Error Context

Error context dataclass for bus listener failures.

BusErrorContext dataclass

Bases: ErrorContext

Context passed to bus error handlers when a listener raises an exception.

Attributes:

Name	Type	Description
exception	BaseException	The exception that was raised by the listener. Retains its __traceback__ chain — use traceback (the string field) for display. The live traceback pins originating stack frame locals until this context is garbage-collected (bounded by error_handler_timeout_seconds).
traceback	str	Formatted traceback string. Always a non-empty string — the design explicitly requires always-populated tracebacks in the user-facing context, unlike the framework's own log suppression which may suppress them.
topic	str	The topic the listener was registered on.
listener_name	str	The name of the listener function that raised the exception.
event	AnyEvent	The event that was being processed when the exception occurred.

Source code in src/hassette/bus/error_context.py

@dataclass(frozen=True)
class BusErrorContext(ErrorContext):
    """Context passed to bus error handlers when a listener raises an exception.

    Attributes:
        exception: The exception that was raised by the listener. Retains its
            ``__traceback__`` chain — use ``traceback`` (the string field) for display.
            The live traceback pins originating stack frame locals until this context
            is garbage-collected (bounded by ``error_handler_timeout_seconds``).
        traceback: Formatted traceback string. Always a non-empty string — the
            design explicitly requires always-populated tracebacks in the user-facing
            context, unlike the framework's own log suppression which may suppress them.
        topic: The topic the listener was registered on.
        listener_name: The name of the listener function that raised the exception.
        event: The event that was being processed when the exception occurred.
    """

    topic: str
    listener_name: str
    event: "AnyEvent"

    @property
    def domain_label(self) -> str:
        """Identify the failing listener by its topic and name, formatted for log messages."""
        return f"topic={self.topic}, listener={self.listener_name}"

domain_label: str property

Identify the failing listener by its topic and name, formatted for log messages.