deepset-ai--haystack/releasenotes/notes/auto-variadic-type-conversion-c476bb265fb81d9f.yaml

---
enhancements:
  - |
    Pipelines now support auto-variadic connections with type conversion.
    When multiple senders are connected to a single list-typed input socket, the senders no longer need to all produce
    the exact same type since compatible conversions are applied per edge.
    Supported scenarios include ``T + T -> list[T]``, ``T + list[T] -> list[T]``, ``str + ChatMessage -> list[str]``,
    ``str + ChatMessage -> list[ChatMessage]``, and all other ``str <-> ChatMessage`` conversion variants.
    This enables pipeline patterns like joining a plain query string with a list of ``ChatMessage`` objects into a
    single ``list[ChatMessage]`` input without any extra components.