errors

class AlreadyAssignedError(AuthoringError):
    """Raised when the same path is cached more than once in one procedure."""

class AuthoringError(RuntimeError):
    """Raised for misuse of the authoring surface.

    The base for every recorder-specific error — e.g. constructing a node with no
    surrounding
    [ProcedureContext][capturegraph.procedures.procedure.authoring.contexts.base.ProcedureContext].
    """

class UncaughtDataError(AuthoringError):
    """Raised when a step produces a value that is never stored or consumed.

    Every leftover root of a context must be a side effect (return ``Void``). A
    bare ``cg.CaptureImage()`` that is neither cached with ``|=`` / ``&=`` nor
    passed to another node leaves its value dangling — that is this error.
    """