_convert_cached_generations() — langchain Function Reference

Source Code

libs/core/langchain_core/language_models/chat_models.py lines 740–777

    def _convert_cached_generations(self, cache_val: list) -> list[ChatGeneration]:
        """Convert cached Generation objects to ChatGeneration objects.

        Handle case where cache contains Generation objects instead of
        ChatGeneration objects. This can happen due to serialization/deserialization
        issues or legacy cache data (see #22389).

        Args:
            cache_val: List of cached generation objects.

        Returns:
            List of ChatGeneration objects.

        """
        converted_generations = []
        for gen in cache_val:
            if isinstance(gen, Generation) and not isinstance(gen, ChatGeneration):
                # Convert Generation to ChatGeneration by creating AIMessage
                # from the text content
                chat_gen = ChatGeneration(
                    message=AIMessage(content=gen.text),
                    generation_info=gen.generation_info,
                )
                converted_generations.append(chat_gen)
            else:
                # Already a ChatGeneration or other expected type
                if hasattr(gen, "message") and isinstance(gen.message, AIMessage):
                    # We zero out cost on cache hits
                    gen.message = gen.message.model_copy(
                        update={
                            "usage_metadata": {
                                **(gen.message.usage_metadata or {}),
                                "total_cost": 0,
                            }
                        }
                    )
                converted_generations.append(gen)
        return converted_generations