isinstance(new, BaseCallbackManager):\n        if isinstance(base, list):\n            mngr = new.copy()\n            for cb in base:\n                mngr.add_handler(cb, inherit=True)\n            return mngr\n        if isinstance(base, BaseCallbackManager):\n            return base.merge(new)\n    raise NotImplementedError(f\"Unsupported callback types: {type(base)}, {type(new)}\")\n\n\ndef merge_configs(*configs: RunnableConfig | None) -> RunnableConfig:\n    \"\"\"Merge multiple configs into one.\n\n    Args:\n        *configs: The configs to merge.\n\n    Returns:\n        RunnableConfig: The merged config.\n    \"\"\"\n    base: RunnableConfig = {}\n    # Even though the keys aren't literals, this is correct\n    # because both dicts are the same type\n    for config in configs:\n        if config is None:\n            continue\n        for key, value in config.items():","sourceCodeStart":126,"sourceCodeEnd":162,"githubUrl":"https://github.com/langchain-ai/langgraph/blob/38031739e551638e373fb553453256c23feeb41f/libs/langgraph/langgraph/_internal/_config.py#L126-L162","documentation":"Error \"Unsupported callback types: {type(base)}, {type(new)}\" thrown in langchain-ai/langgraph.","triggerScenarios":"Thrown at libs/langgraph/langgraph/_internal/_config.py:144 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":[],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"38031739e551638e373fb553453256c23feeb41f","analyzedAt":"2026-08-26T18:02:49.312Z","schemaVersion":2},"datasetVersion":"2026-08-26T21:11:00.512Z"}